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   546篇
  免费   5篇
  国内免费   2篇
电工技术   44篇
综合类   8篇
化学工业   228篇
金属工艺   15篇
机械仪表   10篇
建筑科学   10篇
能源动力   33篇
轻工业   23篇
水利工程   1篇
无线电   41篇
一般工业技术   82篇
冶金工业   17篇
原子能技术   20篇
自动化技术   21篇
  2022年   4篇
  2021年   8篇
  2019年   3篇
  2018年   6篇
  2016年   5篇
  2015年   7篇
  2014年   7篇
  2013年   15篇
  2012年   18篇
  2011年   25篇
  2010年   14篇
  2009年   23篇
  2008年   16篇
  2007年   19篇
  2006年   21篇
  2005年   12篇
  2004年   12篇
  2003年   22篇
  2002年   21篇
  2001年   12篇
  2000年   10篇
  1999年   19篇
  1998年   12篇
  1997年   8篇
  1996年   14篇
  1995年   18篇
  1994年   13篇
  1993年   11篇
  1992年   10篇
  1991年   7篇
  1990年   8篇
  1989年   6篇
  1988年   2篇
  1987年   14篇
  1986年   12篇
  1985年   15篇
  1984年   14篇
  1983年   10篇
  1982年   7篇
  1981年   13篇
  1980年   7篇
  1979年   16篇
  1978年   10篇
  1977年   3篇
  1976年   3篇
  1975年   6篇
  1973年   2篇
  1972年   2篇
  1971年   2篇
  1968年   2篇
排序方式: 共有553条查询结果,搜索用时 15 毫秒
51.
The purpose of our work is to control the interfacial bonds between PVC and NBR using the ammonium salts of triazine thiols and dithiodimorpholine (DTDM) and thereby reveal the relation between the interfacial bonds and the final mechanical properties of products. In the experimental work a two-stage process was used. At first, an NBR/PVC blend was mixed with a mono-tetra-n-butylammonium salt of triazine trithiol at a temperature of 100°C on a two-roll mill to give the branching structure of triazine thiols into PVC. In the second stage branched NBR/PVC reacted with DTDM to afford the branched PVC containing trithiomorphonyl groups. In the presence of ZnO at 160°C trithiomorphonyl groups react with NBR to form a crosslinking structure between NBR and PVC. The mechanical properties of cured NBR/PVC blends were markedly improved by the treatment process and after addition of tetramethylthiuram monosulphide also. The mechanical properties were not improved by increasing the concentration of TT-TBA (tetrabutylammonium salt of 1,3,5-triazine-2,4,6-trithiol) over 4.2 phr.  相似文献   
52.
At the Japan Atomic Energy Research Institute (JAERI), research activities related to probabilistic fracture mechanics (PFM) have been conducted as a part of the research program on aging and structural integrity of LWR components. This paper describes the outline of two activities related to PFM, i.e. the development of a PFM code and a contract research on ‘Application of PFM Methodology to Reliability Assessment of Nuclear Components’ implemented by the Japan Welding Engineering Society (JWES). In the former research, a new PFM code PASCAL (PFM Analysis of Structural Components in Aging LWR) was developed. This code has some new functions in models of semi-elliptical crack extension, elastic–plastic fracture analysis based on R6 method and options for the evaluation of overlay cladding and warm pre-stress (WPS) effect. Besides, the code has the function to evaluate the effect of irradiation embrittlement recovery by thermal annealing of a reactor pressure vessel and re-irradiation embrittlement. Based on the analyses on benchmark problem conducted by USNRC/EPRI, performance and functions introduced in the code were examined. Some case studies were also carried out to investigate the influence of various parameters. On the other hand, JAERI has been sponsoring the PFM related activities in relation to the structural integrity of LWR components. These activities have been conducted at JSME and JWES. The objective of this activity has been to provide for the future need of PFM methodology.  相似文献   
53.
Abstract— The perfluorocarbons (PFCs) used as etching‐process and chamber‐cleaning gases in the manufacture of LCD devices have a high global‐warming potential and a long atmospheric lifetime. Thus, to voluntarily reduce these environmentally harmful PFCs, in 2001 the Japanese LCD association established the World LCD Industry Cooperation Committee (WLICC), together with its counterpart associations in the Republic of Korea and Taiwan. Since that time involving many discussions, the WLICC reached a consensus on reducing the aggregate absolute PFC emissions to the equivalent of less than 0.82 million metric tons of carbon by 2010. Each association has been taking whatever emission reduction steps it considers best to achieve this goal. Thanks to these measures, the PFC emissions from the Japanese LCD industry have remained at the same level, or less, than those of the year 2000, in spite of the fact that PFC purchases have continually increased. In the interim, the Japanese LCD association has been obtaining experimental data for the 2006 IPCC Inventory Guidelines, which will give the emission factors needed to estimate the PFC emissions. As a result, some data are quite different from emission factors given in the current 2000 Inventory Guidelines. All the data obtained have been submitted to the IPCC to be adopted in the new 2006 Guidelines.  相似文献   
54.
55.
Boron ions (11B+ of 3·7 to 7·4 × 1011/cm2 were implanted at 60–120 keV into the channel region of p-channel MNOS double layer insulated gate field effect transistors through 920–940 Å of SiO2 and various thicknesses (300–1800 Å) of Si3N4 deposited on SiO2. Subsequent annealing was performed in a nitrogen atmosphere at 1000°C for 30 min. Acceleration energy, implant dose and Si3N4 thickness dependences of the shift of the threshold voltage showed good agreement with the calculated results based on Ishiwara and Furukawa's theory for distribution of implanted atoms in the double layered substrate, using the projected ranges and standard deviations larger than LSS predictions by the factor of 1·2 for SiO2 and 1·3 for Si3N4, respectively. The results on the gain terms and the breakdown voltages were qualitatively the same as those of 11B+-implanted p-channel MOS transistors.  相似文献   
56.
The discharge behaviour of electrodeposited lead dioxide and lead electrodes was investigated under various conditions; the surfaces of the discharged electrodes were observed with a scanning electron microscope. Both the positive and negative electrodes were passivated by a covering of deposited lead sulphate crystals. The amount of lead sulphate required for passivation depended on the size of the crystals.  相似文献   
57.
58.
59.
The surface tensions of a mixed system of sodium tetradecyl sulfate (STS) and a series of polyoxyethyleneglycol-n-dodecyl ethers (nED) were measured at temperatures of 30 and 40 C, respectively. When the STS concentration was fixed, the surface tension curves of the mixed system showed a flat portion in the range of which the mixed micelles would be formed. With a decrease of the added STS concentration, the length of the flat portion in these curves decreased gradually, and finally disappeared in the presence of 0.05 mM STS. Furthermore, when the concentration of STS was fixed at 1.0 mM, which is below the critical micelle concentration (CMC), the flat portion length in the surface tension curves de-creased with decreasing ethylene oxide chain length in nED and with increasing temperature. The influence of increment of temper-ature was comparable to that for reducing the length of ethylene oxide chain in nED.  相似文献   
60.
This paper describes the basic concepts, design and implementation decisions, standpoints and significance of the database machine Delta in the scope of Japan’s Fifth Generation Computer Project. Delta is planned to be operational in 1985 for researchers’ use as a backend database machine for logic programming software development. Delta is basically a relational database machine system. It combines hardware facilities for efficient relational database operations, which are typically represented by relational algebra, and software which deals with hardware control and actual database management requirements. Notable features include attribute-based internal schema in accordance with the characteristics found in the relation access from logic programming environment. This is also useful for the hardware relational algebra manipulation algorithm based on merge-sorting of attributes by hardware and a large capacity Semiconductor Disk for fast access to databases. Various implementation decisions of database management requirements are made in this novel system configuration, which will be meaningful to give an example for constructing a hardware and software combination of a relational database machine. Delta is in the stage between detailed design and implementation.  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