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   3354篇
  免费   467篇
  国内免费   17篇
耳鼻咽喉   29篇
儿科学   54篇
妇产科学   79篇
基础医学   293篇
口腔科学   85篇
临床医学   567篇
内科学   824篇
皮肤病学   39篇
神经病学   650篇
特种医学   114篇
外国民族医学   1篇
外科学   473篇
综合类   10篇
预防医学   153篇
眼科学   10篇
药学   128篇
中国医学   2篇
肿瘤学   327篇
  2023年   65篇
  2022年   38篇
  2021年   71篇
  2020年   81篇
  2019年   78篇
  2018年   100篇
  2017年   141篇
  2016年   127篇
  2015年   162篇
  2014年   172篇
  2013年   210篇
  2012年   173篇
  2011年   188篇
  2010年   145篇
  2009年   179篇
  2008年   170篇
  2007年   172篇
  2006年   159篇
  2005年   140篇
  2004年   150篇
  2003年   112篇
  2002年   78篇
  2001年   81篇
  2000年   106篇
  1999年   78篇
  1998年   54篇
  1997年   36篇
  1996年   48篇
  1995年   34篇
  1994年   28篇
  1993年   19篇
  1992年   47篇
  1991年   51篇
  1990年   41篇
  1989年   33篇
  1988年   24篇
  1987年   29篇
  1986年   27篇
  1985年   22篇
  1984年   13篇
  1983年   16篇
  1981年   8篇
  1979年   14篇
  1978年   9篇
  1977年   11篇
  1975年   16篇
  1970年   8篇
  1969年   14篇
  1968年   7篇
  1967年   10篇
排序方式: 共有3838条查询结果,搜索用时 15 毫秒
1.
2.
This is a retrospective review of the results at our institution of using multi-detector CT angiography (CTA) to localise lower gastrointestinal (GI) bleeding. We hypothesised that in our patient population: (i) CTA was unlikely to demonstrate bleeding in patients who were haemodynamically stable; (ii) in haemodynamically unstable patients in whom CTA was undertaken, the results could be used to select patients who would benefit from catheter angiography; and (iii) in haemodynamically unstable patients in whom CTA was undertaken, a subgroup of patients could be identified who would benefit from primary surgical treatment, avoiding invasive angiography completely. A retrospective review was conducted of the clinical records of all patients undergoing CTA for lower GI haemorrhage at our institution between 1 January 2005 and 30 June 2007. Out of the 20 patients examined, 10 had positive CTAs demonstrating the bleeding site. Nine were haemodynamically unstable at the time of the study. Four patients with positive CT angiograms were able to be treated directly with surgery and avoided invasive angiography. Ten patients had negative CTAs. Four of these were haemodynamically unstable, six haemodynamically stable. Only one required intervention to secure haemostasis, the rest stopped spontaneously. No haemodynamically stable patient who had a negative CTA required intervention. CTA is a useful non-invasive technique for localising the site of lower GI bleeding. In our patient population, in the absence of haemodynamic instability, the diagnostic yield of CTA was low and bleeding was likely to stop spontaneously. In haemodynamically unstable patients, a positive CTA allowed patients to be triaged to surgery or angiography, whereas there was a strong association between a negative CTA and spontaneous cessation of bleeding.  相似文献   
3.
A common factor V gene haplotype, the FVR2 haplotype (FVHR2), has been associated with a reduced cofactor activity in activated protein C-mediated activated factor VIII inactivation. Our aim was to investigate the role of FVHR2 as a possible determinant of factor VIII levels in a population study. A total of 516 individuals (401 men, 115 women; mean age 58.4 +/- 10.8 years) were enrolled within the frame of a regional cardiovascular survey, characterized for factor VIII coagulant activity (FVIII:c) and factor V coagulant activity (FV:c) levels, and genotyped for factor V polymorphisms. In men without signs of overt inflammation, FVHR2 carriers had higher levels of FVIII:c than noncarriers (154 IU/dl, 95% confidence interval = 143-166 versus 142 IU/dl, 95% confidence interval = 138-147; P = 0.045) and were more represented in individuals with high (> or = 150 IU/dl) FVIII:c levels (21.2 versus 10.8%; odds ratio = 2.27, 95% confidence interval = 1.17-4.39 after adjustment for age, blood group and high-sensitivity C-reactive protein levels). In conclusion, this clinical report suggests the common FVHR2 as a possible independent determinant of FVIII:c levels. The report concomitantly addresses the relationship between factor V and factor VIII levels and supports the hypothesis of a mild prothrombotic role of FVHR2 by means of increased factor VIII levels.  相似文献   
4.
5.
Clinical outcomes data can be used to facilitate patient management decisions, assess clinician and organizational performance, and to provide evidence for the effectiveness of surgery and rehabilitation. The validity of the inferences made from outcomes data are dependent on the validity of the outcomes measures themselves and the circumstances under which the data were collected, analyzed, and interpreted. Clinical outcomes may include measures of impairment of body structure and function, activity limitation, and participation restriction. However, because the relationship between impairment and the resulting activity limitation and participation restriction is not direct, and because activity limitations and participation restrictions are of the utmost concern to the athlete, the primary clinical outcome should be measures of activity limitation and participation restriction. Activity limitation and participation restriction may be measured either through direct observation of performance or by general or specific measures of health related quality of life. Clinical outcomes data must be collected systematically to ensure valid inferences from the data.  相似文献   
6.
7.
Transitional progressive multiple sclerosis: MRI and MTI findings   总被引:1,自引:0,他引:1  
Transitional progressive multiple sclerosis (MS) is quite an unusual form of presentation and course of the disease. A case with this progressive form is presented and brain MRI and MTI findings are discussed in relation to the possible insight they may provide for understanding the mechanisms that determine progressive disability in MS.  相似文献   
8.
Diffusion-weighted imaging study of patients with essential tremor.   总被引:1,自引:0,他引:1  
The pathophysiology of essential tremor (ET) is unknown. PET and fMRI studies have revealed bilateral activation and (1)H-MRS studies metabolic abnormalities in the cerebellum and other functionally related brain structures in ET. Diffusion-weighted imaging (DWI) was used to search for evidence of tissue integrity abnormalities in these areas in ET patients and 10 matched controls by calculating water apparent diffusion coefficients (ADCs). Regions of interest included the left and right cerebellum, red nucleus, thalamus, caudate, putamen, pallidum, and frontal white matter. Histograms of ADCs were generated for all pixels in the infratentorial compartment and manually segmented areas corresponding to brainstem, vermis, and cerebellar hemispheres. ADC values were similar in all brain areas in patients and controls. Our study did not detect changes affecting the investigated brain regions in ET patients. These findings argue against major structural damage in the ET brain, although more subtle neurodegenerative changes cannot be ruled out.  相似文献   
9.
A total of 178 patients with metastatic renal cell cancer were randomized to receive interferon alfa-2a (rIFN alfa-2a) or interferon alfa-2a+vinblastine (VLB). IFN alfa-2a was injected intramuscularly at a dose of 18 MIU 3 times a week and VLB was given intravenously at a dose of 0.1 mg/kg once every 3 weeks. The response rate was 11% for patients on monotherapy and 24% for those on combination treatment. The 5-year survival for 145 eligible patients was 9%, independently from the treatment arm. The performance status was significantly related to long-term prognosis, and 13% of the patients with performance status 0 were alive at 5 years, as compared to 6% and 0% for patients with a WHO grade of 1 and 2, respectively. The most frequent adverse events in both treatment arms were flu-like symptoms (95%), fatigue (70%) and gastrointestinal disturbances (68%). Leukopenia was observed more frequently with combination treatment (53%) than with IFN alfa-2a alone (30%). In conclusion, rIFN alfa-2a monotherapy at this dose and schedule has modest antitumor activity in metastatic renal cell cancer. The combination of rIFN alfa-2a+VLB results in a doubling of the response rate, but this does not translate into prolonged survival. Toxicity (except leukopenia) and tolerance were similar in both treatment arms.  相似文献   
10.
We analyzed the titer of antithyroid autoantibodies Abs) and thyroid function in 17 multiple sclerosis (MS) patients undergoing interferon-β (IFN-β) treatment and in 40 MS control patients. Basal evaluation revealed normal thyroid function in all patients. Abs were detected in 5 IFN-β-treated patients (29%) and in 4 MS control patients (10%). Our results indicate that IFN-β treatment may lead to thyroid autoimmunity. We therefore recommend periodic evaluations of antithyroid Abs and thyroid functionality in IFN-β-treated MS patients.  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