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   2749篇
  免费   304篇
  国内免费   1篇
耳鼻咽喉   83篇
儿科学   230篇
妇产科学   107篇
基础医学   154篇
口腔科学   180篇
临床医学   286篇
内科学   550篇
皮肤病学   64篇
神经病学   221篇
特种医学   145篇
外科学   612篇
综合类   11篇
预防医学   89篇
眼科学   97篇
药学   164篇
中国医学   3篇
肿瘤学   58篇
  2024年   9篇
  2023年   77篇
  2022年   28篇
  2021年   114篇
  2020年   84篇
  2019年   123篇
  2018年   188篇
  2017年   135篇
  2016年   208篇
  2015年   177篇
  2014年   223篇
  2013年   388篇
  2012年   136篇
  2011年   103篇
  2010年   157篇
  2009年   89篇
  2008年   61篇
  2007年   26篇
  2006年   75篇
  2005年   82篇
  2004年   18篇
  2003年   34篇
  2002年   38篇
  2001年   56篇
  2000年   66篇
  1999年   57篇
  1998年   58篇
  1997年   53篇
  1996年   50篇
  1995年   33篇
  1994年   24篇
  1993年   24篇
  1992年   8篇
  1991年   13篇
  1990年   9篇
  1989年   6篇
  1988年   4篇
  1987年   1篇
  1985年   1篇
  1984年   2篇
  1983年   1篇
  1982年   3篇
  1980年   1篇
  1978年   3篇
  1974年   2篇
  1972年   1篇
  1962年   1篇
  1960年   2篇
  1947年   1篇
  1935年   1篇
排序方式: 共有3054条查询结果,搜索用时 31 毫秒
101.
Oxidative stress is considered to play a key role in ageing. Carnosine alone or together with vitamin E may prove to be helpful in dealing with problems of ageing through its antioxidant activity. Testis, by producing steroids and possessing a poor antioxidant system may become a strong target for the chronic oxidative stress generated during ageing. Therefore we investigated the in vivo effect of carnosine alone or together with vitamin E on testicular oxidative stress in aged rats. In this study, young (5 months) and aged (22 months) Wistar rats were used. Carnosine (250 mg kg?1; i.p.; 5 days per week) and vitamin E (200 mg kg?1; i.m.; twice per week) were given to aged rats for 2 months. Increased testicular lipid peroxidation and superoxide dismutase activity in aged rats were declined to the levels of young ones by both treatments. Decreased glutathione peroxidase and glutathione transferase activities returned to the level of young's only by carnosine plus vitamin E treatment. Histopathological evaluation described by Johnsen's score, also showed significant improvement with preserved spermatogenesis. Carnosine plus vitamin E treatment appears to stage a powerful performance by attenuating testicular oxidative stress and sparing the antioxidant system.  相似文献   
102.
103.
104.
105.

Background

Involvement of right-sided heart chambers (RSHCs) in patients infected with human immunodeficiency virus (HIV) is common and is usually attributed to pulmonary arterial or venous hypertension (PH). However, myocardial involvement in patients with HIV is also common and might affect RSHCs even in the absence of overt PH. Our aim was to define morphologic and functional alterations in RSHC in patients with HIV and without PH.

Methods and Results

A total of 50 asymptomatic patients with HIV and 25 control subjects without clinical or echocardiographic signs for PH were included in the study. Transthoracic echocardiography was used to obtain measurements. Patients with HIV had significantly increased right ventricular end-diastolic diameter (RVEDD) and right ventricular free wall thickness (RVFWT), as well as increased right atrial area and pulmonary arterial diameter, compared with control subjects. After adjustment for age, sex, and body surface area, RVFWT (average 1.81 mm, 95% confidence interval [CI] 0.35–3.26 mm) and RVEDD (average 6.82 mm, 95% CI 2.40–11.24 mm) were significantly higher in subjects infected with HIV. More patients with right ventricular hypertrophy were on antiretroviral treatment, and RVFWT was on average 1.3 mm higher (95% CI 0.24–2.37 mm) in patients on antiretroviral treatment after adjustment for confounders.

Conclusions

These findings suggest that alterations in RSHCs were present in patients with HIV without PH.  相似文献   
106.
107.
108.
109.
In this multicenter, retrospective study, we evaluated the efficacy and safety of biologic therapies, including anti-TNFs, in secondary (AA) amyloidosis patients with ankylosing spondylitis (AS) and rheumatoid arthritis (RA). In addition, the frequency of secondary amyloidosis in RA and AS patients in a single center was estimated. Fifty-one AS (39M, 12F, mean age: 46.7) and 30 RA patients (11M, 19F, mean age: 51.7) with AA amyloidosis from 16 different centers in Turkey were included. Clinical and demographical features of patients were obtained from medical charts. A composite response index (CRI) to biologic therapy—based on creatinine level, proteinuria and disease activity—was used to evaluate the efficacy of treatment. The mean annual incidence of AA amyloidosis in RA and AS patients was 0.23 and 0.42/1000 patients/year, respectively. The point prevalence in RA and AS groups was 4.59 and 7.58/1000, respectively. In RA group with AA amyloidosis, effective response was obtained in 52.2 % of patients according to CRI. RA patients with RF positivity and more initial disease activity tended to have higher response rates to therapy (p values, 0.069 and 0.056). After biologic therapy (median 17 months), two RA patients died and two developed tuberculosis. In AS group, 45.7 % of patients fulfilled the criteria of good response according to CRI. AS patients with higher CRP levels at the time of AA diagnosis and at the beginning of anti-TNF therapy had higher response rates (p values, 0.011 and 0.017). During follow-up after anti-TNF therapy (median 38 months), one patient died and tuberculosis developed in two patients. Biologic therapy seems to be effective in at least half of RA and AS patients with AA amyloidosis. Tuberculosis was the most important safety concern.  相似文献   
110.
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