全文获取类型
收费全文 | 91723篇 |
免费 | 11116篇 |
国内免费 | 6967篇 |
专业分类
电工技术 | 7961篇 |
技术理论 | 2篇 |
综合类 | 9644篇 |
化学工业 | 10053篇 |
金属工艺 | 3761篇 |
机械仪表 | 7519篇 |
建筑科学 | 12550篇 |
矿业工程 | 2769篇 |
能源动力 | 4706篇 |
轻工业 | 6415篇 |
水利工程 | 2350篇 |
石油天然气 | 3699篇 |
武器工业 | 1638篇 |
无线电 | 6602篇 |
一般工业技术 | 9865篇 |
冶金工业 | 3458篇 |
原子能技术 | 529篇 |
自动化技术 | 16285篇 |
出版年
2024年 | 635篇 |
2023年 | 1733篇 |
2022年 | 3118篇 |
2021年 | 3544篇 |
2020年 | 3812篇 |
2019年 | 3156篇 |
2018年 | 3130篇 |
2017年 | 3658篇 |
2016年 | 4057篇 |
2015年 | 4121篇 |
2014年 | 5965篇 |
2013年 | 5853篇 |
2012年 | 7182篇 |
2011年 | 7125篇 |
2010年 | 5508篇 |
2009年 | 5505篇 |
2008年 | 5088篇 |
2007年 | 6311篇 |
2006年 | 5356篇 |
2005年 | 4505篇 |
2004年 | 3605篇 |
2003年 | 3017篇 |
2002年 | 2451篇 |
2001年 | 2144篇 |
2000年 | 1764篇 |
1999年 | 1372篇 |
1998年 | 1055篇 |
1997年 | 906篇 |
1996年 | 782篇 |
1995年 | 612篇 |
1994年 | 509篇 |
1993年 | 381篇 |
1992年 | 296篇 |
1991年 | 250篇 |
1990年 | 208篇 |
1989年 | 188篇 |
1988年 | 128篇 |
1987年 | 80篇 |
1986年 | 42篇 |
1985年 | 57篇 |
1984年 | 75篇 |
1983年 | 50篇 |
1982年 | 46篇 |
1981年 | 27篇 |
1980年 | 65篇 |
1979年 | 29篇 |
1964年 | 28篇 |
1963年 | 26篇 |
1961年 | 23篇 |
1955年 | 29篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Acceptance, the willingness to experience thoughts, feelings, and physiological sensations without having to control them or let them determine one's actions, is a major individual determinant of mental health and behavioral effectiveness in a more recent theory of psychopathology. This 2-wave panel study examined the ability of acceptance also to explain mental health, job satisfaction, and performance in the work domain. The authors hypothesized that acceptance would predict these 3 outcomes 1 year later in a sample of customer service center workers in the United Kingdom (N = 412). Results indicated that acceptance predicted mental health and an objective measure of performance over and above job control, negative affectivity, and locus of control. These beneficial effects of having more job control were enhanced when people had higher levels of acceptance. The authors discuss the theoretical and practical relevance of this individual characteristic to occupational health and performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
92.
在聚全氟乙丙烯(FEP)中添加 TiO_2和 Al_2O_3,通过热压成型的方法制备了 FEP/TiO_2复合材料和 FEP/Al_2O_3复合材料,研究了氧化物添加量对复合材料介电常数、介电损耗和高频击穿性能的影响。结果表明,随氧化物含量的增加,复合材料的介电常数和介电损耗均增加;在同一添加量下,TiO_2对复合体系的介电性能影响较大。FEP/TiO_2复合材料的高频击穿性能随 TiO_2含量的增加而下降,在 TiO_2含量为4.0%(质量分数,下同)时,复合材料的损伤阈值已降为 FEP 材料损伤阈值的48.9 %。而 FEP/Al_2O_3复合材料的高频击穿性能随 Al_2O_3含量的增加而升高,当 Al_2O_3含量为1.2%时,复合材料的损伤阈值已增大到 FEP 材料损伤阈值的2倍,达到313 J/m~2。 相似文献
93.
94.
This study provides a meta-analysis of research on the associations between relationship conflict, task conflict, team performance, and team member satisfaction. Consistent with past theorizing, results revealed strong and negative correlations between relationship conflict, team performance, and team member satisfaction. In contrast to what has been suggested in both academic research and introductory textbooks, however, results also revealed strong and negative (instead of the predicted positive) correlations between task conflict, team performance, and team member satisfaction. As predicted, conflict had stronger negative relations with team performance in highly complex (decision making, project, mixed) than in less complex (production) tasks. Finally, task conflict was less negatively related to team performance when task conflict and relationship conflict were weakly, rather than strongly, correlated. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
95.
Maarja Kruusmaa 《Journal of Intelligent and Robotic Systems》2003,38(1):55-83
This paper presents a self-adapting approach to global level path planning in dynamic environments. The aim of this work is to minimize risk and delays in possible applications of mobile robots (e.g., in industrial processes). We introduce a hybrid system that uses case-based reasoning as well as grid-based maps for decision-making. Maps are used to suggest several alternative paths between specific start and goal point. The casebase stores these solutions and remembers their characteristics. Environment representation and casebase design are discussed. To solve the problem of exploration vs. exploitation, a decision-making strategy is proposed that is based on the irreversibility of decisions. Forgetting strategies are discussed and evaluated in the context of case-based maintenance. The adaptability of the system is evaluated in a domain based on real sensor data with simulated occupancy probabilities. Forgetting strategies and decision-making strategies are evaluated in simulated environments. Experiments show that a robot is able to adapt in dynamic environments and can learn to use paths that are less risky to follow. 相似文献
96.
通过改进铅膏的配方及极板的独特处理工艺 ,提高了干电荷电摩托车电池的低温高率放电性能、充电接受能力和储存性能 ,完全可以满足国内外摩托车主机厂的各种要求。 相似文献
97.
A. J. Slifka T. Hall E. S. Boltz 《Journal of research of the National Institute of Standards and Technology》2003,108(2):151-156
A simple measurement system is described for evaluating damage to graphite-epoxy panels, such as those used in high-performance aircraft. The system uses a heating laser and infrared imaging system to measure thermal performance. Thermal conductivity or diffusivity is a sensitive indicator of damage in materials, allowing this thermal measurement to show various degrees of damage in graphite-epoxy composites. Our measurements track well with heat-flux damage to graphite epoxy panels. This measurement system, including analysis software, could easily be used in the field, such as on the deck of an aircraft carrier or at remote air strips. 相似文献
98.
99.
Palogue油田复合油藏动态响应及特征描述 总被引:1,自引:1,他引:0
以简单的复合油藏模型理论和方法为基础,以Palogue油田的实际测试井为例,介绍了复合油藏模型的试井动态识别与模型拟合,及与地质静态资料相结合的油藏综合描述过程.该描述方法将会对实际试井解释和油藏综合描述工作有所借鉴和帮助. 相似文献
100.