全文获取类型
收费全文 | 7288篇 |
免费 | 413篇 |
国内免费 | 317篇 |
专业分类
电工技术 | 304篇 |
综合类 | 1600篇 |
化学工业 | 910篇 |
金属工艺 | 447篇 |
机械仪表 | 302篇 |
建筑科学 | 704篇 |
矿业工程 | 197篇 |
能源动力 | 70篇 |
轻工业 | 657篇 |
水利工程 | 102篇 |
石油天然气 | 292篇 |
武器工业 | 110篇 |
无线电 | 495篇 |
一般工业技术 | 394篇 |
冶金工业 | 579篇 |
原子能技术 | 20篇 |
自动化技术 | 835篇 |
出版年
2024年 | 30篇 |
2023年 | 75篇 |
2022年 | 140篇 |
2021年 | 156篇 |
2020年 | 182篇 |
2019年 | 136篇 |
2018年 | 134篇 |
2017年 | 160篇 |
2016年 | 234篇 |
2015年 | 226篇 |
2014年 | 492篇 |
2013年 | 372篇 |
2012年 | 530篇 |
2011年 | 619篇 |
2010年 | 544篇 |
2009年 | 448篇 |
2008年 | 413篇 |
2007年 | 542篇 |
2006年 | 443篇 |
2005年 | 420篇 |
2004年 | 333篇 |
2003年 | 314篇 |
2002年 | 250篇 |
2001年 | 204篇 |
2000年 | 148篇 |
1999年 | 115篇 |
1998年 | 74篇 |
1997年 | 53篇 |
1996年 | 44篇 |
1995年 | 30篇 |
1994年 | 18篇 |
1993年 | 7篇 |
1992年 | 20篇 |
1991年 | 12篇 |
1990年 | 5篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 8篇 |
1984年 | 4篇 |
1966年 | 3篇 |
1965年 | 4篇 |
1964年 | 4篇 |
1963年 | 6篇 |
1962年 | 7篇 |
1961年 | 7篇 |
1960年 | 4篇 |
1959年 | 5篇 |
1958年 | 9篇 |
1956年 | 5篇 |
1955年 | 10篇 |
排序方式: 共有8018条查询结果,搜索用时 31 毫秒
31.
This article reviews the theory of successful intelligence and attempts to construct-validate the theory of successful intelligence. It describes 4 distinct converging operations that have been used in these attempts. Two sets involve internal validation of the structure of the theory and 2 sets external validation of the theory with outside criteria. The internal validation operations involve information-processing (componential) analyses and both exploratory and confirmatory factor analyses. The external validation operations involve correlational analysis and analyses of instructional interventions based on the theory. The results are generally supportive of the theory and suggest that conventional conceptions of intelligence may be too narrow. The theory is of use in consulting because it broadens the scope of skills one looks for in seeking "intelligent" people for hiring, retention, and promotion and in assessing a person's ability to do his or her current job. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
32.
Children between 7 and 8 years old took pan in a staged event at school and 1 week later were assessed using a short form of the Wechsler Intelligence scale for children (third edition) and measures of metamemory, narrative ability, and socioeconomic status. Two weeks following the event, children either received narrative elaboration training (NET; K.J. Saywitz & L. Snyder, 1996) and were prompted with the four NET cue cards at interview; received verbal prompts corresponding to the cue card categories, but without prior training; or were presented with the cards at interview without prior training. Children given verbal labels as prompts recalled as much information as children who received NET training and cue cards. Measures of intelligence were predictive of amount recalled for cards-only children but not for the other 2 groups, indicating that differences in recall between low- and high-IQ groups were attenuated when recall was supported by NET training or verbal prompting. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
33.
The experimental research in displacement of gold particles in washed-out thickness of sand-gravel layer is conducted. The parameters of ability of gold particles to migrate in pulp flow are determined, and their immersion into loose soil is investigated. 相似文献
34.
L.Q. Xing P. Ochin M. Harmelin F. Faudot J. Bigot J.P. Chevalier 《Materials Science and Engineering: A》1996,220(1-2)
Cylindrical bulk amorphous samples with diameters up to 10 mm have been prepared by casting ZrTiAlCuNi alloys in a copper mould. In order to rank glass-forming ability as a function of alloy composition, alloys were also cast into wedge-shaped moulds; to a first approximation, the thickness of the amorphous region obtained can be taken as an indication of glass-forming ability. The compositions which lead to the production of bulk glasses all have reduced glass transition temperatures in excess of 0.65 and the extremely high glass-forming ability of these compositions is discussed. We suggest that both the Al and Ti contents are determining factors for the production of bulk amorphous samples and these are believed to reduce the driving force for, and hence the rate of, crystallisation. These amorphous alloys have been found to display high thermal stability and can be annealed for several minutes in the supercooled liquid region. They are ductile at room temperature and have a high value of yield stress. 相似文献
35.
36.
孟艳 《徐州工程学院学报》2002,(5)
通过对经济发展与科技发展模式的分析 ,提出做大我国企业的经济规模 ,提高我国企业的国际竞争力 ,进行技术开发与技术创新。采取企业与科技部门相结合 ,处理科技部门与企业之间的关系及科技成果转化困难的问题 相似文献
37.
OPS和OPC系列稠油乳化降黏剂的研制 总被引:1,自引:0,他引:1
以工业品烷基酚聚氧乙烯醚OP-n(n=4,6,8,10,15)为起始原料,合成了烷基酚聚氧乙烯醚乙酸盐OPC-n和磺酸盐OPS-n两个系列的阴-非离子表面活性剂。以酸值和黏度不同的胜利单家寺和陈庄稠油为实验油样。将OPC-n和OPS-n溶于矿化度5811 mg/kg的胜利标准盐水和NaCl、CaCl2盐水中作为水相,按油、水质量比7∶3在50℃用玻棒搅拌混合,观察是否形成水包油乳状液并测黏度进行确认。在胜利标准盐水溶液中,OPC-n和OPS-n乳化稠油所需的最低质量分数,随稠油、表面活性剂类型及氧乙烯链节数n而变,一般而言,OPC-n系列中的OPC-8和OPS-n系列中的OPS-4乳化稠油的性能最好,该最低质量分数值分别为0.05%或0.025%和0.025%。在NaCl盐水溶液中,OPC-n的该最低质量分数值与稠油和n有关,均随盐含量增加而增大,在盐含量≤15%时,抗盐性最好的OPC-8和OPC-10的该值≤0.05%;OPS-n的抗盐性好于OPC-n。OPC-n的抗钙性良好,钙盐含量为2%时该最低质量分数≤0.1%;OPS-n的抗钙性更好,钙盐含量为2%和3%时该最低质量分数仅为0.025%或0.05%。表6参5。 相似文献
38.
学生实践能力的培养越来越成为当今大学教育的关注点,文章结合德州学院的信息管理与信息系统专业教学现状及实践情况分析了当前该专业在培养学生的实践能力方面的不足,并给出了实践教学体系的构建模型。实践成果表明,该体系具有一定的可行性和先进性,为信息管理与信息系统专业的人才培养提供了借鉴。 相似文献
39.
邓洪斌 《电脑编程技巧与维护》2012,(10):154-155
从学生学习计算机编程时能力的重要性出发,介绍了教师在进行编程教学时必须注重学生几种能力的培养,并阐述了教学过程中可以采用的几种教学方法。 相似文献
40.
分析了政府信息能力的内涵,提出电子政务对于政府信息能力的提升作用是从改善政府信息资源的构成要素和提高政府信息资源的应用能力两方面来体现,总结了当前福建省政府信息能力的现状,并提出了如何通过电子政务进一步提升福建省政府的信息能力。 相似文献