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   5116篇
  免费   264篇
  国内免费   40篇
耳鼻咽喉   39篇
儿科学   80篇
妇产科学   60篇
基础医学   619篇
口腔科学   61篇
临床医学   307篇
内科学   1300篇
皮肤病学   157篇
神经病学   444篇
特种医学   372篇
外科学   890篇
综合类   30篇
一般理论   1篇
预防医学   138篇
眼科学   62篇
药学   298篇
中国医学   12篇
肿瘤学   550篇
  2023年   28篇
  2022年   83篇
  2021年   136篇
  2020年   76篇
  2019年   90篇
  2018年   122篇
  2017年   117篇
  2016年   132篇
  2015年   117篇
  2014年   150篇
  2013年   194篇
  2012年   319篇
  2011年   372篇
  2010年   226篇
  2009年   195篇
  2008年   344篇
  2007年   343篇
  2006年   380篇
  2005年   379篇
  2004年   325篇
  2003年   304篇
  2002年   286篇
  2001年   38篇
  2000年   36篇
  1999年   60篇
  1998年   68篇
  1997年   48篇
  1996年   53篇
  1995年   48篇
  1994年   40篇
  1993年   45篇
  1992年   32篇
  1991年   30篇
  1990年   23篇
  1989年   26篇
  1988年   13篇
  1987年   14篇
  1986年   7篇
  1985年   12篇
  1984年   15篇
  1983年   7篇
  1982年   14篇
  1981年   12篇
  1980年   9篇
  1979年   8篇
  1978年   9篇
  1977年   5篇
  1975年   3篇
  1967年   3篇
  1966年   3篇
排序方式: 共有5420条查询结果,搜索用时 31 毫秒
61.
62.
Background and Aim: We compared endoscopic findings of the frequency scale for the symptoms of gastroesophageal reflux disease (FSSG), a written questionnaire developed in Japan, to that for the questionnaire for the diagnosis of reflux esophagitis (QUEST) for the diagnosis of reflux esophagitis. Methods: We registered 475 patients with untreated symptoms of upper abdominal pain (male/female: 252/223, average age 52.4 ± 17.8 years). Subjects were assessed first with the FSSG and QUEST questionnaires, then by endoscopy, before allocation to a gastric ulcer (GU), duodenal ulcer (DU), gastroesophageal reflux disease (GERD) or functional dyspepsia (FD) group. Results: On the basis of the endoscopic findings the diagnoses for the 475 subjects were as follows: FD 52.2%, DU 7.6%, GU 7.8%, and GERD 32.4% (Grade M 10.1%, Grade A + B 20.2%, Grade C + D 2.3%). There was no difference between the FSSG and QUEST in sensitivity, specificity or accuracy for any condition. The FSSG score rose with increasing endoscopic severity of GERD, but there was no correlation between the QUEST score and endoscopic severity. The FSSG total score was inferior to QUEST in terms of distinguishing GERD from other conditions, but when only the questions relating to reflux symptoms were used, the FSSG was able to distinguish GERD from other conditions as well as QUEST. Conclusions: The FSSG score reflects the severity of the endoscopic findings of GERD.  相似文献   
63.
BACKGROUND: Although the anti-atherosclerotic effects of HMG-CoA reductase inhibitors are well known, their specific effect on saphenous vein grafts after coronary artery bypass graft (CABG) operation is not well documented and has not been studied in Japan, so the aim of the present prospective randomized controlled study involving 27 Japanese institutions was to investigate the effects of pravastatin on the progression of atherosclerosis in such grafts and native coronary arteries after CABG. METHODS AND RESULTS: A total of 303 patients who had undergone CABG were randomly assigned to either the pravastatin group (n =168) or the control group (n = 167). Paired coronary angiograms were obtained at baseline and at the end of 5-year follow-up in 182 (60%) patients. The low-density lipoprotein cholesterol concentration significantly decreased in the pravastatin group from 141.4 mg/dl to 113.7 mg/dl (-19.6%), compared with 141.1 mg/dl to 133.7 mg/dl (-5.2%) in the control group (p < 0.001). Although there was no significant difference in the quantitative coronary angiography measurements between the 2 groups, the global change score indicated a significant pravastatin-mediated reduction in plaque progression (p < 0.01). CONCLUSIONS: Pravastatin can potentially reduce atherosclerotic progression in both the bypass graft and native coronary arteries of patients after CABG.  相似文献   
64.
65.
BACKGROUND/AIMS: The serum tumor marker carbohydrate associated antigen 19-9 (CA19-9) has been used for screening for cancer, because its increase has been associated with many cancers. We aimed to evaluate the clinical value of positron emission tomography using F-18 fluorodeoxyglucose (18FDG-PET) that was prompted by increases of serum CA19-9 without findings on conventional imaging. METHODOLOGY: Twenty-two patients were retrospectively selected. Eleven were without a history of cancer and eleven had a history of cancer and were treated with curative intent. All 18FDG-PET findings were compared with the findings of histopathology by surgery or biopsy, or clinical follow-up for at least 1 year. RESULTS: We found only two true positive cases, and eleven cases without a cancer history included 10 true negatives and one false positive. CONCLUSIONS: Increases in serum CA19-9 are caused by many benign conditions. Increases of CA19-9 without findings on conventional imaging do not justify 18FDG-PET examination, particularly in patients without a cancer history.  相似文献   
66.
In this study, we compared the impact of health problems (HPs) on everyday activities and depressive symptoms between middle-aged and older adults. We also examined what type and source of social interactions moderate the noxious effects of HPs. Longitudinal analyses of data with 1,802 Japanese community-dwelling adults indicated that HPs were significantly related to (a) an increase in depressive symptoms among middle-aged adults and (b) a decline in everyday activities among older adults. The former was buffered by emotional family support, whereas the latter (b) was buffered by instrumental family support and, surprisingly, by negative interactions with family. In contrast, social interactions with other friends and acquaintances did not show any moderating effect.  相似文献   
67.
68.

Background

The onset of acute heart failure is known to be associated with increased physical activity and other specific behaviors that can trigger hemodynamic deterioration. This analysis aimed to describe the distribution of triggers in patients hospitalized for acute heart failure, and investigate their effects on in-hospital outcomes.

Methods

Consecutive patients hospitalized for acute heart failure between 2010 and 2014 were registered in a multicenter data registration system (72 institutions within Tokyo, Japan). Baseline demographics and in-hospital mortality were extracted from 17,473 patients. Patients with a trigger were grouped based on their triggering event: those with onset during (a) physical activity; (b) sleeping; (c) eating or watching television; (d) bathing or excretion (use of restrooms); and (e) engaging in other activities. These patients were compared with patients without identifiable triggers. Multiple imputation was used for missing data.

Results

Patients were predominantly men (57.1%), with a mean age of 76.0 ± 13.0 years; a triggering event was present in 49.1%. No significant difference in baseline characteristics was noted between groups except for younger age, higher blood pressure, and prevalence of signs of congestion in the trigger-positive group. In-hospital mortality rate was 7.9%. Presence of triggers was positively associated with a reduced risk of in-hospital mortality (adjusted odds ratio 0.79; 95% confidence interval, 0.70-0.90; P = .0003). In a delta-adjusted pattern mixture model, the effect of a triggering event on in-hospital mortality remained consistently significant.

Conclusion

Triggering events for acute heart failure can provide additional information for risk prediction. Efforts to identify the triggers should be made to classify patients according to risk group.  相似文献   
69.
Signal regulatory protein α (SIRPα), an immunoglobulin superfamily protein that is expressed predominantly in myeloid lineage cells such as dendritic cells (DCs) or macrophages, mediates cell–cell signaling. In the immune system, SIRPα is thought to be important for homeostasis of DCs, but it remains unclear whether SIRPα intrinsic to DCs is indeed indispensable for such functional role. Thus, we here generated the mice, in which SIRPα was specifically ablated in CD11c+ DCs (SirpaΔDC). SirpaΔDC mice manifested a marked reduction of CD4+ CD8α conventional DCs (cDCs) in the secondary lymphoid organs, as well as of Langerhans cells in the epidermis. Such reduction of cDCs in SirpaΔDC mice was comparable to that apparent with the mice, in which SIRPα was systemically ablated. Expression of SIRPα in DCs was well correlated with that of either endothelial cell‐selective adhesion molecule (ESAM) or Epstein–Barr virus‐induced molecule 2 (EBI2), both of which were also implicated in the regulation of DC homeostasis. Indeed, ESAM+ or EBI2+ cDCs were markedly reduced in the spleen of SirpaΔDC mice. Thus, our results suggest that SIRPα intrinsic to CD11c+ DCs is essential for homeostasis of cDCs in the secondary lymphoid organs and skin.  相似文献   
70.
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