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   4398篇
  免费   424篇
  国内免费   1篇
电工技术   36篇
综合类   4篇
化学工业   1112篇
金属工艺   62篇
机械仪表   114篇
建筑科学   152篇
矿业工程   12篇
能源动力   119篇
轻工业   905篇
水利工程   57篇
石油天然气   18篇
无线电   168篇
一般工业技术   706篇
冶金工业   587篇
原子能技术   15篇
自动化技术   756篇
  2024年   15篇
  2023年   57篇
  2022年   79篇
  2021年   174篇
  2020年   167篇
  2019年   140篇
  2018年   243篇
  2017年   236篇
  2016年   260篇
  2015年   174篇
  2014年   216篇
  2013年   423篇
  2012年   311篇
  2011年   288篇
  2010年   214篇
  2009年   237篇
  2008年   186篇
  2007年   211篇
  2006年   102篇
  2005年   103篇
  2004年   83篇
  2003年   86篇
  2002年   62篇
  2001年   33篇
  2000年   27篇
  1999年   35篇
  1998年   193篇
  1997年   118篇
  1996年   77篇
  1995年   51篇
  1994年   42篇
  1993年   35篇
  1992年   11篇
  1991年   14篇
  1990年   6篇
  1989年   11篇
  1988年   13篇
  1987年   8篇
  1986年   7篇
  1985年   12篇
  1984年   7篇
  1983年   3篇
  1982年   5篇
  1981年   6篇
  1980年   7篇
  1979年   2篇
  1977年   8篇
  1976年   15篇
  1975年   3篇
  1973年   2篇
排序方式: 共有4823条查询结果,搜索用时 15 毫秒
1.
Brito  Claúdia  Esteves  Marisa  Peixoto  Hugo  Abelha  António  Machado  José 《Wireless Networks》2022,28(3):1269-1277
Wireless Networks - Continuous ambulatory peritoneal dialysis (CAPD) is a treatment used by patients in the end-stage of chronic kidney diseases. Those patients need to be monitored using blood...  相似文献   
2.
3.
In this study, the behavior of carbon steel and galvanized steel in nontropical coastal marine environments was evaluated. Evaluation was carried out with specimens with dimensions of 10 cm × 10 cm × 0.3 cm. These specimens were exposed to four testing stations (Iquique, Mejillones, Los Vilos, and San Vicente), where racks were installed both at ground level (ground), as well as in the upper zone of electrical transmission towers (tower). In each station, 24 specimens of A36 carbon steel and galvanized steel were placed (12 each). The corrosivity of the environment was measured using the ISO 9223, 9225, and 9226 standards. The specimens were evaluated on-site, monthly, through visual inspection and photographic record. Once withdrawn, the corrosion rate was determined and the corrosion products were analyzed through Raman and Fourier-transform infrared. The results show that, in all cases, the corrosion rate is greater in the tower than on the ground. However, even though the Los Vilos station is located farther from the sea (3,500 vs. ≈500 m), the corrosion rate of steel in the tower is the highest. This is caused by the generation of HCl from the transformation of lepidocrocite into goethite, in the presence of low chloride content, which acidifies the steel/corrosion product interface. In the case of galvanized steel, the corrosion rate is a function of the chloride content in the atmosphere, obtaining an excellent correlation between both parameters.  相似文献   
4.
5.
Nafion membranes were prepared by incorporating in the polymer matrix the 1‐butyl‐3‐methylimidazolium (BMI+) ionic liquid cation at different doping levels. Increasing the doping time of the membranes with the ionic liquid results in increased incorporation of the BMI+ cation but a decrease in the bulk conductivity. The thermogravimetric analysis shows that the BMI+ cation incorporation increases the thermal stability of the membranes. The higher discharge efficiency of the fuel cell at 80°C was obtained by using Nafion membrane after 15 minutes of doping in the ionic liquid solution.  相似文献   
6.
7.
Scientometrics - Science can be examined from several standpoints, such as through a bibliometric analysis of the scientific output of researchers, research groups or institutions. However, there...  相似文献   
8.
Software Quality Journal - Risks are an inherent part of any software project. The presence of risks in environments of software development projects requires the perception so that the associated...  相似文献   
9.
Chagas disease is becoming a worldwide problem; it is currently estimated that over six million people are infected. The two drugs in current use, benznidazole and nifurtimox, require long treatment regimens, show limited efficacy in the chronic phase of infection, and are known to cause adverse effects. Phenotypic screening of an in-house library led to the identification of 2,2′-methylenebis(5-(4-bromophenyl)-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one), a phenyldihydropyrazolone dimer, which shows an in vitro pIC50 value of 5.4 against Trypanosoma cruzi. Initial optimization was done by varying substituents of the phenyl ring, after which attempts were made to replace the phenyl ring. Finally, the linker between the dimer units was varied, ultimately leading to 2,2′-methylenebis(5-(3-bromo-4-methoxyphenyl)-4,4-dimethyl-2,4-dihydro-3H-pyrazol-3-one (NPD-0228) as the most potent analogue. NPD-0228 has an in vitro pIC50 value of 6.4 against intracellular amastigotes of T. cruzi and no apparent toxicity against the human MRC-5 cell line and murine cardiac cells.  相似文献   
10.
Our laboratory has recently identified two nanobodies (small antibodies produced by camelids)—Nb1 and Nb6—that bind efficiently to epithelial growth factor (EGF) and inhibit its ability to activate its receptor (EGFR). Because of the relevance of the EGF/EGFR axis as a target in oncology, these new nanobodies have promising therapeutic potential. This article, however, is focused on another feature of these nanobodies: their distinct thermodynamic signatures. Nb1 binds to EGF through an entropy-driven mechanism whereas Nb6 binds to this factor under enthalpic control. We discuss the advantages and disadvantages of each mechanism in the contexts of traditional medical chemistry (small-molecule drugs) and also of biological drugs. In this latter case, the implications in terms of selectivity are far from being clearly established and further experimental data are required. Their monomeric natures, high stability, and ease of recombinant production make nanobodies ideally suited for thermodynamic studies. Moreover, nanobodies, thanks to their simpler structures in comparison with conventional antibodies, might provide better understanding of the structural basis of the thermodynamic parameters of antigen recognition.  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