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   323579篇
  免费   5078篇
  国内免费   860篇
电工技术   5623篇
综合类   249篇
化学工业   53611篇
金属工艺   12765篇
机械仪表   9362篇
建筑科学   8766篇
矿业工程   2023篇
能源动力   7527篇
轻工业   29511篇
水利工程   3504篇
石油天然气   7166篇
武器工业   16篇
无线电   33894篇
一般工业技术   64649篇
冶金工业   55712篇
原子能技术   7808篇
自动化技术   27331篇
  2021年   2911篇
  2019年   2573篇
  2018年   4662篇
  2017年   4557篇
  2016年   5041篇
  2015年   3448篇
  2014年   5529篇
  2013年   14488篇
  2012年   8588篇
  2011年   11423篇
  2010年   9239篇
  2009年   10210篇
  2008年   10698篇
  2007年   10504篇
  2006年   9194篇
  2005年   8417篇
  2004年   7784篇
  2003年   7504篇
  2002年   7489篇
  2001年   7170篇
  2000年   6759篇
  1999年   6767篇
  1998年   15569篇
  1997年   11682篇
  1996年   9091篇
  1995年   7015篇
  1994年   6375篇
  1993年   6213篇
  1992年   4827篇
  1991年   4690篇
  1990年   4589篇
  1989年   4596篇
  1988年   4502篇
  1987年   3870篇
  1986年   3835篇
  1985年   4507篇
  1984年   4289篇
  1983年   3894篇
  1982年   3690篇
  1981年   3820篇
  1980年   3631篇
  1979年   3600篇
  1978年   3656篇
  1977年   4144篇
  1976年   5277篇
  1975年   3364篇
  1974年   3160篇
  1973年   3174篇
  1972年   2753篇
  1971年   2556篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Abstract

This article discusses different approaches to materiality and material expressions of cultural identity in contemporary Bahrain, a small Arab Gulf state. Various Islamic traditions have different understandings of materiality and its ontological qualities. In the contemporary Gulf this difference is often understood as a sectarian difference between Sunni and Shia Muslims, a division that has gained increasing political importance in recent years. In this article I discuss how these traditions view materiality in religion, in particular focusing on the role of material mediation for Shia Muslims, exemplified by the use and meaning of the turba prayer stone. With this as a point of departure I discuss two other forms of materiality—political graffiti and martyr images—that in the wake of the uprising in 2011 have also been imbued with sectarian meanings, but where this is less clear. I therefore argue that vernacular understandings of material culture show ambiguous identifications that challenge the clear dichotomies with which people—locally and analytically —often operate.  相似文献   
3.
4.
5.
6.
7.
8.
Cable‐shaped supercapacitors (SCs) have recently aroused significant attention due to their attractive properties such as small size, lightweight, and bendability. Current cable‐shaped SCs have symmetric device configuration. However, if an asymmetric design is used in cable‐shaped supercapacitors, they would become more attractive due to broader cell operation voltages, which results in higher energy densities. Here, a novel coil‐type asymmetric supercapacitor electrical cable (CASEC) is reported with enhanced cell operation voltage and extraordinary mechanical‐electrochemical stability. The CASECs show excellent charge–discharge profiles, extraordinary rate capability (95.4%), high energy density (0.85 mWh cm−3), remarkable flexibility and bendability, and superior bending cycle stability (≈93.0% after 4000 cycles at different bending states). In addition, the CASECs not only exhibit the capability to store energy but also to transmit electricity simultaneously and independently. The integrated electrical conduction and storage capability of CASECS offer many potential applications in solar energy storage and electronic gadgets.  相似文献   
9.
10.
Pinhão seed is an unconventional source of starch and the pines grow up in native forests of southern Latin America. In this study, pinhão starch was adjusted at 15, 20 and 25% moisture content and heated to 100, 110 and 120 °C for 1 h. A decrease in λ max (starch/iodine complex) was observed as a result of increase in temperature and moisture content of HMT. The ratio of crystalline to amorphous phase in pinhão starch was determined via Fourier transform infra red by taking 1045/1022 band ratio. A decrease in crystallinity occurred as a result of HMT. Polarised light microscopy indicated a loss of birefringence of starch granules under 120 °C at 25% moisture content. Granule size distribution was further confirmed via scanning electron microscopy which showed the HMT effects. These results increased the understanding on molecular and structural properties of HMT pinhão starch and broadened its food and nonfood industrial applications.  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