全文获取类型
收费全文 | 208篇 |
免费 | 8篇 |
国内免费 | 69篇 |
出版年
2023年 | 15篇 |
2021年 | 12篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2014年 | 5篇 |
2013年 | 6篇 |
2012年 | 1篇 |
2011年 | 1篇 |
2010年 | 1篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 12篇 |
1997年 | 22篇 |
1996年 | 15篇 |
1995年 | 13篇 |
1994年 | 19篇 |
1993年 | 2篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 18篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 1篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 15篇 |
1979年 | 5篇 |
1977年 | 11篇 |
1976年 | 6篇 |
1973年 | 7篇 |
1948年 | 1篇 |
排序方式: 共有285条查询结果,搜索用时 15 毫秒
231.
Hongxu Wang Dakshitha Weerasinghe Paul J.Hazell Damith Mohotti Evgeny V.Morozov Juan P.Escobedo-Diaz 《防务技术》2023,(4):37-53
This study elaborates on the effects of matrix rigidity on the high-velocity impact behaviour of UHMWPE textile composites using experimental and numerical methods. Textile composite samples were manufactured of a plain-weave fabric(comprising Spectra? 1000 fibres) and four different matrix materials.High-velocity impact tests were conducted by launching a spherical steel projectile to strike on the prepared samples via a gas gun. The experimental results showed that the textile composites gradu... 相似文献
232.
The conventional case of patch repair involves bonding a patch over single damage/hole in the laminate.This work investigates the effect of interaction of two holes on the tensile behavior patch repaired carbon epoxy woven laminates. The specimens of [0°/45°/45°/0°] laminates were repaired with adhesively bonded two-ply [45°]2external patches. Three different cases of drilled specimens were produced with different hole arrangements viz. specimens with single central hole(SH), with two holes alig... 相似文献
233.
对海战场综合态势进行态势评估和威胁分析是信息融合系统的最高层级,态势评估结果将对指挥员的指挥决策起到非常重要的作用。根据海军作战理论分析了海战场态势的表示方法,并基于模板方法设计了一种战场当前态势与模板数据库中态势进行匹配的算法。该算法特别适用于高层推理如态势或威胁评估。 相似文献
235.
目前,美国实用的潜艇用电气和电子系统设计实际上是彼此独立的。这样的实践限制了利用过去几十年所获得的技术进步的优点。为了使潜艇平台的能力最大化,必须综合传统的、具有类似处理和通信要求的各个系统。本文研究和分析一种可能的称之为FIFT C~3I系统的实现,该系统综合支援潜艇任务的所有主要的电气和电子系统。这样的系统必须有容错能力,以致于使综合系统的可靠性、可用性和安全性等于或优于要替换的现有系统。这种方法的优点很多且可用现有技术和部件实现。 相似文献
236.
237.
Unexploded ordnance(UXO) poses a threat to soldiers operating in mission areas, but current UXO detection systems do not necessarily provide the required safety and efficiency to protect soldiers from this hazard. Recent technological advancements in artificial intelligence(AI) and small unmanned aerial systems(sUAS) present an opportunity to explore a novel concept for UXO detection. The new UXO detection system proposed in this study takes advantage of employing an AI-trained multi-spectral(MS... 相似文献
238.
In this study, high velocity impact behaviour of friction stir welded AA7075-T651 25 mm thick plates were investigated using a 7.62 mm × 51 mm lead core and 7.62 mm × 39 mm steel core projectiles. Prior to ballistic trails, mechanical and metallurgical properties of friction stir welded AA 7075-T651 25 mm thick plates were studied. Microstructural and hardness studies revealed that friction stir welds constituted three distinct regions namely Weld Nugget(WN), Thermo-Mechanically Affected Zone(TM... 相似文献
239.
As an innovative propulsion technique, laser augmented chemical propulsion(LACP) seems superior to the traditional ones. However, the corresponding combustion theories have still to be ascertained for LACP. Burning rate of 5-aminotetrazole(5-ATZ) propellant has been studied by testing pressed samples under different combustor pressures and laser powers. Based on micro computed tomography(Micro CT),an advanced thickness-over-time(TOT) method to characterize the regression of the produced nonplana... 相似文献
240.
Wojciech Przyby? Adam Januszko Norbert Radek Marcin Szczepaniak Krzysztof A.Bogdanowicz Ireneusz Plebankiewicz Bogus?awa Szczodrowska Robert Mazurczuk 《防务技术》2023,(4):1-9
The paper explores the possibilities of using carbonyl iron in the form of a powder for the manufacture of radar-absorbing paints-reducing the radar signature of the objects that they cover. The attenuation values in the range of 4-18 GHz for various coating thicknesses, ranging from 0.5 to 2.00 mm with 0.5 mm increment, and for different absorber content-75% and 80%, as well as the use of two different binders in the form of epoxy resins with hardeners, were investigated. For the frequency of 1... 相似文献