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   993篇
  免费   32篇
电工技术   4篇
综合类   6篇
化学工业   182篇
金属工艺   8篇
机械仪表   6篇
建筑科学   87篇
矿业工程   1篇
能源动力   10篇
轻工业   156篇
水利工程   20篇
石油天然气   4篇
无线电   34篇
一般工业技术   123篇
冶金工业   289篇
原子能技术   1篇
自动化技术   94篇
  2024年   5篇
  2023年   8篇
  2022年   18篇
  2021年   32篇
  2020年   14篇
  2019年   18篇
  2018年   31篇
  2017年   22篇
  2016年   26篇
  2015年   10篇
  2014年   18篇
  2013年   50篇
  2012年   41篇
  2011年   89篇
  2010年   59篇
  2009年   54篇
  2008年   68篇
  2007年   63篇
  2006年   55篇
  2005年   56篇
  2004年   47篇
  2003年   43篇
  2002年   42篇
  2001年   18篇
  2000年   14篇
  1999年   10篇
  1998年   14篇
  1997年   15篇
  1996年   7篇
  1995年   8篇
  1994年   8篇
  1993年   7篇
  1992年   8篇
  1991年   1篇
  1990年   5篇
  1989年   6篇
  1988年   2篇
  1987年   4篇
  1986年   3篇
  1985年   4篇
  1984年   2篇
  1983年   3篇
  1982年   3篇
  1981年   2篇
  1980年   1篇
  1979年   3篇
  1978年   4篇
  1977年   3篇
  1972年   1篇
排序方式: 共有1025条查询结果,搜索用时 15 毫秒
11.
12.
Directly linking air quality and watershed models could provide an effective method for estimating spatially-explicit inputs of atmospheric contaminants to watershed biogeochemical models. However, to adequately link air and watershed models for wet deposition estimates, each model’s temporal and spatial representation of precipitation needs to be consistent. We explore how precipitation implemented within the Community Multi-Scale Air Quality Model (CMAQ) model algorithms, and multiple spatially-explicit precipitation datasets that could be used to improve the CMAQ model deposition estimates, links with the standard precipitation sources used to calibrate watershed models (i.e., rain gage data) via modeled water fluxes. Simulations are run using a grid-based watershed mercury model (GBMM) in two watersheds. Modeled monthly runoff suggests that multiple resolution Parameter-elevations Regressions on Independent Slopes Model (PRISM) and National Multi-sensor Precipitation Analysis Stage IV (NPA) data generate similar monthly runoff estimates, with comparable or greater accuracy when evaluated against stream gage data than that produced by the base rain gage data. However, across longer time periods, simulated water balances using 36 km Pennsylvania State University/National Center for Atmospheric Research mesoscale model (MM5) data are similar to that of base data. The investigation also examines the implications our results, providing suggestions for linking air quality and watershed fate and transport models.  相似文献   
13.
14.
15.
The authors tested a model of the relations among adolescents' perceptions of parents', teachers', and classmates' support for, valuing of, and beliefs about their competence in math/science; adolescents' own academic self-perceptions concerning math/science; and their academic performance. The sample included 378 middle school students; 65% were Latino, and 21% were European American. Reflected appraisals of adults' beliefs concerning both the importance of and students' competence in math/science, as well as perceived support, predicted students' own self-perceived importance, competence, scholastic behavior, and performance in these courses. Latino students reported lower mean levels of perceived competence than did European American students (controlling for maternal education). Findings have important implications for understanding achievement socialization in ethnically diverse populations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
16.
Four studies examined associations between E. L. Deci and R. M. Ryan's (1985, 2000) construct of autonomy, responses to relationship disagreements, and dissatisfaction after conflict. In Study 1, diary data showed that trait autonomy predicted relationship autonomy, which in turn predicted relative satisfaction after disagreements. In Study 2, trait autonomy predicted relationship autonomy, which was associated with less defensive and more understanding responses to conflict. Studies 3 and 4 examined whether one's partner's relationship autonomy uniquely predicted reported and observed behavior during conflict. Autonomous reasons for being in the relationship (of both self and partner) predicted both reported and observed responses to conflict and feelings of satisfaction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
17.
Reports an error in "Prospective Relations Between Bulimic Pathology, Depression, and Substance Abuse: Unpacking Comorbidity in Adolescent Girls" by Eric Stice, Emily M. Burton and Heather Shaw (Journal of Consulting and Clinical Psychology, 2004[Feb], Vol 72[1], 62-71). The findings of Leon, Fulkerson, Perry, Keel, and Klump ("Three to four year prospective evaluation of personality and behavioral risk factors for later disordered eating in adolescent girls and boys," Journal of Youth and Adolescence, 1999, Vol. 28, No. 2, pp. 181-196), cited on page 62, were incorrectly reported. Leon et al. (1999) found that the latent variable of negative affect/attitudes determined at study entrance significantly correlated with final year eating disorder risk score when conducted with the full sample and when removing Time 1 high eating disorder risk subjects. This latent variable consisted of the GBI Depression, MPQ Negative Emotionality, EDI Ineffectiveness, EDI Interoceptive Awareness, and EDI Body Dissatisfaction scales. A subsequent univariate analysis of Time 1 Negative Emotionality scale score on Time 3 eating disorder risk, adjusting for initial eating disorder risk score, showed a nonsignificant effect size (Stice, E. [2002]. Risk and maintenance factors for eating pathology: A meta-analytic review. Psychological Bulletin, 128, 825-848). (The following abstract of the original article appeared in record 2004-10364-006.) To elucidate the processes that contribute to the comorbidity between bulimic pathology, depression, and substance abuse, the authors tested the temporal relations between these disturbances with prospective data from adolescent girls (N = 496). Multivariate analyses indicated that depressive symptoms predicted onset of bulimic pathology but not of substance abuse, bulimic symptoms predicted onset of depression but not of substance abuse, and substance abuse symptoms predicted onset of depression but not of bulimic pathology. Results suggest that the comorbidity arises because certain disorders are risk factors for the other disorders. Findings also provide support for select etiologic theories and further establish the clinical significance of these conditions by showing that they increase risk for onset of other psychiatric disturbances. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
18.
Two expanded models (i.e., mediated and moderated) of the theory of work adjustment (TWA; R. V. Dawis, G. England, & L. H. Lofquist, 1964; R. V. Dawis & L. H. Lofquist, 1984) were tested for their capacity to explain the job satisfaction of a sample of lesbian, gay, and bisexual employees (N=397). Consistent with cultural critiques of the TWA, person-organization fit perceptions were tested as the mediator of the relationship between heterosexism and job satisfaction in one set of hypotheses, and experiences with informal heterosexism were tested as a moderator in the relationship between person-organization fit perceptions and job satisfaction in a separate set of hypotheses. The mediated model but not the moderated model was supported. Results were confirmed by a cross-validation sample. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
19.
As a method for counseling children, play therapy continues to demonstrate effectiveness through research and to be included in mental health training programs throughout the country. However, like other counseling interventions, capturing the essence of the therapeutic environment is complex and dependent on individual perspectives and experiences. In this article, two case studies are presented to demonstrate the use of quantitative and qualitative measures in comparing the behavioral changes as rated by caregivers on the Child Behavior Checklist (CBCL) and play themes observed by play therapists over a 6-week period. For both children in the study, behaviors and themes were related. As the children made changes in their play themes over the 6-week period, they also made changes in their behaviors at home. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
20.
We present a novel approach to face recognition by constructing facial identity structures across views and over time, referred to as identity surfaces, in a Kernel Discriminant Analysis (KDA) feature space. This approach is aimed at addressing three challenging problems in face recognition: modelling faces across multiple views, extracting non-linear discriminatory features, and recognising faces over time. First, a multi-view face model is designed which can be automatically fitted to face images and sequences to extract the normalised facial texture patterns. This model is capable of dealing with faces with large pose variation. Second, KDA is developed to compute the most significant non-linear basis vectors with the intention of maximising the between-class variance and minimising the within-class variance. We applied KDA to the problem of multi-view face recognition, and a significant improvement has been achieved in reliability and accuracy. Third, identity surfaces are constructed in a pose-parameterised discriminatory feature space. Dynamic face recognition is then performed by matching the object trajectory computed from a video input and model trajectories constructed on the identity surfaces. These two types of trajectories encode the spatio-temporal dynamics of moving faces.  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