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   2542篇
  免费   183篇
  国内免费   3篇
耳鼻咽喉   4篇
儿科学   60篇
妇产科学   81篇
基础医学   321篇
口腔科学   111篇
临床医学   298篇
内科学   584篇
皮肤病学   70篇
神经病学   235篇
特种医学   77篇
外科学   225篇
综合类   14篇
预防医学   241篇
眼科学   42篇
药学   216篇
中国医学   5篇
肿瘤学   144篇
  2023年   36篇
  2022年   26篇
  2021年   51篇
  2020年   58篇
  2019年   67篇
  2018年   84篇
  2017年   66篇
  2016年   66篇
  2015年   67篇
  2014年   76篇
  2013年   139篇
  2012年   183篇
  2011年   182篇
  2010年   104篇
  2009年   80篇
  2008年   141篇
  2007年   138篇
  2006年   139篇
  2005年   137篇
  2004年   127篇
  2003年   80篇
  2002年   97篇
  2001年   51篇
  2000年   40篇
  1999年   51篇
  1998年   20篇
  1997年   15篇
  1996年   19篇
  1995年   15篇
  1994年   9篇
  1993年   12篇
  1992年   20篇
  1991年   24篇
  1990年   28篇
  1989年   33篇
  1988年   18篇
  1987年   19篇
  1986年   20篇
  1985年   35篇
  1984年   18篇
  1983年   11篇
  1982年   11篇
  1981年   9篇
  1979年   10篇
  1978年   9篇
  1977年   11篇
  1976年   7篇
  1970年   9篇
  1969年   8篇
  1966年   6篇
排序方式: 共有2728条查询结果,搜索用时 15 毫秒
71.
The inflammatory recruitment of leucocytes is a main cause of tissue damage in ischaemia/reperfusion (I/R) injury. Under appropriate flow conditions, E-selectin and L-selectin participate in the initial deceleration of neutrophils (PMNs) on inflamed endothelial cells before transmigration of PMNs into the surrounding tissue. Previous work from our lab showed increased survival of I/R injured myocutaneous flaps after treatment with anti-E/L-selectin. In this study, we have evaluated a combined antibody to E-selectin and L-selectin (EL-246) in porcine pure skin flaps exposed to I/R injury. Buttock skin flaps were exposed to eight hours of ischaemia and 20 hours of reperfusion. EL-246 or saline was given intra-arterially into the flaps. Estimated surviving area was not improved in the treated group. The lack of effect of EL-246 supports our suspicion that different mechanisms are involved in I/R injury in myocutaneous flaps compared with pure skin flaps. As a certain shear stress must be present for the selectins to exert their effect, a possible explanation for the diverse results in muscle and skin might be different reflow patterns.  相似文献   
72.
Characteristics, diagnosis, need for care, GAF score, and admission patterns were obtained for a group of patients (n 48) who were heavy users of a psychiatric hospital. The need for care was measured with the Camberwell assessment of need. More than half of the patients had a diagnosis of schizophrenia. The second most common diagnosis was personality disorder. Mean age was 37.5 years. Median number of need for care was 11 according to the patients and 12 according to the staff. Overall, the results showed very heterogeneous patterns with regard to age, disability, need for care, and admission patterns. This could indicate that the mental health services should become more differentiated and flexible owing to the presence of a heterogeneous, long-term patient population. Individual needs assessment and treatment programs tailored the single long-term patient are necessary.  相似文献   
73.
BackgroundEvidence of associations between neurocognitive function and cannabis use in schizophrenia is inconclusive. However, direct measures of cannabis intake and premorbid function are rarely explored in this context. We investigated the relation between cannabis use, determined by its presence in urine, and neurocognitive functioning in schizophrenia controlling for the potential bias of premorbid functioning.MethodsNaturalistic study of 364 patients with schizophrenia spectrum disorder from catchment areas in Oslo, Norway. Hierarchical multiple regression analyses were used to assess the relationship between cannabis in urine and measures of neurocognitive functioning, with adjustment for confounders, including premorbid functioning.ResultsCannabis was detected in the urine of 21 patients, who had significant dysfunction in several neurocognitive domains independent of a current diagnosis of cannabis abuse. However, level of premorbid functioning explained the associations for all measures.ConclusionDifferences in premorbid functioning may explain apparent differences in neurocognitive function between schizophrenia spectrum patients using cannabis or not. The findings suggest that illness-related traits present early in life can affect both later cannabis use and neurocognition, probably by complex mechanisms.  相似文献   
74.
75.
Objective: To evaluate the effect of regular exercise on maternal arterial blood pressure (BP) at rest and during uphill walking, in healthy former inactive pregnant women. Methods: A single-blind, single-center, randomized controlled trial including 61 out of 105 healthy, inactive nulliparous pregnant women, initially enrolled in a controlled trial studying the effect of 12 weeks of aerobic exercise (60 min 2/week) on maternal weight gain. Primary outcome was the mean adjusted difference in change in resting systolic and diastolic BP from baseline to after intervention. Secondary outcome was the mean adjusted difference in change in systolic BP during uphill treadmill walking at critical power. Measurements were performed prior to the intervention (gestation week 17.6 ± 4.2) and after the intervention (gestation week 36.5 ± 0.9). Results: At baseline, resting systolic and diastolic BP was 115/66 ± 12/7 and 115/67 ± 10/9 mmHg in the exercise (n = 35) and control group (n = 26), respectively. After the intervention, resting systolic BP was 112 ± 8 mmHg in the exercise group and 119 ± 14 mmHg in the control group, giving a between-group difference of 7.5 mmHg (95% CI 1.5 to 12.6, p = 0.013). Diastolic BP was 71 ± 9 and 76 ± 8 mmHg, with a between-group difference of 3.9 mmHg (95% CI ?0.07 to 7.8, p = 0.054). During uphill treadmill walking at critical power, the between-group difference in systolic and diastolic BP was 5.9 mmHg (95% CI ?4.4 to 16.1, p = 0.254) and 5.5 mmHg (95% CI –0.2 to 11.1, p = 0.059), respectively. Conclusions: Aerobic exercise reduced resting systolic BP in healthy former inactive pregnant women.  相似文献   
76.
BACKGROUND: Increased plasma homocysteine has been linked to many clinical conditions including atherosclerosis and ischemic stroke. We assessed the genetic and environmental influences on homocysteine in adult twins and tested the influence of 3 candidate polymorphisms. METHODS: Homocysteine was analyzed in 1206 healthy twins, who were genotyped for 3 polymorphisms: MTHFR 677C>T, MTR 2756A>G, and NNMT (dbSNP: rs694539). To perform quantitative trait linkage analysis of the MTHFR locus, the genotyping was supplemented with 2 genetic markers localized on each site of the MTHFR locus. The twin data were analyzed using biometric structural equation models as well as a combined association and linkage analysis in 2 age cohorts. RESULTS: Age, sex, and MTHFR genotype have a significant impact on homocysteine concentrations, whereas the other genotypes were not associated with homocysteine concentrations. The variance in homocysteine could be solely ascribed to additive genetic and nonshared environmental factors, with an estimated additive genetic proportion of total variation at age 18-39 years of 0.63 (95% CI, 0.53-0.71) and at age 40-65 years of 0.27 (95% CI, 0.10-0.41). The impact of the MTHFR locus is estimated to explain 53% (95% CI, 0.07-0.67) of the total phenotypic variation in persons 18-39 years old and 24% (95% CI, 0.00-0.39) in persons 40-65 years old, i.e., almost all additive genetic variance. CONCLUSIONS: Homocysteine concentrations have a high heritability that decreases with age. The MTHFR gene locus is responsible for almost all the variation attributable to genetic factors, leaving very little influence of other genetic variations.  相似文献   
77.
78.
Brain Imaging and Behavior - A higher incidence of cognitive impairment (CI) has previously been reported among orchiectomized testicular cancer patients (TCPs), but little is known about the...  相似文献   
79.
80.
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