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   24944篇
  免费   1546篇
  国内免费   176篇
耳鼻咽喉   240篇
儿科学   535篇
妇产科学   512篇
基础医学   3680篇
口腔科学   259篇
临床医学   2346篇
内科学   6236篇
皮肤病学   370篇
神经病学   2152篇
特种医学   1084篇
外国民族医学   9篇
外科学   4232篇
综合类   70篇
一般理论   4篇
预防医学   1352篇
眼科学   254篇
药学   1469篇
中国医学   42篇
肿瘤学   1820篇
  2023年   135篇
  2022年   222篇
  2021年   607篇
  2020年   365篇
  2019年   590篇
  2018年   692篇
  2017年   465篇
  2016年   558篇
  2015年   715篇
  2014年   941篇
  2013年   1210篇
  2012年   1922篇
  2011年   1902篇
  2010年   1101篇
  2009年   1104篇
  2008年   1691篇
  2007年   1705篇
  2006年   1664篇
  2005年   1711篇
  2004年   1587篇
  2003年   1491篇
  2002年   1400篇
  2001年   213篇
  2000年   162篇
  1999年   224篇
  1998年   274篇
  1997年   235篇
  1996年   196篇
  1995年   162篇
  1994年   116篇
  1993年   148篇
  1992年   110篇
  1991年   95篇
  1990年   97篇
  1989年   81篇
  1988年   79篇
  1987年   61篇
  1986年   65篇
  1985年   51篇
  1984年   48篇
  1983年   52篇
  1982年   44篇
  1981年   55篇
  1980年   43篇
  1979年   35篇
  1978年   23篇
  1977年   21篇
  1975年   21篇
  1974年   19篇
  1969年   22篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
31.
The expression of substance P (SP) was studied in sensory neurons of developing chick lumbosacral dorsal root ganglia (DRG) by using a mixture of periodic acid, lysine and paraformaldehyde as fixative and a monoclonal antibody for SP-like immunostaining. The first SP-like-immunoreactive DRG cells appeared first at E5, then rapidly increased in number to reach a peak (88% of ganglion cells) at E8, and finally declined (59% at E12, 51% after hatching). The fall of the SP-like-positive DRG cells resulted from two concomitant events affecting a subset of small B-neurons: a loss of neuronal SP-like immunoreactivity and cell death. After one hindlimb resection at an early (E6) or late (E12) stage of development (that is before or after establishment of peripheral connections), the DRG were examined 6 days later. In both cases, a drastic neuronal death occurred in the ispilateral DRG. However, the resection at E6 did not change the percentage of SP-like-positive neurons, while the resection at E12 severely reduced the proportion of SP-like-immunoreactive DRG cells (25%). In conclusion, connections established between DRG and peripheral target tissues not only promote the survival of sensory neurons, but also control the maintenance of SP-like-expression. Factors issued from innervated targets such as NGF would support the survival of SP-expressing DRG cells and enhance their SP content while other factors present in skeletal muscle or skin would hinder SP expression and therefore lower SP levels in a subset of primary sensory neurons.  相似文献   
32.
33.
34.
The authors present the case of a new case of Kearns-Sayre syndrome, with early manifestations (7 months) and dramatic cardiac course. They document the ultimate and often fatal stage of the cardiac disorders of this syndrome, which was usually related to an asystole due to a total atrio-ventricular block and represented in this case by a ventricular hyperexcitability (ventricular tachycardia--"torsade de pointes"--ventricular fibrillation) occurring on an atrio-ventricular block; only one previous, undocumented case was found in the literature. The literature is reviewed in order to analyze the nature and chronology of the heart disorders in the course of the disease, and stress the screening modalities and therapeutic indications (continuous heart stimulation).  相似文献   
35.
We believe that rejuvenation of the shapes and volumes of the face is just as important as "tightening of the skin and muscles". In this way a more complete rejuvenation effect is obtained which is better perceived by others. The SMO technique provides a solution by the use of malleable coral microgranules, which may constitute the first biomaterial of a new generation of plastic and malleable onlays. In this context, a more general volumetric concept of ageing is developed, leading to a modification in our consultation and our treatment. Most importantly, this approach opens a whole new field, that of preventative treatment of facial ageing, which will no doubt be multidisciplinary.  相似文献   
36.
Summary Hypertension was induced in uninephrectomized rats by NaCl 0.9% drinking and deoxycorticosterone acetate (DOCA) administration for 6 weeks. Plasma renin activity was markedly reduced but not suppressed. Renal renin concentration and total renal renin content were moderately reduced. Intravenous injection of 0.2 ml of antiangiotensin plasma resulted in transitory hypotension both in salt and DOCA-treated rats, and in normotensive control rats. It is concluded that angiotensin participates in the maintenance of blood pressure in salthypertensive rats as well as in normal animals.This work was supported by grant 67-00-517 from D.G.R.S.T. (Délégation Générale à la Recherche Scientifique et Technique). The authors wish to thank Miss colette Innocenzi and Miss Sonia Culot for technical assistance.  相似文献   
37.
38.
OBJECTIVE: To investigate the association of hormone levels at menopause, lifestyle variables, and body composition with the predicted 10-year risk of a coronary event, calculated using the PROCAM scoring system, in a population-based sample of Australian-born, middle-aged women. DESIGN: A 9-year prospective study of 438 Australian-born women, who at baseline were aged 45 to 55 years and had menstruated in the prior 3 months. Interviews, fasting blood, and physical measurements were taken annually. The risk of an acute coronary event was calculated using the PROCAM scoring system (includes: age, low-density lipoprotein cholesterol, smoking, high-density lipoprotein cholesterol, systolic blood pressure, family history of premature myocardial infarction, diabetes mellitus, and triglycerides). RESULTS: Retention rate after 8 years of follow-up was 88% (n = 387). In women not using hormone therapy (HT): higher than average body mass index (BMI) (P < 0.001), BMI that increased (P < 0.005), lower than average estradiol levels (P < 0.005), estradiol levels that decreased (P < 0.001), and high free testosterone levels (P < 0.05) were associated with increased risk of a coronary event. There was a trend for high exercise frequency to be associated with a decreased risk (P < 0.07). After BMI and lifestyle variables were taken into account, use of HT did not have a significant effect on risk of a coronary event. CONCLUSION: In this longitudinal observational study of middle-aged Australian-born women, high BMI, an increase in BMI, high free testosterone, low estradiol, and a decrease in estradiol levels were the main determinants of increased risk of an acute coronary event, based on the PROCAM scoring system calculation. More frequent exercise tended to lower the risk.  相似文献   
39.
40.
Myocardial dysfunction without coronary involvement may occur in acute cerebral diseases. The inverted Takotsubo pattern has been recently recognized as a novel heart neurologic stress-related syndrome. We report on the case of a 40-year-old woman presenting with massive subarachnoid hemorrhage and brain death. Echocardiography revealed an extensive left ventricular circumferential akinesis except at the apex. Histologic analysis of the heart confirmed the absence of myocardial infarction and revealed only sparse foci of myocyte necrosis with contraction bands in the akinetic areas.  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