首页 | 官方网站   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   113767篇
  免费   2195篇
  国内免费   519篇
工业技术   116481篇
  2023年   199篇
  2022年   704篇
  2021年   1008篇
  2020年   638篇
  2019年   711篇
  2018年   15046篇
  2017年   14061篇
  2016年   10662篇
  2015年   1240篇
  2014年   1218篇
  2013年   1844篇
  2012年   4535篇
  2011年   11062篇
  2010年   9445篇
  2009年   6810篇
  2008年   7912篇
  2007年   8746篇
  2006年   974篇
  2005年   2116篇
  2004年   2075篇
  2003年   2015篇
  2002年   1356篇
  2001年   811篇
  2000年   740篇
  1999年   601篇
  1998年   2102篇
  1997年   1377篇
  1996年   987篇
  1995年   619篇
  1994年   492篇
  1993年   543篇
  1992年   236篇
  1991年   310篇
  1990年   226篇
  1989年   193篇
  1988年   218篇
  1987年   161篇
  1986年   163篇
  1985年   182篇
  1984年   132篇
  1983年   94篇
  1982年   118篇
  1981年   123篇
  1980年   114篇
  1979年   91篇
  1978年   76篇
  1977年   138篇
  1976年   226篇
  1975年   86篇
  1954年   70篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
Here we report some recent biophysical issues on the preparation of solute-filled lipid vesicles and their relevance to the construction of “synthetic cells.” First, we introduce the “semi-synthetic minimal cells” as the liposome-based cell-like systems, which contain a minimal number of biomolecules required to display simple and complex biological functions. Next, we focus on recent aspects related to the construction of synthetic cells. Emphasis is given to the interplay between the methods of synthetic cell preparation and the physics of solute encapsulation. We briefly introduce the notion of structural and compositional “diversity” in synthetic cell populations.  相似文献   
2.
The purpose of this research was to study the capacity of emulsions containing saturated monoglyceride self‐assembly structures to deliver omega‐3 fatty acids in fresh soft cheese. To this aim, fortified emulsions containing different ratios of milk, saturated monoglycerides (MGs) and cod liver oil were added to milk before cheese‐making. These emulsions were characterised by distinct microstructural features observed by polarised light microscopy and apparent viscosity values. The omega‐3 delivery performance of MG emulsions highlighted that this strategy allowed a good retention of the omega‐3‐rich oil in the curd (up to 75%). The fortified cheeses showed yield value and fat content higher than those of control samples. The enriched cheese showed hardness and cohesiveness obtained by texture profile analysis similar to those of the unfortified product. Only a slight decrease in gumminess was detected in fortified cheese.  相似文献   
3.
4.
5.
6.
7.
8.
9.
10.
Mobile software applications have to cope with a particular environment that involves small size, limited resources, high autonomy requirements, competitive business models and many other challenges. To provide development guidelines that respond to these needs, several practices have been introduced; however, it is not clear how these guidelines may contribute to solve the issues present in the mobile domain. Furthermore, the rapid evolution of the mobile ecosystem challenges many of the premises upon which the proposed practices were designed. In this paper, we present a survey of the literature on software assurance practices for mobile applications, with the objective of describing them and assessing their contribution and success. We identified, organized and reviewed a body of research that spans in three levels: software development processes, software product assurance practices, and software implementation practices. By carrying out this literature survey, we reviewed the different approaches that researchers on Software Engineering have provided to address the needs that raise in the mobile software development arena. Moreover, we review the evolution of these practices, identifying how the constant changes and modernization of the mobile execution environment has impacted the methods proposed in the literature. Finally, we introduced discussion on the application of these practices in a real productive setting, opening an area for further research that may determine if practitioners have followed the proposed assurance paradigms.  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-23

京公网安备 11010802026262号