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   9477篇
  免费   802篇
  国内免费   89篇
电工技术   181篇
综合类   41篇
化学工业   2629篇
金属工艺   213篇
机械仪表   397篇
建筑科学   361篇
矿业工程   20篇
能源动力   622篇
轻工业   927篇
水利工程   190篇
石油天然气   140篇
武器工业   5篇
无线电   983篇
一般工业技术   1620篇
冶金工业   211篇
原子能技术   67篇
自动化技术   1761篇
  2024年   40篇
  2023年   193篇
  2022年   348篇
  2021年   615篇
  2020年   553篇
  2019年   691篇
  2018年   776篇
  2017年   737篇
  2016年   729篇
  2015年   433篇
  2014年   716篇
  2013年   1048篇
  2012年   656篇
  2011年   733篇
  2010年   475篇
  2009年   405篇
  2008年   249篇
  2007年   182篇
  2006年   150篇
  2005年   102篇
  2004年   101篇
  2003年   58篇
  2002年   57篇
  2001年   28篇
  2000年   23篇
  1999年   25篇
  1998年   22篇
  1997年   19篇
  1996年   23篇
  1995年   19篇
  1994年   10篇
  1993年   15篇
  1992年   10篇
  1991年   17篇
  1990年   16篇
  1989年   12篇
  1988年   7篇
  1987年   7篇
  1986年   8篇
  1985年   8篇
  1984年   14篇
  1983年   12篇
  1982年   5篇
  1981年   3篇
  1980年   2篇
  1979年   6篇
  1978年   3篇
  1977年   2篇
  1973年   2篇
  1967年   1篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Analog Integrated Circuits and Signal Processing - A new structure for improving the performance of recycling folded cascode (RFC) operational transconductance amplifier (OTA) is presented. The...  相似文献   
102.
Surfaces enabling directional liquid transportation are of great interest for a wide range of applications such as water collection, microfluidics, and heat transfer systems. Surfaces capable of lossless, long-range passive transportation of low surface tension (LST) liquids using wettability patterned, liquidlike coatings with minimal contact angle hysteresis are reported. Lossless LST droplet travel distances over 150 mm are achieved, enabled by a two-phase transportation mechanism: morphological transformation from a bulge to a channel shape, followed by directional transportation along the asymmetrical wedge-shaped channel. The developed surfaces can split, merge, and precisely transport various low-surface tension liquids, including alcohols, alkanes, and solvents. The developed transportation strategy can also enhance LST liquid dropwise condensation through continuous removal of the condensate, even on horizontally positioned surfaces without the assistance of gravity.  相似文献   
103.
The Journal of Supercomputing - This paper designs and develops a computational intelligence-based framework using convolutional neural network (CNN) and genetic algorithm (GA) to detect COVID-19...  相似文献   
104.
In the present article, as a first endeavor, the wave propagation in functionally graded nanocomposites reinforced with carbon nanotubes is investigated on the basis of second-order shear deformation theory. Four different types of functionally graded nanocomposites are presented. An analytical method is used to find the circular frequencies and phase velocities. To show the accuracy of the present methodology, our results for the free vibration are compared with the results of functionally graded plates available in the literature. The influences of different parameters are also investigated on the circular frequencies and phase velocities.  相似文献   
105.
Journal of Failure Analysis and Prevention - There are many available techniques which are widely used for failure probability analysis. Fault tree analysis (FTA) is a well-known method to identify...  相似文献   
106.
The aim of this study is to introduce natural‐based polymers, chitosan and starch, to design a remedial nanocomposite, comprising of cerium oxide nanoparticles and silver nanoparticles, to investigate their effects in accelerating wound healing and in wound microbial load. Cerium oxide nanoparticles synthesized in starch solution added to the colloidal dispersion of synthesized silver nanoparticles in chitosan to make a three‐component nanomaterial. Mice were anaesthetized and two parallel full‐thickness round wounds were excised under aseptic conditions with the help of sterile dermal biopsy punch. Furthermore, effects of silver‐chitosan and silver‐cerium‐chitosan nanocomposite had evaluated on rate of wound closure and collagen density and on microbial load of wound in full‐thickness model. Results showed that both silver chitosan and silver‐cerium‐chitosan had significant impact on acceleration of wound closure and collagen content and on reduction of wound microbial load in comparison with control group, which was, received no treatments. However, the silver‐cerium‐chitosan nanocomposite is more potent than silver‐chitosan group and control group in wound closure. The wound healing effects of silver‐cerium‐chitosan nanocomposite are due to unique features of its three components and this nanocomposite promises impressive remedies for clinical application.Inspec keywords: wounds, nanocomposites, nanomedicine, nanoparticles, proteins, cerium, silver, polymers, colloids, patient treatmentOther keywords: biopolymer‐based nanocomposite wound dressing, wound healing properties, wound microbial load, natural‐based polymers, chitosan, remedial nanocomposite, cerium oxide nanoparticles, nanoceria, silver nanoparticles, starch solution, three‐component nanomaterial, synthesised silver nanoparticles, ketamine intraperitoneal injection, silver‐cerium‐chitosan nanocomposite, wound closure, collagen density, wound healing effects, wound care, aseptic conditions, sterile dermal biopsy punch, Ag‐Ce  相似文献   
107.
108.
109.
Coarse-grained ZnO varistors for low-voltage applications were prepared by microwave sintering technique under different soaking times of 5–150?min. For comparison, a low-voltage ZnO varistor was also prepared through a conventional sintering process. Microwave sintering remarkably enhanced the grain growth rate of ZnO varistors. Average grain size of the sample prepared by microwave sintering in 15?min was about 20?µm, which is similar to the grain size of sample prepared conventionally in 150?min time. In addition to grain growth, an increase in microwave sintering time led to precipitation of zinc titanate (Zn2TiO4) on the top surface of samples which sintered for long dwell times. X-ray diffraction and scanning electron microscopy results from different points of the samples declared that precipitation of Zn2TiO4 phase is due to the high rate of bismuth evaporation of Bi-rich liquid from top surface and the reaction between remaining titanium ions on the surface with ZnO. The results showed that increasing sintering time from 5 to 150?min increased the grain size from 14 to 33?µm, consequently, the breakdown field decreased from 90 to 27?V/mm, respectively. These changes led to a switch in the varistor application, from low to very low voltage.  相似文献   
110.
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