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   10657篇
  免费   524篇
  国内免费   7篇
电工技术   163篇
综合类   41篇
化学工业   2388篇
金属工艺   243篇
机械仪表   207篇
建筑科学   759篇
矿业工程   41篇
能源动力   341篇
轻工业   984篇
水利工程   69篇
石油天然气   8篇
无线电   825篇
一般工业技术   1916篇
冶金工业   1455篇
原子能技术   92篇
自动化技术   1656篇
  2023年   105篇
  2022年   181篇
  2021年   333篇
  2020年   214篇
  2019年   228篇
  2018年   238篇
  2017年   228篇
  2016年   337篇
  2015年   345篇
  2014年   414篇
  2013年   595篇
  2012年   590篇
  2011年   793篇
  2010年   531篇
  2009年   525篇
  2008年   527篇
  2007年   625篇
  2006年   359篇
  2005年   333篇
  2004年   269篇
  2003年   233篇
  2002年   227篇
  2001年   134篇
  2000年   170篇
  1999年   179篇
  1998年   461篇
  1997年   302篇
  1996年   225篇
  1995年   169篇
  1994年   129篇
  1993年   131篇
  1992年   81篇
  1991年   75篇
  1990年   61篇
  1989年   52篇
  1988年   45篇
  1987年   45篇
  1986年   37篇
  1985年   47篇
  1984年   33篇
  1983年   26篇
  1982年   25篇
  1981年   36篇
  1980年   36篇
  1979年   38篇
  1977年   38篇
  1976年   56篇
  1975年   20篇
  1973年   26篇
  1972年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
The recent Decision of the German Federal Constitutional Court from February 2008 sheds light on the constitutional side of the intersection of law and technology. 25 years after its landmark “Census” decision promulgating the fundamental right to information self-determination the Court “invented” a new fundamental right to the integrity and confidentiality of IT systems. On the background of rapid technological development and especially the rising of the internet as a new medium of communication the Court consistently expanded its line of constitutional protection to fill the gap that has arisen. This decision further opens the gap to the restrictive stance of the U.S. Supreme Court on the constitutional foundation of privacy while at the same time providing some comparative insights into the different interpretations of the respective Constitutions in the information age.  相似文献   
992.
The production of printed electronics exhibits an enormous economical potential due to the possibility to manufacture innovative products at low cost. At the moment, one of the major challenges for the fabrication of printed electronics is the controllability of the material properties during processing and the miniaturization of the deposited structures. In this context, the application of soft lithographic techniques appears promising, because they allow a defined patterning of the materials in the range of few nanometers, which is far below the limits of other printing techniques like inkjet-printing or screen printing. This work proves the applicability of the soft lithographic technique micro-molding in capillaries (MIMIC) for the manufacture of conductive indium tin oxide (ITO) electrodes. For the creation of stable dispersions of ITO nano-sized particles, steric as well as electrostatic stabilization concepts are applied. The prepared dispersions are characterized with regard to the later processing via MIMIC. The geometry and the electrical properties of the soft lithographically deposited structures are determined to prove their functionality. Special attention is paid to the influence of the wetting behavior of the dispersions on the resulting geometry of the structures. Finally, the applicability of the optimized structures is demonstrated by the assembly of a thin film transistor (TFT), in which the deposited structures serve as source and drain electrodes.  相似文献   
993.
994.
A meshfree numerical method for the dynamic analysis of porous media is presented. The u,?p form of Biot’s theory is adopted to mathematically model the dynamic interaction of the solid and the fluid phase within the porous media. The obtained partial differential equations (PDEs) are discretized by the generalized smoothed Galerkin weak form, which is established based on smoothed strains and fluxes. Therefore, edge-based and cell-based smoothing domains are used and a T3-scheme is employed for the selection of support nodes. The shape functions are generated by the radial point interpolation method. The focus of this work lies on the spatial integration of the mass/compressibility and coupling terms of the discrete PDE system. A new algorithm is introduced, which reuses the shape function values that are needed for the construction of the stiffness/permeability matrix to keep the computational effort at a minimum. Numerical problems are analyzed in order to test the algorithm regarding accuracy and efficiency.  相似文献   
995.
Andreas Ranz 《Fuel》2010,89(8):2133-2139
Fuel oil plays one of the most important roles as thermal energy source in domestic application. Due to its common use, a careful monitoring of the grade and the deviation of the quality is required. Recently it has been observed that the presence of polar fatty acid derivatives is leading to problems in the fuel injection systems and consequently can cause a damage of the engine. A fast and reliably working procedure is presented, which allows the group determination of these polar compounds, namely glycerides, soaps and fatty acids. A sample preparation succeeded, which accomplishes the extraction, the clean up and the derivatization in one single reaction vessel. Derivatives were methylated with acetyl chloride and methanol and quantified with gas chromatography mass spectrometry. The complexity of fuel oil requires a careful elaboration of the clean up and the extraction procedure. Owing to the novelty of this procedure an accurate investigation and optimization of influential parameters were performed. Optimum conditions for the solid phase extraction with polar sorbents were provided for all target compounds. Additionally, the necessity of the clean up is shown with the relation between investigated analytes and matrix effects. Finally, method performance was verified with an accurate validation and analyses of spiked samples.  相似文献   
996.
建筑外观非常独特,缄默的风格中流露出极富个性的表现力,这对于在周围公共空间中打造出属于自己个性的建筑来说非常重要。Ericus大楼对于大型公园空间的建造来说是至关重要的。Spiegel是通往港口城的大门,从主要的站台和Brooktorkai就可以看到。  相似文献   
997.
The martensite start temperature (Ms), the martensite austenite re‐transformation start temperature (As) and the re‐transformation finish temperature (Af) of six high alloyed Cr‐Mn‐Ni steels with varying Ni and Mn contents in the wrought and as‐cast state were studied. The aim of this investigation is the development of the relationships between the Ms, As, Af, T0 temperatures and the chemical composition of a new type of Cr‐Mn‐Ni steels. The investigations show that the Ms, As and Af temperatures decrease with increasing nickel and manganese contents. The Af temperature depends on the amount of martensite. Regression equations for the transformation temperatures are given. The experimental results are based on dilatometer tests and microstructure investigations.  相似文献   
998.
The article suggests a model for examining the adoption of e-recruiting by individuals. The model is empirically evaluated using survey data from 323 full and under age applicants. The results explain substantial parts of the individual adoption decision. Interestingly, the relative importance of the adoption drivers varies with age, social environment and the level of education. While, as expected, overall Performance Expectancy is the major force behind adopting e-recruiting, the relative importance of the other factors differs a lot. Whereas Facilitating Conditions came out as an important driver for under age pupils, full age students by contrast are highly driven by the influence of their peer groups and the communication of the respective company they apply for. A major outcome is that the Subjective Norm of family and friends, teachers and professors has a weaker influence for under age pupils who mostly live with their parents than for the group of students who already left home to study at college. Consequentially we assume that the social influence of peer groups on an individual’s adoption differs with respect to age, social environment and level of education. This should be investigated more carefully in future adoption research as it might provide an answer for the varying significance of Subjective Norm in adoption research.  相似文献   
999.
Improvement of the interface contact between biological objects and electronic devices can significantly enhance the quality of electronic signal transfer. The surface of biosensor can be artificially modified in order to strengthen the adhesion of biological cells. We report on results of fabrication of micron and submicron golden spines by means of e-beam lithography and electroplating. The fabrication technique allows easy modification of the size and shape of golden spines by variation of processing parameters. The structures with different spine profiles and spacing have been fabricated for optimization of cell growth conditions. We present the results of growth of rat cortical neurons on the surface of spine modified samples. Well-defined cell guidance was established at the spine arrays. Furthermore, the results of transmission electron microscope and focused ion beam technique confirm the good adhesion between the spines and cell structures.  相似文献   
1000.
Objective: It has been suggested that women have a better face recognition memory than men. Here we analyzed whether this advantage depends on a better encoding or consolidation of information and if the advantage is visible during short-term memory (STM), only, or whether it also remains evident in long-term memory (LTM). Method: We tested short- and long-term face recognition memory in 36 nonclinical participants (19 women). We varied the duration of item presentation (1, 5, and 10 s), the time of testing (immediately after the study phase, 1 hr, and 24 hr later), and the possibility to reencode items (none, immediately after the study phase, after 1 hr). Results: Women showed better overall face recognition memory than men (ηp2 = .15, p  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