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   18784篇
  免费   543篇
  国内免费   20篇
电工技术   245篇
综合类   9篇
化学工业   3720篇
金属工艺   288篇
机械仪表   323篇
建筑科学   1136篇
矿业工程   111篇
能源动力   516篇
轻工业   1464篇
水利工程   162篇
石油天然气   195篇
武器工业   1篇
无线电   1117篇
一般工业技术   3010篇
冶金工业   4347篇
原子能技术   170篇
自动化技术   2533篇
  2022年   127篇
  2021年   228篇
  2020年   175篇
  2019年   228篇
  2018年   275篇
  2017年   268篇
  2016年   332篇
  2015年   251篇
  2014年   398篇
  2013年   1149篇
  2012年   684篇
  2011年   900篇
  2010年   700篇
  2009年   692篇
  2008年   889篇
  2007年   908篇
  2006年   710篇
  2005年   745篇
  2004年   576篇
  2003年   582篇
  2002年   530篇
  2001年   344篇
  2000年   311篇
  1999年   319篇
  1998年   359篇
  1997年   334篇
  1996年   320篇
  1995年   347篇
  1994年   279篇
  1993年   317篇
  1992年   290篇
  1991年   176篇
  1990年   244篇
  1989年   290篇
  1988年   212篇
  1987年   221篇
  1986年   220篇
  1985年   278篇
  1984年   264篇
  1983年   230篇
  1982年   226篇
  1981年   217篇
  1980年   174篇
  1979年   191篇
  1978年   184篇
  1977年   194篇
  1976年   168篇
  1975年   186篇
  1974年   169篇
  1973年   136篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
141.
Investigators have concluded that excessive numbers of errors in test administration and scoring are routinely committed by both graduate students and practicing psychologists. Developing new methods for teaching assessment is viewed as a major means of improving competency. Unlike previous studies, this investigation examined the impact of both lecture and laboratory interventions designed to improve graduate student performance in assessment. Interventions consisted of weekly lecture quizzes and a variety of laboratory interventions. The results suggest that the interventions used can significantly improve students' lecture and laboratory performance when compared with controls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
142.
Examined features of an intergroup context that can affect people's preferred responses to a situation of social injustice. 90 undergraduates were randomly assigned to 1 of 3 conditions of group permeability (open, token, or closed) and 1 of 2 conditions of social identity salience (not salient or salient). It was predicted on the basis of social identity theory that individualistic responses would be preferred to a collective response when group boundaries were more open but not when they were closed. It was also expected that under conditions of group impermeability, collective behavior would be preferred to a greater extent by individuals for whom social identity was salient than by individuals for whom it was not salient. The results, which generally supported these hypotheses, are discussed in terms of social psychological theories of intergroup relations and also with regard to their potential practical implications. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
143.
Two experiments addressed the issue of whether endorsement of a position by a numerical majority or a minority leads to greater scrutiny of the information presented in a persuasive message. In Exp 1, a counterattitudinal position was endorsed by a majority or a minority and was supported by strong or weak arguments. Argument quality had a larger impact on attitudes with majority than with minority endorsement. In Exp 2, a proattitudinal or a counterattitudinal message was endorsed by a majority or a minority and was supported by strong or weak arguments. When the source and message position were unexpected (i.e., majority-counter and minority-pro messages), argument quality had a larger impact on attitudes than when the source and message position were expected (i.e., majority-pro and minority-counter messages). Thus, either majority or minority endorsement can enhance message scrutiny if the source-position pairing is surprising. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
144.
Investigated burden experienced by 60 spouses and 71 parents who served as primary caregivers to individuals with traumatic brain injury (BI). Burden levels, as assessed by the Questionnaire on Resources and Stress (QRS-SF), were compared for spouses and parents. Both parents and spouses exhibited high levels of burden. Relative to spouses, parents reported significantly greater burden related to lifespan care. Spouses reported significantly less personal reward than did parents. The presence of social aggression and cognitive disability in the individual with BI was found to have a greater association with subjective burden of caregivers than was the presence of physical disability or injury severity. Results of previous studies with QRS-SF scores show that the responsibility assumed by spouses and parents of persons with BI was as great as that experienced by families of people with severe chronic physical disabilities. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
145.
Reports the death of L. E. Tyler, who served as the 81st president of the American Psychological Association. Her view was that the purpose of counseling was to encourage natural, life-long developmental processes as distinguished from psychotherapy, which she felt was more appropriate to clinicians' dealings with disturbances of personality. It is noted that Tyler's concern for clarifying the human puzzle of personal change moved, over time, from individual differences to individuality and from a psychometric perspective to a systems–ecological view of real-world choices. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
146.
In contrast to D. C. Zuroff, M. Mongrain, and D. A. Santor (2004), the current authors find the promissory note of dependency-sociotropy (DEP-SOC) and self-criticism-autonomy (SC-AUT) as a model of risk for depression to be in default. The authors propose reorganizing what has been cast as unitary effort into 3 distinct endeavors: a psychoanalytic clinical theory, development of a refined empirical model of risk for clinical depression, and research examining the effects of DEP-SOC and SC-AUT on interpersonal relationships in nonclinical samples. The authors identify some issues that need to be accommodated regardless of whether the assessment of Zuroff et al. (2004) or their own is accepted. DEP-SOC and SC-AUT are best construed as correlated, continuous dimensions. Future work also needs to accommodate depression as chronic recurrent condition, advances in developmental psychopathology, and more stringent criteria for positing a risk factor for clinical disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
147.
In this paper we consider two results motivated by Livsic's well-known theorem that, for a hyperbolic system, a Hölder continuous function is determined, up to a coboundary, by its values around closed orbits. The first result relates to negative values around orbits and the second result to values for finitely many orbits. We also present some new results on maximizing measures and the boundary of the unit ball in the stable norm for a surface.  相似文献   
148.
Unconrolled agglomeration of particles and adhesion of the particulate mass to wall surfaces are common severe problems in many drying operations. This paper reviews the mechanisms of interparticle and particle-surface attraction as well as the theory and the existing tests for characterising powders in terms of internal strength, wall friction and adhesion. The usefulness of the information obtained from these tests in dryer design and operation is critically reviewed. The importance of powder stickiness in various types of dryers is discussed and established methods of combating the problem are presented Recommendations an made for further research in the area of powder cohesion and adhesion.  相似文献   
149.
Dielectric relaxation measurements are reported over a frequency range from 10−1 to 109 Hz as a function of exposure time for an epoxy resin-carbon fibre composite, ageing at 60 °C in water. Investigation of the nature of the dipole relaxation of the water molecules, indicates the nature of their interaction with the polymer matrix. Analysis of the dielectric relaxation spectra allow identification of processes that can be attributed to ‘free’ and ‘bonded’ water, water in micro-cracking, located in carbon fibre disbonds and plasticizing the polymer matrix. Identification of the various types of location in which water exists was aided by use of the Ng factor from the Kirkwood-Frölich equation, which describes the constraints on free dipole ration nature imposed by the environment in which it is located. These data indicate the power of the dielectric technique for quantitative analysis of water ingress into epoxy composites.  相似文献   
150.
We conducted two experiments to examine the relations among characteristics of how Type A individuals strive for achievement, including goal achievement, self-evaluation, and psychological distress. We evaluated these relations as subjects performed two sequential general information tests. Experiment 1 indicated that achievement striving associated with the Type A behavior pattern is characterized by a tendency to set personal goals in excess of performance and is associated with a low probability of achieving goals. The results of Experiment 2 indicated that the achievement strategy Type A individuals adopted was associated with low self-evaluation of their actual performance. Furthermore, a pre- and postexperiment self-report questionnaire of psychological state suggested that failure to achieve personal goals was related to increased psychological distress. The results of our study suggest that unrealistically high performance standards and failure to achieve personal goals may be a mechanism that triggers the negative psychological states and performance dissatisfaction associated with the Type A behavior pattern. Our study also supports theoretical conceptualizations that excessive achievement striving can act as a potential motivational mechanism. (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