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   865604篇
  免费   70914篇
  国内免费   1851篇
耳鼻咽喉   12826篇
儿科学   24693篇
妇产科学   25185篇
基础医学   124631篇
口腔科学   25548篇
临床医学   75639篇
内科学   165220篇
皮肤病学   17010篇
神经病学   70246篇
特种医学   35287篇
外国民族医学   171篇
外科学   136692篇
综合类   24722篇
现状与发展   2篇
一般理论   263篇
预防医学   67274篇
眼科学   20677篇
药学   64952篇
中国医学   1685篇
肿瘤学   45646篇
  2018年   7413篇
  2015年   7827篇
  2014年   11239篇
  2013年   16926篇
  2012年   22927篇
  2011年   24054篇
  2010年   13999篇
  2009年   13192篇
  2008年   22795篇
  2007年   24817篇
  2006年   24680篇
  2005年   24356篇
  2004年   23875篇
  2003年   23004篇
  2002年   22057篇
  2001年   35905篇
  2000年   36548篇
  1999年   30975篇
  1998年   9259篇
  1997年   8575篇
  1996年   8499篇
  1995年   8024篇
  1994年   7749篇
  1992年   26722篇
  1991年   26160篇
  1990年   25675篇
  1989年   24721篇
  1988年   23264篇
  1987年   22930篇
  1986年   21771篇
  1985年   21129篇
  1984年   16402篇
  1983年   14019篇
  1982年   8879篇
  1981年   8215篇
  1980年   7680篇
  1979年   16748篇
  1978年   12125篇
  1977年   10188篇
  1976年   9336篇
  1975年   10154篇
  1974年   12649篇
  1973年   12142篇
  1972年   11549篇
  1971年   10693篇
  1970年   10228篇
  1969年   9912篇
  1968年   8909篇
  1967年   8233篇
  1966年   7653篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
OBJECTIVE: To assess the effects of adding combined estradiol/norethisterone acetate therapy (CENT) to goserelin acetate treatment (GA) of dysfunctional uterine bleeding (DUB) in perimenopausal women. METHODS: In a randomized, placebo-controlled, double-blind trial followed by an open follow-up study, 31 perimenopausal women with DUB were recruited from gynecological outpatient departments of two Dutch hospitals and randomized for treatment with either GA/placebo or GA/CENT for 6 months followed by 18 months of GA/CENT for all. The main outcome measures were abdominal pain, number of bleeding days, double-layer endometrial thickness (DET), Greene climacteric score (GCS), visual analog scale for well-being, bone mineral density (BMD) and mammographic density (BI-RAD score). RESULTS: Abdominal pain, number of bleeding days and DET decreased in both groups, the between-group difference in decrease not being statistically significant. GCS initially showed significant improvement in the GA/CENT group. BMD decreased significantly in the GA/placebo group (-4.1%) compared with the GA/CENT group (-0.3%). Another 18 months of GA/CENT did not result in a lasting difference in BMD between groups. BI-RAD scores did not differ significantly between or within the two groups. CONCLUSIONS: Adding CENT to GA treatment for DUB in perimenopausal women initially prevented BMD loss and improved climacteric complaints, while having no negative impact on vaginal bleeding, abdominal pain or BI-RAD scores. However, prolonged treatment did not result in a lasting prevention of bone loss.  相似文献   
22.
23.
24.
25.
The use of additional epidural sympathetic block during and after microvascular surgery in the lower extremities to prevent vasospasm is generally agreed on. However, a significant fall in the perfusion rate of the transplants was seen after application of bupivacaine (Marcain) via the epidural catheter. This effect has, to our knowledge, not been described before and is probably caused by the sympathectomy effect of this type of analgesia.  相似文献   
26.
Median cervical cysts are congenital anomalies arising from remaining thyroglossal duct epithelium. A major problem in the surgical treatment of these cysts is the high frequency of recurrence. Embryonic considerations indicate an important causal role for the hyoid bone in these recurrences. We studied the relationship between operative techniques and the number of recurrences in 36 patients treated in our hospital. Fourteen patients sent from other hospitals had a recurrent fistula; in thirteen cases the hyoid bone was still in place. All patients who had the central part of the hyoid bone excised were cured. In 14 patients without adequate excisions of the hyoid bone we found four recurrences. To prevent recurrence a total excision of thyroglossal duct epithelium is necessary.  相似文献   
27.
28.
Membrane-bound CD14 acts as a receptor for lipopolysaccharide (LPS) on monocytes/macrophages and neutrophils. Studies have suggested that the activation of monocytes/macrophages by the binding of LPS to membrane-bound CD14 may require the association of a signal-transducing molecule with membrane-bound CD14. The observation that non-CD14 expressing cells, such as endothelial cells, can nevertheless be activated by a complex of LPS and a soluble form of CD14 (sCD14) suggests that the receptor for this complex may be identical to the signal transducing molecule associated with membrane-bound CD14. The studies described show that two CD14-specific MoAb are able to block the LPS-induced activation of endothelial cells but do not affect the response of monocytes to LPS. This suggests that the interaction of the sCD14:LPS complex with endothelial cells is distinct from the interaction of membrane-bound CD14 with its putative signal-transducing molecule.  相似文献   
29.
Most prosthetic joint infections (PJI) are due to wound contamination at the time of surgery. Some infections occur due to the hematogenous spread of bacteria from distant sites of infection. A review of the literature fails to associate PJI with transient bacteremias from invasive dental procedures. Several authors have described conditions which, they believe, render patients with prosthetic joints more at risk for infection. Prosthetic joint patients with these "high risk" conditions have the same types of infecting organisms as other patients with PJI. This indicates that the infecting bacteria are from wound contamination or distant sites of infection and not related to dental procedure bacteremias. Based on this review, antibiotic prophylaxis is not indicated for patients with prosthetic joints when receiving invasive dental procedures, since there is no proven benefit and there are known risks involved with the use of antibiotics. However, the American Dental Association (ADA) and the American Academy of Orthopaedic Surgeons (AAOS), in an advisory statement, suggest prophylaxis for "high risk" patients. The ADA and AAOS recommend a single dose of amoxicillin, cephradine, or clindamycin when prophylaxis is selected. The dentist is ultimately responsible for making treatment recommendations for his or her patients.  相似文献   
30.
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