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   2025篇
  免费   79篇
  国内免费   9篇
电工技术   19篇
综合类   1篇
化学工业   506篇
金属工艺   41篇
机械仪表   83篇
建筑科学   42篇
矿业工程   3篇
能源动力   102篇
轻工业   95篇
水利工程   80篇
无线电   229篇
一般工业技术   400篇
冶金工业   175篇
原子能技术   16篇
自动化技术   321篇
  2024年   7篇
  2023年   36篇
  2022年   60篇
  2021年   84篇
  2020年   68篇
  2019年   85篇
  2018年   89篇
  2017年   71篇
  2016年   76篇
  2015年   51篇
  2014年   79篇
  2013年   191篇
  2012年   99篇
  2011年   117篇
  2010年   85篇
  2009年   71篇
  2008年   68篇
  2007年   66篇
  2006年   57篇
  2005年   47篇
  2004年   29篇
  2003年   25篇
  2002年   23篇
  2001年   11篇
  2000年   21篇
  1999年   29篇
  1998年   34篇
  1997年   37篇
  1996年   25篇
  1995年   27篇
  1994年   32篇
  1993年   30篇
  1992年   23篇
  1991年   29篇
  1990年   15篇
  1989年   24篇
  1988年   16篇
  1987年   22篇
  1986年   14篇
  1985年   23篇
  1984年   23篇
  1983年   11篇
  1982年   8篇
  1981年   11篇
  1980年   10篇
  1979年   8篇
  1978年   10篇
  1977年   6篇
  1976年   8篇
  1973年   5篇
排序方式: 共有2113条查询结果,搜索用时 22 毫秒
51.
Rice wine was prepared in the laboratory from a black pigmented rice (cv. Poireton) using standardized methodology. The wine was fortified with the probiotic strains Lactobacillus acidophilus ATCC 4356 and Lactobacillus sakei ATCC 15521 and allowed to undergo a storage period of 28 days at 4°C. These rice wines were compared with a commercial wine used as a standard reference wine. A panel consisting of 30 judges performed the sensory evaluation. The scores obtained were based on the quality attributes of colour, taste, aroma and alcoholic strength. Analysis of the sensory scores and ranking of the different samples were performed using fuzzy analysis. The quality attributes were also ranked according to their importance in the overall acceptability. Colour and alcoholic strength were accorded the highest importance, compared with aroma and taste, as quality attributes. The rice wines were rated as ‘not satisfactory’, ‘fair’, ‘medium’, ‘good’ and ‘excellent’ on the sensory scale. Out of the wines prepared, black pigmented rice wine fortified with L. acidophilus was the most acceptable and was ranked as ‘good’, which was also at par with the commercial wine. On the other hand, black pigmented rice wine fortified with L. sakei and black pigmented rice wine fortified with L. acidophilus and L. sakei were ranked in the ‘satisfactory’ category followed by the unfortified wine ranked in the ‘fair’ category. Copyright © 2015 The Institute of Brewing & Distilling  相似文献   
52.
Monitoring and evaluation of irrigation projects has been a neglected subject in the past. While some lip service has been given to this subject, with few exceptions, it has received very little attention or consideration as a part of the overall management process for the projects. It is argued that without a continuing and effective monitoring and evaluation system, it is unlikely that the project benefits can be achieved or they will be optimal. A comprehensive monitoring and evaluation system is recommended for irrigation projects at four interrelated levels: planning, design and construction of physical facilities; operation and maintenance of irrigation and drainage facilities; agricultural production and achievement of socio‐economic objectives.  相似文献   
53.
54.
The study deals with the vulcanization of carboxylated nitrile butadiene rubber (XNBR) having synergistic combinations of accelerators comprising thiophosphoryl disulfide as one of the components. Other constituent accelerators employed in the present investigation are 2-mercaptobenzothiazole (MBT), 2-mercaptobenzothiazyl disulfide (MBTS), bis(N-oxydiethylene)disulfide (ODDS), N-oxydiethylene 2-benzothiazole sulfenamide (OBTS), etc. The binary combinations of thiophosphoryl disulfides with OBTS exhibited the highest mutual activity in the respective areas, so far as the physical properties are concerned. Structural characterization of different thiophosphoryl disulfide-accelerated XNBR vulcanizates, including those formed from the synergistic combinations with OBTS, were studied using a methyl iodide probe. It was found that the amount of sulfidic crosslinks arising from the reaction between  COOH groups of XNBR and thiophosphoryl disulfides, actually controls the network structure as wellas the physical properties of the vulcanizates. © 1996 John Wiley & Sons, Inc.  相似文献   
55.
Bread wheat is the most widely cultivated crop worldwide, used in the production of food products and a feed source for animals. Selection tools that can be applied early in the breeding cycle are needed to accelerate genetic gain for increased wheat production while maintaining or improving grain quality if demand from human population growth is to be fulfilled. Proteomics screening assays of wheat flour can assist breeders to select the best performing breeding lines and discard the worst lines. In this study, we optimised a robust LC–MS shotgun quantitative proteomics method to screen thousands of wheat genotypes. Using 6 cultivars and 4 replicates, we tested 3 resuspension ratios (50, 25, and 17 µL/mg), 2 extraction buffers (with urea or guanidine-hydrochloride), 3 sets of proteases (chymotrypsin, Glu-C, and trypsin/Lys-C), and multiple LC settings. Protein identifications by LC–MS/MS were used to select the best parameters. A total 8738 wheat proteins were identified. The best method was validated on an independent set of 96 cultivars and peptides quantities were normalised using sample weights, an internal standard, and quality controls. Data mining tools found particularly useful to explore the flour proteome are presented (UniProt Retrieve/ID mapping tool, KEGG, AgriGO, REVIGO, and Pathway Tools).  相似文献   
56.
Multimedia Tools and Applications - Performance of computerized diagnostic systems yearning to be approved by medical regulatory bodies must meet the expectations of human experts. Highly accurate...  相似文献   
57.
58.
Poly(N-vinyl carbazole) was sulfonated with different sulfonating agents and ion exchange capacities of the resins produced were evaluated. A maximum capacity of 4.5 meq · g?1 of dry resin was realized when sulfonation was done with 98.8% H2SO4 at 30°C for 10 h. The pH titration curves reveal the nature of a strong monofunctional cation exchanger with a pK value of 2.2. The resin exhibits a moderate rate of exchange with NaCl and is thermally stable up to ca. 250°C.  相似文献   
59.
A crosslinked polymer has been synthesized from the reaction of N-vinylcarbazole and formalin in toluene in the presence of dry HCl gas. The copolycondensate is insoluble in all common solvents for poly-N-vinylcarbazole, and exhibits higher thermal stability than the unmodified poly-N-vinylcarbazole. However, this polymer is less thermally stable than the corresponding furfural modified poly-N-vinylcarbazole. A mechanism for the overall reaction has been suggested and the factors affecting the synthesis have been discussed.  相似文献   
60.
Thermoplasticized starch (TPS) filled poly(lactic acid) (PLA) blends are usually found to have low mechanical properties due to poor properties of TPS and inadequate adhesion between the TPS and PLA. The purpose of this study was to investigate the reinforcing effect of wood fibers (WF) on the mechanical properties of TPS/PLA blends. In order to improve the compatibility of wood with TPS/PLA blends, maleic anhydride grafted PLA (MA‐g‐PLA) copolymer was synthesized and used. TPS, TPS/PLA blends, and WF reinforced TPS/PLA composites were prepared by twin‐screw extrusion and injection molded. Scanning electron microscope and crystallinity studies indicated thermoplasticity in starch. WF at two different weight proportions, that is, 20% and 40% with respect to TPS content were taken and MA‐g‐PLA at 10% to the total weight was chosen to study the effect on mechanical properties. At 20% WF and 10% MA‐g‐PLA, the tensile strength exhibited 86% improvement and flexural strength exhibited about 106% improvement over TPS/PLA blends. Increasing WF content to 40% further enhanced tensile strength by 128% and flexural strength by 180% with respect to TPS/PLA blends. Thermal behavior of blends and composites was analyzed using dynamic mechanical analysis and thermogravimetric analysis. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46118.  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