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   16661篇
  免费   1712篇
  国内免费   23篇
耳鼻咽喉   144篇
儿科学   545篇
妇产科学   532篇
基础医学   2413篇
口腔科学   272篇
临床医学   1959篇
内科学   3228篇
皮肤病学   192篇
神经病学   1303篇
特种医学   589篇
外国民族医学   3篇
外科学   2067篇
综合类   403篇
一般理论   11篇
预防医学   1904篇
眼科学   368篇
药学   1305篇
中国医学   12篇
肿瘤学   1146篇
  2021年   208篇
  2020年   146篇
  2019年   238篇
  2018年   260篇
  2017年   210篇
  2016年   230篇
  2015年   242篇
  2014年   343篇
  2013年   529篇
  2012年   692篇
  2011年   781篇
  2010年   479篇
  2009年   405篇
  2008年   663篇
  2007年   703篇
  2006年   652篇
  2005年   674篇
  2004年   688篇
  2003年   665篇
  2002年   574篇
  2001年   538篇
  2000年   551篇
  1999年   455篇
  1998年   219篇
  1997年   184篇
  1996年   168篇
  1995年   194篇
  1994年   158篇
  1993年   149篇
  1992年   408篇
  1991年   403篇
  1990年   412篇
  1989年   360篇
  1988年   382篇
  1987年   366篇
  1986年   326篇
  1985年   293篇
  1984年   262篇
  1983年   221篇
  1982年   126篇
  1979年   217篇
  1978年   175篇
  1977年   145篇
  1976年   150篇
  1975年   151篇
  1974年   153篇
  1973年   175篇
  1972年   142篇
  1971年   129篇
  1970年   137篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
61.
The maternal and fetal endocrine effects of the maternal administration of the anti-progestin mifepristone in mid-pregnancy have been investigated. Mifepristone and the metabolite RU 42,633 were detected in the fetal circulation and in the amniotic fluid 4, 24 and 48 h after oral ingestion. Maximum fetal plasma concentrations of mifepristone occurred 4 h after treatment indicating rapid placental transfer of the drug. No significant changes in progesterone, cortisol, oestradiol or aldosterone concentrations were detected in the maternal circulation after mifepristone treatment. No significant changes occurred in the fetal progesterone, oestradiol or cortisol concentrations, but a significant increase in fetal aldosterone occurred 4 and 24 h after treatment. The significance of these results is discussed in relation to the possible therapeutic uses of mifepristone for inducing labour.  相似文献   
62.
Injury associated with alcohol use is a significant problem among adolescents; however, routine evaluation of alcohol use in this population is not conducted. The purpose of this study was to compare injured adolescents presenting to an emergency room with a positive serum alcohol concentration (SAC+) with those injured adolescents wlth a negative serum alcohol concentration (SAC-). Data were collected retrospectively on 176 injured patients, between the ages of 13 and 18, consecutively admitted to a university hospital from January 1, 1989-December 31, 1990. Information collected included mechanism and severity of injury, outcome, SAC, length of stay, prychiatric history, prior or subsequent admission for injury, and hospital charges. Of those tested with an SAC, more than one-third had a positive SAC. Patients with positive SACs had a greater probability of having a psychiatric history and more frequently had a prior or subsequent injury. Furthermore, only 34% of SAC+ patients were referred for counseling. The results indicate that a SAC should be obtained on all adolescents admitted for trauma, that adolescents presenting with injuries and a positive SAC should be referred for alcohol and psychiatric assessment, and that injured adolescents may be at increased risk for repeat injuries in the future.  相似文献   
63.
Summary The cytochalasins are fungal metabolites that have previously been shown to have some chemotherapeutic potential. When various cell types are treated in vitro with both cytochalasin B and vincristine, the resultant DNA fragmentation is greater than the sum of that caused by each agent alone. The levels necessary to achieve this potentiation are obtainable in vivo. DNA fragmentation induced by cytochalasin E, an actin-specific agent, is potentiated by vincristine. Pretreatment of the mastocytoma line P815 with vincristine results in an enhancement of the ability of cytochalasin B to fragment DNA. These results inducate that cytochalasin B might be effective as a chemotherapeutic agent in the presence of vincristine.This work was supported in part by the Women's Cancer Association and by the Sylvester Comprehensive Cancer Center  相似文献   
64.
In one surgical unit, 115 patients undergoing cholecystectomy were studied to compare patient recovery, subjective and objective pain experienced and complications after laparoscopic and open cholecystectomy. The data were collected prospectively where allocation to open or laparoscopic cholecystectomy was by consecutive attendance. Laparoscopic cholecystectomy was feasible in 90% of patients presenting with symptomatic gallstones. Compared with the open operation, laparoscopic cholecystectomy was safe with less peroperative and postoperative morbidity, was more cost-effective and was associated with faster patient recovery as documented by less postoperative pain, earlier return to diet, earlier full mobilisation and discharge home. Laparoscopic cholecystectomy is superior to open cholecystectomy and should be available to all patients requiring elective cholecystectomy.  相似文献   
65.
This study examined the use of autologous fat as an alternative to Teflon® and collagen as the implantable material in vocal cord medialization. Five animals underwent left recurrent laryngeal nerve sections with subsequent fat harvest and implantation into the left true vocal cords. Three animals were killed after 48 hours and 2 after 3 weeks; their larynges were examined with light microscopy. The results of the 48-hour samples show moderate acute inflammation and few areas of focal necrosis. The 3-week samples show no necrotic foci, minimal foreign-body reaction, and maintenance of structure and volume of the injected fat. Autologous fat may prove to be a valuable alternative to nonautologous injectable material in vocal cord augmentation.  相似文献   
66.
67.
68.
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   
69.
70.
To study the effects of electroconvulsive therapy (ECT) on hormone release, we measured circulating concentrations of adrenocorticotropic hormone (ACTH), prolactin (PRL), growth hormone (GH) and cortisol (CORT) immediately before and at 2 min, 5 min, 15 min, and 30 min following ECT. Compared to pre-ECT concentrations, there were significant increases in post-ECT plasma ACTH, PRL and CORT. GH did not change consistently. No significant difference between unilateral and bilateral ECT was observed. Compared to the first ECT, repeated treatments were associated with a significant decrease in the magnitude of hormone surge. These hormonal changes induced by ECT may reflect changes at the neurotransmitter level.  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