全文获取类型
收费全文 | 5185篇 |
免费 | 242篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 43篇 |
综合类 | 4篇 |
化学工业 | 1057篇 |
金属工艺 | 79篇 |
机械仪表 | 97篇 |
建筑科学 | 187篇 |
矿业工程 | 30篇 |
能源动力 | 129篇 |
轻工业 | 339篇 |
水利工程 | 69篇 |
石油天然气 | 12篇 |
武器工业 | 1篇 |
无线电 | 416篇 |
一般工业技术 | 872篇 |
冶金工业 | 1229篇 |
原子能技术 | 33篇 |
自动化技术 | 833篇 |
出版年
2023年 | 30篇 |
2022年 | 46篇 |
2021年 | 90篇 |
2020年 | 69篇 |
2019年 | 77篇 |
2018年 | 83篇 |
2017年 | 85篇 |
2016年 | 115篇 |
2015年 | 108篇 |
2014年 | 166篇 |
2013年 | 285篇 |
2012年 | 255篇 |
2011年 | 369篇 |
2010年 | 264篇 |
2009年 | 287篇 |
2008年 | 306篇 |
2007年 | 307篇 |
2006年 | 246篇 |
2005年 | 193篇 |
2004年 | 183篇 |
2003年 | 176篇 |
2002年 | 154篇 |
2001年 | 113篇 |
2000年 | 109篇 |
1999年 | 96篇 |
1998年 | 95篇 |
1997年 | 92篇 |
1996年 | 84篇 |
1995年 | 73篇 |
1994年 | 73篇 |
1993年 | 79篇 |
1992年 | 50篇 |
1991年 | 43篇 |
1990年 | 53篇 |
1989年 | 61篇 |
1988年 | 51篇 |
1987年 | 42篇 |
1986年 | 38篇 |
1985年 | 47篇 |
1984年 | 47篇 |
1983年 | 32篇 |
1982年 | 30篇 |
1981年 | 43篇 |
1980年 | 22篇 |
1979年 | 20篇 |
1978年 | 36篇 |
1977年 | 20篇 |
1976年 | 23篇 |
1975年 | 15篇 |
1974年 | 15篇 |
排序方式: 共有5430条查询结果,搜索用时 15 毫秒
11.
Responds to the comments by L. T. Hoshmand (see record 2003-08988-012) and J. Aros (see record 2003-08988-013) on the article by J. Arnett (see record 2002-18352-003) regarding the psychology of globalization. In this response, Arnett discusses the moral implications of globalization. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
12.
Using meta-analysis, randomized experiments in education that either clearly did or clearly did not experience student attrition were examined for the baseline comparability of groups. Results from 35 studies suggested that after attrition, the observed measures of baseline comparability of groups did not differ more than would be expected given sampling error. The degree of either overall or differential attrition did not relate to baseline comparability, a finding that held under sensitivity analyses. Also, both overall and differential attrition rates were unrelated to posttest effect sizes. All of these analyses, however, lacked sufficient statistical power to detect small but potentially meaningful effects. Results suggest caution is warranted when applying quality scales and other blanket rules pertaining to attrition that are meant to either serve as inclusion-exclusion criteria or in scoring study quality. Much greater attention is needed to both the reporting of attrition in primary studies and to the development of conceptual and empirical models of the attrition process. These developments would aid further investigation of the relation between attrition and study outcomes. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
13.
PURPOSE: To determine the improvement in pancreatic enhancement at helical computed tomography (CT) performed with an early delay after administration of contrast material compared with that performed with a standard delay. MATERIALS AND METHODS: Dual-phase helical CT of the abdomen was performed in 120 patients with a 150-mL bolus of contrast material infused at 5 mL/sec. Early and standard delayed scanning was performed beginning at 20 seconds and 49-71 seconds, respectively. Regions of interest were measured in the head, body, and tail of the pancreas in 92 patients. The difference in enhancement between early and standard delayed scanning was calculated. RESULTS: Mean pancreatic enhancement was 82 HU +/- 3 (standard error) with an early delay, whereas enhancement on standard delay scans was 62 HU +/- 2 (P < .001). An improvement in enhancement greater than 10 HU was attained in 66 of 92 cases (72%). CONCLUSION: Pancreatic enhancement at helical CT with an early delay after contrast material administration is often significantly greater than the enhancement seen with a standard delay when a monophasic, rapidly infused bolus of contrast material is used. 相似文献
14.
Kelly Jeffrey A.; Murphy Debra A.; Sikkema Kathleen J.; Kalichman Seth C. 《Canadian Metallurgical Quarterly》1993,48(10):1023
Behavior change remains the only means for primary prevention of HIV disease. Psychology should take a leading role in efforts to curtail the epidemic, but has not contributed to HIV prevention at a level proportionate to the urgency of the crisis. The authors propose an updated agenda for behavioral research on AIDS-HIV prevention implementing accelerated community trials of promising behavior change models, conducting trials of community-level interventions on a large scale and focused on populations most vulnerable to HIV infections, establishing partnerships between HIV research and community service organizations, integrating efforts from across psychology disciplines to advance and refine HIV prevention interventions, and mobilizing interdisciplinary HIV prevention resources and communication mechanisms to rapidly translate research findings to community and public policy arenas. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
15.
We cloned the Saccharomyces kluyveri HIS3 homolog, k-HIS3, and made a partial deletion of the gene. The k-HIS3 gene complemented a HIS3 deletion in S. cerevisiae. The DNA sequences of the open reading frames (ORFs) of the HIS3 homologs are 70% identical at the DNA level and 83% identical at the deduced amino acid level. The ORF upstream of the k-HIS3 gene is related to the PET56 gene of S. cerevisiae found upstream of the HIS3 gene of S. cerevisiae. The ORF downstream from the k-HIS3 gene is not related to the DED1 gene found downstream of the HIS3 gene in S. cerevisiae. 相似文献
16.
Reviews the book, The saturated self: Dilemmas of identity in contemporary life by Kenneth J. Gergen (see record 1991-97621-000). There is, perhaps, no other concept as seminal for psychology as the self. For this reason alone, Kenneth Gergen's book represents an important contribution to our understanding of this influential concept. However, Gergen's vision is so broad, his arguments so compelling, and the implications so revolutionary, that the work defies confinement exclusively within the walls of academia. In essence, Gergen is articulating his vision of a postmodern world, and he lays an invitation squarely before the reader to come and partake. The conception of the self as private and autonomous is the focus of Gergen's postmodern challenge. In his chapter, "Social Saturation and the Populated Self," Gergen postulates that technological innovation in contemporary society has made possible a rapid proliferation of relationships. This he refers to as the "process of social saturation." Gergen's book constitutes a substantive contribution to psychology's on going understanding of the self. Copious examples are provided throughout, drawing on and extending scholarly debates. Also included are anecdotes and evidences from such far ranging domains as art, film, music, literature, and architecture. These not only clarify and reinforce his arguments, but also illustrate the scope and practicality of the position he espouses. Although readers may not embrace the gestalt of Gergen's vision of a postmodern culture, they are certain to find this book to be a provocative and rewarding read. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
17.
18.
Joshua Vaughan Joel Fortgang William Singhose Jeffrey Donnell Thomas Kurfess 《Mechatronics》2008,18(4):179-186
It is commonly accepted that hands-on experiences increase both learning and enjoyment during coursework. Mechatronics projects provide both interesting and relevant hands-on experiences for a wide range of topics including design processes, basic mechatronics concepts, technical communication, and working in a group environment. ME2110: Creative Decisions and Design at Georgia Tech integrates mechatronics and technical communication into a sophomore level mechanical design class. This paper describes the course in detail, highlighting the course goals and layout, tools provided to the students, industry involvement, and the main challenges of administering such a course. 相似文献
19.
20.
The present study evaluated the reliability and validity of the Triage Assessment Survey: Organizations (TAS:O), a 27-item, 5-point, Likert summated rating scale. One hundred and seventeen participants responded to the TAS:O after reading mild, moderate, marked and severe organizational crisis scenarios. The overall Cronbach's alpha and split-half reliability were both .93. Confirmatory factor analysis revealed three factors, supporting the hypothesis that the TAS:O is comprised of three distinct factors (i.e., Affect, Behavior, and Cognition). An analysis of variance provided evidence that the TAS:O has the capacity to distinguish among mild, moderate, marked, and severe crises. Because this research is the first to evaluate the TAS:O, further studies are needed to strengthen confidence in the psychometric properties of this scale. 相似文献