全文获取类型
收费全文 | 6133篇 |
免费 | 96篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 50篇 |
综合类 | 6篇 |
化学工业 | 1049篇 |
金属工艺 | 113篇 |
机械仪表 | 77篇 |
建筑科学 | 372篇 |
矿业工程 | 66篇 |
能源动力 | 144篇 |
轻工业 | 627篇 |
水利工程 | 82篇 |
石油天然气 | 31篇 |
武器工业 | 1篇 |
无线电 | 330篇 |
一般工业技术 | 797篇 |
冶金工业 | 1804篇 |
原子能技术 | 37篇 |
自动化技术 | 650篇 |
出版年
2022年 | 49篇 |
2021年 | 72篇 |
2020年 | 52篇 |
2019年 | 64篇 |
2018年 | 72篇 |
2017年 | 63篇 |
2016年 | 86篇 |
2015年 | 43篇 |
2014年 | 94篇 |
2013年 | 374篇 |
2012年 | 189篇 |
2011年 | 302篇 |
2010年 | 240篇 |
2009年 | 188篇 |
2008年 | 278篇 |
2007年 | 261篇 |
2006年 | 277篇 |
2005年 | 268篇 |
2004年 | 230篇 |
2003年 | 195篇 |
2002年 | 156篇 |
2001年 | 114篇 |
2000年 | 127篇 |
1999年 | 136篇 |
1998年 | 157篇 |
1997年 | 127篇 |
1996年 | 126篇 |
1995年 | 104篇 |
1994年 | 111篇 |
1993年 | 106篇 |
1992年 | 100篇 |
1991年 | 64篇 |
1990年 | 105篇 |
1989年 | 97篇 |
1988年 | 76篇 |
1987年 | 83篇 |
1986年 | 76篇 |
1985年 | 76篇 |
1984年 | 102篇 |
1983年 | 71篇 |
1982年 | 87篇 |
1981年 | 78篇 |
1980年 | 64篇 |
1979年 | 52篇 |
1978年 | 45篇 |
1977年 | 48篇 |
1976年 | 44篇 |
1975年 | 44篇 |
1974年 | 37篇 |
1973年 | 36篇 |
排序方式: 共有6236条查询结果,搜索用时 0 毫秒
1.
2.
Beebe-Frankenberger Margaret; Bocian Kathleen M.; MacMillan Donald L.; Gresham Frank M. 《Canadian Metallurgical Quarterly》2004,96(2):204
A cohort of 2nd-grade students provided comparisons of academic and social competence based on school retention/promotion decisions. Sample groups were (a) retained, (b) at risk for retention, (c) special education, and (d) promoted. Findings suggested most children with academic deficiencies are identified by schools early and are sorted into educational treatments differing in intensity that represent a continuum of competence. The authors provide empirical evidence counter to the assumptions that retained students have the requisite ability to catch up and have more problem behaviors than other low-achieving students. The relevance of high-stakes test scores for promotion/retention decisions and the parallels between schools' implementation of retention policy and implementation of regulations for identifying children with disabilities are included in the discussion. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
Vivien Walsh Robin Roy Margaret Bruce Stephen Potter 《Creativity & Innovation Management》1993,2(2):78-86
A series of studies of top European and other firms has revealed patterns of design management associated with commercial success. Firms that invest resources and professional expertise in product and industrial design in traditional and new industries have been commercially more successful than firms that pay less attention to these aspects of design. As an industry matures there is a shift in emphasis from design associated with technological innovation, to designs supporting technical improvements, and then to supporting user needs, fashion and product variants. These issues are illustrated through the history of the evolution of the bicycle. 相似文献
4.
In this paper we analyse issues associated with overloads in tandem switching systems in Common Channel Signalling (CCS) networks. In particular, we examine the need for, and effectiveness of, Automatic Congestion Control (ACC), a CCS mechanism which allows a congested switching system to inform adjacent CCS nodes of its level of overload, and subsequently controls the rate at which traffic is sent to the congested node. We demonstrate the critical need for end-offices and tandem switching systems to implement some form of ACC if network performance is to be maintained during congestion, especially in tandem exchanges. In addition, we find that the presently defined ACC should be expanded to allow more levels of congestion to be reported to adjacent nodes, so that a more effective, finer grained control is produced. 相似文献
5.
Much of the writing on the psychological autopsy is reviewed. Several writers' opinions about what should be included in a comprehensive behavioral analysis conducted after an individual's death are compiled in an Appendix. Several additional and new areas to be covered in a psychological autopsy are included. The primary emphasis is on the provision of a practical guide for the working professional. Twenty-four separate factors, ranging from reconstruction of events that occurred before the death to the deceased's family death history, are presented. Some legal considerations are examined briefly in order to acquaint the professional with the significant impact that the results can have on family benefits and criminal prosecution. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
7.
8.
9.
10.
Ronald R. Delyser Sheila S. Thompson Jerry Edelstein Corinne Lengsfeld Albert J. Rosa Paul J. Rullkoetter Robert Whitman Margaret Whitt 《工程教育杂志》2003,92(3):269-273
A team of faculty members at the University of Denver changed the learning environment in key courses in the Department of Engineering from predominately teacher centered to student centered. Through this funded project new grading methods were implemented, classrooms were renovated and wired with studio layouts to facilitate learning, the Engineering Circuits Laboratory was rewired and instrumented for automated data acquisition and reporting, and two new pedagogical approaches were developed. At the onset of the project, six goals were established related to student learning. The introduction of industry standard hardware and software provided students with unprecedented hands‐on experience and project related activities stimulated faculty innovations in other current and future courses. Assessment results indicate that the new grading system improved the clarity of expectations for students before assignments were given resulting in increased reported motivation for learning in many courses. Even though course GPAs did not always reflect higher achievement on graded work, faculty members firmly believe that deeper understanding was achieved because more complex material was assimilated. 相似文献