全文获取类型
收费全文 | 10166篇 |
免费 | 235篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 161篇 |
综合类 | 7篇 |
化学工业 | 1434篇 |
金属工艺 | 142篇 |
机械仪表 | 188篇 |
建筑科学 | 244篇 |
矿业工程 | 37篇 |
能源动力 | 198篇 |
轻工业 | 939篇 |
水利工程 | 79篇 |
石油天然气 | 32篇 |
无线电 | 964篇 |
一般工业技术 | 1306篇 |
冶金工业 | 3357篇 |
原子能技术 | 123篇 |
自动化技术 | 1199篇 |
出版年
2022年 | 121篇 |
2021年 | 162篇 |
2020年 | 109篇 |
2019年 | 110篇 |
2018年 | 120篇 |
2017年 | 131篇 |
2016年 | 152篇 |
2015年 | 130篇 |
2014年 | 148篇 |
2013年 | 335篇 |
2012年 | 319篇 |
2011年 | 383篇 |
2010年 | 299篇 |
2009年 | 318篇 |
2008年 | 325篇 |
2007年 | 333篇 |
2006年 | 290篇 |
2005年 | 278篇 |
2004年 | 248篇 |
2003年 | 204篇 |
2002年 | 194篇 |
2001年 | 176篇 |
2000年 | 179篇 |
1999年 | 233篇 |
1998年 | 797篇 |
1997年 | 497篇 |
1996年 | 397篇 |
1995年 | 250篇 |
1994年 | 231篇 |
1993年 | 283篇 |
1992年 | 156篇 |
1991年 | 159篇 |
1990年 | 148篇 |
1989年 | 176篇 |
1988年 | 151篇 |
1987年 | 130篇 |
1986年 | 148篇 |
1985年 | 128篇 |
1984年 | 98篇 |
1983年 | 99篇 |
1982年 | 83篇 |
1981年 | 72篇 |
1980年 | 82篇 |
1979年 | 82篇 |
1978年 | 81篇 |
1977年 | 112篇 |
1976年 | 186篇 |
1975年 | 62篇 |
1974年 | 63篇 |
1973年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Russel B. Miller Isaac M. Horowitz Constantine H. Houpis A. Finley Barfield 《国际强度与非线性控制杂志
》1994,4(1):211-230
》1994,4(1):211-230
Nonlinear quantitative feedback theory (QFT) and pilot compensation techniques are used to design a 2 × 2 flight control system for the YF-16 aircraft over a large range of plant uncertainty. The design is based on numerical input-output time histories generated with a FORTRAN implemented nonlinear simulation of the YF-16. The first step of the design process is the generation of a set of equivalent linear time-invariant (LTI) plant models to represent the actual nonlinear plant. It has been proven that the solution to the equivalent plant problem is guaranteed to solve the original nonlinear problem. Standard QFT techniques are then used in the design synthesis based on the equivalent plant models. A detailed mathematical development of the method used to develop these equivalent LTI plant models is provided. After this inner-loop design, pilot compensation is developed to reduce the pilot's workload. This outer-loop design is also based on a set of equivalent LTI plant models. This is accomplished by modelling the pilot with parameters that result in good handling qualities ratings, and developing the necessary compensation to force the desired system responses. 相似文献
22.
23.
24.
DL Arnold PF McGuire D Miller S Malcolm S Hayward A Paquet 《Canadian Metallurgical Quarterly》1998,36(9-10):771-779
Two experiments with Sprague Dawley rats tested their ability to hydrolyse myristoyl-methionine (M-M) into myristic acid and L-methionine (M). In the first experiment, lasting for 3 days. male rats were orally administered [9,10-3H]myristoyl-L-[35S]methionine. The recovery of radioactivity was approximately 90% for both isotopes; 19% of the administered 3H was recovered in the urine and 16% in the faeces, while the recovered 35S activity was 13 and 12%, respectively. The balance of the radioactivity was found among the tissues, organs and blood. In the second experiment, male and female rats received soybean-based diets which were supplemented with either 0.305% M-M or 0.2% M (both diets contained equal amounts of M) for periods up to 4 weeks. The growth rate of the rats receiving the 0.305% M-M diets was slightly slower than that for the rats on the 0.2% M diet, but the difference was not statistically significant (P > 0.05). The M-M rats had a transitory decrease in feed consumption, suggesting that palatability may have contributed to the growth difference and that a somewhat greater amount of M-M was necessary for the rat to attain the same growth rate as that produced by 0.2% M. When the amount of dietary M-M was increased to 3.05% M-M, a greater reduction in feed consumption and body weight gain was observed. This latter diet was an initial attempt to study the potential toxicity of M-M. None of the haematological, clinical chemistry or organ weight data suggested that M-M was overtly toxic per se, but longer-term feeding studies are needed to evaluate the potential toxicity of M-M more fully. 相似文献
25.
A micromechanics analysis is performed for the determination of the five independent elastic moduli of unidirectional fiber composites. By considering viscoelastic phases and by using the correspondence principle and the inversion of the Laplace transform, the five time-dependent functions which characterize the effective behavior of viscoelastic composites are established. The predicted time-dependent behavior is applied for the analysis of viscoelastic laminated plates. The resulting viscoelastic effects are shown, and comparison between the results obtained within the classical laminated plate theory and the first-order shear deformation theory is discussed. 相似文献
26.
D Averill D Blockus B Brabson J Brom C Jung H Ogren DR Rust M Derrick P Kooijman JS Loos B Musgrave LE Price J Repond K Sugano B Cork C Akerlof J Chapman D Errede MT Ken DI Meyer H Neal D Nitz R Thun R Tschirhart S Abachi P Baringer BG Bylsma R DeBonte D Koltick EH Low RL McIlwain DH Miller CR Ng EI Shibata 《Canadian Metallurgical Quarterly》1989,39(1):123-137
27.
28.
Bloomfield R.E. Guerra S. Miller A. Masera M. Weinstock C.B. 《Security & Privacy, IEEE》2006,4(3):66-68
Critical systems are aptly named - from electric power to water and gas to the telephone system and the Internet, they're all critical to some aspect of our daily lives. We're a networked society and as such, it's important to both know whether critical systems are trustworthy and be able to communicate, review, and debate the level of trust achieved in them. In the safety domain, explicit safety cases are increasingly required by law, regulations, and standards. In this article, we outline what a small, international group of experts, spanning various disciplines in safety, security, reliability, and critical infrastructure, been doing with the International Working Group on Assurance Cases (for Security), what we hope to achieve, and where we go next. 相似文献
29.
Gabriel Wainer 《Software》2002,32(13):1261-1306
The features of a toolkit for modeling and simulation based on the DEVS formalism are presented. The tool is built as a set of independent software pieces running on different platforms. Not only are the main characteristics of the environment presented, a focus on its use is also considered by inclusion of application examples for a variety of problems. Many models can be defined in an automated fashion, simplifying the construction of new models and easing their verification. The use of this formal approach has allowed the development of safe and cost‐effective simulations, significantly reducing development time. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
30.
Roland Gabriel Jürgen Kunz Lars Schwarze Peter Fettke Christian Scheer Franz Lehner Konrad Walser Thomas Deelmann 《WIRTSCHAFTSINFORMATIK》2006,48(3):218-222
Ohne Zusammenfassung 相似文献