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   1992篇
  免费   2篇
电工技术   1篇
化学工业   15篇
金属工艺   1篇
建筑科学   6篇
能源动力   1篇
轻工业   1篇
水利工程   1篇
无线电   2篇
一般工业技术   27篇
冶金工业   1934篇
自动化技术   5篇
  2022年   1篇
  2021年   3篇
  2018年   1篇
  2017年   1篇
  2016年   1篇
  2015年   2篇
  2014年   2篇
  2013年   1篇
  2012年   2篇
  2011年   4篇
  2010年   3篇
  2009年   4篇
  2008年   6篇
  2007年   3篇
  2006年   1篇
  2005年   4篇
  2004年   1篇
  2003年   5篇
  2002年   1篇
  2001年   1篇
  1999年   65篇
  1998年   569篇
  1997年   357篇
  1996年   239篇
  1995年   120篇
  1994年   96篇
  1993年   121篇
  1992年   15篇
  1991年   27篇
  1990年   13篇
  1989年   18篇
  1988年   20篇
  1987年   15篇
  1986年   20篇
  1985年   14篇
  1984年   1篇
  1983年   3篇
  1982年   8篇
  1981年   11篇
  1980年   10篇
  1979年   2篇
  1978年   5篇
  1977年   62篇
  1976年   124篇
  1975年   6篇
  1972年   1篇
  1965年   1篇
  1963年   1篇
  1955年   2篇
  1954年   1篇
排序方式: 共有1994条查询结果,搜索用时 0 毫秒
91.
The controversy continues over the appropriate use of vaginal hysterectomy for many indications that were previously treated only with abdominal or laparoscopic methods. Current outcomes data have pointed up the need for established guidelines to ensure that patients receive appropriate surgical treatment that is most cost-effective and that meets the standard of quality care. Dr Kovac reviews recent data regarding the various surgical options for hysterectomy and offers guidelines based on objective pathologic criteria.  相似文献   
92.
93.
94.
Strains of Fusarium moniliforme from maize seed collected in four fields in northeast Mexico were tested for fumonisin production in culture, for sexual compatibility, and for vegetative compatibility by using non-nitrate-utilizing mutants. The test results indicate that a diverse population of fumonisin-producing strains of F. moniliforme (Gibberella fujikuroi) mating population A predominates and that a potential exists for production of fumonisins in Mexican maize.  相似文献   
95.
96.
Monoclonal antibodies (mAbs) and a polyclonal rabbit antiserum were raised against recombinant ovine tumor necrosis factor-alpha (rovTNF alpha). Ten mAbs specific for rovTNF alpha were isolated and designated TNF1-10. All mAbs were of the IgG1 isotype and reacted with rovTNF alpha in Western blot analysis. Eight of the ten mAbs, TNF1, TNF3-7 and TNF9 and 10, completely blocked the activity of rovTNF alpha and macrophage derived native ovTNF alpha, as measured by their ability to inhibit TNF alpha-mediated lysis of WEHI-164 or L929 cells. In addition, TNF3, -7, -9 and -10 blocked the cytolytic activity of recombinant human TNF alpha (rhuTNF alpha). However, when tested for the ability to inhibit TNF alpha induced thymocyte proliferation, only mAbs TNF1, -3, -5, -7, -9 and -10 could completely block activity. Competitive binding analysis using unlabelled and horseradish peroxidase (HRPO) labelled mAbs indicated that the mAbs could be divided into five groups based on their reactivity with rovTNF alpha. The mAbs were used to develop a sensitive sandwich immunoassay for the detection of ovTNF alpha. All combinations of mAbs and the polyclonal antiserum were tested to determine which pair of antibodies gave the most sensitive assay. The combination of TNF5 as the capture antibody and the polyclonal antiserum gave the most sensitive result, detecting less than 0.24 ng rovTNF alpha ml-1. A similar sensitivity was obtained when TNF4 was used as the capture antibody and TNF10 HRPO labelled mAb as the second antibody. The immunoassay was more sensitive than the WEHI-164 bioassay which had a detection limit of 1 ng ml-1 for rovTNF alpha. This immunoassay also detected glycosylated ovTNF alpha in the supernatant of COS-7 cells which had been transfected with an ovTNF alpha cDNA.  相似文献   
97.
Since blood is a biologic product, it is unlikely that the risk for transfusion-transmitted infection will ever be reduced to zero. The approach to emerging infections associated with transfusion of blood and blood products includes assessing the transmissibility of the agent by this route; developing effective prevention strategies, including screening tests and donor deferral policies; improving viral and bacterial inactivation procedures; and surveillance for known, as well as emerging and poorly characterized, transfusion-transmitted agents. Vigilance is needed to help ensure proper balance between safety and the availability of blood. Finally, vigilance needs to extend to the developing world, where the basic elements to reduce transfusion-transmitted infections and systems of disease surveillance are often not available.  相似文献   
98.
Endogenous opioid peptides appear to be involved in acute behavioral effects induced by single doses of ethanol. However, its role in repeated ethanol exposure has not been studied. In the present study ethanol was given to rats at the doses of 2 and 4 g/kg by a stomach gauge for 15 days, and its effects on spontaneous motility, open-field activity, and active avoidance behavior recorded on the 3rd, the 6th and the 15th days. Then the effect of naloxone (0.5 and 2 mg/kg by intraperitoneal route) was tested against a challenge ethanol dose, administrated by oral route, on the 16th day. Control animals received tap water and saline instead of ethanol or naloxone, respectively. Both doses of ethanol induced a decrease in spontaneous motility that was antagonized by naloxone. Open-field ambulations were increased by the high dose of ethanol, low-dose lacking effect; naloxone did not modify these ethanol effects. The low dose of ethanol shortened latency time in shuttlebox, the high dose causing escape and freezing responses; none of these effects were modified by naloxone. Therefore, endogenous opioid peptides appear to play a limited role in the chronic effects of ethanol in rats; particularly its effects in tests inducing an increase in the level of anxiety were resistant to naloxone.  相似文献   
99.
100.
A case of uremia resulting from bilateral Hodgkin's lymphomatous infiltration of kidneys is reported. Uremia was an initial feature in the case and was the eventual cause of death.  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