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   1347084篇
  免费   115863篇
  国内免费   6372篇
耳鼻咽喉   16803篇
儿科学   43333篇
妇产科学   36887篇
基础医学   185277篇
口腔科学   36491篇
临床医学   122087篇
内科学   280482篇
皮肤病学   32020篇
神经病学   111305篇
特种医学   55886篇
外国民族医学   277篇
外科学   211573篇
综合类   31751篇
现状与发展   2篇
一般理论   425篇
预防医学   107999篇
眼科学   28339篇
药学   94599篇
  5篇
中国医学   2237篇
肿瘤学   71541篇
  2018年   13559篇
  2017年   10782篇
  2016年   12961篇
  2015年   14472篇
  2014年   20198篇
  2013年   30129篇
  2012年   36750篇
  2011年   39478篇
  2010年   24721篇
  2009年   24200篇
  2008年   36862篇
  2007年   39295篇
  2006年   40365篇
  2005年   38976篇
  2004年   37214篇
  2003年   36323篇
  2002年   34267篇
  2001年   66355篇
  2000年   68239篇
  1999年   56861篇
  1998年   16866篇
  1997年   15134篇
  1996年   16112篇
  1995年   16350篇
  1994年   15198篇
  1993年   14256篇
  1992年   47342篇
  1991年   45980篇
  1990年   44220篇
  1989年   42039篇
  1988年   38981篇
  1987年   38310篇
  1986年   36054篇
  1985年   34818篇
  1984年   26535篇
  1983年   22266篇
  1982年   13934篇
  1981年   12519篇
  1980年   11796篇
  1979年   23693篇
  1978年   17188篇
  1977年   14486篇
  1976年   13288篇
  1975年   13825篇
  1974年   16204篇
  1973年   15503篇
  1972年   14265篇
  1971年   13125篇
  1970年   11971篇
  1969年   11178篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
962.
Eight lymphatic fluid collections were drained percutaneously. There were no immediate or late complications. Seven patients had follow-up; 1 required surgical drainage of a residual or recurrent lymphocele, and another had reaccumulated fluid in a lymphocele which was detected on autopsy. The remaining lymphatic collections responded to percutaneous drainage. Percutaneous drainage is safe and can be an effective tool in the management of lymphatic collections.  相似文献   
963.
Drawing upon preliminary research findings, this paper considers whether pharmacists in Britain face a crisis in their occupational status and identity as a result of changes in their work and market situations. It further examines some of the ways in which they are responding to the challenges and opportunities presented. The paper also comments on the utility of the concepts of 'reprofessionalization' and 'occupational imperialism' in the study of British pharmacy.  相似文献   
964.
The caffeine content of all tea or coffee beverages consumed by 17 healthy adults over 24 hours was measured. Plasma caffeine, theophylline, theobromine, and paraxanthine concentrations were determined over the same 24 hours. The average caffeine content per drink was 60.4 +/- 21.8 mg for instant coffee (14-fold range), 80.1 +/- 19.2 mg for brewed coffee (2.8-fold range), and 28.8 +/- 13.7 mg for tea (5.5-fold range). The number of drinks of coffee and tea consumed was a poor index of actual caffeine intake (r2 = 0.42). Caffeine intake correlated poorly with the 24-hour average caffeine concentration (r2 = 0.41), but there was a very good correlation between a single plasma caffeine concentration measured at 5 PM and the 24-hour average concentration (r2 = 0.94). The same was true for paraxanthine (r2 = 0.86). Paraxanthine accounted for 67.3% of the total dimethylxanthines in plasma, while theobromine and theophylline accounted for 24.4% and 8.3%, respectively. Mean caffeine clearance was 1.2 +/- 0.3 ml/min/kg. Plasma caffeine concentration before the first drink in the morning correlated very poorly with caffeine clearance (r2 = 0.07), even when adjusted for caffeine intake (r2 = 0.21).  相似文献   
965.
Secretory antibodies protect mucosal surfaces against transmission of many viruses. Human T-lymphotropic Virus, Type I (HTLV-I) is transmitted via blood products and via sexual contact across mucosal surfaces. We investigated the presence of HTLV-I-specific antibodies in whole saliva samples from 10 seronegative and 28 seropositive volunteers from a hospital in southern Japan. Antibodies directed to HTLV-I antigens were found in the salivas from 22 of 28 (79%) of the seropositive subjects. None of the seronegative individuals showed evidence of salivary antibodies. Antibodies directed to the envelope antigens of the virus were found in 21 of 22 positive saliva samples. Secretory antibodies may be important in preventing mucosal transmission.  相似文献   
966.
967.
968.
The results of treatment with intrauterine transfusion are presented. The analysis comprised 48 successful transfusions into 29 foetuses. The reference group consisted of 11 transfusions which proved nonfeasible or ineffective and 54 untreated cases. Following blood treatment, the newborn mortality rate dropped more than threefold. Long-term follow-up of 21 children generally showed their good physical and mental development. We also present 4 cases of supsequent pregnancies after intrauterine blood treatment in a preceding pregnancy, showing that it is possible to save the next baby of the same mother.  相似文献   
969.
J D Carroll  W H Gaasch 《Herz》1981,6(3):131-137
Following surgical correction of chronic aortic regurgitation, left ventricular (LV) volume falls to normal or near normal in most patients; this change generally occurs within the first week after surgery. During the ensuing six months, a significant regression of LV hypertrophy occurs, but most patients do not achieve a normal LV mass. The systolic ejection fraction may increase while the LV end-diastolic pressure almost uniformly falls to normal. Postoperative studies of LV volume mass and function should be aimed at identifying those patients which do not undergo these favorable changes so that medical therapy can be directed at this high risk group.  相似文献   
970.
Pigeons were trained to peck a red or green center key 15 times to turn it off. After a delay, two side keys, one red and one green were illuminated. Pecks on the side key whose color matched the color that the center key had been produced food. Pecks on the other side key produced a timeout. The effects of various drugs were studied as the delay between extinguishing of the center key light and illumination of side keys was varied from 1 to 8 sec. Pentobarbital and phencyclidine consistently decreased matching, but morphine, d-amphetamine and delta 9-tetrahydrocannabinol had little effect on matching even at doses that increased latency to respond and decreased the rate of responding. Pentobarbital frequently decreased matching at doses below those that increased response latency and decreased response rate, but phencyclidine decreased matching only at doses that increased latencies and decreased rates. The effects of pentobarbital on matching did not depend on the delay duration.  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