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   1401篇
  免费   37篇
  国内免费   4篇
电工技术   74篇
综合类   6篇
化学工业   356篇
金属工艺   28篇
机械仪表   35篇
建筑科学   27篇
矿业工程   1篇
能源动力   71篇
轻工业   129篇
水利工程   2篇
无线电   130篇
一般工业技术   259篇
冶金工业   192篇
原子能技术   42篇
自动化技术   90篇
  2023年   6篇
  2022年   13篇
  2021年   20篇
  2020年   9篇
  2019年   18篇
  2018年   10篇
  2017年   20篇
  2016年   20篇
  2015年   18篇
  2014年   36篇
  2013年   63篇
  2012年   38篇
  2011年   71篇
  2010年   55篇
  2009年   78篇
  2008年   67篇
  2007年   55篇
  2006年   54篇
  2005年   49篇
  2004年   48篇
  2003年   50篇
  2002年   43篇
  2001年   31篇
  2000年   27篇
  1999年   33篇
  1998年   83篇
  1997年   68篇
  1996年   49篇
  1995年   39篇
  1994年   25篇
  1993年   25篇
  1992年   21篇
  1991年   29篇
  1990年   16篇
  1989年   15篇
  1988年   23篇
  1987年   5篇
  1986年   17篇
  1985年   11篇
  1984年   10篇
  1983年   13篇
  1982年   8篇
  1981年   11篇
  1980年   2篇
  1979年   9篇
  1978年   6篇
  1977年   9篇
  1976年   3篇
  1973年   4篇
  1970年   2篇
排序方式: 共有1442条查询结果,搜索用时 31 毫秒
991.
It seems both necessary and promising to develop an intelligent human-machine system, considering the objective of the human-machine system and the recent advance in cognitive engineering and artificial intelligence together with the ever-increasing importance of human factor issues in nuclear power plant operation and maintenance. It should support human operators in their knowledge-based behaviour and allow them to cope with unanticipated abnormal events, including recovery from erroneous human actions. A top-down design approach has been adopted based on cognitive work analysis, and (1) an ecological interface, (2) a cognitive model-based advisor and (3) a robust automatic sequence controller have been established. These functions have been integrated into an experimental control room. A validation test was carried out by the participation of experienced operators and engineers. The results showed the usefulness of this system in supporting the operator's supervisory plant control tasks.  相似文献   
992.
993.
A new technique for measuring the total normal emittance of a metal in a semi-transparent liquid has been proposed and this technique has been applied to measure the emittance of stainless steel (SUS304), nickel, and gold in molten potassium nitrate KNO3. These emittance data are indispensable to analyzing the radiative heat transfer between a metal and a semitransparent liquid, such as a molten salt.  相似文献   
994.
Mitsunori Makino  Yuzo Toda 《Fuel》1979,58(3):231-234
In order to make clear the effect of pressure upon the gaseous products on pyrolysis of coal, experiments were carried out using a flow-type apparatus under helium pressure up to 900 °C, changing both the superficial velocity of carrier gas and the height of the coal bed. No significant pressure effects on the gaseous products were observed. An increase of methane evolution was found above 600 °C on account of the decrease in superficial velocity and the increase in height of the coal bed.  相似文献   
995.
To develop a new type of carbothermal reduction for the preparation of nitrides, a montmorillonite-polyacrylonitrile intercalation compound was heated inflowing N2 using intercalated polyacrylonitrile as a reducing agent. Nitridation occurred at >1150°C, and β-sialon was obtained, with the formation of β-Sic and AlN.  相似文献   
996.
997.
We searched for fission yeast (Schizosaccharomyces pombe) proteins that preferentially bind to a synthetic curved DNA sequence, by means of a DNA-binding gel shift assay in the presence of an excess amount of a non-curved DNA sequence as a competitor. We identified such a protein in S. pombe. The protein, thus purified, has an apparent molecular weight of 42 000, as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was suggested that this protein (42 K-protein) recognizes and binds to a curved DNA structure in a given nucleotide sequence, although it also binds to a non-curved DNA sequence with lower affinity. As its putative coding sequence, a 1·9-kilobase genomic DNA from S. pombe was cloned and sequenced. Sequencing of a cDNA clone also revealed the existence of an open reading frame, with no intron, encoding a 381-amino-acid protein with a calculated molecular mass, 41 597. This protein appears to be located in the nucleus. The predicted protein sequence revealed that the 42 K-protein exhibits no significant similarity to any other known proteins, except to a hypothetical protein of Caenorhabditis elegans.  相似文献   
998.
In the previous study, we clarified that enteric granules were appropriate dosage forms of lansoprazole. The establishment of these formulations, however, was difficult because some of the excipients needed for these formulations are incompatible with the drug. We examined the effects of adding magnesium carbonate as an alkaline stabilizer and could get stable enteric granules. We also discuss the mechanism of stabilization.  相似文献   
999.
On heating films of long-chain alkylamino-1,3,5-triazine-2,4-dithiols, substituted with unsaturated groups in the 6-position, on copper plates in air, the films become partially insoluble in benzene. The polymerization rate and monomer conversion increased with temperature above 80°C and with time. At low temperatures, an induction period was observed. The detailed behavior was dependent upon the number and length of the alkyl chains. Films with high packing density polymerized more slowly. In the presence of azobis(isobutyro)nitrile (AIBN) and benzoyl peroxide (BPO), the rate and conversion increased and the induction period disappeared. The optimum concentration of initiators was approximately 0.0025 mol% of monomer. The polymerization of the films was initiated by oxygen activated with copper, or by radicals derived from AIBN and BPO. It is proposed that the growth of polymer proceeded mainly by the addition of thiyl radicals to unsaturated groups, the insoluble polymers being formed by the coupling of thiyl radicals.  相似文献   
1000.
The oxidative stability at 37°C and 12% relative humidity of arachidonoyl moiety of 6-O-arachidonoyl l-ascorbate, which was synthesized through lipase-catalyzed condensation with l-ascorbic acid, was higher than that of unmodified arachidonic acid. Arachidonic acid and arachidonoyl ascorbate were microencapsulated with maltodextrin, gum arabic or a soluble soybean polysaccharide by spray-drying. The oxidation of arachidonic acid under the conditions was retarded by its microencapsulation with gum arabic or the soluble soybean polysaccharide. The oxidation of arachidonoyl moiety of the ascorbate encapsulated with gum arabic or the soluble soybean polysaccharide more slowly proceeded than unmodified or encapsulated arachidonic acid. The fractions of the unoxidized arachidonoyl moiety on day 29 were greater than 0.7. Thus, esterification of arachidonic acid with ascorbic acid and subsequent microencapsulation with gum arabic or the soluble soybean polysaccharide significantly improved its oxidative stability.  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