全文获取类型
收费全文 | 56838篇 |
免费 | 6688篇 |
国内免费 | 5141篇 |
专业分类
电工技术 | 5223篇 |
技术理论 | 15篇 |
综合类 | 7346篇 |
化学工业 | 892篇 |
金属工艺 | 376篇 |
机械仪表 | 2138篇 |
建筑科学 | 3290篇 |
矿业工程 | 1563篇 |
能源动力 | 649篇 |
轻工业 | 862篇 |
水利工程 | 1457篇 |
石油天然气 | 637篇 |
武器工业 | 1000篇 |
无线电 | 9998篇 |
一般工业技术 | 2321篇 |
冶金工业 | 1687篇 |
原子能技术 | 121篇 |
自动化技术 | 29092篇 |
出版年
2024年 | 253篇 |
2023年 | 680篇 |
2022年 | 1302篇 |
2021年 | 1632篇 |
2020年 | 1774篇 |
2019年 | 1306篇 |
2018年 | 1177篇 |
2017年 | 1585篇 |
2016年 | 1847篇 |
2015年 | 2106篇 |
2014年 | 4372篇 |
2013年 | 3750篇 |
2012年 | 4724篇 |
2011年 | 4929篇 |
2010年 | 3779篇 |
2009年 | 4009篇 |
2008年 | 4236篇 |
2007年 | 4618篇 |
2006年 | 4090篇 |
2005年 | 3552篇 |
2004年 | 2961篇 |
2003年 | 2628篇 |
2002年 | 1795篇 |
2001年 | 1405篇 |
2000年 | 1075篇 |
1999年 | 678篇 |
1998年 | 452篇 |
1997年 | 349篇 |
1996年 | 294篇 |
1995年 | 224篇 |
1994年 | 209篇 |
1993年 | 150篇 |
1992年 | 107篇 |
1991年 | 83篇 |
1990年 | 52篇 |
1989年 | 59篇 |
1988年 | 47篇 |
1987年 | 27篇 |
1986年 | 28篇 |
1985年 | 45篇 |
1984年 | 52篇 |
1983年 | 43篇 |
1982年 | 28篇 |
1981年 | 18篇 |
1980年 | 19篇 |
1979年 | 17篇 |
1977年 | 8篇 |
1965年 | 10篇 |
1964年 | 11篇 |
1961年 | 7篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
To clarify whether motion information per se has a separable influence on action control, the authors investigated whether irrelevant direction of motion of stimuli whose overall position was constant over time would affect manual left-right responses (i.e., reveal a motion-based Simon effect). In Experiments 1 and 2, significant Simon effects were obtained for sine-wave gratings moving in a stationary Gaussian window. In Experiment 3, a direction-based Simon effect with random-dot patterns was replicated, except that the perceived direction of motion was based on the displacement of single elements. Experiments 4 and 5 studied motion-based Simon effects to point-light figures that walked in place--displays requiring high-level analysis of global shape and local motion. Motion-based Simon effects occurred when the displays could be interpreted as an upright human walker, showing that a high-level representation of motion direction mediated the effects. Thus, the present study establishes links between high-level motion perception and action. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
162.
虚假的会计信息,将严重扭曲股票的价值,扰乱资本市场秩序,侵害投资者的利益。笔者就会计信息失真的原因进行了分析,并就如何防范进行了探讨。 相似文献
163.
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
164.
Tokar David M.; Withrow Jason R.; Hall Rosalie J.; Moradi Bonnie 《Canadian Metallurgical Quarterly》2003,50(1):3
Structural equation modeling was used to test theoretically based models in which psychological separation and attachment security variables were related to career indecision and those relations were mediated through vocational self-concept crystallization. In contrast to previous studies, which have found either weak or no support for a relation between separation or attachment security variables and career indecision, results based on a sample of 350 college students indicated that some components of separation and attachment security did relate to career indecision in a theoretically supportable direction. Results also revealed that regardless of whether global or component career indecision measures were used, separation and attachment security effects on indecision were at least partially mediated through vocational self-concept crystallization. The strongest mediated relations were observed for the effects of attachment anxiety and maternal separation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
165.
166.
This article argues that it is not uncommon for people forming justice judgments to lack information that is most relevant in the particular situation. In information-uncertain conditions, people may therefore construct justice judgments by relying on how they feel about the events they have encountered, and justice judgments may hence be strongly influenced by affect information. Findings show that in information-uncertain conditions, the affective states that people had been in prior and unrelated to the justice event indeed strongly influenced their justice judgments. These findings thus reveal that in situations of information uncertainty, people's judgments of justice can be very subjective, susceptible to affective states that have no logical relationship with the justice judgments they are constructing. Implications for the social psychology of justice and the literature on social cognition and affect are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
167.
城市燃气管网GIS系统的开发 总被引:1,自引:1,他引:0
随着我国天然气工业的不断发展,对于城市天然气管网的智能化管理已经作为一个全新的课题出现在燃气企业里。过去所使用的MIS系统(Management Information System),无论从效率、准确度、智能程度上讲,都已经不能满足目前城市燃气管网的精确管理。因此地理信息系统(Geography Information System,简称GIS系统)作为一种新的计算机管理系统应运而生,其主要特点是:有精确的管理、有标准的地图提供直接判断、空间关系与实物对应明确、管理直观。文章以企业对管理系统的需求以及技术可行性为出发点,阐述了GIS系统应具有的基本性能;同时结合燃气工程技术的发展,对燃气GIS系统做了应用开发研究;此外还对现阶段部分燃气GIS信息系统的不足做出了分析。 相似文献
168.
将无线数传模块和具有低噪声的策控制电路集成设计为一体,构成检测信号和开关量控制信号无线传输的功能模块,并将该模块嵌入到探头和控制器内部,建立无线通讯子网,应用于智能能楼宇安防系统。很好的解决了无线信息冲突问题。经过试运行,系统工作稳定,无线探头报警可靠性达到了使用需求。 相似文献
169.
170.
In the past few years many systems for learning decision rules from examples were developed. As different systems allow different types of answers when classifying new instances, it is difficult to appropriately evaluate the systems' classification power in comparison with other classification systems or in comparison with human experts. Classification accuracy is usually used as a measure of classification performance. This measure is, however, known to have several defects. A fair evaluation criterion should exclude the influence of the class probabilities which may enable a completely uninformed classifier to trivially achieve high classification accuracy. In this paper a method for evaluating the information score of a classifier's answers is proposed. It excludes the influence of prior probabilities, deals with various types of imperfect or probabilistic answers and can be used also for comparing the performance in different domains. 相似文献