全文获取类型
收费全文 | 8755篇 |
免费 | 542篇 |
国内免费 | 309篇 |
专业分类
电工技术 | 839篇 |
技术理论 | 1篇 |
综合类 | 1119篇 |
化学工业 | 413篇 |
金属工艺 | 244篇 |
机械仪表 | 490篇 |
建筑科学 | 795篇 |
矿业工程 | 331篇 |
能源动力 | 252篇 |
轻工业 | 221篇 |
水利工程 | 262篇 |
石油天然气 | 502篇 |
武器工业 | 36篇 |
无线电 | 458篇 |
一般工业技术 | 353篇 |
冶金工业 | 2346篇 |
原子能技术 | 51篇 |
自动化技术 | 893篇 |
出版年
2024年 | 23篇 |
2023年 | 59篇 |
2022年 | 131篇 |
2021年 | 145篇 |
2020年 | 201篇 |
2019年 | 139篇 |
2018年 | 131篇 |
2017年 | 150篇 |
2016年 | 183篇 |
2015年 | 234篇 |
2014年 | 420篇 |
2013年 | 362篇 |
2012年 | 569篇 |
2011年 | 685篇 |
2010年 | 557篇 |
2009年 | 513篇 |
2008年 | 458篇 |
2007年 | 598篇 |
2006年 | 592篇 |
2005年 | 538篇 |
2004年 | 469篇 |
2003年 | 475篇 |
2002年 | 371篇 |
2001年 | 302篇 |
2000年 | 176篇 |
1999年 | 127篇 |
1998年 | 97篇 |
1997年 | 79篇 |
1996年 | 71篇 |
1995年 | 57篇 |
1994年 | 49篇 |
1993年 | 32篇 |
1992年 | 23篇 |
1990年 | 25篇 |
1989年 | 23篇 |
1988年 | 21篇 |
1987年 | 19篇 |
1966年 | 17篇 |
1965年 | 56篇 |
1964年 | 32篇 |
1963年 | 16篇 |
1962年 | 27篇 |
1961年 | 23篇 |
1960年 | 20篇 |
1959年 | 32篇 |
1958年 | 22篇 |
1957年 | 26篇 |
1956年 | 21篇 |
1955年 | 31篇 |
1954年 | 23篇 |
排序方式: 共有9606条查询结果,搜索用时 15 毫秒
21.
在KZON-50/120空分设备的安装调试和试运行过程中,对其机械和电器部分进行了多处改造,克服了原设计中存在的不足之处。改造后,机械和电器性能更加趋于合理,操作简单,便于维护,降低了制气费用,提高了制气纯度和经济效益,保证了空分设备更加安全可靠运行。 相似文献
22.
Ryba Nancy L.; Cooper Virginia G.; Zapf Patricia A. 《Canadian Metallurgical Quarterly》2003,34(5):499
What is the current standard of practice for evaluations of juvenile competence to stand trial (JCST)? The present study surveyed psychologists regarding the practices used when conducting JCST evaluations. Respondents rated the importance of 17 elements that might be included in a JCST evaluation report. Of these elements, 7 were considered essential by 70% or more of respondents, with 9 additional elements rated as either essential or recommended. A majority of respondents felt that the use of psychological and forensic instruments was important. A list of tests used is provided, and the implications for the development of standards and policy are discussed to provide practitioners with additional knowledge that will help to further the state of the discipline. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
23.
24.
刘洪 《湖南冶金职业技术学院学报》2004,(3)
心理健康不仅是时代发展对教育的必然要求,而且是实施素质教育的目标之一。为了培养高职学生良好的心理素质,针对高职学生心理素质存在的问题,就如何加强学生心理素质教育进行了探讨。 相似文献
25.
D. P. Phillips, T. E. Ruth, and L. M. Wagner (1993) reported that 1969-1990 California mortality data show that Chinese Americans are particularly vulnerable to diseases that Chinese astrology and traditional Chinese medicine associate with their birth years. For example, because fire is associated with the heart, a Chinese person born in a fire year (such as 1937) is more likely to die of heart disease than is a Chinese person born in a nonfire year. However, many diseases were excluded from this study, some diseases that were included have ambiguous links to birth years, and the statistical tests were indirect. A more complete statistical analysis and independent California mortality data for the years 1960-1968 and 1991-2002 did not replicate the original results. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
26.
27.
We study low-frequency vibrations of a vibroprotective system of solid bodies formed by a roller damper and a moving load-carrying body under the action of external harmonic excitations. The dynamic equations of combined motion of the working body of the damper over the hinged roller without sliding and the load-carrying body are deduced and numerically analyzed. A new procedure is proposed for the evaluation of the optimal parameters of adjustment of roller dampers in nonlinear systems. 相似文献
28.
29.
Jost John T.; Glaser Jack; Kruglanski Arie W.; Sulloway Frank J. 《Canadian Metallurgical Quarterly》2003,129(3):383
A meta-analysis by J. T. Jost, J. Glaser, A. W. Kruglanski, and F. J. Sulloway (2003) concluded that political conservatism is partially motivated by the management of uncertainty and threat. In this reply to J. Greenberg and E. Jonas (2003), conceptual issues are clarified, numerous political anomalies are explained, and alleged counterexamples are incorporated with a dynamic model that takes into account differences between "young" and "old" movements. Studies directly pitting the rigidity-of-the-right hypothesis against the ideological extremity hypothesis demonstrate strong support for the former. Medium to large effect sizes describe relations between political conservatism and dogmatism and intolerance of ambiguity; lack of openness to experience; uncertainty avoidance; personal needs for order, structure, and closure; fear of death; and system threat. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
30.
Utilizing data from the Riggs-Yale Project, 45 male and 45 female 18-29-year-old treatment-resistant inpatients undergoing intensive psychoanalytically oriented treatment were studied. Twenty-seven mixed-type anaclitic-introjective inpatients were compared with 29 "pure" anaclitic and 34 "pure" introjective inpatients. At intake, mixed-type inpatients were more clinically impaired (i.e., were more symptomatic, cognitively impaired, and thought disordered) and more vulnerable (i.e., less accurate object representations and more frequently used maladaptive defense mechanisms) in comparison with clearly defined anaclitic and introjective patients. Mixed-type patients, however, improved significantly more in the course of psychoanalytically oriented treatment, in terms of clinical functioning (i.e., symptoms, cognitive functioning) and psychological vulnerability (i.e., utilization of more adaptive defense mechanisms). (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献