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   5165篇
  免费   263篇
  国内免费   14篇
电工技术   56篇
综合类   3篇
化学工业   1176篇
金属工艺   119篇
机械仪表   123篇
建筑科学   209篇
矿业工程   14篇
能源动力   170篇
轻工业   471篇
水利工程   35篇
石油天然气   24篇
无线电   342篇
一般工业技术   1045篇
冶金工业   878篇
原子能技术   42篇
自动化技术   735篇
  2023年   69篇
  2022年   108篇
  2021年   181篇
  2020年   141篇
  2019年   140篇
  2018年   168篇
  2017年   150篇
  2016年   174篇
  2015年   119篇
  2014年   174篇
  2013年   324篇
  2012年   271篇
  2011年   362篇
  2010年   226篇
  2009年   260篇
  2008年   294篇
  2007年   252篇
  2006年   187篇
  2005年   151篇
  2004年   131篇
  2003年   122篇
  2002年   85篇
  2001年   77篇
  2000年   77篇
  1999年   77篇
  1998年   94篇
  1997年   73篇
  1996年   88篇
  1995年   66篇
  1994年   52篇
  1993年   30篇
  1992年   41篇
  1991年   24篇
  1990年   40篇
  1989年   39篇
  1988年   26篇
  1987年   36篇
  1986年   31篇
  1985年   44篇
  1984年   25篇
  1983年   35篇
  1982年   29篇
  1981年   31篇
  1980年   31篇
  1979年   25篇
  1978年   28篇
  1977年   29篇
  1976年   31篇
  1975年   20篇
  1973年   23篇
排序方式: 共有5442条查询结果,搜索用时 15 毫秒
1.
Photoresponsive biomaterials are experiencing a transition from in vitro models to in vivo demonstrations that point toward clinical translation. Dynamic hydrogels for cell encapsulation, light-responsive carriers for controlled drug delivery, and nanomaterials containing photosensitizers for photodynamic therapy are relevant examples. Nonetheless, the step to the clinic largely depends on their combination with technologies to bring light into the body. This review highlights the challenge of photoactivation in vivo, and presents strategies for light management that can be adopted for this purpose. The authors’ focus is on technologies that are materials-driven, particularly upconversion nanoparticles that assist in “direct path” light delivery through tissue, and optical waveguides that “clear the path” between external light source and in vivo target. The authors’ intention is to assist the photoresponsive biomaterials community transition toward medical technologies by presenting light delivery concepts that can be integrated with the photoresponsive targets. The authors also aim to stimulate further innovation in materials-based light delivery platforms by highlighting needs and opportunities for in vivo photoactivation of biomaterials.  相似文献   
2.
International Journal on Software Tools for Technology Transfer - This paper describes a technique for solving temporal-logic queries over finite sets of finite-length data streams. Such data...  相似文献   
3.
A study using three different pairs of electrochromic polymers (ECPs) synthesized onto plaques by means of a modified vapor phase polymerization (VPP) technique is presented. Restriction of the respective polymerization times, allowed both faster and slower polymerizing monomers to be controlled, and produced blended plaques with visually diffuse interfaces. The ECPs within the blended plaques retain their individual electrochromic behavior and when encapsulated into an electrochromic device, show outstanding optical switching performance with little degradation evident over 10,000 cycles, coupled with a switching time of the order of 1 second. Blends also allow multiple diffuse color changes within an electrochromic device, due to the difference in oxidation potentials of the individual ECPs, making them candidates for adaptive camouflage use. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42158.  相似文献   
4.
Activity-directed synthesis (ADS) is a structure-blind, functional-driven molecular discovery approach. In this Concept, four case studies highlight the general applicability of ADS and showcase its flexibility to support different medicinal chemistry strategies. ADS deliberately harnesses reactions with multiple possible outcomes, and allows many chemotypes to be evaluated in parallel. Resources are focused on bioactive molecules, which emerge in tandem with associated synthetic routes. Some of the future challenges for ADS are highlighted, including the realisation of an autonomous molecular discovery platform. The prospects for ADS to become a mainstream lead generation approach are discussed.  相似文献   
5.
Powder Metallurgy and Metal Ceramics - Multiphase La 2 MgNi 9 alloys are synthesized by induction melting. The crystalline structures of all phases in the alloys are determined with X-ray...  相似文献   
6.
7.
8.
9.
Many models of spoken word recognition posit the existence of lexical and sublexical representations, with excitatory and inhibitory mechanisms used to affect the activation levels of such representations. Bottom-up evidence provides excitatory input, and inhibition from phonetically similar representations leads to lexical competition. In such a system, long words should produce stronger lexical activation than short words, for 2 reasons: Long words provide more bottom-up evidence than short words, and short words are subject to greater inhibition due to the existence of more similar words. Four experiments provide evidence for this view. In addition, reaction-time-based partitioning of the data shows that long words generate greater activation that is available both earlier and for a longer time than is the case for short words. As a result, lexical influences on phoneme identification are extremely robust for long words but are quite fragile and condition-dependent for short words. Models of word recognition must consider words of all lengths to capture the true dynamics of lexical activation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  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