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   1413241篇
  免费   113776篇
  国内免费   3333篇
耳鼻咽喉   18387篇
儿科学   46613篇
妇产科学   41084篇
基础医学   201186篇
口腔科学   37755篇
临床医学   126302篇
内科学   284753篇
皮肤病学   33411篇
神经病学   117068篇
特种医学   53966篇
外国民族医学   464篇
外科学   210837篇
综合类   32827篇
现状与发展   3篇
一般理论   490篇
预防医学   110234篇
眼科学   31589篇
药学   98799篇
  1篇
中国医学   3351篇
肿瘤学   81230篇
  2021年   10888篇
  2019年   11708篇
  2018年   16617篇
  2017年   12707篇
  2016年   14290篇
  2015年   16062篇
  2014年   22616篇
  2013年   33477篇
  2012年   45520篇
  2011年   48056篇
  2010年   28244篇
  2009年   27114篇
  2008年   44429篇
  2007年   46937篇
  2006年   47484篇
  2005年   45964篇
  2004年   43861篇
  2003年   41772篇
  2002年   40262篇
  2001年   73076篇
  2000年   74592篇
  1999年   61637篇
  1998年   17039篇
  1997年   15461篇
  1996年   15598篇
  1995年   14815篇
  1994年   13417篇
  1993年   12598篇
  1992年   45895篇
  1991年   43536篇
  1990年   41548篇
  1989年   39598篇
  1988年   36241篇
  1987年   35407篇
  1986年   32911篇
  1985年   31304篇
  1984年   23864篇
  1983年   20051篇
  1982年   12228篇
  1981年   10800篇
  1979年   20734篇
  1978年   14608篇
  1977年   12104篇
  1976年   11376篇
  1975年   11643篇
  1974年   14006篇
  1973年   13552篇
  1972年   12664篇
  1971年   11493篇
  1970年   10931篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
OBJECTIVE: To evaluate the prenatal distribution, associated conditions and outcome of the different types of right aortic arch (RAA) detected in fetal life. METHODS: This was a retrospective review of all cases of RAA detected prenatally between 1998 and 2005 in two tertiary referral centers. RESULTS: In the study period 71 cases of RAA were detected; 26 (37%) had RAA with aberrant left subclavian artery, 23 (32%) had RAA with mirror-image branching, 20 (28%) had RAA of unknown type and two (3%) had double aortic arch. While 20/26 cases with RAA and aberrant left subclavian artery were isolated findings, all 23 cases with RAA and mirror-image branching were associated with cardiac defects, namely tetralogy of Fallot (43%) or pulmonary atresia with ventricular septal defect (22%). Of the 20 cases with RAA, 19 of unknown type were associated with heterotaxy syndromes and had additional cardiac malformations and ambiguities of the situs. The two cases with DAA were isolated findings. Seven cases in our series (10%) had a microdeletion 22q11 and these were significantly associated with extracardiac malformations. The outcome in our series depended solely on the associated cardiac and extracardiac malformations, with the exception of one infant with isolated DAA, in whom a surgical correction was warranted. CONCLUSIONS: RAA detected in fetal life is associated frequently with other cardiac/non-cardiac malformations, heterotaxy syndromes and microdeletions 22q11. The associated conditions vary depending on the branching type of the brachiocephalic vessels and the presence of extracardiac malformations.  相似文献   
82.
INTRODUCTION: Autoimmune hepatitis (AIH) is a well-defined entity in the West but there are sparse Indian data on this disease. AIM: To study the clinical profile and response to treatment of Indian patients with AIH. METHODS: This is a part retrospective and part prospective study of 50 patients (median age 48 years, range 11-82; 43 women) seen between 1995 to 2001, diagnosed to have AIH as per the revised scoring system. Clinical and laboratory profile, response to treatment, and complications of treatment were analyzed. RESULTS: AIH accounted for 6% of all patients with liver disease seen during the period. The presenting symptoms were gastrointestinal in 43 and non-gastrointestinal in 7, with median symptom duration of 6 months (range 2 weeks to 40 years). Forty patients (80%) had chronic liver disease. Associated illnesses were present in 28 patients. Twenty-six patients were classified as definite and the rest as probable AIH. Forty-nine patients had Type 1 AIH. Five patients had overlap syndrome. Forty-five patients (90%) received immunosuppressive therapy. Twelve of 18 patients receiving only prednisolone and 21 of 27 patients receiving prednisolone and azathioprine combination responded. Thirteen (26%) patients had therapy-related complications (infectious 5, non infectious 8) with two treatment-related deaths. CONCLUSION: Type 1 AIH was the predominant type of AIH. The majority of patients with AIH presented with chronic liver disease. There was good response to immunosuppressive therapy. Therapy-related complications occurred in one-fourth of patients.  相似文献   
83.
84.
85.
A new semi-empirical formula for the evaluation of (n,(3)He) reaction cross-sections at the energy of 14.6 and 20 MeV is presented. Formula was derived using the analytical expression for the evaluation of the (3)He spectrum within the frame of pre-equilibrium exciton model. The systematics obtained is compared with the empirical formula for the (n,(3)He) reaction cross-section.  相似文献   
86.
87.
88.
89.
Liposarcomas are extremely rare in the mediastinum. They may achieve considerable size before causing any symptoms. Mediastinal liposarcomas may invade surrounding structures like the pericardium or the superior vena cava. Complete surgical excision is the optimal treatment in resectable cases. Excision of adjacent structures like the pericardium may be needed if the tumor infiltrates them. We report on a case of a giant liposarcoma of the mediastinum involving both hemithoraces and extending into the neck, which was successfully managed by complete surgical excision.  相似文献   
90.
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