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   452篇
  免费   27篇
电工技术   8篇
化学工业   152篇
金属工艺   5篇
机械仪表   3篇
建筑科学   2篇
能源动力   5篇
轻工业   105篇
水利工程   1篇
石油天然气   1篇
无线电   59篇
一般工业技术   52篇
冶金工业   48篇
原子能技术   6篇
自动化技术   32篇
  2023年   4篇
  2022年   27篇
  2021年   24篇
  2020年   12篇
  2019年   19篇
  2018年   11篇
  2017年   14篇
  2016年   10篇
  2015年   17篇
  2014年   19篇
  2013年   27篇
  2012年   18篇
  2011年   18篇
  2010年   14篇
  2009年   27篇
  2008年   17篇
  2007年   20篇
  2006年   18篇
  2005年   14篇
  2004年   14篇
  2003年   10篇
  2002年   16篇
  2001年   14篇
  2000年   7篇
  1999年   2篇
  1998年   10篇
  1997年   13篇
  1996年   14篇
  1995年   8篇
  1994年   10篇
  1993年   8篇
  1992年   4篇
  1991年   4篇
  1989年   1篇
  1988年   1篇
  1986年   1篇
  1983年   2篇
  1980年   2篇
  1977年   1篇
  1976年   2篇
  1975年   1篇
  1972年   2篇
  1968年   2篇
排序方式: 共有479条查询结果,搜索用时 0 毫秒
31.
32.
In this report, we conducted a secondary analysis of the Treatment of SSRI-Resistant Depression in Adolescents (TORDIA) study to explore the impact of specific cognitive–behavioral therapy (CBT) treatment components on outcome. In TORDIA, 334 youths (ages 12 to 18 years) with major depressive disorder who had failed to respond to an adequate course of selective serotonin reuptake inhibitor (SSRI) medication were randomized to a medication switch (either to an alternative SSRI or venlafaxine) with or without 12 weeks of adjunctive CBT. Participants who had more than 9 CBT sessions were 2.5 times more likely to have adequate treatment response than those who had 9 or fewer sessions. CBT participants who received problem-solving and social skills treatment components, controlling for number of sessions and other confounding variables, were 2.3 and 2.6 times, respectively, more likely to have a positive response. These preliminary findings underscore the importance of receiving an adequate number of sessions to attain an adequate clinical response. Finally, social skills and problem solving may be active elements in CBT for adolescent depression and should be considered in treatment by those working with seriously depressed youths. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
33.
Thallium-201 was given to 71 patients with various pulmonary diseases. Positive uptake was noted in primary malignant neoplasms and also in 6 cases of Hodgkin's lymphoma. No uptake was seen in pulmonary diseases other than active tuberculosis. A disadvantage is the high myocardial accumulation of this radionuclide which impairs proper visualization of paracardiac neoplasms.  相似文献   
34.
35.
Nitrated poly(oxa‐p‐phenylene‐3,3‐phthalido‐p‐phenylene‐oxa‐p‐phenylene‐ oxy‐phenylene) (PEEK‐WC) with various average degrees of substitution was obtained by reaction with several nitrating agents. By working under controlled reaction conditions, little degradation of the parent polymer is observed. The nitro derivatives of PEEK‐WC show a high thermal stability, and are able to form membranes by means of phase inversion technique. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1037–1045, 2001  相似文献   
36.
37.
Laser Doppler velocimetry with polarization-bistable VCSELs   总被引:1,自引:0,他引:1  
We present a rate equation model of a single mode vertical-cavity surface-emitting laser (VCSEL) with two states of linear polarization, subject to Doppler-shifted optical feedback. Recent experimental work has shown that the polarization bistability often observed in VCSELs can be exploited to enhance the responsivity of these semiconductor lasers in speed-sensing applications. We review these experimental results briefly and use the rate equation model to explain the increased signal-to-noise ratio.  相似文献   
38.
The marine operation of floating liquefied natural gas (FLNG) demands process compactness, flexibility, simplicity of operation, safety, and higher efficiency. The modified single mixed refrigerant (MSMR) process satisfies the FLNG process requirements and is accepted as a suitable technology for FLNG operation. The aim of this study was to develop a plant-wide control structure or strategy that can sustain the economic efficiency of the MSMR process. The NGL recovery and liquefaction units were integrated in the MSMR process to provide a compact plant structure with an efficient operation. Steady-state optimality analysis was intensively conducted in a rigorous dynamic simulation environment to determine the correct variable to sustain the economic efficiency of MSMR process. The results showed that the flow rate ratio of heavy and light mixed refrigerant (HK/LK ratio) is a promising self-optimizing controlled variable. Controlling this variable can sustain the MSMR optimality, even when the process is operated under off-design operating conditions or in the presence of disturbances. Based on the control structure tests, the control configuration with the HK/LK ratio loop showed excellent performance, maintaining the process stability against a range of disturbances. The proposed approach can also be applied to any cryogenic liquefaction technology for determining a possible optimizing controlled variable.  相似文献   
39.
Investment advisory services of financial service providers (FSPs) exhibit several characteristics that are detrimental to advisory quality. The interaction of advisor and client is strained by a lack of transparency regarding the advisory process (what activities are performed and why) and the information used therein (what information is used for what purpose and with what effect), as well as regarding the precise costs of the service and the recommended products. In prior research, we suggested that process and information transparency issues may be appropriately addressed with collaborative information technology (IT) artifacts. In this paper, we argue that collaborative, transparent artifacts may also be a premise of enabling cost transparency. To this end, we describe a complete research cycle of designing, implementing, and evaluating a shared cost-transparent IT artifact to support client-advisor interaction in investment advisory encounters. Evaluation results suggest the efficacy of our design in improving the clients?? perceived cost transparency as well as increase their satisfaction and their willingness to pay for the received investment advice. These findings may also challenge the common belief of FSPs that transparent, fee-based advisory services would neither be accepted by clients nor be economically viable. Practical implications of these findings for designing advisory encounters with supportive IT are discussed.  相似文献   
40.
The control of a legged robot walking on difficult terrain demands the development of efficient and reliable algorithms to coordinate the movement of multiple legs according to a diversity of requirements. We present a control structure, implemented on a six-legged robot, in which the aspects of stability, mobility, ground accommodation, gait generation, and robot heading are integrated in a coherent and simple way  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