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   24457篇
  免费   1554篇
  国内免费   161篇
耳鼻咽喉   299篇
儿科学   761篇
妇产科学   719篇
基础医学   2481篇
口腔科学   715篇
临床医学   2058篇
内科学   5346篇
皮肤病学   510篇
神经病学   1125篇
特种医学   817篇
外国民族医学   9篇
外科学   4374篇
综合类   706篇
现状与发展   1篇
一般理论   21篇
预防医学   1694篇
眼科学   725篇
药学   2145篇
中国医学   160篇
肿瘤学   1506篇
  2023年   344篇
  2022年   1008篇
  2021年   1441篇
  2020年   755篇
  2019年   956篇
  2018年   1270篇
  2017年   770篇
  2016年   793篇
  2015年   872篇
  2014年   1091篇
  2013年   1338篇
  2012年   1844篇
  2011年   1887篇
  2010年   973篇
  2009年   793篇
  2008年   1179篇
  2007年   1274篇
  2006年   1103篇
  2005年   966篇
  2004年   902篇
  2003年   764篇
  2002年   698篇
  2001年   330篇
  2000年   319篇
  1999年   294篇
  1998年   157篇
  1997年   115篇
  1996年   101篇
  1995年   107篇
  1994年   69篇
  1993年   54篇
  1992年   131篇
  1991年   120篇
  1990年   114篇
  1989年   103篇
  1988年   97篇
  1987年   96篇
  1986年   97篇
  1985年   87篇
  1984年   68篇
  1983年   88篇
  1982年   38篇
  1981年   44篇
  1980年   33篇
  1979年   78篇
  1978年   44篇
  1977年   52篇
  1976年   41篇
  1975年   44篇
  1974年   38篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
OBJECTIVE: Heart failure (HF) and depression are both common in older adults, and the presence of depression is known to worsen HF outcomes. For community-dwelling older adults, admission to a nursing home (NH) is associated with loss of independent living and poor outcomes. The objective of this study was to examine the effect of depression on NH admission for older adults with HF. METHODS: Using the 2001-2003 National Hospital Discharge Survey datasets, the authors identified all community-dwelling older adults who were discharged alive with a primary discharge diagnosis of HF. The authors then identified those with a secondary diagnosis of depression. Using a multivariable logistic regression model, the authors then determined probability or propensity to have depression for each patient. The authors used propensity scores for depression to match all 680 depressed patients with 2,040 nondepressed patients. Finally, the authors estimated the association between depression and NH admission using bivariate and multivariable logistic regression analyses. RESULTS: Patients had a mean (+/- standard deviation) age of 79 (+/- 8) years, 72% were women, and 9% were blacks. Compared with 17% nondepressed patients, 25% depressed patients were discharged to a NH. Depression was associated with 50% increased risk of NH admission (unadjusted relative risk [RR]: 1.50; 95% confidence interval [CI]: 1.28-1.74). The association became somewhat stronger after multivariable adjustment for various demographic and care covariates (adjusted RR: 1.60; 95% CI: 1.35-1.68). CONCLUSION: In ambulatory older adults hospitalized with HF, a secondary diagnosis of depression was associated with a significant increased risk of NH admission.  相似文献   
73.
BACKGROUND: Thiazolidinediones (TZD) have been reported to improve early stages of diabetic nephropathy independent of glycaemic control. Since blockade of the renin-angiotensin system (RAS) is known to reduce the risk of nephropathy, we hypothesised that the renal effect of TZDs might be related to a favourable effect on the intrarenal RAS. We aimed to determine if the TZD rosiglitazone could reduce RAS activation. METHODS: We studied adult type 2 diabetic patients and placed them on rosiglitazone for three months. We have previously used the renal haemodynamic response to angiotensin-converting enzyme (ACE) inhibition to demonstrate the state of RAS activation, and thus measured renal plasma flow (RPF) and glomerular filtration rate (GFR) before and after administration of captopril at 0 month and at three months. Plasma renin activity (PRA), active renin, aldosterone and natriuretic peptides were analysed. RESULTS: The RPF response to ACE inhibition was not altered. There was no change in GFR, PRA, active renin and aldosterone levels. Two patients developed oedema one had an elevated baseline active renin and another had an elevated baseline aldosterone level. CONCLUSION: The favourable effects of TZDs on diabetic nephropathy is likely not related to an influence on the RAS.  相似文献   
74.
75.
76.
77.
78.
79.
Background: Surgical intervention in patients with malignant hematological disorders is a major undertaking due to the expected risks of bleeding, infection and poor wound healing. Methods and materials: A retrospective study of patients treated at the Riyadh Armed Forces Hospital, Saudi Arabia between January 1991 and December 2002 was conducted. The results of patients with acute leukemia and lymphoma who underwent surgical procedures (study group) were compared with those of a control group composed of patients with the same spectrum of disorders treated over the same period of time and given the same treatment protocols but never required any surgery. Results: No single death occurred intraoperatively or in the immediate postoperative period due to surgical therapy per se. However, follow up of both groups of patients revealed a shorter long‐term survival and higher rates of relapse and severe invasive infections in the surgical group compared to the control group of patients. The mean survival for the study group was 1871 ± 307 days versus 3094 ± 279 days for the control group of patients (P = 0.0027). Thirty (75%) study patients suffered relapses of their malignant hematological disorders versus 23 (37.1%) control patients. Forty‐five relapses were encountered in the study group of patients (1.5 relapses per relapsed patient) versus 26 relapses in the control group (1.13 relapses per relapsed patient). Various infections occurred in 37 (92.5%) study patients and 32 (51.6%) control patients. Recurrent infections developed in 30 (75%) study patients and 22 (35.5%) control patients (P = 0.00008). Infections causing tissue invasion were encountered in 29 (72.5%) study patients and 22 (35.5%) control patients. Conclusion: Even major surgical procedures can be performed in patients with leukemia or lymphoma provided enough preparatory measures are made to minimize bleeding and infectious complications. Surgery may, however, be associated with long‐term complications such as a high incidence of relapse of the primary malignant hematological disorder and an increased rate of severe and invasive infections.  相似文献   
80.
A 48‐year‐old male patient with long‐standing ulcerative colitis since February 2001 which was diagnosed by endoscopy, developed acute digital ischemia affecting both hands with fixed colour changes in the left index finger which was followed shortly by digital ulceration. Magnetic resonance angiography (MRA) of both upper limbs showed evidence of vasculitis affecting digital arterioles on both sided and right subclavian occlusion. The patient received pulse methylprednisolone followed by cyclophosphamide pulse therapy, the latter continuing on a monthly basis for 6 months with appreciable improvement and remission of the vasculitic process; follow‐up MRA showed reperfusion of the previously occluded subcalvian artery. To the authors’ knowledge vasculitis complicating the course of ulcerative colitis is a rare association and is only sporadically reported in the literature. This rare entity should be diagnosed early and aggressively treated; MRA is a very promising diagnostic tool that is suitable for both diagnosis and follow‐up of patients with this rare entity.  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