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   11413篇
  免费   597篇
  国内免费   13篇
电工技术   149篇
综合类   38篇
化学工业   2688篇
金属工艺   261篇
机械仪表   255篇
建筑科学   757篇
矿业工程   31篇
能源动力   428篇
轻工业   1070篇
水利工程   109篇
石油天然气   44篇
武器工业   1篇
无线电   894篇
一般工业技术   2020篇
冶金工业   753篇
原子能技术   73篇
自动化技术   2452篇
  2023年   95篇
  2022年   182篇
  2021年   398篇
  2020年   235篇
  2019年   260篇
  2018年   333篇
  2017年   304篇
  2016年   400篇
  2015年   308篇
  2014年   441篇
  2013年   819篇
  2012年   675篇
  2011年   858篇
  2010年   579篇
  2009年   638篇
  2008年   621篇
  2007年   561篇
  2006年   460篇
  2005年   398篇
  2004年   364篇
  2003年   337篇
  2002年   257篇
  2001年   191篇
  2000年   173篇
  1999年   148篇
  1998年   168篇
  1997年   166篇
  1996年   116篇
  1995年   109篇
  1994年   101篇
  1993年   93篇
  1992年   74篇
  1991年   73篇
  1990年   75篇
  1989年   78篇
  1988年   63篇
  1987年   53篇
  1986年   62篇
  1985年   65篇
  1984年   79篇
  1983年   58篇
  1982年   46篇
  1981年   46篇
  1980年   49篇
  1979年   46篇
  1978年   38篇
  1977年   44篇
  1976年   50篇
  1975年   49篇
  1973年   45篇
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
51.
Zusammenfassung  Aus der Sicht eines informationstechnischen Laien scheinen Denial of Service-Angriffe mit Online-Demonstrationen in keinem Zusammenhang zu stehen. Das Gegenteil ist der Fall, wenn durch derartige Angriffe der Anbieter einer Webseite buchst?blich lahm gelegt wird. Ob die an sich lautere Intention einer kritischen Meinungs?u?erung derartige Angriffe rechtfertigen kann, ist fraglich und besch?ftigt die Justiz. Der Verfasser dieses Beitrages bewertet den Sachverhalt eines Denial-of-Service-Angriffes strafrechtlich. Dr. jur. Jan Eichelberger, LL.M.oec. Rechtsreferendar am Kammergericht Interessenschwerpunkte im Gewerblichen Rechtsschutz, im Kapitalmarktrecht und im Recht der neuen Medien  相似文献   
52.
We describe a formal language/notation for DNA molecules that may contain nicks and gaps. The elements of the language, DNA expressions, denote formal DNA molecules. Different DNA expressions may denote the same formal DNA molecule. We analyse the shortest DNA expressions denoting a given formal DNA molecule. We determine lower bounds on their lengths and explain how we construct these minimal DNA expressions.  相似文献   
53.
The television (TV) is one of the most common entertainment devices in homes. Searching and finding TV programs is a common task and using TV guides is one way of performing this. This paper presents three studies that are focused on examining audiences’ TV habits and TV guide usage, evaluating a new concept based on linking paper and pen with TV technology, and studying the audiences’ attitudes toward and anticipated interest in the future guide. The results of our first study emphasize the value of using paper based TV guides and also identify the deficiencies. We also found indications that the advantages and disadvantages of paper-based TV guides are related to the physical properties of paper. Thus, we suggest a solution that uses digital pen and paper technology to offer a new interaction method for TV. A research system “Paper Remote”, is developed and used in the two subsequent studies. Viewers tick designated areas on the paper-based guide to perform actions such as channel switching. However, this solution is not a substitute for the remote control device. We argue that these user studies on linking digital paper to the TV for everyday information navigation illuminate the possibilities of providing innovative solutions also for home information systems also.  相似文献   
54.
This paper presents a new approach to the blind deconvolution and superresolution problem of multiple degraded low-resolution frames of the original scene. We do not assume any prior information about the shape of degradation blurs. The proposed approach consists of building a regularized energy function and minimizing it with respect to the original image and blurs, where regularization is carried out in both the image and blur domains. The image regularization based on variational principles maintains stable performance under severe noise corruption. The blur regularization guarantees consistency of the solution by exploiting differences among the acquired low-resolution images. Several experiments on synthetic and real data illustrate the robustness and utilization of the proposed technique in real applications.  相似文献   
55.
56.
The authors used visual search tasks in which components of the classic flanker task (B. A. Eriksen & C. W. Eriksen, 1974) were introduced. In several experiments the authors obtained evidence of parallel search for a target among distractor elements. Therefore, 2-stage models of visual search predict no effect of the identity of those distractors. However, clear compatibility effects of the distractors were obtained: Responses were faster when the distractors were compatible with the response than when they were incompatible. These results show that even in parallel search tasks identity information is extracted from the distractors. In addition, alternative interpretations of the results in terms of the occasional identification of a distractor before or after the target was identified could be ruled out. The results showed that flat search slopes obtained in visual search experiments provide no benchmark for preattentive processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
57.
Innovating is a multi‐faceted process. In this paper, four different, yet intertwined aspects of this process are distinguished. The first aspect concerns the content of the innovation; a new product, a new technology or a new market. The second aspect concerns the group dynamics of the innovation team. The third aspect concerns seeing the innovation process as a creative process. And the fourth aspect has to do with leadership. Since these four aspects are simultaneously working together during the innovation process, the leaders of this process are working in a very difficult situation, as all four aspects need to be dealt with in different ways. Nearly all of them are, in one way or another, in conflict with one another. They may conflict in real actions, in time horizons (past, present or future) or in effect (positive reactions during market introduction do not garantee ultimate market success). This means that innovation leaders need to show a special kind of leadership. This leadership must be balanced, people‐focused and must include a high tolerance for ambiguity and paradoxes. They have to be nice and nasty at the same time. In short: innovation leaders should be some kind of controlled schizophrenics.  相似文献   
58.
A modified method is discussed that is based on Farooque and Deshpande's method to obtain polymer–polymer interaction parameters using inverse gas chromatography (IGC) data. In the Farooque and Deshpande method, the ratio of the difference of probe–polymer interaction parameters between two polymers and the probe volume [(χ12 ? χ13)/V1] is used as the abscissa. In the modified method, the ratio [(?2χ12 + ?3χ13)/V1] is used as the abscissa. Experimental data previously reported for a poly(?‐caprolactone)‐polyepichlorohydrin (PCL/PECH) blend and a poly(ethyl acrylate)‐poly(vinyl propionate) (PEA/PVPr) blend are analyzed. It is found that the slopes obtained by the new method had smaller deviations from the theoretical values than the Farooque and Deshpande method. The standard deviations of both slopes and intercepts obtained from the new method are also smaller. Using the new method, the polymer–polymer interaction parameters obtained from the intercept are negative numbers for the PCL/PECH system and very small positive numbers for PEA/PVPr. Explanations are given for the probe and concentration dependency of the polymer–polymer interaction parameters that are generally observed in IGC studies. A new method for selecting the best probe for calculating the interaction parameter is discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 671–680, 2003  相似文献   
59.
即使在系统中事实上仍然有许多空闲内存时,内存碎片还会最终导致出现内存用完的情况.一个不断产生内存碎片的系统,不管产生的内存碎片多么小,只要时间足够长,就会将内存用完.  相似文献   
60.
We present a study of magneto-thermal instabilities in polycrystalline MgB2 superconductor, by magnetic hysteresis loop measurements and by investigations of magnetic flux dynamics with a miniature Hall probe. Temperature and magnetic field ranges where the flux jumps may be observed have been determined. On the basis of measurements of the magnetic flux dynamics, an average magnetic diffusivity describing the process of the flux jump is estimated. This parameter is compared with the thermal and magnetic diffusivities calculated on the basis of available data for thermal conductivity, heat capacity and resistivity. It is shown that the estimated value of the field of the first flux jump is influenced significantly by the field dependence of specific heat. In order to explain the observed phenomenon, the temperature reached by the sample during the flux jump at different magnetic fields is calculated.  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