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   170124篇
  免费   8208篇
  国内免费   477篇
耳鼻咽喉   2467篇
儿科学   5398篇
妇产科学   4590篇
基础医学   23450篇
口腔科学   4658篇
临床医学   11600篇
内科学   38874篇
皮肤病学   5468篇
神经病学   13871篇
特种医学   3960篇
外国民族医学   31篇
外科学   22001篇
综合类   1062篇
一般理论   42篇
预防医学   17433篇
眼科学   3521篇
药学   12152篇
中国医学   528篇
肿瘤学   7703篇
  2023年   934篇
  2022年   1558篇
  2021年   3761篇
  2020年   2011篇
  2019年   3719篇
  2018年   5029篇
  2017年   3210篇
  2016年   3215篇
  2015年   3555篇
  2014年   4697篇
  2013年   6861篇
  2012年   10272篇
  2011年   10598篇
  2010年   5872篇
  2009年   5040篇
  2008年   8696篇
  2007年   9137篇
  2006年   8903篇
  2005年   8885篇
  2004年   8292篇
  2003年   7684篇
  2002年   7384篇
  2001年   5279篇
  2000年   5431篇
  1999年   4548篇
  1998年   1285篇
  1997年   915篇
  1996年   866篇
  1995年   740篇
  1994年   627篇
  1992年   2269篇
  1991年   2154篇
  1990年   2006篇
  1989年   1765篇
  1988年   1620篇
  1987年   1580篇
  1986年   1471篇
  1985年   1412篇
  1984年   1045篇
  1983年   889篇
  1979年   1007篇
  1978年   669篇
  1975年   677篇
  1974年   884篇
  1973年   856篇
  1972年   743篇
  1971年   706篇
  1970年   752篇
  1969年   711篇
  1968年   676篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
83.

Background

Most elderly trauma patients suffer blunt head injury and many utilize antithrombotic (AT) medications. The utility of delayed CT-head (D-CTH) in neurologically intact elderly patients using AT who have an intracranial hemorrhage (ICH) on presentation is unknown. We hypothesized that D-CTH would not alter clinical management and aimed to evaluate the role of D-CTH in this population.

Methods

A retrospective cohort study was performed. Patients ≥65 years sustaining blunt head injuries from January 2010 to July 2017 were identified using our level 1 trauma center database. AT-patients presenting with ICH who underwent D-CTH were included. Patients with worsened ICH were compared to those with stable to improved ICH on D-CTH. AT-patients were compared to a cohort of non-AT patients. Fisher’s Exact and Mann-Whitney U tests were utilized and a power analysis conducted.

Results

137?A?T and 34 non-AT patients were identified. There was no difference in hemorrhage progression or appearance of new ICH. No patient had a change in management from D-CTH in either cohort. AT-patients were slightly older (p?<?0.001), but cohorts were otherwise similar.50 AT-patients with worsened ICH were compared to 87 with stable ICH. There was no difference in cohort demographics. Hemorrhage progression did not vary with type of AT used but did increase if multiple types of synchronous ICH were present (p?<?0.001).

Conclusions

Our data supports abstaining from routine D-CTH of elderly ICH patients with an intact neurologic examination who are utilizing aspirin, clopidogrel or warfarin. Conclusions cannot be drawn regarding new oral anticoagulants (NOACs) given low enrollment. Further multicenter study is required to provide adequate power and detect small levels of management change.  相似文献   
84.

Objective

To explore from a gender perspective the association with subjective health of the interaction between education and household arrangements within the framework of social determinants of health placed at the micro and mezzo levels.

Methods

The data comes from the Spanish sample of the European Union Statistics on Income and Living Conditions for 2014. Independent logistic regression models for men and women were run to analyze the association with subjective health of the interaction between education and household arrangements. An additive model was run to assess possible advantages over the interaction approach.

Results

The interaction models show a lower or even no significant effect on health of household arrangements usually negatively associated with health among individuals with high education, displaying specific patterns according to sex.

Conclusions

Health profiles of women and men are more precisely drawn if both social determinants of health are combined. Among the women, the important role was confirmed of both social determinants of health in understanding their health inequalities. Among the men, mainly those with low educational achievement, the interaction revealed that the household was a more meaningful social determinant of health. This could enable the definition of more efficient public policies to reduce health and gender inequalities.  相似文献   
85.
86.
87.
Loss of function variants in NOTCH1 cause left ventricular outflow tract obstructive defects (LVOTO). However, the risk conferred by rare and noncoding variants in NOTCH1 for LVOTO remains largely uncharacterized. In a cohort of 49 families affected by hypoplastic left heart syndrome, a severe form of LVOTO, we discovered predicted loss of function NOTCH1 variants in 6% of individuals. Rare or low-frequency missense variants were found in 16% of families. To make a quantitative estimate of the genetic risk posed by variants in NOTCH1 for LVOTO, we studied associations of 400 coding and noncoding variants in NOTCH1 in 1,085 cases and 332,788 controls from the UK Biobank. Two rare intronic variants in strong linkage disequilibrium displayed significant association with risk for LVOTO amongst European-ancestry individuals. This result was replicated in an independent analysis of 210 cases and 68,762 controls of non-European and mixed ancestry. In conclusion, carrying rare predicted loss of function variants in NOTCH1 confer significant risk for LVOTO. In addition, the two intronic variants seem to be associated with an increased risk for these defects. Our approach demonstrates the utility of population-based data sets in quantifying the specific risk of individual variants for disease-related phenotypes.  相似文献   
88.
89.

Background and aims

Since accelerated atherosclerosis has been reported in systemic lupus erythematosus (SLE), predictive biomarkers of cardiovascular disease (CVD) are needed. Among non-traditional risk factors, bone mineral density (BMD) has been related to CVD. However, its role in SLE remains controversial. This study aims to analyze the associations of subclinical atherosclerosis with traditional and non-traditional CV risk factors.

Methods and results

In a cross-sectional study, atherosclerosis burden was compared between 112 female SLE patients and 31 controls. Plaque number and carotid intima-media wall thickness (cIMT) were assessed by ultrasonography. In a retrospective study, BMD determinations obtained 5-years before the ultrasonography assessment were analyzed in a subgroup of 62 patients. Plaque frequency was increased in SLE, even in patients without CV events or carotid wall thickening. cIMT was increased in patients with CVD, positively correlated with body mass index (BMI). Interestingly, a paradoxical effect of BMI on carotid parameters was observed. Whereas underweight patients (BMI < 20) showed increased prevalence of carotid plaques with low cIMT, those with BMI > 30 showed higher cIMT and plaque burden. Overweight patients (25 < BMI<30) exhibited both elevated cIMT and plaque number. BMI was an independent predictor of BMD. In our retrospective study, patients with either clinical or subclinical CVD exhibited lower BMD levels than their CV-free counterparts. A low lumbar spine BMD independently predicted CVD development after adjusting for confounders.

Conclusion

SLE was associated with a higher subclinical atherosclerosis burden, a bimodal effect being observed for BMI. Decreased BMD can be a CV risk biomarker in SLE.  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