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   1664篇
  免费   14篇
电工技术   3篇
化学工业   227篇
金属工艺   12篇
机械仪表   21篇
建筑科学   63篇
矿业工程   3篇
能源动力   13篇
轻工业   177篇
水利工程   21篇
石油天然气   3篇
无线电   35篇
一般工业技术   219篇
冶金工业   683篇
原子能技术   7篇
自动化技术   191篇
  2022年   16篇
  2021年   24篇
  2020年   16篇
  2019年   14篇
  2018年   12篇
  2017年   10篇
  2016年   21篇
  2014年   25篇
  2013年   76篇
  2012年   48篇
  2011年   72篇
  2010年   48篇
  2009年   58篇
  2008年   59篇
  2007年   68篇
  2006年   79篇
  2005年   67篇
  2004年   59篇
  2003年   68篇
  2002年   55篇
  2001年   32篇
  2000年   23篇
  1999年   25篇
  1998年   50篇
  1997年   36篇
  1996年   46篇
  1995年   22篇
  1994年   28篇
  1993年   31篇
  1992年   25篇
  1991年   10篇
  1990年   28篇
  1989年   30篇
  1988年   23篇
  1987年   26篇
  1986年   27篇
  1985年   24篇
  1984年   38篇
  1983年   40篇
  1982年   16篇
  1981年   28篇
  1980年   18篇
  1979年   18篇
  1978年   24篇
  1977年   10篇
  1976年   14篇
  1975年   19篇
  1974年   14篇
  1973年   10篇
  1971年   9篇
排序方式: 共有1678条查询结果,搜索用时 15 毫秒
91.
Studied the influence of sex-role identity on the career involvement of 70 25–45 yr old professional women who were members of dual-career families that included young children. As predicted, Ss categorized as masculine on the Personality Research Form, ANDRO scales, were employed a significantly greater proportion of time after having children than Ss categorized as feminine. In addition, the more equalitarian the marriage, the more likely S was to continue her career participation after having children. Regardless of employment status and the equalitarianism of the marriage, Ss reported that they spent significantly more time alone with their children than their husbands did. Implications for various counseling situations are noted. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
92.
36 3-mo-old infants interacted with their mothers under conditions in which they could see and hear their mothers (correlated auditory plus visual information: A?+?V), see but not hear their mothers (V), and hear but not see their mothers (A); the latter 2 conditions are termed perceptual paradox. The interactions were videotaped, and the Ss' behavior was judged by naive observers who used a subjective 7-point rating scale of infant affect. For 2 groups of Ss, 3 1-min presentations of the A?+?V condition were alternated with 3 1-min presentations of either A (Group 1) or V (Group 2) conditions. In both groups, Ss were judged as being more distressed during unimodal presentations than during bimodal presentations. In a 3rd group, unimodal (A) presentations were alternated with unimodal (V) presentations. Ss in this group were significantly more distressed when they could hear but not see their mothers than when they could see but not hear their mothers. Results demonstrate the suitability of global subjective ratings of affective state in studies of infant perception. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
93.
Conducted 1- and 3-yr follow-ups of 685 alcoholic patients treated with aversive conditioning during a 2-wk inpatient program followed by periodic single-day reinforcement sessions. 63% of the Ss reported continuous abstinence for 1 yr, and 31% were still abstinent after 3 yrs. Results indicate that Ss were at highest risk for relapse 3–4 mo after treatment and that continued aftercare was an important component of successful treatment. Outcomes were better for older than younger males and for married than unmarried males. Few significant differences in outcomes for males and females were apparent, and outcome was also unrelated to prior treatment history, education, or occupation. Findings support the use of aversive techniques in the treatment of alcoholism. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
94.
95.
Three experiments with 48 cats investigated memory for CR as a function of proactive inhibition. The proactive operation was the preexposure to quasi-random presentations of the potential CS and UCS. The possible CSs were light and tone, and the UCSs were brief mild shocks to either the right or left paw, which produced a brisk leg jerk. In Exp I, all possible combinations of CS and UCS components of the eventual CR were present in the preexposure period for one or another group as in the traditional interference paradigms of human paired-associate memory research. Exp II demonstrated that the decline cannot be attributed to a strategy type of interpretation that asserts that when the retention–extinction situation occurs, Ss "backward scan" and judge themselves to be once again in the preexposure period. Performance immediately after reaching the conditioning criterion did not differ between the controls that experienced no preexposure and the experimentals, but it did so after the 10-wk retention interval. Exp III investigated the role of context in the memory deficits by maintaining the same context in the preexposure, conditioning, and memory test situations or giving the preexposure experience in an environment different from the other 2 situations. Context change greatly reduced but did not eliminate the proactive inhibition. It is concluded that the CR is readily forgotten given appropriate interference and does not differ from other kinds of learning in this respect. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
96.
Easy access to large information collections is of great importance in many aspects of everyday life. However, limitations in information and communication technologies have so far prevented the average person from taking much advantage of existing resources. Historical documentaries held by national archives constitute some of the most precious yet least accessible cultural information. The ECHO project has facilitated accessibility to this type of precious information by developing a digital library (DL) service for historical films belonging to large national audiovisual archives.  相似文献   
97.
98.
We give a complexity analysis of a variety of languages across the spectrum of the CLP scheme. By varying the logic and memory management, the role of the constraints and the role of the logic can be measured. The analysis clarifies the relation between linear/integer programming and constraint logic programming. We also determine how the power of constraints can easily lead to undecidable queries in Datalog languages with constraints. This work is motivated in large part by the problems of efficient implementation of CLP languages and the concomitant need for low level constraint languages.Research partially supported by PSC-CUNY Grant 669287.Research partially supported by NSF Grant IRI-8902511.  相似文献   
99.
ABSTRACT

In April 2006, Alliance Library System and Online Programming for All Libraries partnered to start the Second Life Library 2.0 in the online world Second Life and in August 2006 purchased an island on the Teen grid of Teen Second Life. Second Life is a virtual world, a descendant of multiplayer online games. Educational institutions have recently been drawn into Second Life's robust economy and vibrant cultural life. The Second Life Library 2.0 works with librarians from around the world and with other educational partners such as TechSoup, WorldBridges, and the New Media Consortium. Second Life Library 2.0 provides “traditional” library services such as ready reference, book discussions, and search assistance, but, at heart, it explores what it means to be a virtual library in a virtual world.  相似文献   
100.
We describe how the functional database programming language PFL is extended with an active component without compromising either its declarative semantics or its syntax. We give a formal specification of the active component using PFL itself, including event specification and detection, parameter-binding, reaction scheduling and abort handling. We describe how a user-specified function can be cast as a primitive event, and discuss the expressiveness of events and the optimisation of event detection.  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