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   153篇
  免费   7篇
各国政治   4篇
工人农民   17篇
世界政治   11篇
外交国际关系   7篇
法律   77篇
政治理论   44篇
  2023年   2篇
  2022年   1篇
  2020年   6篇
  2019年   5篇
  2018年   1篇
  2017年   5篇
  2016年   7篇
  2015年   3篇
  2014年   9篇
  2013年   17篇
  2012年   9篇
  2011年   5篇
  2010年   4篇
  2009年   5篇
  2008年   5篇
  2007年   6篇
  2006年   9篇
  2005年   4篇
  2004年   4篇
  2003年   5篇
  2002年   1篇
  2001年   3篇
  2000年   4篇
  1999年   2篇
  1998年   1篇
  1995年   4篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1989年   7篇
  1987年   1篇
  1985年   2篇
  1984年   3篇
  1983年   1篇
  1982年   3篇
  1981年   4篇
  1980年   2篇
  1966年   2篇
排序方式: 共有160条查询结果,搜索用时 78 毫秒
1.
A case of the sudden death of a 14-month-old girl due to massive hemorrhage in a primitive neuroectodermal tumor (PNET) is presented along with a review of the relevant literature. PNET is a rare, malignant brain neoplasm occurring predominantly in children.  相似文献   
2.
3.
4.
The authors investigated the expression of basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) during skin wound healing using immunohistochemical techniques. After a full-thickness incision was made on the dorsal skin, mice were killed 0.5, 1, 3, 8, 24, 72, 144, or 240 hours after incision, and the wound was excised. To evaluate the influences of postmortem degeneration, cutaneous wound excision was performed 1 to 5 days after the mice were killed. The excised wounds were stained by the conventional streptoavidin-biotinylated peroxidase complex method, using specific antibodies, and the ratio of the number of positive cells to total cells was determined. Expression of bFGF was detected in the nuclei of epidermal cells and fibroblasts in the early 0.5- to 1-hour phases and the late 24- to 144-hour phases. Expression of VEGF was detected in the cytoplasm of epidermal cells in the 24- to 144-hour phases. Immunoreactivity of both cytokines was detected 1 day post mortem and was especially well preserved in the fibroblasts. Time-dependent expression of both factors suggested that they would be useful markers for the determination of wound age. However, bFGF should be superior to VEGF because of its earlier expression and because of its more persistent expression in dermal fibroblasts with increasing postmortem interval.  相似文献   
5.
Methamphetamine in urine samples from abusers was detected by the latex agglutination inhibition reaction test with latex-antibody (Latex-Ab) and latex-methamphetamine (Latex-MA) reagents. Anti-methamphetamine antibody was produced in rabbits by immunization with bovine serum albumin (BSA)-methamphetamine conjugate. Latex particles were coated with antibodies or with rabbit serum albumin (RSA)-methamphetamine conjugate to obtain Latex-Ab and Latex-MA reagents, respectively. The results are read at 4-5 min after mixing the latex reagents. The sensitivity of this method for methamphetamine was 0.4 micrograms/ml urine. Methamphetamine analogs (methylephedrine, amphetamine, phentermine, methoxyphenamine, ephedrine, beta-phenylethylamine, OH-methamphetamine, OH-amphetamine, and OH-ephedrine) all cross-react in varying degrees, while glucosiurea and albuminurea give false positive results in the tests. Though attention must be paid to these effects this simple and rapid test is suitable for the mass screening of urine samples.  相似文献   
6.
7.
Newly available geographical information from the Panel Study of Income Dynamics (PSID) is used to estimate a variety of relationships involving high-poverty metropolitan census tracts. The longitudinal data from the PSID show a great deal of geographical mobility even for persistently poor adults, with as many as one fourth of certain groups of these entering and leaving poor urban census tracts in a year. At the same time, solution of the transition matrices for various groups—whites and blacks of various income classes, in families with and without children, living in different types of census tracts—in the early 1980s shows the gradual emptying out of poor urban tracts, particularly of whites and blacks in families without children. As a consequence, despite the great degree of geographical “churning,” poor urban areas gradually become poorer, blacker, and the home of a larger share of black families with children. Some of these aggregate trends had been noticed by researchers comparing these areas in the 1970 and 1980 censuses; our more up-to-date results demonstrate the relationships between the micro and macro data.  相似文献   
8.
9.
An improved method for detecting diatom in blood is reported. Blood of cadavers was obtained by cardiac puncture at inquest or from the left atrium directly at autopsy. The blood was hemolyzed by sodium dodecyl sulfate (SDS) and filtered through membrane filter (47 mm in diameter and 5 microns in pore size). When the blood was putrefied, two or three pieces of membranes filters were needed because of choking membrane pore. The membrane filters were digested with fuming nitric acid and diluted with distilled water. The diluted solution was filtered through membrane filter (25 mm in diameter) again. After drying the membrane filter was immersed in oil. Diatoms on the membrane filter were clearly observed microscopically.  相似文献   
10.
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