全文获取类型
收费全文 | 37545篇 |
免费 | 3838篇 |
国内免费 | 2623篇 |
专业分类
电工技术 | 2648篇 |
技术理论 | 8篇 |
综合类 | 5427篇 |
化学工业 | 2857篇 |
金属工艺 | 925篇 |
机械仪表 | 2380篇 |
建筑科学 | 3586篇 |
矿业工程 | 1321篇 |
能源动力 | 1295篇 |
轻工业 | 566篇 |
水利工程 | 1048篇 |
石油天然气 | 919篇 |
武器工业 | 608篇 |
无线电 | 3332篇 |
一般工业技术 | 4418篇 |
冶金工业 | 2853篇 |
原子能技术 | 341篇 |
自动化技术 | 9474篇 |
出版年
2024年 | 147篇 |
2023年 | 594篇 |
2022年 | 791篇 |
2021年 | 1001篇 |
2020年 | 1160篇 |
2019年 | 1116篇 |
2018年 | 1146篇 |
2017年 | 1276篇 |
2016年 | 1354篇 |
2015年 | 1378篇 |
2014年 | 2115篇 |
2013年 | 2569篇 |
2012年 | 2340篇 |
2011年 | 2702篇 |
2010年 | 2159篇 |
2009年 | 2276篇 |
2008年 | 2319篇 |
2007年 | 2462篇 |
2006年 | 2300篇 |
2005年 | 1991篇 |
2004年 | 1627篇 |
2003年 | 1375篇 |
2002年 | 1185篇 |
2001年 | 964篇 |
2000年 | 787篇 |
1999年 | 683篇 |
1998年 | 540篇 |
1997年 | 482篇 |
1996年 | 404篇 |
1995年 | 392篇 |
1994年 | 323篇 |
1993年 | 271篇 |
1992年 | 251篇 |
1991年 | 183篇 |
1990年 | 151篇 |
1989年 | 172篇 |
1988年 | 132篇 |
1987年 | 68篇 |
1986年 | 94篇 |
1985年 | 72篇 |
1984年 | 67篇 |
1983年 | 48篇 |
1982年 | 54篇 |
1981年 | 43篇 |
1980年 | 31篇 |
1979年 | 34篇 |
1978年 | 29篇 |
1977年 | 26篇 |
1964年 | 30篇 |
1955年 | 51篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
61.
This paper describes the theory and implementation ofBabel, a system which explores the hypothesis that much of the differences in the world's languages may be characterized by the inventory and properties of the lexical items and functional categories of those languages. The structure ofBabel assumes that functional categories are originally lacking in a child's syntax, and are acquired through a statistical induction process of lexical acquisition.Babel then uses information induced from the structure of the lexicon to create a model of syntax via a deductive, rule-based process. This model makes a number of predictions about the time course of language acquisition. These predictions are tested by runningBabel as a simulation of child language acquisition, using large samples of adult speech to children as input. The simulation results are shown to highly correlate to longitudinal studies of child language acquisition in English and Polish. Finally, the approach to handling noisy data withBabel is detailed. 相似文献
62.
Bachant Janet L.; Lynch Arthur A.; Richards Arnold D. 《Canadian Metallurgical Quarterly》1996,13(1):153
The authors respond to the "relational" issue of Psychoanalytic Psychology (PP; Vol. 12, No. 1) and support Karol Marshall's remonstration about the need to clarify what exactly the category relational refers to. It is noteworthy that in this issue of PP the relational thinkers do not engage the specific topics of our essay. The author's article attempted to review the most comprehensive relational thinkers of that time across theoretical variables. Relationalists have begun to spell out the technical consequences of their perspective in recent discussions of neutrality, authority, and self-disclosure, among other issues. This is a useful trend in the relational literature, and we hope it continues. We are concerned, however, that the relational thinkers writing in this issue tend to dismiss the contributions to PP 12(1) because the perspectives presented there did not satisfy the relationalist vision of how scientific exchange should be undertaken. Although we feel that it is important for emerging points of view to be able to elaborate assumptions, constructs, and principles within their own framework and in their own way, constructive dialogue, much less a comparative analysis of the contributions and limitations of different points of view, requires that we have some common ground. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
63.
64.
65.
66.
任雪莲 《电脑编程技巧与维护》2012,(8):135-136
根据《Flash动画制作》课程在教学实践中的特点,提出构建"理实同步,实例引导,任务驱动"的教学模式,在教学内容、教学方法等方面进行教学改革,并阐述了在Flash教学中的具体实施方法,提高了学生动手能力及综合素质。 相似文献
67.
Thermal conductivity, viscosity, and self-diffusion coefficient data for liquid n-alkanes are satisfactorily correlated simultaneously by a method based on the hard-sphere theory of transport properties. Universal curves are developed for the reduced transport properties
*,
*, and D
* as a function of the reduced volume. A consistent set of equations is derived for the characteristic volume and for the parameters R
, R
, and R
D, introduced to account for the nonsphericity and roughness of the molecules. The temperature range of the above scheme extends from 110 to 370 K, and the pressure range up to 650 MPa. 相似文献
68.
Though they constitute the major knowledge source in problem-solving systems, no unified theory of heuristics has emerged. Pearl [15] defines heuristics as criteria, methods, or principles for deciding which among several alternative courses of action promises to be the most effective in order to achieve some goal. The absence of a more precise definition has impeded our efforts to understand, utilize, and discover heuristics. Another consequence is that problem-solving techniques which rely on heuristic knowledge cannot be relied upon to act rationally — in the sense of the normative theory of rationality.To provide a sound basis for BPS, the Bayesian Problem-Solver, we have developed a simple formal theory of heuristics, which is general enough to subsume traditional heuristic functions as well as other forms of problem-solving knowledge, and to straddle disparate problem domains. Probabilistic heuristic estimates represent a probabilistic association of sensations with prior experience — specifically, a mapping from observations directly to subjective probabilities which enables the use of theoretically principled mechanisms for coherent inference and decision making during problem-solving. This paper discusses some of the implications of this theory, and describes its successful application in BPS.This research was made possible by support from Heuristicrats, the National Aeronautics and Space Administration, and the Rand Corporation. 相似文献
69.
Analyzed the film Three Approaches to Psychotherapy (E. L. Shostrom, 1966), which depicts C. Rogers (client-centered therapy), A. Ellis (rational-emotive therapy), and F. S. Perls (Gestalt therapy) interviewing the same client, Gloria. Verbal exchanges between participants were analyzed, using T. S. Essig and R. L. Russell's (1988) categories for analyzing psychological relations between subjects and events in discourse. Predictable patterns in how therapists of different theoretical orientations represent subjectivity in discourse can be screened with these categories. Classification categories are appended. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
70.