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   4248篇
  免费   3篇
  国内免费   3篇
化学工业   39篇
金属工艺   4篇
建筑科学   2篇
轻工业   10篇
无线电   27篇
一般工业技术   10篇
冶金工业   4147篇
原子能技术   3篇
自动化技术   12篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2018年   3篇
  2017年   2篇
  2016年   1篇
  2015年   2篇
  2014年   2篇
  2013年   9篇
  2012年   7篇
  2011年   4篇
  2010年   6篇
  2009年   7篇
  2008年   2篇
  2007年   4篇
  2006年   6篇
  2005年   3篇
  2004年   2篇
  2003年   14篇
  2002年   3篇
  2001年   2篇
  2000年   4篇
  1999年   131篇
  1998年   1288篇
  1997年   714篇
  1996年   461篇
  1995年   267篇
  1994年   192篇
  1993年   261篇
  1992年   42篇
  1991年   50篇
  1990年   47篇
  1989年   71篇
  1988年   61篇
  1987年   64篇
  1986年   44篇
  1985年   53篇
  1983年   9篇
  1982年   18篇
  1981年   29篇
  1980年   27篇
  1979年   2篇
  1978年   6篇
  1977年   110篇
  1976年   210篇
  1975年   6篇
  1972年   1篇
  1964年   1篇
  1961年   1篇
  1955年   1篇
排序方式: 共有4254条查询结果,搜索用时 0 毫秒
151.
The presence of gas in bowel could lead to higher than expected doses being given in the radiotherapy of abdominal and pelvic tumors. Radiation detectors were placed in the uterus and vagina of ten patients with caricnoma of cervix, and the actual dose compared with that expected when anterior fields of treatment were employed. Elvations greater than 10% were obtained in six, and severe postradiation morbidity subsequently occured in two of the three showing the highest readings.  相似文献   
152.
153.
154.
The study of the morphology of eggs, larvae, pupae and adults of Aedes excrucians from Germany, Italy and France has led the authors to rise again the binomen Aedes surcoufi (Theobald, 1912) to particularize the european populations. At the same time, the characteristics of the different species of the Aedes excrucians complex are discussed.  相似文献   
155.
N6-(p-Azidobenzyl)adenosine (ABA) and nitrobenzylthioinosine (NBMPR) were employed as covalent probes of the nucleoside transport mechanism in human erythrocytes. NBMPR, a potent inhibitor of nucleoside transport, binds tightly (KD 0.3-1 nM) to specific sites on nucleoside transporter elements. ABA, a less potent inhibitor of uridine influx, competitively inhibited NBMPR binding (Ki 15 nM). [3H]ABA was bound tightly (KD 13.4 nM) but reversibly to sites on erythrocytes which appeared to be those which bind NBMPR. ABA binding was inhibited by uridine and adenosine. Irradiation with UV light caused site-bound [3H]ABA on erythrocyte membranes to become covalently bound and, similarly, photoactivation resulted in covalent attachment of membrane-bound [3H]NBMPR. In the presence of dithiothreitol, a free radical scavenger, photoactivation of the site-bound 3H-ligand on membranes depleted of extrinsic membrane proteins resulted in selective incorporation of 3H into band 4.5 of the membrane polypeptides which were resolved on sodium dodecyl sulfate-polyacrylamide gel electropherograms. This result, when considered with previous findings, indicates that the NBMPR-binding component of the nucleoside transport mechanism (or the entire mechanism, if the NBMPR site is an integral part) is a band 4.5 polypeptide.  相似文献   
156.
157.
The cost of managing 114 adult haemophiliacs in the west of Scotland was assessed for the period 1 March 1971 to 28 February 1974. Altogether 23 of them (20%) accounted for 80% of the resources used. The cost of hospital treatment of these patients during the period was compared with the predicted cost of home treatment, given the availability of freeze-dried factor VIII concentrate in sufficient amounts. We calculate that adequate on-demand home treatment would cost only 16% more than the present treatment, which is substantially less efficient.  相似文献   
158.
We used certain physiologic maneuvers to perturb the autonomic nervous system (ANS) in an attempt to detect a link between the ANS and pain. In the unperturbed state, we found no difference in the electrodermal response among normal controls, preoperative patients (increased stress without pain) and postoperative patients (increased stress and pain). The electrodermal response elicited by autonomic maneuvers was significantly attenuated in postoperative patients but not in preoperative patients or in normal control subjects.  相似文献   
159.
160.
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