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   2086篇
  免费   36篇
  国内免费   1篇
电工技术   5篇
综合类   12篇
化学工业   288篇
金属工艺   16篇
机械仪表   20篇
建筑科学   80篇
矿业工程   28篇
能源动力   41篇
轻工业   136篇
水利工程   14篇
石油天然气   8篇
武器工业   1篇
无线电   60篇
一般工业技术   130篇
冶金工业   1111篇
原子能技术   8篇
自动化技术   165篇
  2021年   5篇
  2020年   12篇
  2019年   11篇
  2018年   19篇
  2017年   13篇
  2016年   15篇
  2015年   17篇
  2014年   23篇
  2013年   83篇
  2012年   35篇
  2011年   59篇
  2010年   35篇
  2009年   35篇
  2008年   58篇
  2007年   49篇
  2006年   42篇
  2005年   39篇
  2004年   29篇
  2003年   28篇
  2002年   45篇
  2001年   19篇
  2000年   26篇
  1999年   41篇
  1998年   305篇
  1997年   189篇
  1996年   127篇
  1995年   84篇
  1994年   75篇
  1993年   59篇
  1992年   16篇
  1991年   17篇
  1990年   21篇
  1989年   17篇
  1988年   18篇
  1987年   19篇
  1986年   22篇
  1985年   20篇
  1984年   16篇
  1983年   23篇
  1982年   20篇
  1981年   29篇
  1980年   28篇
  1979年   15篇
  1978年   15篇
  1977年   59篇
  1976年   111篇
  1975年   15篇
  1974年   5篇
  1973年   9篇
  1955年   5篇
排序方式: 共有2123条查询结果,搜索用时 359 毫秒
21.
The influence of fibrin glue on adhesion formation and peritoneal healing is evaluated in a prospective, randomized, controlled study. In all, 20 Wistar rats underwent microsurgical suturing of two silicone sheets, one covered with a fibrin glue barrier, to the anterior peritoneum. Each animal thus served as its own control. After 10 days, adhesions and peritoneal healing were evaluated by a blinded observer through a second-look laparotomy. Adhesions were scored using a modification of the classification of Diamond. Tissue around the silicone sheet was examined histologically and by scanning electron microscopy to evaluate the inflammatory reaction and peritoneal healing (ingrowth of blood vessels and quality of peritoneal cells). Adhesion scores for treated and control sides were (mean +/- SD) 2.89 +/- 4.68 and 6.79 +/- 9.09 (P = 0.181) respectively, and the percentage of the sheet covered by peritoneum was 26.25 +/- 31.50 and 29.21 +/- 40.21 (P = 0.226) respectively. Using the paired Wilcoxon rank test, the P values for the ingrowth of blood vessels and peritoneal healing evaluated by histology and scanning electron microscopy were 0.842, 0.692 and 0.695 respectively. We conclude that although the mean adhesion score was reduced by > 50% by fibrin glue, there is no statistically significant difference concerning adhesion formation or peritoneal healing with the use of fibrin glue.  相似文献   
22.
Two studies identified and labeled the dimensions that people use to judge others' attitudes. In the 1st study, 50 male and 50 female undergraduates viewed pairs of attitude statements drawn from 1 or 2 large sets. For each pair of statements, Ss judged whether or not a person who agreed with one statement in the pair would be likely to agree with the other. The dimensions of liberalism and traditional values were found to underlie perceived attitudes. Validity was confirmed in a 2nd study with 60 male and 60 female undergraduates who rated the characteristics of hypothetical people who agreed strongly with particular statements. Results suggest that there is a common structure to people's perceptions of others' attitudes. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
23.
Flory–Huggins interaction parameters, λ, were determined for a series of probes in an amine cured epoxy resin matrix (433–493 K) and its precursors (324–363 K) by inverse gas chromatography (IGC). Hildebrand–Scatchard theory was combined with Flory–Huggins theory in order to estimate infinte dilution solubility parameters (δ2) for the matrix and its precursors at 298 K. It was shown that the value of the solubility parameter for the cured resin matrix lies between those of its precursors. Compared to the majority of published work, an unusual aspect of this application of IGC is that solubility parameters have been determined when the stationery phases are (i) small molecules and (ii) a highly crosslinked polymer. Moreover, all possible attempts have been made to ensure equilibrium conditions between probe and stationary phase, and compensation for asymmetry of peak profile has been applied in determining δ2. The solubility parameters estimated by IGC are in good agreement with those calculated by other methods.  相似文献   
24.
25.
Magnetorheological materials have been used in many applications in recent years. To develop new materials, polyurethane and silicone polymer gels were investigated. Rheology is qualitatively controlled for each system by controlling the concentration of reactants and diluents. The resulting polymers have solid, gel, or liquid states, depending on the crosslinking and dilution. The gels were characterized through kinetic analysis. Differential scanning calorimetry (DSC) was used with analysis methods to find the kinetic properties for diluted and undiluted polyurethane systems. Heat of reaction, order of reaction, preexponential constant, and activation energy were obtained from the experimental DSC data. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2733–2742, 2002  相似文献   
26.
In the context of the radiation exposure of the Ukrainian population resulting from the Chernobyl accident, the quantification of the thyroid doses due to iodine incorporation is of special interest. This first part of a series of planned publications deals with the dose and risk estimation for Kiev citizens. Although these doses are expected to be considerably lower than those for some other regions of Ukraine, the investigations started with this population because the quantification of the thyroid doses due to iodine incorporation is of special interest. This first part of a series of planned publications deals with the dose and risk estimation for Kiev citizens. Although these doses are expected to be considerably lower than those for some other regions of Ukraine, the investigations started with this population because of the availability of rather reliable measurements and because of the size of this population. The methods developed allowed the estimation of individual thyroid doses. The average values of individual thyroid doses for five age groups (birth years 1983-1986, 1979-1982, 1975-1978, 1971-1974, and < 1971) are 104, 62, 19, 18, and 41 mGy, respectively. The collective thyroid doses were estimated as 83 x 10(3) person-Gy for those born before 1971 and as 38 x 10(3) person-Gy for younger inhabitants. The numbers of expected thyroid cancers in the whole Kiev population are 66 and 130, respectively.  相似文献   
27.
28.
A technique for forming Langmuir films from antibodies based on an amphiphilic polyelectrolyte was developed. The physicochemical and immunochemical properties of the Langmuir films obtained were studied. The interaction of HBsAg with the films was found to be described by a model with one binding site, whereas that of HBsAg with antibodies adsorbed on a polystyrene plate, by a model with a positive cooperativity. The use of the novel Langmuir films from antibodies increases the sensitivity of the immunoenzyme assay.  相似文献   
29.
30.
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