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   1238篇
  免费   124篇
  国内免费   27篇
耳鼻咽喉   28篇
儿科学   18篇
妇产科学   15篇
基础医学   99篇
口腔科学   26篇
临床医学   160篇
内科学   322篇
皮肤病学   4篇
神经病学   82篇
特种医学   89篇
外科学   180篇
综合类   43篇
一般理论   1篇
预防医学   112篇
眼科学   48篇
药学   102篇
中国医学   1篇
肿瘤学   59篇
  2021年   18篇
  2019年   13篇
  2018年   23篇
  2017年   10篇
  2015年   9篇
  2014年   27篇
  2013年   39篇
  2012年   33篇
  2011年   39篇
  2010年   33篇
  2009年   25篇
  2008年   51篇
  2007年   46篇
  2006年   48篇
  2005年   55篇
  2004年   52篇
  2003年   54篇
  2002年   42篇
  2001年   30篇
  2000年   31篇
  1999年   25篇
  1998年   29篇
  1997年   23篇
  1996年   26篇
  1995年   15篇
  1994年   16篇
  1993年   18篇
  1992年   29篇
  1991年   23篇
  1990年   33篇
  1989年   39篇
  1988年   37篇
  1987年   30篇
  1986年   22篇
  1985年   17篇
  1984年   17篇
  1983年   13篇
  1982年   20篇
  1981年   12篇
  1979年   14篇
  1978年   14篇
  1977年   13篇
  1976年   21篇
  1975年   14篇
  1974年   19篇
  1973年   17篇
  1972年   13篇
  1971年   12篇
  1970年   14篇
  1968年   14篇
排序方式: 共有1389条查询结果,搜索用时 31 毫秒
1.
The effects of physiological and pathological concentrations of glucocorticoids were investigated using the glucocorticoid antagonist RU486 and the synthetic glucocorticoid dexamethasone, respectively. The effects of these treatments on the concentrations of glutamine and other amino acids in skeletal muscle and plasma and on the rates of release of glutamine and alanine from incubated preparations of skeletal muscle of the rat were investigated. Dexamethasone treatment increased the concentration of glutamine and the rate of release of this amino acid from incubated soleus muscle preparations. This treatment decreased the concentration of glutamine in both gastrocnemius and EDL muscles, but was without effect on the rate of glutamine release from EDL muscles. In contrast, administration of the glucocorticoid antagonist RU486 decreased the rate of glutamine release from muscle. It is concluded that glucocorticoids have marked effects on the metabolism of glutamine by skeletal muscle per se and that these hormones may be important in the control of the rate of glutamine release from muscle in both physiological and pathological conditions.  相似文献   
2.
3.
TOPIC: Bereavement therapy as a catalyst for spiritual growth. PURPOSE: This study aims to review the literature and reflect on the bereavement therapy undertaken with two adolescents who had been bereaved during childhood. SOURCES: Research articles and books identified through a combination of electronic and manual searches. CONCLUSIONS: It would appear that grief therapy could facilitate spiritual growth in such circumstances. Further in-depth studies are required to identify how typical or atypical this experience is, and to contribute to the evidence base for working with bereaved children and adolescents.  相似文献   
4.
5.
Summary Formation of epithelial tissues in culture so that they become facsimiles in their structure of such tissues in nature requires procedures that comply with several spatial imperatives: a) three-dimensional growth; b) histophysiologic conditions that provide, concurrently, gradients of maturation and of diffusion of metabolites; and c) growth as layers of cells without free edges. Many steps have been required in the evolution of these methods. Two systems are described here in sufficient detail to serve as a manual. Three-dimensional growth of masses of epithelial tissue is accomplished in matrix culture using Gelfoam sponge and collagen-coated cellulose sponge. Radial gradient culture, a recent development, provides conditions that comply with the requirements of histophysiologic gradients and of epithelial tissue growth in layers without interruption in their continuity.  相似文献   
6.

Background  

Many factors impacting cecal intubation rates have been examined in detail; however, little information exists regarding the effect of the timing of the procedure. We sought to examine any difference in cecal intubation rates between morning and afternoon colonoscopies and identify factors contributing to a discrepancy.  相似文献   
7.
可逆性胆硷酯酶抑制剂二甲氨基甲酸-5-二氢吲哚酯的合成   总被引:1,自引:0,他引:1  
陈邦华  纪庆娥 《药学学报》1990,25(4):247-252
为了深入研究催醒宁类化合物的结构与抑酶活性的关系,设计合成了-系列1-,3-或5-位不同取代的二氢吲哚类衍生物(中间体和终产物共24个新化合物)。中间体1,3-二甲基-5-烷氧基-2-二氢吲哚酮(A)的C3烷化。采用相转移催化方法进行;反应中还分离到三个副产物(Ⅶ~Ⅸ)。初筛结果表明:这些化合物大多有较强的抑酶活性;1,3-或5-位取代基的改变均明显影响其活性。  相似文献   
8.
9.
The reduction in food intake induced by i.p. injections of the cholecystokinin (CCK) analogue caerulein was antagonised by a low dose (0.25 mumol/kg s.c.) of the selective CCK antagonist L-364,718. To block the anorectic effect of centrally administered caerulein a dose of 25 mumol/kg of L-364,718 was required, demonstrating that central CCK receptors can be blocked effectively in the rat by choosing appropriate doses of L-364,718.  相似文献   
10.
Serum cholinesterase activity decreases 30% during pregnancy and remains depressed during the postpartum period. However, succinylcholine recovery is not prolonged in term-pregnant patients. This contrasts with results obtained in other patients with decreased serum cholinesterase activity. To better understand this paradox, the authors compared serum cholinesterase activity and recovery from succinylcholine, 1 mg/kg, in nonpregnant (with and without oral contraceptive use), in term-pregnant, and in postpartum patients. Serum cholinesterase activity was lower in both term-pregnant (3.66 +/- 0.39 U/ml, means +/- SE) and postpartum (2.84 +/- 0.35 U/ml) patients than in nonpregnant patients not taking oral contraceptives (5.01 +/- 0.33 U/ml, P less than 0.05). Cholinesterase activity in postpartum patients also was significantly lower than in nonpregnant patients taking oral contraceptives (4.81 +/- 0.63, P less than 0.05). In contrast, the time to 25% twitch-height recovery did not differ between term-pregnant (470 +/- 56 s) and nonpregnant patients taking (499 +/- 29 s) or not taking (501 +/- 21 s) oral contraceptives, but was significantly increased in postpartum patients (685 +/- 22 s, P less than 0.001). The similar duration of action of succinylcholine in term-pregnant patients (with decreased serum cholinesterase activities) and nonpregnant patients may be related to the increased volume of distribution of succinylcholine at term.  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