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   55785篇
  免费   3864篇
  国内免费   1178篇
耳鼻咽喉   348篇
儿科学   1192篇
妇产科学   1511篇
基础医学   4942篇
口腔科学   968篇
临床医学   6201篇
内科学   8543篇
皮肤病学   420篇
神经病学   1958篇
特种医学   1917篇
外国民族医学   9篇
外科学   5191篇
综合类   8729篇
现状与发展   1篇
预防医学   9096篇
眼科学   349篇
药学   5613篇
  108篇
中国医学   1826篇
肿瘤学   1905篇
  2024年   103篇
  2023年   727篇
  2022年   1489篇
  2021年   2210篇
  2020年   2144篇
  2019年   1810篇
  2018年   1880篇
  2017年   1776篇
  2016年   1896篇
  2015年   1882篇
  2014年   3900篇
  2013年   3910篇
  2012年   3685篇
  2011年   3829篇
  2010年   2863篇
  2009年   2579篇
  2008年   2526篇
  2007年   2648篇
  2006年   2206篇
  2005年   1963篇
  2004年   1666篇
  2003年   1407篇
  2002年   1199篇
  2001年   1047篇
  2000年   932篇
  1999年   843篇
  1998年   687篇
  1997年   706篇
  1996年   633篇
  1995年   565篇
  1994年   547篇
  1993年   419篇
  1992年   445篇
  1991年   385篇
  1990年   337篇
  1989年   312篇
  1988年   268篇
  1987年   217篇
  1986年   206篇
  1985年   278篇
  1984年   234篇
  1983年   147篇
  1982年   207篇
  1981年   173篇
  1980年   160篇
  1979年   130篇
  1978年   102篇
  1977年   98篇
  1976年   91篇
  1975年   96篇
排序方式: 共有10000条查询结果,搜索用时 906 毫秒
11.
12.
《Journal of vascular surgery》2020,71(6):1921-1929
ObjectiveIdentifying biomarkers for abdominal aortic aneurysms (AAA) could prove beneficial in prognosis of AAA and thus the selection for treatment. Microfibrillar-associated protein 4 (MFAP4) is an extracellular matrix protein that is highly expressed in aorta. MFAP4 is involved in several tissue remodeling-related diseases. We aimed to investigate the potential role of plasma MFAP4 (pMFAP4) as a biomarker of AAA.MethodsPlasma samples and data were obtained for 504 male AAA patients and 188 controls in the Viborg Vascular (VIVA) screening trial. The pMFAP4 levels were measured by Alphalisa. The Mann-Whitney U test assessed differences in pMFAP4 levels between the presence and absence of different exposures of interest. The correlation between pMFAP4 and aorta growth rate were investigated through spearman's correlation analysis. Immunohistochemistry and multiple logistic regression adjusted for potential confounders assessed the association between pMFAP4 and AAA. Multiple linear regression assessed the correlation between pMFAP4 and aorta growth rate. Cox regression and competing risk regression were used to investigate the correlation between AAA patients with upper tertile pMFAP4 and the risk of undergoing later surgical repair.ResultsA significant negative correlation between pMFAP4 and aorta growth rate was observed using spearman's correlation analysis (ρ = −0.14; P = .0074). However, this finding did not reach significance when applying multiple linear regression. A tendency of decreased pMFAP4 was observed in AAA using immunohistochemistry. Competing risk regression adjusted for potential confounders indicated that patients with upper tertile pMFAP4 had a hazard ratio of 0.51 (P = .001) for risk of undergoing later surgical repair.ConclusionsHigh levels of pMFAP4 are associated with a decreased likelihood of receiving surgical repair in AAA. This observation warrants confirmation in an independent cohort.  相似文献   
13.
14.
突发公共卫生事件应急管理是一个全球性的课题。本文就2019年12月以来发生在中国的新型冠状病毒肺炎这一突发公共卫生事件,口腔医疗机构及其从业人员面临的相关问题进行法律层面的分析与思考,以期对口腔医疗行业应对突发公共卫生事件提供帮助和指导。  相似文献   
15.
16.
17.
18.
19.
BackgroundThe relationship of atrial fibrillation (AF) with coronary artery disease (CAD) is well established, yet it is often missed. There is evidence of myocardial ischemia on stress imaging in AF patients in the absence of obstructive CAD. In this prospective cohort, we studied the angiographic profiles of non-valvular AF patients.MethodsThe study was a nonrandomized, prospective, single-center observational study of consecutive patients of persistent non-valvular AF. Patients symptomatic for AF despite optimal medical therapy for 3 months were recruited and all underwent coronary angiograms (CAG). Patients with prior history of CAD were excluded.ResultsA total of 70 patients were followed for a mean duration of 12 ± 1.4 months. The mean age of the study group was 66.07 (±11.49) years. Hypertension was the commonest comorbidity seen in 74% patients. Obstructive CAD was present in 32 (46%) patients, non-obstructive (<50% stenosis) CAD in 17 (24%) patients and normal coronaries in 21 (30%) patients. Overall 49 (70%) patients had evidence of CAD. Amongst patients without obstructive CAD, slow flow was seen in 16 (42%) patients. Lower baseline ejection fraction, lower haemoglobin & albumin levels and higher creatinine levels was associated with increased mortality. In patients without obstructive CAD, hospitalizations for fast ventricular rate were significantly increased in those having slow flow on CAG (p = 0.005).ConclusionsMajority (70%) of our patients had evidence of atherosclerotic CAD on CAG. A large proportion of patients without obstructive CAD had slow flow on CAG.  相似文献   
20.
Background and aimsResting heart rate variability (HRV) and maximal fat oxidation (MFO) during exercise are both considered as a noninvasive biomarkers for early detection of cardiovascular risk factors. Thus, this study aimed to analyze the relationship between resting HRV parameters and MFO during exercise, and the intensity of exercise that elicit MFO (Fatmax) in healthy sedentary adults.Methods and resultsA total of 103 healthy young adults (22.2 ± 2.3 years old, 67% female; from the ACTIBATE cohort) and 67 healthy middle-aged adults (53.1 ± 5.0 years old, 52% female; from the FIT-AGEING cohort) were included in this cross-sectional study. HRV was assessed using a Polar RS800CX heart rate monitor, while MFO and Fatmax were determined during a graded exercise treadmill test using indirect calorimetry. No significant associations were observed for healthy young adults (standardized β coefficients ranged from ?0.063 to 0.094, and all P ≥ 0.347) and for middle-aged adults (standardized β coefficients ranged from ?0.234 to 0.090, and all P ≥ 0.056). Nevertheless, only a weak association was observed between one HRV parameter in time-domain (the percentage of R-R intervals that shows a difference higher than 50 ms [pNN50]) and MFO in the cohort of middle-aged adults (β coefficient = ?0.279, and P = 0.033).ConclusionThe results of this study suggest that resting HRV parameters are not associated with MFO and Fatmax during exercise in two independent cohorts of healthy sedentary young and middle-aged adults, respectively.  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