首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   658篇
  免费   32篇
电工技术   3篇
化学工业   165篇
金属工艺   4篇
机械仪表   3篇
建筑科学   21篇
矿业工程   1篇
能源动力   11篇
轻工业   98篇
水利工程   5篇
无线电   50篇
一般工业技术   93篇
冶金工业   154篇
原子能技术   6篇
自动化技术   76篇
  2022年   13篇
  2021年   12篇
  2020年   9篇
  2019年   15篇
  2018年   15篇
  2017年   13篇
  2016年   15篇
  2015年   11篇
  2014年   18篇
  2013年   41篇
  2012年   30篇
  2011年   44篇
  2010年   31篇
  2009年   29篇
  2008年   23篇
  2007年   39篇
  2006年   18篇
  2005年   28篇
  2004年   21篇
  2003年   16篇
  2002年   19篇
  2001年   7篇
  2000年   8篇
  1999年   10篇
  1998年   32篇
  1997年   15篇
  1996年   20篇
  1995年   11篇
  1994年   8篇
  1993年   11篇
  1992年   7篇
  1990年   3篇
  1989年   3篇
  1988年   3篇
  1987年   8篇
  1986年   7篇
  1985年   2篇
  1984年   6篇
  1983年   3篇
  1982年   3篇
  1981年   7篇
  1980年   3篇
  1979年   11篇
  1978年   5篇
  1977年   9篇
  1976年   8篇
  1975年   6篇
  1973年   2篇
  1972年   2篇
  1967年   2篇
排序方式: 共有690条查询结果,搜索用时 0 毫秒
71.
This paper presents a formal semantics for the Taverna 2 scientific workflow system. Taverna 2 is a successor to Taverna, an open-source workflow system broadly adopted within the e-science community worldwide. The new version improves upon the existing model in two main ways: (i) by adding support for data pipelining, which in turns enables input streams of indefinite length to be processed efficiently; and (ii) by providing new extensibility points that make it possible to add new operators to the workflow model. Consistent with previous work by some of the authors, we use trace semantics to describe the effect of workflow computations, and we show how they can be used to describe the new features in the Taverna 2 model.  相似文献   
72.
This article presents results from a survey of ethical beliefs about practice dilemmas unique to clinical work with children and adolescents. Survey data suggest that identical practices are not always ethically equivalent, particularly when the developmental status of the client is varied. The survey also reveals widespread ambiguity about what constitutes ethical practice, as manifested both in individual uncertainty and in the absence of group consensus. Ethically guided clinical practice is presented as a far more complex undertaking than adherence to a single set of professional standards. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
73.
GaN microcrystallites have been prepared by a solvothermal process. The influence of the synthesis temperature on the crystallinity of the resulting GaN has been studied on three samples, prepared at 400, 600 and 800°C in the same pressure conditions (150 MPa) and duration (6 h). The resulting powders were characterized by several techniques: X-ray diffraction to evaluate the reaction rate, scanning electron microscopy (SEM) to determine the morphology and size of the microcrystallites and photoluminescence to evaluate the quality of the powders.  相似文献   
74.
The purpose of this study was to verify the validity of a French version of the Positive and Negative Perfectionism Scale developed by L. A. Terry-Short (1995). This instrument measures the type as well as the level of perfectionism in adolescents. The instrument was first administered to 734 7th, 9th, and 11th grade students. Four weeks later, 596 Ss were invited to answer the questionnaire once more. The factorial structure, temporal stability and internal consistency of each subscales of the translated version of the instrument correspond to those of the original version. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
75.
Because errors in recall are an important contributor to assessments of children's credibility as witnesses, the author explored children's errors when recounting details of trauma injuries that resulted in hospital Emergency Room treatment. 37 preschool aged children (aged 2–5 yrs) and 11 9-yr-olds (comparison Ss) were recruited in the emergency room and interviewed at home both within a few days of the injury and after 6 mo. Adult witnesses were also interviewed to corroborate children's accounts. Although 2-yr-old Ss made more errors than did older children, the information provided was accurate, even 6 mo after their injuries. The errors were not random; rather, information that was likely to be important in real-world cases was retained quite accurately, while some other categories of information (e.g., the 1st person to respond to their injury) were more error-prone. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
76.
This study examined drinking to cope with distress and drinking behavior in a baseline sample of 412 unipolar depressed patients assessed 4 times over a 10-year period. Baseline drinking to cope operated prospectively as a risk factor for more alcohol consumption at 1-, 4, and 10-year follow-ups and for more drinking problems at 1- and 4-year follow-ups. Findings elucidate a key mechanism in this process by showing that drinking to cope strengthened the link between depressive symptoms and drinking behavior. Individuals who had a stronger propensity to drink to cope at baseline showed a stronger connection between depressive symptoms and both alcohol consumption and drinking problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
77.
Single-walled carbon nanotubes (CNTs) convert absorbed near infrared (NIR) light into heat. The use of CNTs in the NIR-mediated photothermal ablation of tumor cells is attractive because the penetration of NIR light through normal tissues is optimal and the side effects are minimal. Targeted thermal ablation with minimal collateral damage can be achieved by using CNTs attached to tumor-specific monoclonal antibodies (MAbs). However, the role that the cellular internalization of CNTs plays in the subsequent sensitivity of the target cells to NIR-mediated photothermal ablation remains undefined. To address this issue, we used CNTs covalently coupled to an anti-Her2 or a control MAb and tested their ability to bind, internalize, and photothermally ablate Her2(+) but not Her2(-) breast cancer cell lines. Using flow cytometry, immunofluorescence, and confocal Raman microscopy, we observed the gradual time-dependent receptor-mediated endocytosis of anti-Her2-CNTs whereas a control MAb-CNT conjugate did not bind to the cells. Most importantly, the Her2(+) cells that internalized the MAb-CNTs were more sensitive to NIR-mediated photothermal damage than cells that could bind to, but not internalize the MAb-CNTs. These results suggest that both the targeting and internalization of MAb-CNTs might result in the most effective thermal ablation of tumor cells following their exposure to NIR light.  相似文献   
78.
79.
Despite the involvement of several serine hydrolases (SHs) in the metabolism of xenobiotics such as dibutyl phthalate (DBP), no study has focused on mapping this enzyme class in zebrafish, a model organism frequently used in ecotoxicology. Here, we survey and identify active SHs in zebrafish larvae and search for biological markers of SH type after exposure to DBP. Zebrafish were exposed to 0, 5, and 100 µg/L DBP from 4 to 120 h post-fertilization. A significant decrease in vitellogenin expression level of about 2-fold compared to the control was found in larvae exposed to 100 µg/L DBP for 120 h. The first comprehensive profiling of active SHs in zebrafish proteome was achieved with an activity-based protein profiling (ABPP) approach. Among 49 SHs identified with high confidence, one was the carboxypeptidase ctsa overexpressed in larvae exposed to 100 µg/L DBP for 120 h. To the best of our knowledge, this is the first time that a carboxypeptidase has been identified as deregulated following exposure to DBP. The overall results indicate that targeted proteomics approaches, such as ABPP, can, therefore, be an asset for understanding the mechanism of action related to xenobiotics in ecotoxicology.  相似文献   
80.
Assessed the impact of school-based social competence training on skills, social adjustment, and self-reported substance use of 282 6th and 7th graders. Training emphasized broad-based competence promotion in conjunction with domain-specific application to substance abuse prevention. The 20-session program comprised 6 units: stress management, self-esteem, problem solving, substances and health information, assertiveness, and social networks. Findings indicated positive training effects on Ss' skills in handling interpersonal problems and coping with anxiety. Teacher ratings revealed improvements in Ss' constructive conflict resolution with peers, impulse control, and popularity. Self-report ratings indicated gains in problem-solving efficacy. Results suggest some preventive impact on self-reported substance use intentions and excessive alcohol use. In general, the program was found to be beneficial for both inner-city and suburban students. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号