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   963篇
  免费   58篇
电工技术   9篇
化学工业   262篇
金属工艺   15篇
机械仪表   16篇
建筑科学   16篇
能源动力   41篇
轻工业   197篇
水利工程   3篇
石油天然气   3篇
无线电   83篇
一般工业技术   148篇
冶金工业   74篇
原子能技术   4篇
自动化技术   150篇
  2023年   9篇
  2022年   37篇
  2021年   33篇
  2020年   22篇
  2019年   38篇
  2018年   32篇
  2017年   34篇
  2016年   35篇
  2015年   35篇
  2014年   34篇
  2013年   70篇
  2012年   56篇
  2011年   75篇
  2010年   46篇
  2009年   57篇
  2008年   60篇
  2007年   30篇
  2006年   46篇
  2005年   37篇
  2004年   36篇
  2003年   26篇
  2002年   21篇
  2001年   18篇
  2000年   10篇
  1999年   11篇
  1998年   22篇
  1997年   14篇
  1996年   13篇
  1995年   11篇
  1994年   5篇
  1993年   6篇
  1992年   3篇
  1991年   5篇
  1990年   2篇
  1989年   9篇
  1988年   1篇
  1987年   1篇
  1986年   2篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
  1978年   1篇
  1977年   1篇
  1976年   4篇
  1975年   1篇
  1973年   1篇
  1968年   1篇
排序方式: 共有1021条查询结果,搜索用时 0 毫秒
121.
About 10% of the world has access to information and communication technologies (ICTs). Telecenters and cyber cafés are one prevalent way to increase access. This paper suggests increasing access through currently existing, local businesses where people already gather and where proprietors already posses existing business relationships with suppliers and customers. This paper questions the prevailing emphasis on the “cyber'' characteristics of access, e.g., computing and internet access as is currently known, and attempts to refocus the conversation by considering computing and access in the context of the “café,” e.g., as public life in the sense of Habermas, which permits an in situ evolution of relevant access. This analysis is based on extant literature and direct ethnographic research in several public places in six countries. We offer example design perspectives based on a reflection of “third places” as inspiration for appropriate innovation in the provision of computing and communications. © 2005 Wiley Periodicals, Inc.  相似文献   
122.
123.
Background: GRIN-related disorders (GRD), the so-called grinpathies, is a group of rare encephalopathies caused by mutations affecting GRIN genes (mostly GRIN1, GRIN2A and GRIN2B genes), which encode for the GluN subunit of the N-methyl D-aspartate (NMDA) type ionotropic glutamate receptors. A growing number of functional studies indicate that GRIN-encoded GluN1 subunit disturbances can be dichotomically classified into gain- and loss-of-function, although intermediate complex scenarios are often present. Methods: In this study, we aimed to delineate the structural and functional alterations of GRIN1 disease-associated variants, and their correlations with clinical symptoms in a Spanish cohort of 15 paediatric encephalopathy patients harbouring these variants. Results: Patients harbouring GRIN1 disease-associated variants have been clinically deeply-phenotyped. Further, using computational and in vitro approaches, we identified different critical checkpoints affecting GluN1 biogenesis (protein stability, subunit assembly and surface trafficking) and/or NMDAR biophysical properties, and their association with GRD clinical symptoms. Conclusions: Our findings show a strong correlation between GRIN1 variants-associated structural and functional outcomes. This structural-functional stratification provides relevant insights of genotype-phenotype association, contributing to future precision medicine of GRIN1-related encephalopathies.  相似文献   
124.
Zeolite MFI membranes were successfully prepared on both alumina and stainless steel tubular supports by crystallization of previously deposited silicate layers under a steam atmosphere. The resultant membranes were able to separate n/isobutane mixtures at relatively high temperatures, displaying separation selectivities of 11.3, 8.9 and 2.5 at 100, 230 and 330 °C, respectively.  相似文献   
125.
In a study of the enlargement of pores of coals it has been found that treatment of a bituminous coal (PSOC No. 371, from the Pennsylvania State University Coal Section) with a 5:95 O2:N2 stream 4 h at 400 °C increases the surface area as measured by nitrogen adsorption at 77K by a factor of at least 50 to a value 52 m2 g?1. The increase in pore size was accompanied by a 9.7% weight loss. Simultaneously, the area as measured by carbon dioxide at 195K increased from 61 to 136 m2 g?1 and that measured by carbon dioxide at room temperature increased from 125 to 237 m2 g?1. Attempts to enlarge the pores by oxidation with hydrogen peroxide or ozone were unsuccessful. A Pittsburgh coal subject to a small percentage of oxygen in nitrogen or steam at 300 to 400 °C showed a surface area as measured by nitrogen adsorption of less than 1 m2 g?1 both before and after such pretreatment. This same coal with a 5:95 O2:N2 stream for 4 h at 450 °C showed a surface area of 110 m2 g?1 measured by nitrogen adsorption at 77K.  相似文献   
126.
127.
128.
129.
130.
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