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   247篇
  免费   5篇
电工技术   5篇
化学工业   72篇
金属工艺   9篇
机械仪表   3篇
建筑科学   4篇
矿业工程   1篇
能源动力   8篇
轻工业   49篇
无线电   7篇
一般工业技术   56篇
冶金工业   17篇
原子能技术   3篇
自动化技术   18篇
  2024年   1篇
  2023年   1篇
  2022年   9篇
  2021年   9篇
  2020年   4篇
  2019年   2篇
  2018年   3篇
  2017年   1篇
  2016年   8篇
  2015年   3篇
  2014年   11篇
  2013年   13篇
  2012年   15篇
  2011年   21篇
  2010年   9篇
  2009年   9篇
  2008年   5篇
  2007年   8篇
  2006年   9篇
  2005年   12篇
  2004年   4篇
  2003年   5篇
  2002年   9篇
  2001年   7篇
  2000年   8篇
  1999年   2篇
  1998年   7篇
  1997年   4篇
  1996年   4篇
  1995年   4篇
  1994年   2篇
  1993年   6篇
  1991年   2篇
  1990年   1篇
  1988年   2篇
  1986年   4篇
  1985年   7篇
  1984年   3篇
  1983年   2篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1977年   4篇
  1976年   3篇
  1974年   2篇
  1967年   1篇
  1928年   1篇
  1925年   1篇
排序方式: 共有252条查询结果,搜索用时 15 毫秒
101.
Study on small diameter drilling in GFRP   总被引:2,自引:0,他引:2  
In small diameter drilling with the drilling machine, the drilled hole quality of the printed wiring board (PWB), made of GFRP, is evaluated by investigating the surface roughness and the internal damage to the hole. An investigation of the damage is conducted by changing the number of drilled holes. Additionally, in laser drilling using a CO2 source and a YAG source, the laser drilling process is clarified by observing the damage to the hole, and moreover the relation between the drilling conditions and the damage of the hole is obtained. In conclusion, it is shown that, in the case of the present drilling machine, the anisotropy of the hole surface roughness is able to be developed by the tool tip profile, and as the new process is of no contact drilling, the application of a laser beam machine using a CO2 laser source is effective in the smaller diameter drilling in PWB's.  相似文献   
102.
103.
Anodic dissolution of an Fe–5Ni alloy in deoxygenated acidic chloride solutions of 1.0 M ionic strength has been studied. Steady state partial current densities of the iron and nickel components were obtained by atomic absorption spectrophotometry analysis of the solutions. Alloy and component electrodissolution rates show two anodic Tafel regions indicating simultaneous parallel reactions as reported previously for pure iron. Anodic Tafel slopes of 0.075 and 0.04V dec–1 were obtained in the lower (A) and higher (B) polarization regions, respectively. The kinetic results for the alloy are consistent with the Cl accelerated mechanism in Region (A) and the Bockris or OH accelerated mechanism in Region (B) for both iron and nickel components as proposed previously for pure iron.  相似文献   
104.
TimeBank evolution as a community resource for TimeML parsing   总被引:1,自引:1,他引:0  
TimeBank is the only reference corpus for TimeML, an expressive language for annotating complex temporal information. It is a rich resource for a broad range of research into various aspects of the expression of time and temporally related events. This paper traces the development of TimeBank from its initial—and somewhat noisy—version (1.1) to a substantially revised release (1.2), now available via the Linguistic Data Consortium. The development path is motivated by the encouraging empirical results of TimeML-compliant annotators developed on the basis of TimeBank 1.1, and is informed by a detailed study of the characteristics of that initial release, which guides a clean-up process turning TimeBank 1.2 into a consistent and robust community resource.
Branimir BoguraevEmail:
  相似文献   
105.
Rie?an gave in Rie?an (2004) [9] an axiomatic characterization of a probability on IFS-events and proved in Rie?an (2006) [10] a representation theorem for it. In Ren?ová [9], Ren?ová introduced the notions of additive φ-probability and strongly additive φ-probability and gave a representation theorem for strongly additive φ-probabilities.In this paper we give a generalization of the axiomatic characterization given by Rie?an in Rie?an (2006) [10]; from this, the representation theorem for strongly additive φ-probabilities will follow.  相似文献   
106.
A novel, centrifugal disk-based micro-total analysis system (μTAS) for low cost and high throughput semi-automated immunoassay processing was developed. A key innovation in the disposable immunoassay disk design is in a fluidic structure that enables very efficient micro-mixing based on a reciprocating mechanism in which centrifugal acceleration acting upon a liquid element first generates and stores pneumatic energy that is then released by a reduction of the centrifugal acceleration, resulting in a reversal of direction of flow of the liquid. Through an alternating sequence of high and low centrifugal acceleration, the system reciprocates the flow of liquid within the disk to maximize incubation/hybridization efficiency between antibodies and antigen macromolecules during the incubation/hybridization stage of the assay. The described reciprocating mechanism results in a reduction in processing time and reagent consumption by one order of magnitude.  相似文献   
107.
A resorcinol resin/water dispersion and a rubber latex are added to 1% 2,2,6,6,-tetramethylpyperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TEMPO-CNFs) dispersed in water, followed by oven drying at 40 °C for 20 h to prepare a dried TEMPO-CNF/resorcinol resin/latex rubber (DTRL) mixture with a weight ratio of 1/0.5/3. DTRL is then added to a nitrile-butadiene rubber (NBR) or a carboxy group-containing NBR (X-NBR) sheet, and the mixture is kneaded by a two-roll mill at 20–30 °C with high shear forces. The tensile strength and Young's modulus of the crosslinked DTRL/rubber composite sheets remarkably increased from 10 and 12 MPa, respectively, for the reference sheet to 24 and 82 MPa, respectively, for the DTRL/rubber composite sheets containing ≈10 vol% TEMPO-CNFs. Scanning electron microscopy revealed that no TEMPO-CNF agglomerates are present in the DTRL/rubber composite sheets. The tensile properties of the composite sheets are the best when a X-NBR sheet and NBR latex are used as the matrix rubber and latex in DTRL preparation, respectively. When water-extracted DTRL (WDTRL, mass recovery ratio ≈94%) is used in place of DTRL, the WDTRL/rubber composite sheets show sufficient water resistance, while the tensile properties are almost the same as those of the DTRL/rubber composite sheets.  相似文献   
108.
随着不同电压等级专线用户大量接入电网,各电压等级的无损电量占比逐步增大,含无损电量的统计线损率减小,针对无损电量占比掩盖了有损电量部分的真实线损情况这一问题,分析了无损电量占比与扣除无损电量前、后线损率的关系,并得出结论:无损电量占比增大,含无损电量的线损率成比例减小。据此可对线损率进行估算、对各地区的实际线损情况进行横向对比,有效提高线损管理水平。  相似文献   
109.

Background  

We have previously shown that irregular lifestyle of young Japanese female students are significantly related to their desire to be thinner. In the present study, we examined the nutritional knowledge and food habits of Chinese university students and compared them with those of other Asian populations.  相似文献   
110.
Linoleic acid hydroperoxide (LAOOH) was effectively degraded by horseradish peroxidase (HRP) in the presence of quercetin. Several natural phenolic antioxidants, such as quercetin, capsaicin, and alpha-tocopherol, acted as good hydrogen donors in the peroxidase reaction that occurs during lipid hydroperoxide degradation. However, glutathione, which is a non-phenolic antioxidant that acts as a hydrogen donor for glutathione peroxidase, could not suppress lipid peroxidation in the presence of HRP. Lipid hydroperoxides generated from eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were also degraded with HRP in the presence of quercetin, and oxidative decomposition of DHA was suppressed by this reaction.  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