全文获取类型
收费全文 | 1054篇 |
免费 | 10篇 |
专业分类
电工技术 | 10篇 |
化学工业 | 49篇 |
金属工艺 | 6篇 |
机械仪表 | 6篇 |
建筑科学 | 31篇 |
能源动力 | 12篇 |
轻工业 | 28篇 |
水利工程 | 4篇 |
石油天然气 | 2篇 |
无线电 | 74篇 |
一般工业技术 | 73篇 |
冶金工业 | 644篇 |
原子能技术 | 13篇 |
自动化技术 | 112篇 |
出版年
2020年 | 6篇 |
2017年 | 4篇 |
2016年 | 5篇 |
2015年 | 5篇 |
2013年 | 27篇 |
2012年 | 21篇 |
2011年 | 11篇 |
2010年 | 17篇 |
2009年 | 12篇 |
2008年 | 17篇 |
2007年 | 19篇 |
2006年 | 27篇 |
2005年 | 16篇 |
2004年 | 14篇 |
2003年 | 16篇 |
2002年 | 11篇 |
2001年 | 12篇 |
2000年 | 13篇 |
1999年 | 31篇 |
1998年 | 147篇 |
1997年 | 83篇 |
1996年 | 57篇 |
1995年 | 32篇 |
1994年 | 29篇 |
1993年 | 45篇 |
1992年 | 16篇 |
1991年 | 17篇 |
1990年 | 20篇 |
1989年 | 19篇 |
1988年 | 11篇 |
1987年 | 14篇 |
1986年 | 20篇 |
1985年 | 24篇 |
1984年 | 12篇 |
1983年 | 20篇 |
1982年 | 11篇 |
1981年 | 13篇 |
1980年 | 13篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 29篇 |
1976年 | 34篇 |
1975年 | 11篇 |
1974年 | 15篇 |
1973年 | 17篇 |
1972年 | 7篇 |
1971年 | 7篇 |
1970年 | 7篇 |
1969年 | 7篇 |
1966年 | 5篇 |
排序方式: 共有1064条查询结果,搜索用时 15 毫秒
1.
Scientometrics - Science funders are increasingly requiring evidence of the broader impacts of even basic research. Initiatives such as NIH’s CTSA program are designed to shift the research... 相似文献
2.
3.
Ronen Gottesman Angang Song Igal Levine Maximilian Krause A. T. M. Nazmul Islam Daniel Abou‐Ras Thomas Dittrich Roel van de Krol Abdelkrim Chemseddine 《Advanced functional materials》2020,30(21)
A new method for enhancing the charge separation and photo‐electrochemical stability of CuBi2O4 photoelectrodes by sequentially depositing Bi2O3 and CuO layers on fluorine‐doped tin oxide substrates with pulsed laser deposition (PLD), followed by rapid thermal processing (RTP), resulting in phase‐pure, highly crystalline films after 10 min at 650 °C, is reported. Conventional furnace annealing of similar films for 72 h at 500 °C do not result in phase‐pure CuBi2O4. The combined PLD and RTP approach allow excellent control of the Bi:Cu stoichiometry and results in photoelectrodes with superior electronic properties compared to photoelectrodes fabricated through spray pyrolysis. The low photocurrents of the CuBi2O4 photocathodes fabricated through PLD/RTP in this study are primarily attributed to their low specific surface area, lack of CuO impurities, and limited, slow charge transport in the undoped films. Bare (without protection layers) CuBi2O4 photoelectrodes made with PLD/RTP shows a photocurrent decrease of only 26% after 5 h, which represents the highest stability reported to date for this material. The PLD/RTP fabrication approach offers new possibilities of fabricating complex metal oxides photoelectrodes with a high degree of crystallinity and good electronic properties at higher temperatures than the thermal stability of glass‐based transparent conductive substrates would allow. 相似文献
4.
Gupta Saurabh Tolani Varun Davidson James Levine Sergey Sukthankar Rahul Malik Jitendra 《International Journal of Computer Vision》2020,128(5):1311-1330
International Journal of Computer Vision - We introduce a neural architecture for navigation in novel environments. Our proposed architecture learns to map from first-person views and plans a... 相似文献
5.
Dr. Carolyn C. Woodroofe Dr. Joseph Ivanic Dr. Sarah Monti Dr. Rodney L. Levine Dr. Rolf E. Swenson 《Chembiochem : a European journal of chemical biology》2020,21(4):508-516
The reversible oxidation of methionine residues in proteins has emerged as a biologically important post-translational modification. However, detection and quantitation of methionine sulfoxide in proteins is difficult. Our aim is to develop a method for specifically derivatizing methionine sulfoxide residues. We report a Pummerer rearrangement of methionine sulfoxide treated sequentially with trimethylsilyl chloride and then 2-mercaptoimidazole or pyridine-2-thiol to produce a dithioacetal product. This derivative is stable to standard mass spectrometry conditions, and its formation identified oxidized methionine residues. The scope and requirements of dithioacetal formation are reported for methionine sulfoxide and model substrates. The reaction intermediates have been investigated by computational techniques and by 13C NMR spectroscopy. These provide evidence for an α-chlorinated intermediate. The derivatization allows for detection and quantitation of methionine sulfoxide in proteins by mass spectrometry and potentially by immunochemical methods. 相似文献
6.
7.
8.
This research explores the relationship between campus political norms and student political participation. This study conceptualizes norms as a group‐level construct by collecting data at several universities (k = 32 universities, n = 1,389 students) where norms vary without campaign intervention. Multilevel modeling reveals that perceptions of political norms converge within universities. Further, frequency of political communication at the group‐ and individual‐level explains increases in normative perceptions. This increase is meaningful because norms at the group level were predictive of political behaviors at the individual level. This research documents the existence of political norms beyond the individual level of analysis and highlights the important role of political norms, political communication, and social context in understanding political participation. 相似文献
9.
This is Part II of a two-part paper on the problem of the title. In this part the analysis of the two-message problem started in Part I is completed. In addition a brief discussion is given of a computer-assisted solution. A list of twelve two-message problems involving several types of conditions is attached for the benefit of the reader. 相似文献
10.
In this part it is shown how the scalar unit coefficient a appearing in the W key formula (see Part I) can be replaced by an invertible matrix coefficient Γ. (A similar discussion with respect to the V key will appear In Part IV.) Various examples illustrate in detail the different procedures involved. Some examples in the encipherment and decipherment calculations are left as problems for the reader. The Appendix contains a proof of the main theorem. 相似文献