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   1415篇
  免费   54篇
  国内免费   7篇
耳鼻咽喉   32篇
儿科学   37篇
妇产科学   38篇
基础医学   187篇
口腔科学   11篇
临床医学   69篇
内科学   313篇
皮肤病学   17篇
神经病学   80篇
特种医学   29篇
外科学   126篇
综合类   15篇
预防医学   206篇
眼科学   37篇
药学   98篇
中国医学   4篇
肿瘤学   177篇
  2024年   1篇
  2023年   3篇
  2022年   43篇
  2021年   72篇
  2020年   38篇
  2019年   28篇
  2018年   38篇
  2017年   29篇
  2016年   31篇
  2015年   36篇
  2014年   45篇
  2013年   62篇
  2012年   108篇
  2011年   112篇
  2010年   57篇
  2009年   54篇
  2008年   86篇
  2007年   122篇
  2006年   120篇
  2005年   86篇
  2004年   94篇
  2003年   62篇
  2002年   80篇
  2001年   8篇
  2000年   2篇
  1999年   5篇
  1998年   9篇
  1997年   3篇
  1996年   9篇
  1995年   2篇
  1994年   4篇
  1992年   3篇
  1989年   3篇
  1988年   3篇
  1987年   1篇
  1986年   1篇
  1985年   3篇
  1984年   1篇
  1983年   2篇
  1982年   1篇
  1980年   4篇
  1977年   2篇
  1976年   1篇
  1974年   1篇
  1960年   1篇
排序方式: 共有1476条查询结果,搜索用时 0 毫秒
101.
102.
BACKGROUND: Recent epidemiologic studies have generally reported a modest inverse association between calcium intake and the risk of colorectal cancer. However, findings pertaining to specific subsites in the colorectum have been conflicting. OBJECTIVE: Our objective was to prospectively examine the relations between intakes of calcium and dairy foods and the risk of colorectal cancer, overall and by anatomic subsite, in men from the Cohort of Swedish Men. DESIGN: In 1997, 45 306 men aged 45-79 y and without a history of cancer completed a food-frequency questionnaire. The men were followed through 31 December 2004. RESULTS: During a mean follow-up of 6.7 y, we ascertained 449 incident cases of colorectal cancer. After adjustment for age and other known or potential risk factors, the multivariate rate ratio (RR) of colorectal cancer for men in the highest quartile of total calcium intake compared with those in the lowest quartile was 0.68 (95% CI: 0.51, 0.91; P for trend = 0.01). A high consumption of dairy foods was also associated with a lower risk of colorectal cancer. The multivariate RR of colorectal cancer for > or = 7 servings/d of total dairy foods compared with <2 servings/d was 0.46 (0.30, 0.71; P for trend = 0.01). For cancer subsites, the corresponding RRs were 0.37 (0.16, 0.88) for proximal colon, 0.43 (0.20, 0.93) for distal colon, and 0.48 (0.23, 0.99) for rectum. CONCLUSION: Our findings provide support for inverse associations between intakes of calcium and dairy foods and the risk of colorectal cancer.  相似文献   
103.
Reduced physical activity (PA), smoking, and coffee and alcohol drinking constitute risk factors of osteoporosis in patients with inflammatory bowel disease (IBD). The aim of the study was to measure the bone mineral density (BMD) and frequency of osteopenia and osteoporosis in patients with IBD and their correlation with PA, smoking, coffee, and alcohol. The study group consisted of 208 patients with IBD-103 with Crohn’s disease (CD), 105 suffering from ulcerative colitis (UC). Densitometric measurements were performed using the DXA. All patients completed a questionnaire concerning PA, smoking, and coffee and alcohol consumption. The prevalence of osteopenia and osteoporosis (L2–L4) in the IBD group was 48.1%; in the CD group, it amounted to 48.6%, and in the UC group, the prevalence was equal to 33.3%. Patients with CD who were diagnosed with osteopenia and osteoporosis demonstrated reduced PA compared to patients with a normal BMD who exercised regularly (p = 0.0335). A similar observation was made in the group of women with IBD. Women with a normal BMD exercised significantly more often than women suffering from osteopenia and osteoporosis (p = 0.0146). However, no differences in BMD were observed with regard to coffee use, alcohol consumption, or smoking. Thus, since the incidence of osteoporosis in IBD patients is high, it may be dependent on PA.  相似文献   
104.
Patients with end-stage kidney disease, treated with renal transplantation, are at increased risk of cardio-vascular disease (CVD) and cardio-vascular mortality. They are also characterized by an atherogenic dyslipidemia. Alterations of the fatty acids (FA) profile contribute to increased cardio-vascular risk in the general population. In the current study we test the hypothesis that kidney transplantation is associated with ab-normalities in FA profile. FA profile was analysed by gas chromatography–mass spectrometry in 198 renal transplant recipients, and 48 control subjects. The most profound differences between renal transplant patients and controls were related to the content of branched chain FA, monounsaturated FA, and n-6 polyunsaturated FA, respectively. The FA profile significantly separated the patients from the controls in the principal component analysis (PCA). The abnormalities of FA profile showed a tendency for normalization in long-term kidney recipients, as compared to patients with recent transplants. The n-3 PUFA content demonstrated a strong inverse association with the presence of inflammation. Most profound alterations of the FA profile were observed in patients with impaired graft function (glomerular filtration rate < 45 mL/min). The study demonstrated significant disorders of the FA profile in kidney transplant recipients, that might contribute to cardio-vascular risk in this vulnerable patient population.  相似文献   
105.
106.
107.
Background and aims  Intraoperative parathyroid hormone assay (IOPTH) has been used during minimally invasive parathyroidectomy (MIP) to predict operative success. However, the applied criteria are not equivalent in detection of multiglandular disease (MGD) and predicting cure. The purpose of this study was to evaluate the most commonly applied criteria of IOPTH in patients undergoing MIP in a tertiary referral center. Materials and methods  A retrospective review of 260 patients with sporadic primary hyperparathyroidism and concordant results of sestamibi scanning and ultrasound of the neck undergoing MIP (135 video-assisted and 125 open) between Dec 2002 and May 2008, with a 6-month postoperative follow-up of intact parathyroid hormone and serum calcium levels, was performed. The main outcome measures included evaluation of predictive values of Halle, Miami, Rome, and Vienna IOPTH interpretation criteria. Results  The following overall accuracy, sensitivity, specificity, positive predictive value, and negative predictive values were found, respectively: 65%, 62.9%, 100%, 100%, and 14.2% for Halle criterion; 97.3%, 97.6%, 93.3%, 99.6%, and 70% for Miami criterion; 83.8%, 82,9%, 100%, 100%, and 26.3% for Rome criterion; and 92.3%, 92.2%, 93.3%, 99.6%, and 60.9% for Vienna criterion. Conclusions  Miami criterion followed by Vienna criterion was found to be the best balanced among other criteria, with the highest accuracy in intraoperative prediction of cure. However, Rome criterion followed by Halle criterion was found to be the most useful in intraoperative detection of MGD. Nevertheless, their application in patients qualified for MIP with concordant results of sestamibi scanning and ultrasound of the neck would result in a significantly higher number of negative conversions to bilateral neck explorations and only a marginal improvement in the success rate of primary operations. Presented at the 3rd Workshop of the European Society of Endocrine Surgeons (ESES), “Modern techniques in primary hyperparathyroidism surgery: An evidence based perspective”, 19-21 of March 2009, Lund, Sweden.  相似文献   
108.
109.
110.
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