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   1617篇
  免费   89篇
  国内免费   43篇
耳鼻咽喉   6篇
儿科学   35篇
妇产科学   245篇
基础医学   202篇
口腔科学   43篇
临床医学   156篇
内科学   303篇
皮肤病学   21篇
神经病学   65篇
特种医学   133篇
外科学   192篇
综合类   25篇
一般理论   2篇
预防医学   131篇
眼科学   5篇
药学   112篇
中国医学   13篇
肿瘤学   60篇
  2023年   8篇
  2022年   11篇
  2021年   29篇
  2020年   11篇
  2019年   18篇
  2018年   32篇
  2017年   20篇
  2016年   20篇
  2015年   30篇
  2014年   53篇
  2013年   73篇
  2012年   94篇
  2011年   116篇
  2010年   67篇
  2009年   60篇
  2008年   85篇
  2007年   95篇
  2006年   59篇
  2005年   62篇
  2004年   58篇
  2003年   42篇
  2002年   42篇
  2001年   49篇
  2000年   43篇
  1999年   58篇
  1998年   32篇
  1997年   34篇
  1996年   27篇
  1995年   22篇
  1994年   17篇
  1993年   17篇
  1992年   28篇
  1991年   29篇
  1990年   24篇
  1989年   26篇
  1988年   25篇
  1987年   18篇
  1986年   19篇
  1985年   22篇
  1984年   9篇
  1983年   17篇
  1982年   10篇
  1980年   10篇
  1979年   9篇
  1977年   6篇
  1976年   10篇
  1972年   7篇
  1841年   7篇
  1840年   13篇
  1838年   8篇
排序方式: 共有1749条查询结果,搜索用时 15 毫秒
31.
Objectives: Systemic mastocytosis (SM) is a myeloproliferative disease characterized by the accumulation of aberrant mast cells. Since advanced subtypes of SM can lead to organ dysfunction and shortened survival, timely recognition of progressive disease is important for the adequate treatment of SM patients.

Methods: Here, we report the results of our cohort study on the value of routine abdominal ultrasonography for the detection of progression of indolent systemic mastocytosis (ISM).

Results: We included 88 patients with ISM, of whom 9 developed new hepatosplenomegaly during follow-up. In this group, the median serum tryptase level increased by 11.60?μg/l, compared with a decrease of ?0.20?μg/l in the 79 patients with unchanged ultrasonography results (p?=?0.016). A change in liver and/or spleen size never led to a change in clinical classification, nor management.

Discussion: Based on the finding that a change in ultrasonography findings did not correlate to disease progression in general, it appears that isolated hepatosplenomegaly does not have prognostic implications in patients with ISM.

Conclusions: Routine abdominal ultrasonography is redundant in the follow-up of patients with ISM. A combination of physical examination with serum tryptase levels can be used to screen for hepatosplenomegaly.  相似文献   
32.
33.
34.
35.
36.
Novel inhibitors of cholinesterases, especially butyrylcholinesterase (BuChE), were obtained by coupling melatonin–tacrine heterodimers via the carbamate bond. Compounds 14a‐i possessed potent cholinesterase inhibitory activity (with IC50 values as low as 1.18 nm for acetylcholinesterase (AChE) and 0.24 nm for butyrylcholinesterase (BuChE)). These heterodimers exhibit selectivity toward BuChE, being from 4‐ to 256‐fold more active toward BuChE than AChE, but still acting as better AChE inhibitors than tacrine 4 .  相似文献   
37.
38.
39.

BACKGROUND:

Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is the leading reason for hospitalization in Canada and a significant financial burden on hospital resources. Identifying factors that influence the time a patient spends in the hospital and readmission rates will allow for better use of scarce hospital resources.

OBJECTIVES:

To determine the factors that influence length of stay (LOS) in the hospital and readmission for patients with AECOPD in an inner-city hospital.

METHODS:

Using the Providence Health Records, a retrospective review of patients admitted to St Paul’s Hospital (Vancouver, British Columbia) during the winter of 2006 to 2007 (six months) with a diagnosis of AECOPD, was conducted. Exacerbations were classified according to Anthonisen criteria to determine the severity of exacerbation on admission. Severity of COPD was scored using the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. For comparative analysis, severity of disease (GOLD criteria), age, sex and smoking history were matched.

RESULTS:

Of 109 admissions reviewed, 66 were single admissions (61%) and 43 were readmissions (39%). The number of readmissions ranged from two to nine (mean of 3.3 readmissions). More than 85% of admissions had the severity of COPD equal to or greater than GOLD stage 3. The significant indicators for readmission were GOLD status (P<0.001), number of related comorbidities (OR 1.47, 95% CI 1.10 to 1.97; P<0.009) and marital status (single) (OR 4.18, 95% CI 1.03 to 17.02; P<0.046). The requirement for social work involvement during hospital admission was associated with a prolonged LOS (P<0.05).

CONCLUSIONS:

The results of the present study show that disease severity (GOLD status) and number of comorbidities are associated with readmission rates of patients with AECOPD. Interestingly, social factors such as marital status and the need for social work intervention are also linked to readmission rates and LOS, respectively, in patients with AECOPD.  相似文献   
40.
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