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   3914篇
  免费   182篇
  国内免费   30篇
耳鼻咽喉   9篇
儿科学   91篇
妇产科学   14篇
基础医学   440篇
口腔科学   71篇
临床医学   289篇
内科学   1194篇
皮肤病学   57篇
神经病学   185篇
特种医学   165篇
外科学   858篇
综合类   14篇
预防医学   58篇
眼科学   42篇
药学   220篇
中国医学   19篇
肿瘤学   400篇
  2023年   16篇
  2022年   44篇
  2021年   81篇
  2020年   49篇
  2019年   64篇
  2018年   93篇
  2017年   102篇
  2016年   89篇
  2015年   122篇
  2014年   134篇
  2013年   181篇
  2012年   254篇
  2011年   289篇
  2010年   157篇
  2009年   145篇
  2008年   209篇
  2007年   246篇
  2006年   243篇
  2005年   264篇
  2004年   251篇
  2003年   246篇
  2002年   207篇
  2001年   46篇
  2000年   42篇
  1999年   53篇
  1998年   38篇
  1997年   31篇
  1996年   37篇
  1995年   38篇
  1994年   23篇
  1993年   21篇
  1992年   27篇
  1991年   22篇
  1990年   29篇
  1989年   24篇
  1988年   21篇
  1987年   23篇
  1986年   18篇
  1985年   19篇
  1984年   17篇
  1983年   12篇
  1982年   9篇
  1981年   14篇
  1980年   12篇
  1979年   9篇
  1978年   12篇
  1977年   8篇
  1975年   4篇
  1974年   8篇
  1973年   5篇
排序方式: 共有4126条查询结果,搜索用时 578 毫秒
121.

Aims/hypothesis

In type 2 diabetic patients at low risk for cardiovascular disease (CVD), the relationship between the clinical course of nephropathy by stage of chronic kidney disease (CKD) and onset of CVD remains unclear. Clarification of this relationship is important for clinical decision-making for both low- and high-risk diabetic patients.

Methods

This 4?year prospective study enrolled 2,954 type 2 diabetic patients with no prevalent CVD, and serum creatinine <176.8?μmol/l. The risk for CVD onset (non-fatal and fatal CVD and stroke, and peripheral arterial disease) was assessed according to CKD stage categorised by urinary albumin-to-creatinine ratio (ACR; mg/mmol) and estimated GFR (eGFR; ml?min?1 1.73?m?2). Association of progression from ‘no CKD’ stage (ACR <3.5?mg/mmol and eGFR ≥90?ml?min?1 1.73?m?2) with risk for CVD onset was also evaluated.

Results

During follow-up (median 3.8?years), 89 CVD events occurred. Compared with patients with ‘no CKD’ as reference, those with ACR?≥?35.0?mg/mmol with co-existing eGFR 60–89?ml?min?1 1.73?m?2 or <60?ml?min?1 1.73?m?2 showed increased risk for CVD onset, whereas those with eGFR ≥90?ml?min?1 1.73?m?2 did not. Those with ACR <3.5?mg/mmol and eGFR <60?ml?min?1 1.73?m?2 did not show any increased risk. Among patients with ‘no CKD’ stage at baseline, those who progressed to ACR ≥3.5?mg/mmol during follow-up showed an increased risk compared with those who did not, whereas those who progressed to eGFR <90?ml?min?1 1.73?m?2 did not have increased risk.

Conclusions/interpretation

The risk for CVD was associated with progression of albuminuria stage rather than eGFR stage in type 2 diabetic patients at relatively low risk for CVD.  相似文献   
122.
ObjectiveThe purpose of this study was to identify histologic characteristics of advanced coronary atherosclerotic plaques that are related with the detection of the napkin-ring sign (NRS) in coronary CT angiography (CCTA).MethodsCCTA was performed in 7 human donor hearts. Histological slicing and stainings were performed in 1 mm increments of each major coronary artery. Histology was co-registered with the CT-data and classified according to the modified AHA classification.ResultsAdvanced plaques (types IV–VI) were present in 139 (23%) of 611 cross sections. Of these 33 (24%) demonstrated an NRS in CCTA. NRS plaques were associated with greater non-core plaque area (median 10.2 vs. 6.4 mm2, p < 0.01) and larger vessel area (median 17.1 vs. 13.0 mm2, p < 0.01). The area of the necrotic/lipid core was larger in plaques with NRS (median 1.1 vs. 0.5 mm2, p = 0.05). Angiogenesis tended to be more frequent in plaques with NRS (48% vs. 30%) whereas micro-calcifications tended to be more frequent in plaques without NRS (27% vs. 46%) (p = 0.06 and 0.07 respectively). In a multivariate analysis, necrotic/lipid core area (OR = 1.9), non-core plaque area (OR = 1.6), and total vessel area (OR = 0.9) independently predicted the appearance of the NRS in coronary CT angiography.ConclusionDelineation of NRS in CCTA is independently linked to the size of the necrotic/lipid core, the size of the non-core plaque and to the vessel area as measured in histology of advanced coronary atherosclerotic plaques.  相似文献   
123.
124.
BackgroundSubstance P (SP) and calcitonin gene-related peptide (CGRP) are released by the nociceptive sensory nerve and are involved in blood flow, pain and inflammation in the nasal mucosa. The purpose of this study was to assess the distribution of the SP and CGRP nerve fibres related to blood supply within human Schneiderian membrane of the maxillary sinus (MS).Material and methodsIn this study, the MS from Japanese cadavers was examined by whole-mount immunohistochemistry. Human male cadavers (ranging in age from 80 to 90 years) were used in this study.ResultsSP- and CGRP-positive fibres were found around large vessels of the medialis superior alveolar branches and also within the floor region of the MS. The floor region of the MS was composed of complex branches of these fibres.ConclusionOur results give useful information for surgical sinus floor elevation in this region of the MS. These anatomical features may assist in the execution of a successful surgical procedure.  相似文献   
125.
126.
127.
128.
129.
The aim of this cross-sectional cohort study was to clarify risk factors for severe vertebral fractures in postmenopausal Japanese women. Subjects were ambulatory volunteers age over 50 years who were recruited from a population of outpatients at a primary care institute. At registration, age, body mass index (BMI), bone mineral density (BMD), and present illness were investigated. Biochemical parameters including urinary levels of type I collagen cross-linked N-telopeptides (NTXs), and pentosidine and plasma levels of homocysteine were measured. Values were compared with different fracture grades (grade 0–3). A total of 1,475 postmenopausal women (66.6 ± 9.0 years) were included in the present study. Distributions of vertebral fracture grades were grade 1, 137 cases (9.3 %); grade 2, 124 cases (8.4 %); and grade 3, 162 cases (11.0 %). Age, BMI, BMD, NTX, pentosidine, and homocysteine were significantly associated with vertebral fracture in unadjusted analysis. In addition, a higher prevalence of hypertension was observed in patients with severe fracture. When comparing vertebral fracture grade 0 versus grade 2–3 by multiple regression analysis, pentosidine and homocysteine levels were a significant risk for moderate/severe vertebral fracture (odds ratio [OR] = 1.17, 95 % confidence interval [CI] 1.00–1.38, p = 0.049; OR = 1.22, 95 % CI 1.03–1.46, p = 0.013). Homocysteine levels were also a significant risk when comparing vertebral fracture grade 0 versus grade 3 (OR = 1.27, 95 % CI 1.04–1.58, p = 0.021). Plasma level of homocysteine was an independent risk for severe vertebral fractures.  相似文献   
130.
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