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   1423248篇
  免费   104721篇
  国内免费   3310篇
耳鼻咽喉   18472篇
儿科学   46617篇
妇产科学   41085篇
基础医学   201043篇
口腔科学   37768篇
临床医学   126358篇
内科学   285261篇
皮肤病学   33426篇
神经病学   117275篇
特种医学   53954篇
外国民族医学   464篇
外科学   210978篇
综合类   32784篇
现状与发展   3篇
一般理论   487篇
预防医学   110210篇
眼科学   31569篇
药学   98669篇
  38篇
中国医学   3350篇
肿瘤学   81468篇
  2021年   11079篇
  2019年   12135篇
  2018年   16646篇
  2017年   12730篇
  2016年   14328篇
  2015年   16036篇
  2014年   22595篇
  2013年   33445篇
  2012年   45440篇
  2011年   48004篇
  2010年   28193篇
  2009年   27090篇
  2008年   44388篇
  2007年   46885篇
  2006年   47450篇
  2005年   45910篇
  2004年   43779篇
  2003年   41726篇
  2002年   40214篇
  2001年   73034篇
  2000年   74572篇
  1999年   61577篇
  1998年   17008篇
  1997年   15438篇
  1996年   15594篇
  1995年   14796篇
  1994年   13415篇
  1993年   12588篇
  1992年   45878篇
  1991年   43514篇
  1990年   41519篇
  1989年   39575篇
  1988年   36194篇
  1987年   35364篇
  1986年   32877篇
  1985年   31293篇
  1984年   23842篇
  1983年   20035篇
  1982年   12212篇
  1981年   10782篇
  1979年   20709篇
  1978年   14583篇
  1977年   12096篇
  1976年   11373篇
  1975年   11628篇
  1974年   14005篇
  1973年   13543篇
  1972年   12636篇
  1971年   11475篇
  1970年   10916篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The aim of the current study was to investigate whether alterations in N-terminal pro brain natriuretic peptide (NT-proBNP) reflect changes in right ventricular structure and function in pulmonary hypertension patients during treatment. The study consisted of 30 pulmonary hypertension patients; 15 newly diagnosed and 15 on long-term treatment. NT-proBNP, right heart catheterisation and cardiac magnetic resonance imaging measurements were performed, at baseline and follow-up. There were no significant differences between newly diagnosed patients and those on treatment at baseline or follow-up with respect to NT-proBNP, haemodynamics and right ventricular parameters. Relative changes in NT-proBNP during treatment were correlated to the relative changes in right ventricular end-diastolic volume index (r = 0.59), right ventricular mass index (r = 0.62) and right ventricular ejection fraction (r = -0.81). N-terminal pro brain natriuretic peptide measurements reflect changes in magnetic resonance imaging-measured right ventricular structure and function in pulmonary hypertension patients. An increase in N-terminal pro brain natriuretic peptide over time reflects right ventricular dilatation concomitant to hypertrophy and deterioration of systolic function.  相似文献   
42.
43.
The pharmacokinetics (PK) of moxifloxacin in healthy white New Zealand rabbits was studied following intravenous (IV) and subcutaneous (SC) administration routes as well as a SC long‐acting poloxamer 407 gel formulation (SC‐P407). Moxifloxacin concentrations were determined by high‐performance liquid chromatography assay with fluorescence detection. Mean half‐life for IV, SC and SC‐P407 routes was 2.15, 5.41 and 11.09 h. Clearance value after IV dosing was 0.78 l/kg/h. After SC administration, the mean absolute bioavailability was 117% and the Cmax was 1.61 ± 0.49 mg/l. After SC‐P407 administration, the bioavailability was 44% and the Cmax 1.83 was ±0.62 mg/l. No adverse effects were observed in any of the rabbits following IV, SC and SC‐P407 administration of moxifloxacin. Minimal inhibitory concentrations of moxifloxacin against different strains of Staphylococcus aureus from different european countries were used to compute the main pharmacodynamic (PD) surrogate markers of efficacy. The high tolerability of this SC‐P407 formulation and the favourable PK behaviour such as the long half‐life, acceptable bioavailability and excellent PK–PD ratios achieved indicate that it is likely to be effective in rabbits.  相似文献   
44.
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   
45.
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   
46.
47.
48.
49.
50.
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   
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