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   536篇
  免费   20篇
  国内免费   1篇
电工技术   1篇
化学工业   120篇
金属工艺   10篇
机械仪表   19篇
建筑科学   29篇
能源动力   14篇
轻工业   31篇
水利工程   2篇
石油天然气   2篇
无线电   34篇
一般工业技术   134篇
冶金工业   76篇
原子能技术   4篇
自动化技术   81篇
  2023年   7篇
  2022年   9篇
  2021年   13篇
  2020年   10篇
  2019年   7篇
  2018年   17篇
  2017年   19篇
  2016年   19篇
  2015年   15篇
  2014年   23篇
  2013年   52篇
  2012年   15篇
  2011年   39篇
  2010年   22篇
  2009年   23篇
  2008年   33篇
  2007年   26篇
  2006年   21篇
  2005年   17篇
  2004年   18篇
  2003年   13篇
  2002年   11篇
  2001年   10篇
  2000年   4篇
  1999年   15篇
  1998年   22篇
  1997年   13篇
  1996年   10篇
  1995年   5篇
  1994年   7篇
  1993年   3篇
  1992年   4篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   6篇
  1987年   1篇
  1985年   4篇
  1984年   1篇
  1983年   4篇
  1982年   1篇
  1981年   1篇
  1980年   7篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
  1975年   1篇
  1974年   1篇
  1963年   1篇
排序方式: 共有557条查询结果,搜索用时 62 毫秒
1.
Wireless Personal Communications - Chronic kidney disease (CKD) is a gradual loss of kidney function over the period of time and it is irrevocable once functionality reaches the critical state....  相似文献   
2.
Hsiehchen  David  Espinoza  Magdalena  Hsieh  Antony 《Scientometrics》2018,117(1):391-407
Scientometrics - The expanding presence of multinational research teams highlights the importance of characterizing the outcomes of international collaboration. Herein, we characterize the...  相似文献   
3.
4.
Fodor and Pylyshyn (1988) have argued that the cognitive architecture is not Connectionist. Their argument takes the following form: (1) the cognitive architecture is Classical; (2) Classicalism and Connectionism are incompatible; (3) therefore the cognitive architecture is not Connectionist. In this essay I argue that Fodor and Pylyshyn's defenses of (1) and (2) are inadequate. Their argument for (1), based on their claim that Classicalism best explains the systematicity of cognitive capacities, is an invalid instance of inference to the best explanation. And their argument for (2) turns out to be question-begging. The upshot is that, while Fodor and Pylyshyn have presented Connectionists with the important empirical challenge of explaining systematicity, they have failed to provide sufficient reason for inferring that the cognitive architecture is Classical and not Connectionist.  相似文献   
5.
6.
7.
Transdermal drug delivery has given cardinal contribution to medical practices. First-generation transdermal delivery of small, lipophilic, low-dose drugs and second-generation delivery systems using chemical enhancers, non-cavitational ultrasound and iontophoresis have also resulted in various clinical products provides added functionality. Third-generation delivery systems using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound targeting skin’s barrier layer of stratum corneum. Microneedles acquire pronounced intrigue in recent days. Currently, microneedles are advancing through clinical trials for delivery of macromolecules and vaccines, such as insulin, parathyroid hormone and influenza vaccine. The review explains about the concept of transdermal drug microneedle system comprising of microreservoir, micropumps, flow sensors, types of microneedles. Various researches carried out on these components of microneedle system is elaborately discussed in this review.  相似文献   
8.
Sulfate-reducing bacteria (SRB) play significant role in the corrosion of stainless steels exposed to marine and soil environment. Sulfate reduction by bacterial species results in the production of H2S, which can significantly influence the anodic and cathodic processes and ultimately enhances the corrosion of materials. In the present study, 2205 type duplex stainless steel (DSS) coupons in solution-annealed condition were exposed to chloride medium containing SRB species, Desulfovibrio desulfuricans, for 40 days and examined by microscopy. Etching of the duplex structure, pitting as well as crevice attack were noticed. Similar results were obtained by microscopic studies with coupons exposed for 14 days in medium containing SRB followed by anodic polarization. SEM studies, of crevices observed after anodic polarization, indicated that the attack was initiated at the grain boundaries and slowly encroached into austenite grains. The initiation of attack was also evident from AFM studies of coupon exposed under freely corroding conditions for 7 days. ESCA studies reveal that under anaerobic conditions of SRB growth sulfidation of passive film occurs. The modified passive film found to depolarize the cathodic reactions. The nature and mechanism of SRB attack on DSS and possibility of detection at early stages were discussed.  相似文献   
9.
The endoglucanase CenA and the exoglucanase Cex from Cellulomonasfimi each contain a discrete cellulose-binding domain (CBD),at the amino-terminus or carboxyl-terminus respectively. Thegene fragment encoding the CBD can be fused to the gene of aprotein of interest. Using this approach hybrid proteins canbe engineered which bind reversibly to cellulose and exhibitthe biological activity of the protein partner. Alkaline phosphatase(PhoA) from Escherichia coli, and a ß-glucosidase(Abg) from an Agrobacterium sp. are dimeric proteins. The fusionpolypeptides CenA-PhoA and Abg-CBCcex are sensitive to proteolysisat the junctions between the fusion partners. Proteolysis resultsin a mixture of homo- and heterodimers; these bind to celluloseif one or both of the monomers carry a CBD, e.g. CenA-PhoA/CenA-PhoAand CenA-PhoA/PhoA. CBD fusion polypeptides could be used inthis way to purify polypeptides which associate with the fusionpartner.  相似文献   
10.
In classical deterministic scheduling problems, it is assumed that all jobs have to be processed. However, in many practical cases, mostly in highly loaded make-to-order production systems, accepting all jobs may cause a delay in the completion of orders which in turn may lead to high inventory and tardiness costs. Thus, in such systems, the firm may wish to reject the processing of some jobs by either outsourcing them or rejecting them altogether. The field of scheduling with rejection provides schemes for coordinated sales and production decisions by grouping them into a single model. Since scheduling problems with rejection are very interesting both from a practical and a theoretical point of view, they have received a great deal of attention from researchers over the last decade. The purpose of this survey is to offer a unified framework for offline scheduling with rejection by presenting an up-to-date survey of the results in this field. Moreover, we highlight the close connection between scheduling with rejection and other fields of research such as scheduling with controllable processing times and scheduling with due date assignment, and include some new results which we obtained for open problems.  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