全文获取类型
收费全文 | 3382篇 |
免费 | 82篇 |
国内免费 | 1篇 |
出版年
2021年 | 37篇 |
2019年 | 90篇 |
2018年 | 54篇 |
2017年 | 81篇 |
2016年 | 80篇 |
2015年 | 62篇 |
2014年 | 66篇 |
2013年 | 722篇 |
2010年 | 35篇 |
2009年 | 38篇 |
2008年 | 47篇 |
2007年 | 52篇 |
2006年 | 36篇 |
2005年 | 42篇 |
2004年 | 56篇 |
2003年 | 43篇 |
2002年 | 60篇 |
1999年 | 42篇 |
1998年 | 47篇 |
1997年 | 49篇 |
1996年 | 62篇 |
1995年 | 43篇 |
1994年 | 59篇 |
1993年 | 63篇 |
1992年 | 59篇 |
1991年 | 76篇 |
1990年 | 39篇 |
1989年 | 73篇 |
1988年 | 78篇 |
1987年 | 68篇 |
1986年 | 74篇 |
1985年 | 64篇 |
1984年 | 37篇 |
1983年 | 42篇 |
1982年 | 43篇 |
1981年 | 46篇 |
1980年 | 51篇 |
1979年 | 45篇 |
1978年 | 49篇 |
1977年 | 45篇 |
1976年 | 45篇 |
1975年 | 46篇 |
1974年 | 52篇 |
1973年 | 50篇 |
1972年 | 53篇 |
1971年 | 43篇 |
1970年 | 40篇 |
1969年 | 40篇 |
1968年 | 35篇 |
1967年 | 34篇 |
排序方式: 共有3465条查询结果,搜索用时 31 毫秒
291.
This article is concerned with the scaling variant of Karmarkar's algorithm for linear programming problems. Several researchers have presented convergence analyses for this algorithm under various nondegeneracy types of assumptions, or under assumptions regarding the nature of the sequence of iterates generated by the algorithm. By employing a slight perturbation of the algorithm, which is computationally imperceptible, we are able to prove without using any special assumptions that the algorithm converges finitely to an ε-optimal solution for any chosen ε > 0, from which it can be (polynomically) rounded to an optimum, for ε > 0 small enough. The logarithmic barrier function is used as a construct for this analysis. A rounding scheme which produces an optimal extreme point solution is also suggested. Besides the non-negatively constrained case, we also present a convergence analysis for the case of bounded variables. An application in statistics to the L1 estimation problem and related computational results are presented. 相似文献
292.
A general age replacement is introduced which incorporates minimal repair, planned and unplanned replacements, and costs which depend on time. Finite and infinite horizon results are obtained. Various special cases are considered. Furthermore, a shock model with general cost structure is considered. 相似文献
293.
Observations from inspection by a “test” method and a standard method are combined to provide estimators of population proportion, and of probabilities of misclassification for the test method. Results of Hochberg and Tenenbein [3] and of Albers and Veldman [1] are extended to the case where the standard method is not perfect, but its misclassification probabilities have known values. Both moment and maximum-likelihood estimators are considered and some asymptotic properties of the resulting estimators are compared. 相似文献
294.
An approximation for analyzing transient and nonstationary two-priority non-preemptive queueing systems is presented. This system has a three-dimensional state space, and through use of state-space partitioning in conjunction with use of conditional surrogate distributions with constant parameters an approximation is designed. Regardless of system capacity K, the approximation requires the numerical solution of only ten differential equations, compared to the K2 + K+1 Kolmogorov-forward equations required for the classic solution. Time-dependent approximations of the mean number of entities of type i and of the probability of a type-i entity being in service are obtained. Empirical test results over a wide range of systems indicate the approximation is quite accurate. 相似文献
295.
We study the (s,S) inventory system in which the server takes a rest when the level of the inventory is zero. The demands are assumed to occur for one unit at a time. The interoccurrence times between successive demands, the lead times, and the rest times are assumed to follow general distributions which are mutually independent. Using renewal and convolution techniques we obtain the state transition probabilities. 相似文献
296.
Kenton G. Fasana 《Defence Studies》2018,18(2):167-187
Cyberspace is an avenue of approach through which a military force can attain objectives of value. Through these cyber avenues of approach, military forces can engage, vet, organize, and direct human agents to accomplish specific activities. Although the objectives of these activities could differ from traditional military objectives, they still have military relevance. This particular manifestation of cyber conflict is neither a new domain of war nor something outside of warfare. Rather, it can be viewed as an emerging avenue of approach in the larger context of military operations, auguring benefits in the integration of cyber activities with operations. 相似文献
297.
298.
Some U.S. military leaders have asserted that the United States, Japan, Australia, and India and the Republic of Korea are developing multilateral defense cooperation to deter aggression and uphold norms much like North Atlantic Treaty Organization (NATO) has in Europe. Frequent military exercises and China’s threats to freedom of navigation (FoN) and North Korea’s nuclear missiles comprise the motive force for such cooperation. However, cooperation thus far has been trilateral and minimal, given divergent national interests and dispersed geopolitical locations. Cooperation among Japan, Republic of Korea (ROK), and the United States is increasing given the threat, but ROK’s public opinion is divided about Japan. Australia, Japan, and India have increased cooperation with the United States but are reluctant to conduct FoN operations with the United States to challenge China’s expansionism in the South China Sea. If China becomes more aggressive and blocks FoN or seizes territory, development toward an Asian NATO is possible. 相似文献
299.
Matthew S. Goldberg 《Defence and Peace Economics》2018,29(1):44-61
AbstractIn Operation Iraqi Freedom, which ended in August 2010, nearly 3500 hostile deaths occurred among US military personnel and 32,000 more were wounded in action (WIA). More than 1800 hostile deaths occurred during Operation Enduring Freedom (in and around Afghanistan) through 2014 and about 20,000 were WIA. A larger proportion of wounded personnel survived in Iraq and Afghanistan than during the Vietnam War, but the increased survival rates were not as high as some studies have asserted. The survival rates were 90.2% in Iraq and 91.6% in Afghanistan, compared with 86.5% in Vietnam. The casualty rates varied between the conflicts in Iraq and Afghanistan and before, during, and after the respective surges. Amputation rates are difficult to measure consistently, but I estimate that 2.6% of all WIA and 9.0% of medically evacuated WIA from the Iraq and Afghanistan theaters combined resulted in the major loss of a limb. Elevated non-hostile death rates (including deaths due to accidents, illnesses, homicides, or suicides) resulted in about 220 more deaths in Iraq and about 200 more deaths in Afghanistan than would have been expected in peacetime among populations of the size deployed to those two conflicts. 相似文献
300.
AbstractThe Military Compensation and Retirement Modernization Commission was established by the Congress in 2013 to perform a systematic review of military compensation to address rising costs and other trends. Their recommendation for reforming the TRICARE health care program was sweeping, and differed greatly from earlier proposals that focused on increasing beneficiary cost shares. Specifically, the commission proposed overhauling the current benefit delivery model and replacing it with a premium-based insurance model offering a menu of DoD-sponsored private health plans. The analysis presented here is based on work that supported the commission by estimating the budgetary impact of its proposed reforms. Results indicate that movement towards the premium-based model would produce an annual budgetary cost savings in the $2 billion to $4 billion range, with a best savings estimate of $3.2 billion. 相似文献