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   22418篇
  免费   1323篇
  国内免费   57篇
电工技术   312篇
综合类   25篇
化学工业   4904篇
金属工艺   879篇
机械仪表   1298篇
建筑科学   426篇
矿业工程   7篇
能源动力   864篇
轻工业   1850篇
水利工程   91篇
石油天然气   18篇
无线电   3655篇
一般工业技术   4627篇
冶金工业   2192篇
原子能技术   291篇
自动化技术   2359篇
  2024年   22篇
  2023年   275篇
  2022年   399篇
  2021年   683篇
  2020年   471篇
  2019年   497篇
  2018年   699篇
  2017年   661篇
  2016年   768篇
  2015年   602篇
  2014年   938篇
  2013年   1390篇
  2012年   1456篇
  2011年   1791篇
  2010年   1298篇
  2009年   1331篇
  2008年   1211篇
  2007年   937篇
  2006年   815篇
  2005年   710篇
  2004年   639篇
  2003年   589篇
  2002年   593篇
  2001年   517篇
  2000年   437篇
  1999年   443篇
  1998年   922篇
  1997年   522篇
  1996年   476篇
  1995年   298篇
  1994年   203篇
  1993年   201篇
  1992年   120篇
  1991年   114篇
  1990年   82篇
  1989年   99篇
  1988年   83篇
  1987年   76篇
  1986年   63篇
  1985年   52篇
  1984年   36篇
  1983年   28篇
  1982年   32篇
  1981年   29篇
  1980年   32篇
  1979年   13篇
  1977年   33篇
  1976年   46篇
  1975年   17篇
  1974年   13篇
排序方式: 共有10000条查询结果,搜索用时 739 毫秒
91.
In this report, the FE characteristics of carbon nanotubes (CNTs) treated using both thermal annealing and mechanical coatings on the as-grown CNTs systematically studied. It was found that in the high temperature annealed samples, CNTs were attacked at its root during annealing due to a small amount of oxygen, and were pulled out of the substrate in places after FE measurements because of the contact resistance. However, for the mechanically coated samples both with spin on glass (SOG) and polymethyl methacrylate (PMMA), CNTs were found to be nearly intact after FE measurements and showed reliable FE characteristics over repeatable voltage scan. The reliability of CNTs during FE could be owing to the strong adhesion of CNTs to the substrate both by SOG and PMMA coatings.  相似文献   
92.
It has been well recognized that a diagnosis procedure that allows operators to successfully identify the nature of an on-going event is inevitable for an effective and appropriate recovery. Unfortunately, studies for a framework that can suggest a unified and consistent process in constructing a serviceable diagnosis procedure seem to be scant. Thus, Park et al. have suggested a systematic framework that can be used to construct a useful diagnosis procedure. In addition, the diagnosis procedure that is currently in use at the reference nuclear power plant (NPP) is reformed in order to demonstrate the appropriateness of the suggested framework. However, the necessity of a well-designed experiment is proposed to confirm the appropriateness of the suggested framework.In this regard, in this study, an experiment is conducted using a full-scope simulator of the reference NPP. From the experiment, two sets of operators' diagnosis performance data are collected, and then they are compared to investigate the change of an operator's diagnosis performance with respect to two types of diagnosis procedures.As a result, it is shown that an operator's diagnosis performance is improved when the revised diagnosis procedure is used. Therefore, it is reasonable to conclude that the suggested framework is useful in constructing an effective diagnosis procedure.  相似文献   
93.
A new process for the fabrication of high current and very low profile micromachined inductors has been developed. This process involves the combination of mechanical lamination and electrodeposition of copper windings by means of LIGA-like lithography through thick epoxy photoresists. The dimension of the fabricated inductor is 16 mm×19 mm×1 mm. The fabricated inductor has an inductance value of 1.2 μH with DC saturation current of 3 A and an electrical resistance of less than 30 mΩ at 10 kHz  相似文献   
94.
A new technique to reduce the phase noise in microwave oscillators is developed using the resonant characteristic of the defected ground structure (DGS). Two kinds of oscillators have been designed and measured for the examination of the reduction of phase noise by the DGS. The first adopts the DGS section under the microstrip line at the gate circuit, while the second has only the conventional microstrip line. Measurement shows reduced phase noise by 10-15 dB in the oscillator with the DGS compared to the conventional one  相似文献   
95.
Public participation is essential in each step of the nuclear-related decision-making process. Recently, the electronic systems using the Internet have become quite popular, and have emerged as a good medium for communicating with the public. In this study, a comprehensive utilization of electronic public participation was used to analyze public opinion on a given nuclear-related decision-making process. The degree of deliberation and meditation of the public participating in an electronic poll survey was evaluated, and the decision-making factors representing the personal characteristics of the poll respondents such as age, income, education, residence, degree of knowledge and concern were carefully incorporated when preparing the poll-survey questionnaire for its evaluation. Fuzzy analysis was used to assess and aggregate the responses to each decision-making factor. As a case study, this procedure was used to analyzing public opinion on the location of a low-level radioactive waste disposal facility on the campus of Seoul National University. The results show that there is a tendency of respondents who are on the negative side of the argument to be more deliberate and meditative in their decision-making process than those on the positive side. Knowledge and residence were found to be important decision-making factors.  相似文献   
96.
97.
Characterisation of a BioFET for detection of albumin in a mixture of human urine is presented. To avoid electrolyte effect of the urine, it was measured in PBS (phosphate buffer saline) at a fixed pH after albumin binding. The drain current was modulated by the albumin bound to the anti-albumin immobilised on the gate surface of the BioFET. The current variation ratio was likely to be proportional to the concentration of the albumin in the range 50-250 mg/1. The results show the feasibility of the BioFET as a urinary albumin sensor.  相似文献   
98.
99.
A sweeping operation called polygonal extrusion is defined to improve the modeling power of CSG-based modeling. It is assumed that a 2D cross-sectional polygon (sweeping polygon) moves in space while its containing plane is kept orthogonal to the tangent direction of the trajectory curve, a planar polygonal chain having no self-intersections. The objective of the paper is to compute the boundary of the swept volume of the sweeping polygon as a set of polygons (or triangles). The most significant challenge to accomplishing this objective is the problem of trimming the swept volume. To solve the trimming problem, 2D-curve offsetting methods are employed. Two algorithms are presented for polygonal extrusion that are based on different offsetting methods, the Voronoi diagram and PWID offset. The proposed algorithms have been implemented and tested with various examples. Published online: 28 January 2003  相似文献   
100.
Presented in this paper is a topology reconstruction algorithm from a set of unorganized trimmed surfaces. Error-prone small geometric elements are handled to give proper topological information. It gives complete topology to topologically complete models, and it is also tolerant to incomplete models. The proposed algorithm is vertex-based in that clues for topological information are searched from the set of vertices first, not from that of edges.  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