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   3699篇
  免费   293篇
  国内免费   8篇
耳鼻咽喉   19篇
儿科学   108篇
妇产科学   70篇
基础医学   603篇
口腔科学   30篇
临床医学   297篇
内科学   965篇
皮肤病学   28篇
神经病学   327篇
特种医学   262篇
外科学   396篇
综合类   25篇
预防医学   326篇
眼科学   49篇
药学   261篇
  2篇
中国医学   1篇
肿瘤学   231篇
  2023年   19篇
  2022年   28篇
  2021年   65篇
  2020年   45篇
  2019年   65篇
  2018年   77篇
  2017年   71篇
  2016年   53篇
  2015年   70篇
  2014年   105篇
  2013年   150篇
  2012年   188篇
  2011年   202篇
  2010年   138篇
  2009年   113篇
  2008年   181篇
  2007年   204篇
  2006年   196篇
  2005年   164篇
  2004年   190篇
  2003年   153篇
  2002年   152篇
  2001年   126篇
  2000年   120篇
  1999年   118篇
  1998年   62篇
  1997年   49篇
  1996年   59篇
  1995年   52篇
  1994年   37篇
  1993年   32篇
  1992年   76篇
  1991年   68篇
  1990年   65篇
  1989年   63篇
  1988年   48篇
  1987年   45篇
  1986年   31篇
  1985年   28篇
  1984年   31篇
  1983年   22篇
  1982年   22篇
  1979年   27篇
  1978年   17篇
  1977年   14篇
  1976年   18篇
  1975年   13篇
  1974年   15篇
  1973年   13篇
  1971年   16篇
排序方式: 共有4000条查询结果,搜索用时 15 毫秒
991.
Hereditary non-polyposis colorectal carcinoma (HNPCC) is an autosomal dominant disorder associated with colorectal and endometrial cancer and a range of other tumor types. Germline mutations in the DNA mismatch repair (MMR) genes, particularly MLH1, MSH2, and MSH6, underlie this disorder. The vast majority of these HNPCC-associated mutations have been proven, or assumed, given the family history of cancer, to be transmitted through several generations. To the best of our knowledge, only a single case of a de novo germline MMR gene mutation (in MSH2) has been reported till now. Here, we report a patient with a de novo mutation in MLH1. We identified a MLH1 Q701X truncating mutation in the blood lymphocytes of a male who had been diagnosed with rectal cancer at the age of 35. His family history of cancer was negative for the first- and second-degree relatives. The mutation could not be detected in the patient' parents and sibling and paternity was confirmed with a set of highly polymorphic markers. Non-penetrance and small family size is the common explanation of verified negative family histories of cancer in patients with a germline MMR gene mutation. However, in addition to some cases explained by non-paternity, de novo germline mutations should be considered as a possible explanation as well. As guidelines that stress not to restrict MMR gene mutation testing to patients with a positive family history are more widely introduced, more cases of de novo MMR gene germline mutations may be revealed.  相似文献   
992.

Background

Chronic obstructive pulmonary disease (COPD) and asthma are underdiagnosed in primary care.

Aim

To determine how often COPD or asthma are present in middle-aged and older patients who consult their GP for persistent cough.

Design of study

A cross-sectional study in 353 patients older than 50 years, visiting their GP for persistent cough and not known to have COPD or asthma.

Setting

General practice in the Netherlands.

Method

All participants underwent extensive diagnostic work-up, including symptoms, signs, spirometry, and body plethysmography. All results were studied by an expert panel to diagnose or exclude COPD and/or asthma. The reproducibility of the panel diagnosis was assessed by calculation of Cohen''s κ statistic in a sample of 41 participants.

Results

Of the 353 participants, 102 (29%, 95% confidence interval [CI] = 24 to 34%) were diagnosed with COPD. In 14 of these 102 participants, both COPD and asthma were diagnosed (4%, 95% CI = 2 to 7%). Asthma (without COPD) was diagnosed in 23 (7%, 95% CI = 4 to 10%) participants. Mean duration of cough was 93 days (median 40 days). The reproducibility of the expert panel was good (Cohen''s κ = 0.90).

Conclusion

In patients aged over 50 years who consult their GP for persistent cough, undetected COPD or asthma is frequently present.  相似文献   
993.
The discussion was initiated by a paper on the influence of a pre-dialysis education programme on the mode of renal replacement therapy by Goovaerts et al (NDT 2005). Barriers to the uptake of self-care treatment modalities, including late referral, limited availability of treatment options, reimbursement, support from staff and families, the requirement for a helper and the length of the training programmes for home haemodialysis (HD) were discussed by 21 participants from 12 countries. The 'take-home' messages from the discussion were that to optimise the uptake of self-care modalities, renal units should try to ensure the all patients who are able to choose are fully informed before starting dialysis, even if they are referred to the unit very late. Offering a wide range of treatment options to new patients, and allowing (or encouraging) home HD without a helper, may also increase the number of patients who start and stay on a self-care modality. It should be possible to provide an acceptable level of training, without compromising on safety, within 3 weeks if the patient is confident with needling.  相似文献   
994.
995.
The European Practice Database (EPD) project, developed by the EDTNA/ERCA Research Board, collects data on renal practice at centre level in different European countries. Results presented in this paper focus on the European Practice in Haemodialysis centres from 8 European countries or regions following data collection from 2002 to 2004. These results will enable international comparison in practice and will stimulate further research and the development of new practice recommendations.  相似文献   
996.
997.
998.
999.
目的:探讨12周运动心脏康复锻炼对心梗后患者(PMI患者)心脏机能的影响。方法:112名男性PMI患者(均进行了12周运动心脏康复锻炼)进行一次递增负荷运动实验(Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ级负荷跑速分别为1.7、1.7、1.7、2.5、3.5mph;坡度分别为0.5 %、10 %、12 %、14 %,每一级负荷运动3分钟) ,其间记录每级负荷时的VO2、HR、血压和自我用力感觉(RPE) ,计算心率血压乘积(RPP) ,并持续监测12导联心电图(ECG) ,然后对上述指标进行相关分析并建立了用HR和RPE推测VO2和RPP的回归方程。结果:(1)相邻两级负荷间的VO2、HR、RPP、RPE具有显著差异(P<0.01) ;(2)VO2、HR、最大心率百分数( %HRmax)、RPP、ST段水平(ST)和RPE的峰值分别为26.4±7.1ml·kg-1·min-1、126.8±20.3beats·min-1、80.4±12.9 %、209.0±46.3beats·mmHg·100-1、-1.0±0.7mm和14.9±2.1;(3)运动中VO2、HR、%HRmax、RPP、RPE呈高度正相关,它们与ST呈高度负相关(P<0.01或P<0.05) ,建立了用HR和RPE推测VO2和RPP的回归方程。结论:(1)康复锻炼后利用改良Bruce跑台方案进行机能测试有效;(2)12周康复锻炼后,PMI患者进行运动时其强度不宜超过80 %HRmax或RPE不超过15 ;(3)利用本研究建立的预测方程,可在PMI患者康复活动中,根据其心率或RPE变化间接得知其呼吸循环机能的反应和心肌的耗氧状况。  相似文献   
1000.
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