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   1997篇
  免费   107篇
  国内免费   7篇
电工技术   21篇
化学工业   404篇
金属工艺   36篇
机械仪表   25篇
建筑科学   60篇
矿业工程   11篇
能源动力   41篇
轻工业   309篇
水利工程   7篇
石油天然气   4篇
无线电   153篇
一般工业技术   319篇
冶金工业   360篇
原子能技术   6篇
自动化技术   355篇
  2023年   8篇
  2022年   23篇
  2021年   45篇
  2020年   25篇
  2019年   31篇
  2018年   55篇
  2017年   52篇
  2016年   58篇
  2015年   40篇
  2014年   77篇
  2013年   133篇
  2012年   121篇
  2011年   127篇
  2010年   99篇
  2009年   95篇
  2008年   97篇
  2007年   80篇
  2006年   71篇
  2005年   59篇
  2004年   63篇
  2003年   58篇
  2002年   42篇
  2001年   42篇
  2000年   35篇
  1999年   39篇
  1998年   98篇
  1997年   52篇
  1996年   46篇
  1995年   31篇
  1994年   36篇
  1993年   25篇
  1992年   20篇
  1990年   16篇
  1989年   8篇
  1988年   13篇
  1987年   11篇
  1985年   16篇
  1984年   7篇
  1983年   12篇
  1982年   7篇
  1981年   14篇
  1980年   11篇
  1979年   9篇
  1978年   8篇
  1977年   13篇
  1976年   11篇
  1975年   7篇
  1974年   7篇
  1973年   12篇
  1967年   8篇
排序方式: 共有2111条查询结果,搜索用时 814 毫秒
1.
Fan  Deng-Ping  Huang  Ziling  Zheng  Peng  Liu  Hong  Qin  Xuebin  Van Gool  Luc 《国际自动化与计算杂志》2022,19(4):257-287
Machine Intelligence Research - This paper aims to conduct a comprehensive study on facial-sketch synthesis (FSS). However, due to the high cost of obtaining hand-drawn sketch datasets, there is a...  相似文献   
2.
3.
The potential use of stem cell-based therapies for the repair and regeneration of various tissues and organs is a major goal in repair medicine. Stem cells are classified by their potential to differentiate into functional cells. Compared with other sources, adipose-derived stem cells (ADSCs) have the advantage of being abundant and easy to obtain. ADSCs are considered to be tools for replacing, repairing, and regenerating dead or damaged cells. The capacity of ADSCs to maintain their properties depends on the balance of complex signals in their microenvironment. Their properties and the associated outcomes are in part regulated by reactive oxygen species, which mediate the oxidation-reduction state of cells as a secondary messenger. ADSC therapy has demonstrated beneficial effects, suggesting that secreted factors may provide protection. There is evidence that ADSCs secrete a number of cytokines, growth factors, and antioxidant factors into their microenvironment, thus regulating intracellular signaling pathways in neighboring cells. In this review, we introduce the roles of ADSCs in the protection of cells by modulating inflammation and immunity, and we develop their potential therapeutic properties.  相似文献   
4.
5.
6.
7.
The present paper studies a feedback regulation problem that arises in at least two different biological applications. The feedback regulation problem under consideration may be interpreted as an adaptive control problem for tuning bifurcation parameters, and it has not been studied in the control literature. The goal of the paper is to formulate this problem and to present some preliminary results.  相似文献   
8.
Reviews the book, L'insomnie: Traitement comportemental by Robert Ladouceur and Yves Gros-Louis (1984). The work offers a prospect broader than the medical vision which traditionally dominates the treatment of insomnia. More specifically, the work is articulated around two chapters. The first locates the relative source data of insomnia, and provides the criteria for a precise diagnosis, establishing a clear distinction between primary insomnia and secondary insomnia, and methods generally utilized to measure sleep. As for the second chapter, it is centered on the behavioral methods of treatment of insomnia. According to the authors, any treatment must be preceded by factual information on insomnia, to facilitate the application of the chosen method. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
We study the transient gratings photogenerated in the picosecond regime in three families of structures, namely : - structures of thickness in the order of one micron, including quantum wells (GaAs/GaAlAs, CdTe/ CdZnTe). A transmission modulation due to the electric field has been observed. We show that, in accordance with our calculations, this modulation is screened faster than 10 ps at a fluence of a few µJ/cm2. - A structure including GalnAs/GalnAsP MQWS in a cavity. This structure shows a top diffraction efficiency of 2.5 × 10-2 at 1.55 µm for an energy of excitation in the order of 100 µJ/cm2. The diffraction efficiency exhibits several oscillations due to Fabry-Pårot effects. By introducing cavity effects in our model, we show that the diffraction efficiency is amplified by more than a factor 2 with respect to the no-cavity case. Calculations show that the diffraction efficiency may reach 6 × 10-2 around 1.625 µm, for a front mirror reflectivity of 90 %. - Structures including bulk GaAs microcavities. The risetime is lower or in the order of 1 ps while the diffraction efficiency attains 1 %, with an average power of 4 mW (i.e. an energy of 2 µJ/cm2/pulse), compatible with a commutation of packets at 80 MHz.  相似文献   
10.
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