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   1874篇
  免费   69篇
  国内免费   40篇
电工技术   14篇
综合类   75篇
化学工业   32篇
金属工艺   20篇
机械仪表   36篇
建筑科学   77篇
矿业工程   11篇
能源动力   11篇
轻工业   13篇
水利工程   61篇
石油天然气   8篇
武器工业   6篇
无线电   36篇
一般工业技术   28篇
冶金工业   27篇
原子能技术   3篇
自动化技术   1525篇
  2022年   6篇
  2021年   10篇
  2020年   13篇
  2019年   12篇
  2018年   17篇
  2017年   36篇
  2016年   41篇
  2015年   43篇
  2014年   95篇
  2013年   84篇
  2012年   84篇
  2011年   98篇
  2010年   89篇
  2009年   94篇
  2008年   85篇
  2007年   89篇
  2006年   84篇
  2005年   76篇
  2004年   73篇
  2003年   75篇
  2002年   65篇
  2001年   48篇
  2000年   42篇
  1999年   35篇
  1998年   38篇
  1997年   43篇
  1996年   35篇
  1995年   30篇
  1994年   46篇
  1993年   25篇
  1992年   22篇
  1991年   23篇
  1990年   11篇
  1989年   18篇
  1988年   17篇
  1987年   8篇
  1986年   7篇
  1985年   26篇
  1984年   17篇
  1983年   30篇
  1982年   25篇
  1981年   23篇
  1980年   11篇
  1979年   30篇
  1978年   23篇
  1977年   15篇
  1976年   22篇
  1975年   13篇
  1974年   6篇
  1973年   8篇
排序方式: 共有1983条查询结果,搜索用时 15 毫秒
11.
Obtaining shorter regular expressions from finite-state automata   总被引:1,自引:0,他引:1  
We consider the use of state elimination to construct shorter regular expressions from finite-state automata (FAs). Although state elimination is an intuitive method for computing regular expressions from FAs, the resulting regular expressions are often very long and complicated. We examine the minimization of FAs to obtain shorter expressions first. Then, we introduce vertical chopping based on bridge states and horizontal chopping based on the structural properties of given FAs. We prove that we should not eliminate bridge states until we eliminate all non-bridge states to obtain shorter regular expressions. In addition, we suggest heuristics for state elimination that leads to shorter regular expressions based on vertical chopping and horizontal chopping.  相似文献   
12.
13.
为确保原有的乌江渡水电站水工建筑物和发电设备以及扩建工程建筑物的施工安全,加快扩建工程施工进度,本扩建工程施工中对关键部位开挖所产生的爆破震动影响实施全面而有效的实时爆破监控,并根据监控成果的研究指导开挖爆破作业,以确定符合实际的安全爆破震动参数。  相似文献   
14.
The combination of SGML and database technology allows to refine both declarative and navigational access mechanisms for structured document collection: with regard to declarative access, the user can formulate complex information needs without knowing a query language, the respective document type definition (DTD) or the underlying modelling. Navigational access is eased by hyperlink-rendition mechanisms going beyond plain link-integrity checking. With our approach, the database-internal representation of documents is configurable. It allows for an efficient implementation of operations, because DTD knowledge is not needed for document structure recognition. We show how the number of method invocations and the cost of parsing can be significantly reduced. Edited by Y.C. Tay. Received April 22, 1996 / Accepted March 16, 1997  相似文献   
15.
C. Pronk 《Software》1992,22(10):885-897
During standardization discussions on Modula-2 the question was raised whether the future standard should need a clause stating a set of minimal requirements for conforming implementations regarding the ‘structuredness’ of lexical, syntactical and run-time constructs in programs written in this language. It was decided to test a number of compilers to find their actual limits on the structuredness of some of these constructs. The test results do not only show these limits, but the inability of some compilers to handle large and complex inputs is shown as well.  相似文献   
16.
Reviews the book, Language in the Americas by Joseph H. Greenberg (1987). Greenberg's work on universals of language has crossed disciplinary boundaries to become known to many psychologists interested in language. His equally important work in language classification, of which Language in the Americas is one part, remains unfamiliar to psychologists. This book is a pioneering work in that it is the first genetic classification of the indigenous languages of both North and South America. Greenberg maintains that all of the languages of the Americas belong to three families: Eskimo-Aleut, Na-Dene, and a family that he has named Amerind. This assertion is both important and controversial; the controversy lies in the grouping of most of the languages including all of those of South and Central America into the Amerind family. Most of Language in the Americas consists of the Amerind etymological dictionary, arranged so that the reader can assess lexical similarities within and between subgroups. Greenberg's discussion is informed, articulate, profound, and to the point. He draws on relevant sources and examples from diverse fields of knowledge. The depth and breadth of his scholarship and the clarity of his presentation create a work that is an intellectual pleasure to read. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
17.
热处理工艺对冲击曲线的影响   总被引:1,自引:0,他引:1  
通过SA515Gr.70钢的不同温度正火和13MnNiMoNbR钢正火不同温度回火试样的示波冲击试验,研究了不同热处理工艺对冲击曲线的影响。  相似文献   
18.
In this paper a methodology for the use of temporal logic as an executable imperative language is introduced. The approach, which provides a concrete framework, calledMetateM, for executing temporal formulae, is motivated and illustrated through examples. In addition, this introduction provides references to further, more detailed, work relating to theMetateM approach to executable logics.  相似文献   
19.
A whole‐program MATLAB to C translation system is presented. The paper outlines the motivation for the problem, discusses the system's architecture, its features and limitations. The translator's operation is explained using an example input program. Details are given on how the system implements and specializes some of the language's built‐in primitives. Finally, the paper reports measurements evaluating the execution time and memory usage of the translated sources, and the compilation time required for the translations. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
20.
本文利用锥函数方法,给出空间环型区域上关联函数的一种计算方法。  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