全文获取类型
收费全文 | 5869篇 |
免费 | 628篇 |
国内免费 | 681篇 |
专业分类
电工技术 | 330篇 |
综合类 | 1177篇 |
化学工业 | 163篇 |
金属工艺 | 35篇 |
机械仪表 | 152篇 |
建筑科学 | 304篇 |
矿业工程 | 103篇 |
能源动力 | 84篇 |
轻工业 | 159篇 |
水利工程 | 69篇 |
石油天然气 | 74篇 |
武器工业 | 38篇 |
无线电 | 782篇 |
一般工业技术 | 484篇 |
冶金工业 | 695篇 |
原子能技术 | 32篇 |
自动化技术 | 2497篇 |
出版年
2024年 | 26篇 |
2023年 | 79篇 |
2022年 | 134篇 |
2021年 | 142篇 |
2020年 | 188篇 |
2019年 | 194篇 |
2018年 | 176篇 |
2017年 | 193篇 |
2016年 | 199篇 |
2015年 | 233篇 |
2014年 | 304篇 |
2013年 | 361篇 |
2012年 | 487篇 |
2011年 | 458篇 |
2010年 | 427篇 |
2009年 | 357篇 |
2008年 | 323篇 |
2007年 | 378篇 |
2006年 | 384篇 |
2005年 | 304篇 |
2004年 | 277篇 |
2003年 | 231篇 |
2002年 | 204篇 |
2001年 | 196篇 |
2000年 | 154篇 |
1999年 | 107篇 |
1998年 | 89篇 |
1997年 | 80篇 |
1996年 | 57篇 |
1995年 | 62篇 |
1994年 | 47篇 |
1993年 | 41篇 |
1992年 | 30篇 |
1991年 | 31篇 |
1990年 | 30篇 |
1989年 | 25篇 |
1988年 | 13篇 |
1987年 | 12篇 |
1986年 | 11篇 |
1985年 | 10篇 |
1984年 | 11篇 |
1983年 | 6篇 |
1982年 | 8篇 |
1978年 | 5篇 |
1966年 | 8篇 |
1963年 | 11篇 |
1960年 | 4篇 |
1959年 | 6篇 |
1957年 | 6篇 |
1955年 | 13篇 |
排序方式: 共有7178条查询结果,搜索用时 10 毫秒
1.
Anis Zeglaoui Anouar Houmia Maher Mejai Radhouane Aloui 《International Journal of Adaptive Control and Signal Processing》2021,35(9):1842-1859
In compressive sampling theory, the least absolute shrinkage and selection operator (LASSO) is a representative problem. Nevertheless, the non-differentiable constraint impedes the use of Lagrange programming neural networks (LPNNs). We present in this article the -LPNN model, a novel algorithm that tackles the LASSO minimization together with the underlying theory support. First, we design a sequence of smooth constrained optimization problems, by introducing a convenient differentiable approximation to the non-differentiable -norm constraint. Next, we prove that the optimal solutions of the regularized intermediate problems converge to the optimal sparse signal for the LASSO. Then, for every regularized problem from the sequence, the -LPNN dynamic model is derived, and the asymptotic stability of its equilibrium state is established as well. Finally, numerical simulations are carried out to compare the performance of the proposed -LPNN algorithm with both the LASSO-LPNN model and a standard digital method. 相似文献
2.
3.
A. Yu. Luchka 《Cybernetics and Systems Analysis》2003,39(6):880-888
A modified variational-gradient method is proposed and substantiated for quasilinear operator equations in a Hilbert space. 相似文献
4.
杨文静 《广东工业大学高等工程教育研究》2007,7(1):23-25
信用经济是市场经济发展到一定阶段的必然趋势和客观要求。在这种经济中,信用不仅仅是作为交换媒介存在,更为重要的是信用作为除市场以外的另一种资源配置方式。它的产生需要一些特定的条件,文章即从个人、企业、政府三方面信用建设入手,提出创建信用经济条件产生的具体措施。 相似文献
5.
Abstract. The estimation of the spectral density function of a stationary Gaussian process at the input of an instantaneous nonlinearity is considered when the nonlinearity is known and a finite set of observations of the output process is given. A class of spectral estimates is considered and their quadratic-mean consistency is established; precise asymptotic expressions for their bias and covariance are derived and their asymptotic normality is obtained. 相似文献
6.
The authors present a theory for understanding risk for problem drinking among reservation-dwelling American Indians. The theory offers an overall framework for understanding the risk process for this group. It considers the distinction between factors that influence mean levels of American Indian problem drinking and factors that influence individual differences in American Indian drinking. It proposes important contextual differences between reservation-dwelling American Indians and Caucasians that may help explain the higher mean levels of American Indian problem drinking. The theory further holds that, within the high mean level of problem drinking characteristic of many American Indian reservations, individual differences in problem drinking can be explained by very similar personality and learning factors as those that influence problem-drinking levels for other ethnic groups. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
Review of Arthur R. Jensen (2006)--Clocking the mind: Mental chronometry and individual differences.
Reviews the book Clocking the Mind: Mental chronometry and individual differences by Arthur Jensen (see record 2006-20276-000). Mental chronometry, as Arthur Jensen stresses, is the study of reaction time (RT) in its various guises, contexts, and applications. As with respect to much of experimental psychology (cognitive and other), there is a venerable past here lying in the background, providing a wide-ranging context in which to embed our current (that is, our 40-odd year) preoccupation with RT as a primary dependent measure in cognitive psychology. This recent book, Clocking the Mind: Mental Chronometry and Individual Differences (published by Elsevier), weds both differential psychology's concern with the measurement of individual differences in RT (e.g., Austin, Deary, Gibson, McGregor, & Dent, 1998) and experimental psychology's concern with "the effects of manipulating various external conditions on variation in the measurements of RT" (p. 1). The reader of this journal will most probably be more familiar with the latter use of RT in the literature, especially when embedded within such familiar experimental tasks as those tapping both Garner and Stroop effects (Pansky & Algom, 1999). The book should be perused with care in order to ensure the further profitable use of RT in both experimental and differential lines of research. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
Williams Paula G.; Wasserman Michelle S.; Lotto Andrew J. 《Canadian Metallurgical Quarterly》2003,22(1):3
In 2 studies, the relation between measures of self-assessed health (SAH) and automatic processing of health-relevant information was investigated. In Study 1, 84 male and 86 female undergraduate students completed a modified Stroop task. Results indicated that participants with poorer SAH showed enhanced interference effects for illness versus non-illness words. In Study 2, 27 male and 30 female undergraduate students completed a self-referent encoding task. Results offered a conceptual replication and extension of Study 1 by confirming the specificity of the relation between SAH measures and automatic processing of health (vs negative or positive general trait) information. These studies provide evidence that individual differences in SAH are reflected in schematic processing of health-relevant information. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
J. C. Sevy 《Calcolo》1993,30(1):41-68
Explicit error estimates are given for the iterated Boolean sum of a sequence of simultaneous approximants; the rate of convergence
is shown to be improved for smooth functions. The general results are applied in the case of the Bernstein, Durrmeyer and
Stancu operators. 相似文献
10.
Memorializes John Bissell (Jack) Carroll, an early leader in the development of psycholinguistics and a dominant contributor to psychometrics and the study of individual differences in cognitive abilities. His seminal work in evaluating foreign language proficiencies across multiple cultures combined his expertise in psycholinguistics with that in psychometrics and defined fundamental issues in the study of language acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献