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   4793篇
  免费   303篇
  国内免费   18篇
耳鼻咽喉   64篇
儿科学   66篇
妇产科学   65篇
基础医学   731篇
口腔科学   331篇
临床医学   382篇
内科学   973篇
皮肤病学   112篇
神经病学   433篇
特种医学   119篇
外科学   593篇
综合类   15篇
一般理论   1篇
预防医学   543篇
眼科学   57篇
药学   421篇
中国医学   31篇
肿瘤学   177篇
  2023年   45篇
  2022年   93篇
  2021年   164篇
  2020年   125篇
  2019年   128篇
  2018年   178篇
  2017年   135篇
  2016年   143篇
  2015年   165篇
  2014年   223篇
  2013年   285篇
  2012年   419篇
  2011年   434篇
  2010年   201篇
  2009年   210篇
  2008年   322篇
  2007年   302篇
  2006年   270篇
  2005年   210篇
  2004年   157篇
  2003年   157篇
  2002年   149篇
  2001年   112篇
  2000年   102篇
  1999年   73篇
  1998年   28篇
  1997年   21篇
  1996年   11篇
  1995年   15篇
  1994年   14篇
  1993年   9篇
  1992年   21篇
  1991年   14篇
  1990年   18篇
  1989年   9篇
  1988年   6篇
  1987年   13篇
  1986年   14篇
  1985年   6篇
  1984年   7篇
  1982年   8篇
  1980年   5篇
  1979年   8篇
  1978年   6篇
  1977年   6篇
  1976年   5篇
  1970年   5篇
  1969年   20篇
  1968年   6篇
  1967年   8篇
排序方式: 共有5114条查询结果,搜索用时 31 毫秒
101.
102.
Modulation of the autonomic nervous system on heart rate can be compromised in chronic kidney disease and may result in changes in the frequency and duration of the cardiac cycle. The aim of this study was to evaluate autonomic modulation in active and sedentary renal transplant recipients. Twenty renal‐transplanted individuals were analyzed at the Centro de Prevenção de Doenças Renais (Kidney Disease Education Centre), in the academic hospital of Universidade Federal do Maranhão, and were divided into the active group (AG) and the sedentary group (SG). The AG comprised of six men and four women (age 43.10 ± 13.02) and was in regular concurrent training intervention for 8 weeks, while the SG was composed of three men and seven women (age 36.8 ± 9.26). Analysis of heart rate (HR) variability in time and frequency domain demonstrated that HR mean values in the SG and AG were 787.32 ± 79.60 and 870 ± 106.66 ms, respectively. Differences were observed in the time domain and frequency domain. The total index of low frequency and high frequency showed no differences between the SG and AG. Biochemical variables presented significantly lower levels after 8 weeks of training. Higher heart rate variability in the time domain and greater vagal modulation was observed in the AG. The AG ad greater vagal modulation when compared to the SG, with removal of the sympathetic and increased parasympathetic in the behaviour was confirmed by sympatho‐vagal balance. The AG also presented significant improvements in the frequency domain.  相似文献   
103.
104.
105.
Chronic consumption of processed food causes structural changes in membrane phospholipids, affecting brain neurotransmission. Here we evaluated noxious influences of dietary fats over two generations of rats on amphetamine (AMPH)-conditioned place preference (CPP). Female rats received soybean oil (SO, rich in n-6 fatty acids (FA)), fish oil (FO, rich in n-3 FA) and hydrogenated vegetable fat (HVF, rich in trans fatty acids (TFA)) for two successive generations. Male pups from the 2nd generation were maintained on the same supplementation until 41 days of age, when they were conditioned with AMPH in CPP. While the FO group showed higher incorporation of n-3 polyunsaturated-FA (PUFA) in cortex/hippocampus, the HVF group showed TFA incorporation in these same brain areas. The SO and HVF groups showed AMPH-preference and anxiety-like symptoms during abstinence. Higher levels of protein carbonyl (PC) and lower levels of non-protein thiols (NPSH) were observed in cortex/hippocampus of the HVF group, indicating antioxidant defense system impairment. In contrast, the FO group showed no drug-preference and lower PC levels in cortex. Cortical PC was positively correlated with n-6/n-3 PUFA ratio, locomotion and anxiety-like behavior, and hippocampal PC was positively correlated with AMPH-preference, reinforcing connections between oxidative damage and AMPH-induced preference/abstinence behaviors. As brain incorporation of trans and n-6 PUFA modifies its physiological functions, it may facilitate drug addiction.  相似文献   
106.
Ecotoxicology - Potassium sorbate is the potassium salt of sorbic acid, is a widespread and efficient antioxidant that has multiple functions in plants, traditionally associated with the reactions...  相似文献   
107.
A prospective study of visceral leishmaniasis in an endemic area of Brazil   总被引:13,自引:0,他引:13  
The epidemiology, clinical patterns, and risk factors for visceral leishmaniasis were prospectively studied in an endemic area of Brazil. The prevalence of disease was 3.1% for children less than 15 years of age, and the annual incidence was 4.3 cases per 1,000 children. The number of children with disease fluctuated yearly and seasonally, and distribution of the disease varied within the endemic area. Risk factors included young age (median, three years) and malnutrition before the onset of disease. Intestinal parasitism, recent migration into the area, and house location within the area did not influence the progression of infection to disease. Serological testing indicated that 7.5% of children were infected with Leishmania each year and that the ratio of disease to infection was 1:18.5 for the whole area and 1:6.5 for the section with the highest prevalence of disease. Early diagnosis and therapy altered clinical patterns of the disease.  相似文献   
108.
We describe the case of a 40-day-old female patient with a history of breathlessness since birth who was referred to our hospital for surgical correction of common arterial trunk. The invasive investigation disclosed a Fallot cent s tetralogy anatomy associated with an anomalous origin of the left pulmonary artery from the ascending aorta. Immediately after diagnosis, the patient underwent a successful total surgical correction of the defect, including simultaneous anastomosis of the left pulmonary artery to the pulmonary trunk.  相似文献   
109.
Background

Resistance training has proven to be an excellent method for counteracting aging physical dysfunctions. However, its application in the liquid environment is not yet fully elucidated.

Aim

To investigate the effects of water-based resistance training (WBRT) with the concentric phase performed as fast as possible, compared to conventional resistance training (CRT), on physical functional capacity, muscle strength, and body composition in older women.

Methods

Thirteen healthy older women participated in the WBRT and 11 in the CRT. Estimation statistics focused on the effect size of the experiment/intervention were used. We also analyzed the intervention effect based on the percentage delta between WBRT and CRT.

Results

The WBRT group showed a negative large effect (d?=?? 0.922; p?=?0.0274) for the timed up and go, and a large effect for chair rise in 30″ and the elbow flex test (d?=?1.58; p?=?0.0012; d?=?2.8; p?=?0.01) respectively. Intervention comparisons based on the delta percentage between WBRT and CRT presented an intermediate effect (d?=?0.606; p?=?0.157) for the stair climb, a large effect (d?=?0.988; p?=?0.0282) for the timed up and go, and a large negative effect [d?=?? 1.32 (90.0% CI ? 1.92, ? 0.646); p?=?0.0038] for the elbow flex test. Concentric extensor-flexor peak torque (60°/s) showed an intermediate effect (d?=?0.749; p?=?0.0876; d?=?0.65; p?=?0.122 respectively). Body fat (%) demonstrated an intermediate effect (d?=?0.523; p?=?0.234).

Conclusion

WBRT with the concentric phase performed as fast as possible was able to improve physical functional capacity and maximal knee extension strength of older women.

  相似文献   
110.
OBJECTIVES: The safety of donors is paramount in adult living donor liver transplantation. Our goal is to compare the pattern of recovery of hepatic synthetic function and aminotransferases in healthy adult donors with and without complications. METHODS: We reviewed 47 consecutive patients undergoing right donor hepatectomy at our center. Laboratory data were collected through the first 2 postoperative weeks and results from donors with and without complications were compared. RESULTS: Donor morbidity was 25% and there were no donor deaths. Total bilirubin peaked on postoperative day 3, whereas aminotransferases and international normalized ratio peaked on postoperative day 1. Peak total bilirubin was higher in patients with fluid collections (n = 7) compared with those without fluid collections (n = 40), 4.6 mg/dL and 2.3 mg/dL, respectively, P = 0.02. On postoperative day 3 the peak total bilirubin was greater than 3.0 mg/dL in 86% of donors with fluid collections and 15% of donors without fluid collections, (P = 0.0005) whereas aminotransferases and alkaline phosphatase were not significantly different between these 2 groups. CONCLUSIONS: After right donor hepatectomy a total bilirubin greater than 3.0 mg/dL on postoperative day 3 should prompt an evaluation for a fluid collection, even if other liver tests are normal or declining.  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