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   626篇
  免费   43篇
电工技术   6篇
化学工业   160篇
金属工艺   5篇
机械仪表   14篇
建筑科学   28篇
能源动力   17篇
轻工业   93篇
水利工程   5篇
石油天然气   4篇
无线电   47篇
一般工业技术   102篇
冶金工业   87篇
原子能技术   6篇
自动化技术   95篇
  2024年   3篇
  2023年   13篇
  2022年   28篇
  2021年   46篇
  2020年   20篇
  2019年   23篇
  2018年   30篇
  2017年   22篇
  2016年   23篇
  2015年   16篇
  2014年   30篇
  2013年   37篇
  2012年   27篇
  2011年   44篇
  2010年   41篇
  2009年   31篇
  2008年   21篇
  2007年   28篇
  2006年   21篇
  2005年   16篇
  2004年   13篇
  2003年   11篇
  2002年   8篇
  2001年   7篇
  2000年   7篇
  1999年   9篇
  1998年   21篇
  1997年   9篇
  1996年   10篇
  1995年   4篇
  1994年   8篇
  1993年   5篇
  1992年   1篇
  1991年   2篇
  1990年   4篇
  1989年   1篇
  1987年   2篇
  1986年   5篇
  1985年   5篇
  1984年   6篇
  1983年   3篇
  1982年   2篇
  1980年   2篇
  1979年   1篇
  1971年   1篇
  1970年   2篇
排序方式: 共有669条查询结果,搜索用时 15 毫秒
41.
42.
Typically developing children understand and predict others' behavior by extracting and processing relevant information such as the logic of their actions within the situational constraints and the intentions conveyed by their gaze direction and emotional expressions. Children with autism have difficulties understanding and predicting others' actions. With the use of eye tracking and behavioral measures, we investigated action understanding mechanisms used by 18 children with autism and a well-matched group of 18 typically developing children. Results showed that children with autism (a) consider situational constraints in order to understand the logic of an agent's action and (b) show typical usage of the agent's emotional expressions to infer his or her intentions. We found (c) subtle atypicalities in the way children with autism respond to an agent's direct gaze and (d) marked impairments in their ability to attend to and interpret referential cues such as a head turn for understanding an agent's intentions. (PsycINFO Database Record (c) 2011 APA, all rights reserved)  相似文献   
43.
An approach aimed to the quantitative assessment of the risk caused by escalation scenarios triggered by fire was developed. Simplified models for the estimation of the vessel time to failure (ttf) with respect to the radiation intensity on the vessel shell were obtained using a multi-level approach to the analysis of vessel wall failure under different fire conditions. Each vessel “time to failure” calculated by this approach for the specific fire scenario of concern was compared to a reference time required for effective mitigation actions and related to the escalation probability. The failure probability of each vessel was correlated to the probability of scenarios involving multiple vessel failure as a consequence of the primary fire, thus allowing a comprehensive assessment of domino scenarios triggered by fire. The application of the methodology to the analysis of several case-studies allowed the estimation of the quantitative contribution of escalation events triggered by fire to the overall individual and societal risk indexes.  相似文献   
44.
45.
46.
Phenolic compounds in Sicilian wines were directly detected using an HPLC with a PDA detector coupled on-line with a MS system equipped with Electrospray Ionisation (ESI) source operated in the negative-ion mode and a quadrupole mass analyzer. In this work, MS spectra were recorded at different voltage, to obtain structural elucidations in addition to molecular mass informations. The different response of the compounds identified has been also evaluated. MS characteristics of cis- and trans-piceid were determined on the basis of the response obtained with the ESI interface.  相似文献   
47.
48.
The effect of carbonate and/or lignosulfonate on the hydration of C3S alone and in the presence of C3A has been examined by DTG and TG curves and by zeta potential measurements. The combined addition of sodium carbonate and lignosulfonate strongly retards C3A hydration. However by mixing 20 % C3A with C3S the retarding effect is significantly lower. On the other hand the early C3A hydration is completely blocked by sodium carbonate and lignosulfonate simultaneously added. It seems that the fluidifying effect of the combined addition of those admixtures could be ascribed to both the dispersing action and the completely blocking effect on the early C3A hydration.  相似文献   
49.
We consider the classical algebra of observables that are diagonal in a given orthonormal basis, and define a complete decoherence process as a completely positive map that asymptotically converts any quantum observable into a diagonal one, while preserving the elements of the classical algebra. For quantum systems in dimension two and three any decoherence process can be undone by collecting classical information from the environment and using such an information to restore the initial system state. As a relevant example, we illustrate the quantum eraser of Scully et al. [Nature 351, 111 (1991)] as an example of environment-assisted correction, and present the generalization of the eraser setup for d-dimensional systems. Presented at the 38th Symposium on Mathematical Physics “Quantum Entanglement & Geometry”, Toruń, June 4–7, 2006.  相似文献   
50.
There is growing interest in complicated grief reactions as a possible new diagnostic category for inclusion in the Diagnostic and Statistical Manual of Mental Disorders. However, no research has yet shown that complicated grief has incremental validity (i.e., predicts unique variance in functioning). The authors addressed this issue in 2 studies by comparing grief, depression, and posttraumatic stress disorder (PTSD) symptoms with different measures of functioning (interviewer ratings, friend ratings, self-report, and autonomic arousal). The 1st study (N = 73) used longitudinal data collected at 4 and 18 months postloss, and the 2nd study (N = 447) used cross-sectional data collected 2.5-3.5 years postloss. With depression and PTSD controlled, grief emerged as a unique predictor of functioning, both cross-sectionally and prospectively. The findings provide convergent support for the incremental validity of complicated grief as an independent marker of bereavement-related psychopathology. (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