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   2437篇
  免费   262篇
  2023年   7篇
  2022年   20篇
  2021年   45篇
  2020年   51篇
  2019年   56篇
  2018年   72篇
  2017年   62篇
  2016年   94篇
  2015年   115篇
  2014年   107篇
  2013年   156篇
  2012年   150篇
  2011年   159篇
  2010年   100篇
  2009年   93篇
  2008年   106篇
  2007年   109篇
  2006年   92篇
  2005年   95篇
  2004年   98篇
  2003年   91篇
  2002年   77篇
  2001年   91篇
  2000年   81篇
  1999年   63篇
  1998年   34篇
  1997年   25篇
  1996年   20篇
  1995年   13篇
  1994年   23篇
  1993年   19篇
  1992年   42篇
  1991年   36篇
  1990年   34篇
  1989年   25篇
  1988年   31篇
  1987年   24篇
  1986年   29篇
  1985年   24篇
  1984年   13篇
  1983年   17篇
  1982年   13篇
  1981年   12篇
  1980年   11篇
  1979年   4篇
  1978年   5篇
  1977年   10篇
  1976年   10篇
  1974年   7篇
  1969年   4篇
排序方式: 共有2699条查询结果,搜索用时 203 毫秒
71.
The effects of naltrexone, a specific opiate antagonist, on stimulation by estradiol benzoate (EB) of prolactin (PRL) release and anterior pituitary (AP) weight, were studied in gonadectomized female and male Sprague-Dawley rats. One week after castration, rats were injected for 10 days once daily with 2 μg EB alone, or together with twice daily injections of 2 mg naltrexone/kg body weight (BW). Blood was collected for radioimmunoassay of PRL by orbital sinus puncture on days 0 and 6, and by decapitation on day 11, at which time the AP was quickly removed, weighed and assayed for PRL.Serum PRL concentrations and AP weights were significantly increased by EB administration. These effects of EB were partially but significantly inhibited by naltrexone. These results suggest that endegenous opiates may be involved in the estrogen-induced rise in serum PRL and increase in pituatary weight.  相似文献   
72.
Summary We have studied members of three generations of the same family affected by brachydactyly, which is accompanied by intraventricular conduction defects in three cases (proband's father and two of his sons) and sick sinus syndrome in the proband.The brachydactyly described affects mainly the middle phalanges of both hands; the index and fifth fingers are more severely affected than the other fingers. It also includes a rare variant with an ossicle on the proximal phalanx of both index fingers, which reduces them in length and causes them to deviate towards the ulnar border of the hand. The feet also tend to be affected, but to a lesser degree. No other pathological findings were recorded.It is therefore suggested that the anomalies detected in this family are transmitted by an autosomal dominant mode of inheritance, thus forming a syndrome.  相似文献   
73.
Cytogenetic and electrophoretic analyses on 2n = 28 strains ofAsphodelus cerasiferus strongly suggest that the basic number x = 14 of the genusAsphodelus is of secondary polyploid origin from x = 7.  相似文献   
74.
75.
Cyclic AMP, protein kinase activity and glycerol were measured in adipose tissue from fasted rats incubated with epinephrine with or without glucose. A drastic loss in the sensitivity of the adipose tissue to respond to the lipolytic action of the hormone was observed during fasting, when incubated without glucose. The addition of glucose reverses this process, and a greater lipolytic capacity was observed in the tissue of fasted rats than in fed rats. The three parameters measured were well correlated when there was epinephrine in the medium. Lipolysis is observed with glucose alone, but there was no variation in the cAMP levels nor in the protein kinase activity. These results are discussed in relation to the regulator effect of FFA, which is mobilized during starvation, on lipolysis.  相似文献   
76.
77.
The manner in which centromere regions of mitotic chromosomes are distributed with respect to the age of their DNA was studied. Cells of the Indian deer, Muntiacus muntjak, were grown in the presence of bromodeoxyuridine (BrdU) for two generations and stained with the fluorescent dye Hoechst 33258. Chromatids containing granddaughter DNA appear dim when compared with those containing grandparental DNA. The frequencies of the various anaphase patterns of bright and dim centromere regions were binomially distributed, indicating random distribution of chromatids with respect to the age of their DNA templates.  相似文献   
78.
79.
Mycopathologia - Se estudiaron los resultados comparativos de las reacciones intradérmicas a la Tuberculina, Histoplasmina y Coccidioidina, practicadas simultáneamente a 644 enfermos...  相似文献   
80.
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