全文获取类型
收费全文 | 13682篇 |
免费 | 152篇 |
国内免费 | 194篇 |
专业分类
电工技术 | 198篇 |
综合类 | 81篇 |
化学工业 | 675篇 |
金属工艺 | 659篇 |
机械仪表 | 185篇 |
建筑科学 | 404篇 |
矿业工程 | 43篇 |
能源动力 | 120篇 |
轻工业 | 241篇 |
水利工程 | 100篇 |
石油天然气 | 59篇 |
武器工业 | 1篇 |
无线电 | 607篇 |
一般工业技术 | 558篇 |
冶金工业 | 884篇 |
原子能技术 | 107篇 |
自动化技术 | 9106篇 |
出版年
2023年 | 10篇 |
2022年 | 16篇 |
2021年 | 26篇 |
2020年 | 19篇 |
2019年 | 40篇 |
2018年 | 49篇 |
2017年 | 32篇 |
2016年 | 51篇 |
2015年 | 40篇 |
2014年 | 287篇 |
2013年 | 363篇 |
2012年 | 858篇 |
2011年 | 3244篇 |
2010年 | 1232篇 |
2009年 | 1101篇 |
2008年 | 776篇 |
2007年 | 694篇 |
2006年 | 563篇 |
2005年 | 683篇 |
2004年 | 710篇 |
2003年 | 764篇 |
2002年 | 423篇 |
2001年 | 364篇 |
2000年 | 283篇 |
1999年 | 124篇 |
1998年 | 242篇 |
1997年 | 153篇 |
1996年 | 109篇 |
1995年 | 126篇 |
1994年 | 99篇 |
1993年 | 57篇 |
1992年 | 35篇 |
1991年 | 22篇 |
1990年 | 42篇 |
1989年 | 52篇 |
1988年 | 27篇 |
1987年 | 28篇 |
1986年 | 23篇 |
1985年 | 18篇 |
1984年 | 34篇 |
1983年 | 27篇 |
1982年 | 22篇 |
1981年 | 20篇 |
1980年 | 10篇 |
1979年 | 14篇 |
1978年 | 10篇 |
1977年 | 15篇 |
1976年 | 26篇 |
1974年 | 13篇 |
1973年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Belcher Calvin H. Zheng Baolong MacDonald Benjamin E. Langlois Eric D. Lehman Benjamin Pearce Charles Delaney Robert Apelian Diran Lavernia Enrique J. Monson Todd C. 《Journal of Materials Science》2022,57(9):5518-5532
Journal of Materials Science - For transformers and inductors to meet the world’s growing demand for electrical power, more efficient soft magnetic materials with high saturation magnetic... 相似文献
2.
Jasmin Kuhn Philipp M. Klein Nader Al Danaf Joel Z. Nordin Sren Reinhard Dominik M. Loy Miriam Hhn Samir El Andaloussi Don C. Lamb Ernst Wagner Yoshitsugu Aoki Taavi Lehto Ulrich Lchelt 《Advanced functional materials》2019,29(48)
Phosphorodiamidate morpholino oligomers (PMOs) are oligonucleotide analogs that can be used for therapeutic modulation of pre‐mRNA splicing. Similar to other classes of nucleic acid‐based therapeutics, PMOs require delivery systems for efficient transport to the intracellular target sites. Here, artificial peptides based on the oligo(ethylenamino) acid succinyl‐tetraethylenpentamine (Stp), hydrophobic modifications, and an azide group are presented, which are used for strain‐promoted azide‐alkyne cycloaddition conjugation with splice‐switching PMOs. By systematically varying the lead structure and formulation, it is determined that the type of contained fatty acid and supramolecular assembly have a critical impact on the delivery efficacy. A compound containing linolenic acid with three cis double bonds exhibits the highest splice‐switching activity and significantly increases functional protein expression in pLuc/705 reporter cells in vitro and after local administration in vivo. Structural and mechanistic studies reveal that the lipopeptide PMO conjugates form nanoparticles, which accelerate cellular uptake and that the content of unsaturated fatty acids enhances endosomal escape. In an in vitro Duchenne muscular dystrophy exon skipping model using H2K‐mdx52 dystrophic skeletal myotubes, the highly potent PMO conjugates mediate significant splice‐switching at very low nanomolar concentrations. The presented aminoethylene‐lipopeptides are thus a promising platform for the generation of PMO‐therapeutics with a favorable activity/toxicity profile. 相似文献
3.
4.
Navab SinghAuthor Vitae Moitreyee Mukherjee-RoyAuthor VitaeSohan Singh MehtaAuthor Vitae 《Microelectronics Journal》2003,34(4):237-245
The patterning of contact holes by selecting out-of-focus image plane (defocus) using attenuated phase shift masks (APSM) has been studied. Defocus is found to enhance the image modulation at low partial coherence for contact holes with negative local average of mask function. Semi-dense holes up to 130 nm in 8% APSM have been printed by 0.5 μm defocus at a partial coherence of 0.31 using KrF scanner with highest numerical aperture of 0.68. However, these holes were closed with in-focus imaging. Defocus is also found to be beneficial for patterning the pitches that have extensive side lobes with in-focus imaging. 相似文献
5.
6.
Wallace A.M. Sung R.C.W. Buller G.S. Harkins R.D. Warburton R.E. Lamb R.A. 《Vision, Image and Signal Processing, IEE Proceedings -》2006,153(2):160-172
A new multi-spectral laser radar (ladar) system based on the time-correlated single photon counting, time-of-flight technique has been designed to detect and characterise distributed targets at ranges of several kilometres. The system uses six separated laser channels in the visible and near infrared part of the electromagnetic spectrum. The authors present a method to detect the numbers, positions, heights and shape parameters of returns from this system, used for range profiling and target classification. The algorithm has two principal stages: non-parametric bump hunting based on an analysis of the smoothed derivatives of the photon count histogram in scale space, and maximum likelihood estimation using Poisson statistics. The approach is demonstrated on simulated and real data from a multi-spectral ladar system, showing that the return parameters can be estimated to a high degree of accuracy. 相似文献
7.
8.
用仿真工具优化车辆动力系统(一) 总被引:1,自引:0,他引:1
在本文的第一部分,介绍了一种理想的车辆动力系统的计算机辅助开发过程。它显示了现代仿真技术在产品持续发展过程中的作用,该技术采用硬件回路作非在线的仿真,并通过现代化的试验手段对车辆进行匹配。特别重要的是提供了将电控变速器和发动机控制单元综合的可能性。接着是在线仿真在诸如发动机和变速器模式方面的应用和发展,它是上述开发过程的基础。根据上述的方法论,本文论述了仿真技术已取得的成绩和将来的应用可能性。 相似文献
9.
Kazdin Alan E.; Bass Debra; Siegel Todd; Thomas Christopher 《Canadian Metallurgical Quarterly》1989,57(4):522
112 children (aged 7-13 yrs) were randomly assigned to one of three treatments: problem-solving skills training (PSST), problem-solving skills training with in vivo practice (PSST-P), which included therapeutically planned activities to extend training to settings outside of treatment, or client-centered relationship therapy (RT). PSST and PSST-P children showed significantly greater reductions in antisocial behavior and overall behavior problems, and greater increases in prosocial behavior than RT children. These effects were evident on measures obtained immediately after treatment and at a 1-year follow-up, and on measures of child performance at home and at school. PSST-P children showed greater changes than PSST children on measures of functioning at school at posttreatment, but these differences were no longer evident at follow-up. Children in both PSST conditions showed significant reductions in deviant behavior and improvements in prosocial behavior from pretreatment to follow-up, whereas RT children tended to remain at their pretreatment level of functioning. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
Adaptive motion control using neural network approximations 总被引:1,自引:0,他引:1
In this paper, we present a new adaptive technique for tracking control of mechanical systems in the presence of friction and periodic disturbances. Radial Basis Functions (RBFs) are used to compensate for the effects of nonlinearly occurring parameters in the friction and periodic disturbance model. Theoretical analysis, such as stability and transient performance, is provided. Furthermore, the performance of the adaptive RBF controller and its non-adaptive counterpart are compared. 相似文献