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   9805篇
  免费   936篇
  国内免费   483篇
电工技术   518篇
技术理论   1篇
综合类   727篇
化学工业   1617篇
金属工艺   677篇
机械仪表   663篇
建筑科学   669篇
矿业工程   306篇
能源动力   267篇
轻工业   719篇
水利工程   195篇
石油天然气   610篇
武器工业   95篇
无线电   1100篇
一般工业技术   1196篇
冶金工业   460篇
原子能技术   108篇
自动化技术   1296篇
  2024年   44篇
  2023年   206篇
  2022年   331篇
  2021年   469篇
  2020年   341篇
  2019年   286篇
  2018年   333篇
  2017年   397篇
  2016年   271篇
  2015年   424篇
  2014年   553篇
  2013年   614篇
  2012年   716篇
  2011年   662篇
  2010年   673篇
  2009年   595篇
  2008年   542篇
  2007年   543篇
  2006年   568篇
  2005年   445篇
  2004年   312篇
  2003年   255篇
  2002年   261篇
  2001年   217篇
  2000年   186篇
  1999年   192篇
  1998年   154篇
  1997年   124篇
  1996年   99篇
  1995年   84篇
  1994年   84篇
  1993年   46篇
  1992年   51篇
  1991年   38篇
  1990年   23篇
  1989年   15篇
  1988年   18篇
  1987年   9篇
  1986年   18篇
  1985年   3篇
  1984年   2篇
  1983年   11篇
  1982年   3篇
  1981年   2篇
  1980年   4篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
The surface tension of the Ni3S2-FeS-Cu2S ternary mattes have been calculated from those of the Ni3S2-FeS·FeS-Cu2S and Cu2S-Ni3S2 pseudo-binary boundary systems by using geometric models (Kohler and Toop model) and a general solution model (Chou model). Taking account of the experimental accuracy of ±2.5%, the respective calculated results are in agreement with the experimental data. At the same time, surface tensions of molten Ni3S2-FeS-Cu2S mattes and their pseudo-binary boundary systems are predicted based on Butler's original treatment with great attention to the model parameter β. The predicted results also agree with the experimental data. Therefore, the resulting iso-surface tension curves in molten Ni3S2-FeS-Cu2S mattes at 1473K, especially calculated by using Kohler, Toop and Chou models, are generally acceptable.  相似文献   
152.
用统计方法实现汉字输入的智能联想   总被引:3,自引:1,他引:2  
联想是汉字输入法的重要补充手段,能够大大加快输入的速度。本文首次提出了智能联想的概念,分析了智能联想的原理和遇到的困难,使用汉语语料库的方法构造并分析比较了3种智能联想方案,充分利用汉语字词间的相关性,使平均联想成功率超过40%。  相似文献   
153.
This paper presents a microelectromechanical systems (MEMS) differential thermal biosensor integrated with microfluidics for metabolite measurements in either flow-injection or flow-through mode. The MEMS device consists of two identical freestanding polymer diaphragms, resistive heaters, and a thermopile between the diaphragms. Integrated with polymer-based microfluidic measurement chambers, the device allows sensitive measurement of small volumes of liquid samples. Enzymes specific to a metabolic analyte system are immobilized on microbeads packed in the chambers. When a sample solution containing the analyte is introduced to the device, the heat released from the enzymatic reactions of the analyte is detected by the thermopile. The device has been tested with glucose solutions at physiologically relevant concentrations. In flow-injection mode, the device demonstrates a sensitivity of approximately 2.1 muV/mM and a resolution of about 0.025 mM. In flow-through mode with a perfusion flow rate of 0.5 mL/h, the sensitivity and resolution of the device are determined to be approximately 0.24 muV/mM and 0.4 mM, respectively. These results illustrate that the device, when integrated with subcutaneous sampling methods, can potentially allow for continuous monitoring of glucose and other metabolites.  相似文献   
154.
Surface tensions of the Sn–Ga–In ternary alloy are calculated from the surface tensions of the Sn–Ga, Ga–In and In–Sn sub-binary systems by using geometric models (the Kohler model and the Toop model), and a general solution model (the Chou model). The calculated results are in excellent agreement with the experimental data (except for the Kohler model), assuming an experimental accuracy of ±2.5%. At the same time, the surface tensions of the Sn–Ga–In ternary alloy at 773 K and their sub-binary systems are predicted on the basis of Butler’s equation, in combination with thermodynamic data, and different model parameters ββ equal to the ratio of the coordination number in the surface phase to that in the bulk phase. Different values of ββ have almost no influence on the surface tensions. The predicted results agree with the experimental data. Therefore, the resulting iso-surface tension curves for the Sn–Ga–In ternary alloy at 773 K, especially those calculated by using the Toop model, are reasonable.  相似文献   
155.
乔国龙  夏在森 《吉林水利》2013,(6):11-13,18
无应力变形分析是大坝安全监测资料分析中应力应变分析的基础。文章以江垭大坝无应力变形实际监测资料为依据,通过温度因子、时效因子的选择建立无应力变形的统计模型,进而对模型的各个分量进行分析,得出江垭大坝目前无应力变形的状态。  相似文献   
156.
In recent years, some Chinese doctors have proposed a new concept, gallstone removal without gallbladder excision, along with transition of the medical model. As there is no specialized endoscope for gallstone removal without gallbladder excision, we designed and produced a new series of gallbladder endoscopes and accessories that have already been given a Chinese invention patent (No. ZL200810199041.2). The design of these gallbladder endoscopes was based on the anatomy and physiology of the gallbladder, characteristics of gallbladder disease, ergonomics, and industrial design. This series of gallbladder endoscopes underwent clinical trials in two hospitals appointed by the State Administration of Traditional Chinese Medicine. The clinical trials showed that surgeries of gallstones, gallbladder polyps, and cystic duct calculus could be smoothly performed with these products. In summary, this series of gallbladder endoscopes is safe, reliable, and effective for gallstone removal without gallbladder excision. This note comprehensively introduces the research and design of this series of gallbladder endoscopes.  相似文献   
157.
从技战术实际需要出发,给出了某型飞机作战损毁后机载电缆的智能化诊断系统的硬件结构框图。根据硬件系统模拟开关组件的原理,定义了电缆的连接矩阵、测量矩阵以及断口的映像矩阵运算,给出了断头查找的算法。计算表明,系统可在20 min内完成一个循环的断头查找并给出故障定位。  相似文献   
158.
采用商用ANSYS软件的二次开发语言,选用适宜于CO2气体保护焊的双椭球热源模型,建立了Y型坡口的两块钢板对接多层多道焊模型,分别采用三种不同"单元生死"技术对其温度场分布规律进行数值模拟及对比分析,验证了模拟过程中采用逐步、逐层激活焊缝单元的"单元生死"技术的必要性.得到了模型在各时间点的温度场分布,绘制了典型位置的热循环曲线,据此可掌握和预测实际焊接过程以及焊接之后焊件的组织、性能以及残余应力的变化情况.  相似文献   
159.
子群H在群G中被称为是c1-可补的(c1-supplemented),如果存在G的子群K使得G=HK且H∩T≤Z∞(G),其中Z∞(G)是G的超中心.本文研究素数幂阶子群的广义可补性对有限群结构的的影响,得到以下主要定理:对于G的任意Sylow p-子群P,如果P有子群D满足1<|D|<|P|且P每一个|D|阶及p|D|阶子群在G中均c1-可补,那么G超可解.该结果推广了一些已知的结果.  相似文献   
160.
王震森  乔辉  曹福宾 《自动化仪表》2012,33(1):73-75,78
为满足最新颁布的铠装热电偶校准规范对校准用校验炉的要求,研发了精密热电偶校验炉.运用内外二级温度控制及插孔安装方式,使校验炉在进行热电偶校准时具备极佳的技术性能.实际应用表明,精密热电偶校验炉完全可以应用于Ⅰ级工业热电偶的校准.  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