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   4795篇
  免费   84篇
  国内免费   1篇
电工技术   66篇
综合类   13篇
化学工业   473篇
金属工艺   61篇
机械仪表   55篇
建筑科学   353篇
矿业工程   2篇
能源动力   99篇
轻工业   522篇
水利工程   28篇
石油天然气   3篇
无线电   227篇
一般工业技术   451篇
冶金工业   2109篇
原子能技术   54篇
自动化技术   364篇
  2022年   34篇
  2021年   67篇
  2020年   28篇
  2019年   38篇
  2018年   53篇
  2017年   44篇
  2016年   63篇
  2015年   50篇
  2014年   66篇
  2013年   93篇
  2012年   120篇
  2011年   171篇
  2010年   120篇
  2009年   113篇
  2008年   127篇
  2007年   271篇
  2006年   85篇
  2005年   90篇
  2004年   81篇
  2003年   86篇
  2002年   79篇
  2001年   61篇
  2000年   70篇
  1999年   115篇
  1998年   667篇
  1997年   360篇
  1996年   231篇
  1995年   183篇
  1994年   139篇
  1993年   139篇
  1992年   48篇
  1991年   60篇
  1990年   55篇
  1989年   61篇
  1988年   50篇
  1987年   47篇
  1986年   43篇
  1985年   42篇
  1984年   26篇
  1983年   20篇
  1982年   26篇
  1981年   35篇
  1980年   33篇
  1979年   36篇
  1978年   18篇
  1977年   51篇
  1976年   94篇
  1974年   17篇
  1973年   24篇
  1969年   16篇
排序方式: 共有4880条查询结果,搜索用时 9 毫秒
1.
2.
Test Case Generation as an AI Planning Problem   总被引:6,自引:0,他引:6  
While Artificial Intelligence techniques have been applied to a variety of software engineering applications, the area of automated software testing remains largely unexplored. Yet, test cases for certain types of systems (e.g., those with command language interfaces and transaction based systems) are similar to plans. We have exploited this similarity by constructing an automated test case generator with an AI planning system at its core. We compared the functionality and output of two systems, one based on Software Engineering techniques and the other on planning, for a real application: the StorageTek robot tape library command language. From this, we showed that AI planning is a viable technique for test case generation and that the two approaches are complementary in their capabilities.  相似文献   
3.
Understanding the mechanism for sucrose-induced protein stabilization is important in many diverse fields, ranging from biochemistry and environmental physiology to pharmaceutical science. Timasheff and Lee [Lee, J. C. & Timasheff, S. N. (1981) J. Biol. Chem. 256, 7193-7201] have established that thermodynamic stabilization of proteins by sucrose is due to preferential exclusion of the sugar from the protein's surface, which increases protein chemical potential. The current study measures the preferential exclusion of 1 M sucrose from a protein drug, recombinant interleukin 1 receptor antagonist (rhIL-1ra). It is proposed that the degree of preferential exclusion and increase in chemical potential are directly proportional to the protein surface area and that, hence, the system will favor the protein state with the smallest surface area. This mechanism explains the observed sucrose-induced restriction of rhIL-1ra conformational fluctuations, which were studied by hydrogen-deuterium exchange and cysteine reactivity measurements. Furthermore, infrared spectroscopy of rhlL-1ra suggested that a more ordered native conformation is induced by sucrose. Electron paramagnetic resonance spectroscopy demonstrated that in the presence of sucrose, spin-labeled cysteine 116 becomes more buried in the protein's interior and that the hydrodynamic diameter of the protein is reduced. The preferential exclusion of sucrose from the protein and the resulting shift in the equilibrium between protein states toward the most compact conformation account for sucrose-induced effects on rhIL-1ra.  相似文献   
4.
5.
6.
Some of the more salient aspects of the digital processing technology of PD signals are examined. Most of the efforts in this field are concentrated on the application of digital analyzers for pulse height analysis, pattern recognition and identification of the physical phenomena. It is demonstrated that errors in the signal processing unit can lead to dominant mistakes in the interpretation of the test results  相似文献   
7.
A system for person-independent classification of hand postures against complex backgrounds in video images is presented. The system employs elastic graph matching, which has already been successfully applied for object and face recognition. We use the bunch graph technique to model variance in hand posture appearance between different subjects and variance in backgrounds. Our system does not need a separate segmentation stage but closely integrates finding the object boundaries with posture classification.  相似文献   
8.
9.
Bestehen ausreichende Anhaltspunkte für die Hochwassergef?hrdung, ist die Gemeinde verpflichtet, sich durch Nachforschungen Gewissheit über das Vorliegen oder Nichtvorliegen eines Hochwasserabflussgebietes gem § 38 Abs 3 WRG zu verschaffen. Liegt ein solches vor, hat sie gem § 12 Abs 1 Z 2 krnt GplG dieses im Fl?chenwidmungsplan ersichtlich zu machen. Erteilt die Gemeinde eine Baubewilligung ohne diese von der Erteilung einer wasserrechtlichen Bewilligung abh?ngig zu machen, haftet sie für die Kosten der Bauführung, die bei gesetzes-konformer Vorgangsweise unterlassen worden w?re.  相似文献   
10.
Using boundary element based three dimensional modelling for linear fracture mechanics, we present an analysis of cracking in a homogeneous medium subject to contact load. The proposed iterative solution procedure allows a simultaneous treatment of a reasonable number of partially closed cracks. It is shown that the most probable direction of propagation of a vertical internal crack is strongly dependent on its size compared to the contact radius and its location with respect to the axis of maximum normal load.  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