全文获取类型
收费全文 | 7050篇 |
免费 | 109篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 80篇 |
综合类 | 3篇 |
化学工业 | 913篇 |
金属工艺 | 80篇 |
机械仪表 | 169篇 |
建筑科学 | 275篇 |
矿业工程 | 12篇 |
能源动力 | 158篇 |
轻工业 | 521篇 |
水利工程 | 43篇 |
石油天然气 | 44篇 |
无线电 | 628篇 |
一般工业技术 | 1012篇 |
冶金工业 | 2436篇 |
原子能技术 | 96篇 |
自动化技术 | 693篇 |
出版年
2021年 | 68篇 |
2020年 | 50篇 |
2019年 | 72篇 |
2018年 | 58篇 |
2017年 | 71篇 |
2016年 | 66篇 |
2015年 | 53篇 |
2014年 | 92篇 |
2013年 | 282篇 |
2012年 | 122篇 |
2011年 | 210篇 |
2010年 | 183篇 |
2009年 | 155篇 |
2008年 | 224篇 |
2007年 | 198篇 |
2006年 | 193篇 |
2005年 | 168篇 |
2004年 | 148篇 |
2003年 | 156篇 |
2002年 | 189篇 |
2001年 | 129篇 |
2000年 | 126篇 |
1999年 | 198篇 |
1998年 | 678篇 |
1997年 | 446篇 |
1996年 | 317篇 |
1995年 | 190篇 |
1994年 | 169篇 |
1993年 | 171篇 |
1992年 | 81篇 |
1991年 | 110篇 |
1990年 | 74篇 |
1989年 | 87篇 |
1988年 | 113篇 |
1987年 | 73篇 |
1986年 | 77篇 |
1985年 | 88篇 |
1984年 | 92篇 |
1983年 | 71篇 |
1982年 | 67篇 |
1981年 | 89篇 |
1980年 | 80篇 |
1979年 | 72篇 |
1978年 | 65篇 |
1977年 | 109篇 |
1976年 | 170篇 |
1975年 | 42篇 |
1974年 | 69篇 |
1973年 | 64篇 |
1972年 | 39篇 |
排序方式: 共有7163条查询结果,搜索用时 15 毫秒
31.
Predicts the future of behavior therapy, focusing on theoretical development, therapeutic techniques, and empirical research. The importance of cognitive and affective processes in behavior change will attract increasing attention. Already one of the most widely adopted approaches, behavior therapy will be used to treat an expanded range of psychiatric disorders and health problems. Research will focus on comparative outcome studies and provide probes for investigating the nature of specific disorders and the mechanisms of therapeutic change. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
32.
In this paper, the TRNSYS Simulation Program is used to investigate the monthly and annual solar fraction of a Thermosyphon Solar Water Heater and to evaluate its economic viability in terms of its life cycle savings over a conventional water heating system. The results of the simulation indicate that the yearly solar contribution of the system ranges from 63% for a high hot water consumption profile to 89% for a low consumption pattern. The payback period of the system is as low as 3 years when compared to electric water heating systems. As long as the competitor is diesel oil, the payback period increases to 7–9 years, depending on the hot water consumption profile used. 相似文献
33.
34.
35.
36.
The rôle of saponins in the undesirable sensory properties of the dried pea P sativum is reported. The sensory properties of isolated soyasaponin I are defined and described as bitter, astringent and metallic. The distribution of saponin in various air-classified pea flour fractions shows that the protein-rich fraction may contain sufficient saponin to cause undesirable tastes. 相似文献
37.
The generalized assignment problem with special ordered sets (GAPS2), is the problem of allocating n tasks to m time-periods, where each task must be assigned to a time-period, or shared between two consecutive time-periods. For reasonably large values of m and n the NP-hard combinatorial problem GAPS2 becomes intractable for standard mathematical programming software, hence there is a need for heuristic algorithms to solve such problems. It will be shown how an LP-based heuristic developed previously for the well-established generalized assignment problem can be modified and extended to solve GAPS2. Encouraging results, in terms of speed and accuracy, in particular when compared to an existing heuristic for GAPS2, are described. 相似文献
38.
Lada E.K. Jye-Chyi Lu Wilson J.R. 《Semiconductor Manufacturing, IEEE Transactions on》2002,15(1):79-90
To detect faults in a time-dependent process, we apply a discrete wavelet transform (DWT) to several independently replicated data sets generated by that process. The DWT can capture irregular data patterns such as sharp "jumps" better than the Fourier transform and standard statistical procedures without adding much computational complexity. Our wavelet coefficient selection method effectively balances model parsimony against data reconstruction error. The few selected wavelet coefficients serve as the "reduced-size" data set to facilitate an efficient decision-making method in situations with potentially large-volume data sets. We develop a general procedure to detect process faults based on differences between the reduced-size data sets obtained from the nominal (in-control) process and from a new instance of the target process that must be tested for an out-of-control condition. The distribution of the test statistic is constructed first using normal distribution theory and then with a new resampling procedure called "reversed jackknifing" that does not require any restrictive distributional assumptions. A Monte Carlo study demonstrates the effectiveness of these procedures. Our methods successfully detect process faults for quadrupole mass spectrometry samples collected from a rapid thermal chemical vapor deposition process 相似文献
39.
S. J. Pearton K. P. Lee M. E. Overberg C. R. Abernathy N. Theodoropoulou A. F. Hebard R. G. Wilson S. N. G. Chu J. M. Zavada 《Journal of Electronic Materials》2002,31(5):336-339
High concentrations (0.1–5 at.%) of Mn or Fe were introduced into the near-surface region (≤2000 Å) of 6H-SiC substrates by direct implantation at ~300°C. After annealing at temperatures up to 1000°C, the structural properties were examined by transmission electron microscopy (TEM) and selected-area diffraction pattern (SADP) analysis. The magnetic properties were examined by SQUID magnetometry. While the Mn-implanted samples were paramagnetic over the entire dose range investigated, the Fe-implanted material displayed a ferromagnetic contribution present at <175 K for the highest dose conditions. No secondary phases were detected, at least not to the sensitivity of TEM or SADP. 相似文献
40.