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   22627篇
  免费   1936篇
  国内免费   54篇
耳鼻咽喉   137篇
儿科学   650篇
妇产科学   356篇
基础医学   2949篇
口腔科学   407篇
临床医学   2416篇
内科学   4598篇
皮肤病学   194篇
神经病学   2115篇
特种医学   873篇
外国民族医学   5篇
外科学   3101篇
综合类   399篇
现状与发展   1篇
一般理论   47篇
预防医学   2720篇
眼科学   463篇
药学   1791篇
中国医学   22篇
肿瘤学   1373篇
  2023年   176篇
  2022年   269篇
  2021年   607篇
  2020年   375篇
  2019年   553篇
  2018年   607篇
  2017年   482篇
  2016年   518篇
  2015年   595篇
  2014年   765篇
  2013年   1054篇
  2012年   1597篇
  2011年   1603篇
  2010年   930篇
  2009年   795篇
  2008年   1419篇
  2007年   1413篇
  2006年   1328篇
  2005年   1332篇
  2004年   1247篇
  2003年   1109篇
  2002年   977篇
  2001年   391篇
  2000年   349篇
  1999年   293篇
  1998年   213篇
  1997年   207篇
  1996年   172篇
  1995年   116篇
  1994年   130篇
  1993年   120篇
  1992年   211篇
  1991年   191篇
  1990年   175篇
  1989年   155篇
  1988年   136篇
  1987年   146篇
  1986年   119篇
  1985年   131篇
  1984年   112篇
  1983年   105篇
  1982年   98篇
  1981年   77篇
  1980年   76篇
  1979年   130篇
  1978年   84篇
  1977年   77篇
  1974年   69篇
  1973年   69篇
  1968年   66篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
3.
An exaggerated fall in blood pressure has been reported with the combination of an alpha 1-blocker and a calcium antagonist. This study investigated, in a placebo-controlled, randomized crossover trial, the clinical usefulness of the combination of prazosin (2 mg b.i.d.) and verapamil (160 mg b.i.d.). Therapeutic efficacy was monitored at regular outpatient visits: average supine and erect blood pressures were, respectively, 175/99 and 176/103 mm Hg with placebo, 160/91 and 164/96 mm Hg with single drug treatment, and 152/84 and 152/89 mm Hg with combination therapy. This significant and clinically useful reduction in blood pressure had an overall magnitude of approximately 28/18 mm Hg (supine) and 29/19 mm Hg (erect). Further measurements were made during a series of intensive study days, and the most important additional finding was a pharmacokinetic interaction that resulted in increased peak concentrations and bioavailability of prazosin. In conclusion, the combination of prazosin and verapamil proved effective in the treatment of 12 patients with essential hypertension who had been poorly responsive to conventional treatment with a beta-blocker and thiazide diuretic.  相似文献   
4.
Nerve growth factor (NGF) gene expression in central nervous system (CNS) glia appears to be associated with active glial growth. To study the underlying molecular mechanisms, we examined the effects of a number of growth-related factors on NGF mRNA expression in glial cultures. Our results suggest that glial membrane interaction, as a consequence of growth, actively inhibits NGF gene expression in CNS glia.  相似文献   
5.
Transcranial Magnetic Stimulation (TMS) induces electrical currents in the brain to stimulate neural tissue. This article reviews our present understanding of TMS methodology, focusing on its biophysical foundations. We concentrate on how the laws of electromagnetic induction apply to TMS; addressing issues such as the location, area (i.e., focality), depth, and mechanism of TMS. We also present a review of the present limitations and future potential of the technique.  相似文献   
6.

Background  

To determine patterns of childhood lead exposure in a community living near a lead and zinc smelter in North Lake Macquarie, Australia between 1991 and 2002.  相似文献   
7.
8.
9.
OBJECTIVE: To assess the impact of activity restriction (AR) on the incidence of preterm birth in women treated for preterm labor testing negative for fetal fibronectin (fFN). STUDY DESIGN: Women who were diagnosed with preterm labor and tocolyzed with magnesium sulfate were concurrently screened with fFN for the purpose of subsequent management. Included were consenting patients with negative fFN, gestational age 23 0/7-33 6/7 weeks, cervical dilation < or =3 cm, and minimal vaginal bleeding. Patients were randomized to AR or no AR. Primary study outcome was incidence of preterm delivery and interval from randomization to delivery. RESULTS: A total of 73 women with negative fFN were randomized (36 with AR, 37 without AR). The overall preterm birth rate was 40%, with 44.4% of patients with AR and 35.1% of patients without AR delivering preterm, p=0.478. CONCLUSION: Maternal AR did not impact pregnancy outcome. The incidence of preterm birth in symptomatic women testing fFN negative was higher than previously reported.  相似文献   
10.
Transabdominal sacrocolpopexy has been shown, in multiple long-term studies of its success and durability, to be the definitive treatment option for post-hysterectomy vaginal vault prolapse. It is, however, associated with greater morbidity than vaginal repair. We describe a minimally invasive technique for vaginal vault prolapse repair and present our experience with a minimum of one-year follow-up. The surgical technique involves five laparoscopic ports—three for the da Vinci robot and two for the assistant. After appropriate dissection a polypropylene mesh is attached to the sacral promontory and to the vaginal apex by use of Gore-Tex sutures. The mesh material is then covered by the peritoneum. Patient analysis focused on complications, urinary continence, patient satisfaction, and morbidity, with a minimum of 12 months follow-up. Forty-two patients with post-hysterectomy vaginal vault prolapse underwent robot-assisted laparoscopic sacrocolpopexy at our institute and 35 have a minimum of 12 months follow-up, with a mean follow-up of 36 months (range 12–48) in the group. Mean age was 67 (47–83) years and mean operating time was 3.1 (2.15–4.75) h for the entire cohort. All but one patient were discharged home on postoperative day one; one patient left on postoperative day two. One developed recurrent grade three rectocele, one had recurrent vault prolapse, and two suffered from vaginal extrusion of mesh. All patients were satisfied with their outcome. The robot-assisted laparoscopic sacrocolpopexy is a minimally invasive technique for vaginal vault prolapse repair, combining the advantages of open sacrocolpopexy with the reduced morbidity of laparoscopy. We observed reduced hospital stay, low occurrence of complications, and high patient satisfaction, with a minimum of 1-year follow-up. Most importantly, the long-term results of the robotic repair are similar to those of open repair, but with significantly less morbidity.  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