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   13393篇
  免费   570篇
  国内免费   50篇
电工技术   147篇
综合类   23篇
化学工业   2531篇
金属工艺   240篇
机械仪表   236篇
建筑科学   866篇
矿业工程   47篇
能源动力   370篇
轻工业   1049篇
水利工程   162篇
石油天然气   57篇
武器工业   1篇
无线电   915篇
一般工业技术   2444篇
冶金工业   2596篇
原子能技术   64篇
自动化技术   2265篇
  2023年   68篇
  2022年   125篇
  2021年   246篇
  2020年   178篇
  2019年   202篇
  2018年   274篇
  2017年   227篇
  2016年   340篇
  2015年   260篇
  2014年   414篇
  2013年   859篇
  2012年   672篇
  2011年   917篇
  2010年   702篇
  2009年   659篇
  2008年   765篇
  2007年   758篇
  2006年   622篇
  2005年   585篇
  2004年   508篇
  2003年   403篇
  2002年   474篇
  2001年   294篇
  2000年   277篇
  1999年   241篇
  1998年   254篇
  1997年   223篇
  1996年   188篇
  1995年   236篇
  1994年   190篇
  1993年   196篇
  1992年   164篇
  1991年   80篇
  1990年   140篇
  1989年   123篇
  1988年   112篇
  1987年   116篇
  1986年   85篇
  1985年   139篇
  1984年   129篇
  1983年   82篇
  1982年   68篇
  1981年   64篇
  1980年   48篇
  1979年   54篇
  1978年   42篇
  1977年   27篇
  1976年   35篇
  1974年   25篇
  1973年   22篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
71.
Examined the effect of lesions of the caudate nucleus or fimbria-fornix on the acquisition of 2 water maze tasks. In both tasks, 2 rubber balls with different visual patterns were used as cues. The correct cue was attached to a submerged rectangular platform and could be mounted by an animal to escape the water. The incorrect cue was attached to a thin round pedestal and could not be mounted. In a spatial version of the task, the correct cue was located in the same quadrant of the maze on all trials, whereas the visual pattern on the cue was varied from trial to trial. Lesions of the fornix, but not the caudate nucleus, impaired acquisition of this spatial task in relation to control animals. In a simultaneous visual discrimination version of the task, the correct cue on all trials was one with a specific visual pattern, and the spatial location of the correct cue was varied from trial to trial. Lesions of the caudate nucleus, but not the fornix, impaired acquisition of this visual discrimination task in relation to control animals. The double dissociation observed supports the hypothesis that the hippocampus and caudate nucleus are parts of systems that differ in the type of memory they mediate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
72.
73.
74.
An integrated energy supply and demand model for the state of Illinois is described. This equilibrium model is an important tool for integrating information from a variety of planning studies and data bases. A wide range of energy issues affecting diverse areas of the energy system, such as Illinois coal production under alternate oil price assumptions, renewable energy resource potential, and conservation options, can be analyzed by using the model.  相似文献   
75.
76.
Discusses ethical guidelines of the American Psychological Association regarding confidentiality in psychotherapy. Possible inconsistencies between these guidelines and privileged communication are explored. It is asserted that additional research is needed to determine the implications for psychotherapy of the ethical limitations to confidentiality and the legal restrictions on privileged communication. The relevance of moral philosophy to issues of confidentiality is considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
77.
South Africa’s Reconstruction and Development Programme set ambitious goals for providing basic services to all, including housing and electrification. More efficient use of energy has the potential to socially and politically support these goals, particularly when it is targeted at low-income communities lacking adequate energy services. This paper examines the economics of energy efficiency for the urban poor from the perspective of society, utilities and poor consumers, using five example programmes. While the five energy efficiency programmes generally have significant economic and environmental benefits from a social perspective, they may not be as attractive to utilities and consumers. Also examined are the policy options for overcoming the significant barriers to energy efficiency, and ways government can bridge the gap between what is good for society and what is good for the electricity industry.  相似文献   
78.
To eliminate potential "backward" priming effects, S. Glucksberg et al (see record 1986-29080-001) introduced a variant of the cross-modal lexical priming task in which subjects made lexical decisions to nonword targets that were modeled on a word related to either the contextually biased or unbiased sense of an ambiguous word. Lexical decisions to nonwords were longer than controls only when the nonword was related to the contextually biased sense of the ambiguous word, leading Glucksberg et al to conclude that context does constrain lexical access and that the multiple access pattern observed in previous studies was probably an artifact of backward priming. We did not find nonword interference when the nonword targets used by Glucksberg et al were preceded by semantically related ambiguous or unambiguous word primes. However, we did replicate their sentence context results when the ambiguous words were removed from the sentences. We conclude that the interference obtained by Glucksberg et al is due to postlexical judgments of the congruence of the sentence context and the target, not to context constraining lexical access. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
79.
Previous studies have shown that bizarre and common images produce equivalent levels of recall in unmixed-list designs. Using unmixed lists, we tested the view that bizarre images would be less susceptible than common images to common sources of interference. In all experiments, subjects imaged a list of either bizarre or common sentences and then performed some kind of interfering task before recalling the initial list of sentences. Experiment 1 showed that bizarre images were better accessed than common images after imaging an intervening list of common sentences. Also, components of common images tended to be better recalled than those of bizarre images after imaging an intervening list of bizarre sentences. Experiments 2a and 2b showed that interfering tasks consisting of studying lists of common concrete nouns did not differentially affect memory for bizarre and common images. In Experiment 3, labeling and imaging an interfering list of common pictures produced higher recall of bizarre images. Generally, bizarre images appeared to be less susceptible than common images to interference from certain types of common encodings. Importantly, the superior recall of bizarre images was always due to greater image (sentence) access, whereas higher recall of common images was associated with greater recovery of the image (sentence) constituents. Explanation of the precise pattern of results requires consideration of the distinctive properties of bizarre images. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
80.
Abstract.  While a large body of research exists on the development and implementation of software, organizations are increasingly acquiring enterprise software packages [e.g. enterprise resource planning (ERP) systems] instead of custom developing their own software applications. To be competitive in the marketplace, software package development firms must manage the three-pronged trade-off between cost, quality and functionality. Surprisingly, prior research has made little attempt to investigate the characteristics of packaged software that influence management information system (MIS) managers' likelihood of recommending purchase. As a result, both the criteria by which MIS managers evaluate prospective packaged systems and the attributes that lead to commercially competitive ERP software products are poorly understood. This paper examines this understudied issue through a conjoint study. We focus on ERP systems, which are among the largest and most complex packaged systems that are purchased by organizations. In a conjoint study, 1008 evaluation decisions based on hypothetical ERP software package profiles were completed by managers in 126 organizations. The study represents the first empirical investigation of the relative importance that managers ascribe to various factors that are believed to be important in evaluating packaged software. The results provide important insights for both organizations that acquire such systems and those that develop them. The results show that functionality, reliability, cost, ease of use and ease of customization are judged to be important criteria, while ease of implementation and vendor reputation were not found to be significant. Functionality and reliability were found to be the most heavily weighted factors. We conclude the paper with a detailed discussion of the results and their implications for software acquisition and development practice.  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