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   10427篇
  免费   600篇
  国内免费   31篇
耳鼻咽喉   123篇
儿科学   302篇
妇产科学   193篇
基础医学   1306篇
口腔科学   286篇
临床医学   1036篇
内科学   2001篇
皮肤病学   101篇
神经病学   1127篇
特种医学   291篇
外科学   1438篇
综合类   50篇
一般理论   6篇
预防医学   894篇
眼科学   196篇
药学   794篇
中国医学   20篇
肿瘤学   894篇
  2023年   41篇
  2022年   37篇
  2021年   135篇
  2020年   144篇
  2019年   185篇
  2018年   236篇
  2017年   193篇
  2016年   218篇
  2015年   235篇
  2014年   304篇
  2013年   544篇
  2012年   684篇
  2011年   692篇
  2010年   410篇
  2009年   383篇
  2008年   654篇
  2007年   655篇
  2006年   667篇
  2005年   627篇
  2004年   581篇
  2003年   572篇
  2002年   550篇
  2001年   122篇
  2000年   89篇
  1999年   115篇
  1998年   105篇
  1997年   99篇
  1996年   89篇
  1995年   118篇
  1994年   96篇
  1993年   100篇
  1992年   84篇
  1991年   99篇
  1990年   69篇
  1989年   73篇
  1988年   66篇
  1987年   62篇
  1986年   67篇
  1985年   76篇
  1984年   92篇
  1983年   58篇
  1982年   88篇
  1981年   74篇
  1980年   40篇
  1979年   40篇
  1978年   42篇
  1977年   54篇
  1976年   33篇
  1975年   34篇
  1973年   29篇
排序方式: 共有10000条查询结果,搜索用时 17 毫秒
1.
Tamoxifen prevents recurrence of breast cancer and is suggested for preventive risk-reducing therapy. Tamoxifen reduces mammographic density, a proxy for therapy response, but little is known about its effects in remodelling normal breast tissue. Our study, a substudy within the double-blinded dose-determination trial KARISMA, investigated tamoxifen-specific changes in breast tissue composition and histological markers in healthy women. We included 83 healthy women randomised to 6 months daily intake of 20, 10, 5, 2.5, 1 mg of tamoxifen or placebo. The groups were combined to “no dose” (0-1 mg), “low-dose” (2.5-5 mg) or “high-dose” (10-20 mg) of tamoxifen. Ultrasound-guided biopsies were collected before and after tamoxifen exposure. In each biopsy, epithelial, stromal and adipose tissues was quantified, and expression of epithelial and stromal Ki67, oestrogen receptor (ER) and progesterone receptor (PR) analysed. Mammographic density using STRATUS was measured at baseline and end-of-tamoxifen-exposure. We found that different doses of tamoxifen reduced mammographic density and glandular-epithelial area in premenopausal women and associated with reduced epithelium and increased adipose tissue. High-dose tamoxifen also decreased epithelial ER and PR expressions in premenopausal women. Premenopausal women with the greatest reduction in proliferation also had the greatest epithelial reduction. In postmenopausal women, high-dose tamoxifen decreased the epithelial area with no measurable density decrease. Tamoxifen at both low and high doses influences breast tissue composition and expression of histological markers in the normal breast. Our findings connect epithelial proliferation with tissue remodelling in premenopausal women and provide novel insights to understanding biological mechanisms of primary prevention with tamoxifen.  相似文献   
2.
3.
Objective. Skeletal muscle perfusion during walking relies on complex interactions between cardiac activity and vascular control mechanisms, why cardiac dysfunction may contribute to intermittent claudication (IC) symptoms. The study aims were to describe cardiac function at rest and during stress in consecutive IC patients, to explore the relations between cardiac function parameters and treadmill performance, and to test the hypothesis that clinically silent myocardial ischemia during stress may contribute to IC limb symptomatology. Design. Patients with mild to severe IC (n?=?111, mean age 67 y, 52% females, mean treadmill distance 195 m) underwent standard echocardiography, dobutamine stress echocardiography (SE) and treadmill testing. The patient cohort was separated in two groups based on treadmill performance (HIGH and LOW performance). Results. Ten patients (9%) had regional wall motion abnormalities of which three had left ventricular ejection fraction <50% at standard echocardiography. A majority had lower than expected systolic- and diastolic ventricular volumes. LOW performers had smaller diastolic left ventricular volumes and lower global peak systolic velocity during dobutamine stress. No patient demonstrated significant cardiac dysfunction during dobutamine provocation that was not also evident at standard echocardiography. Conclusions. Most IC patients were without signs of ischemic heart disease or cardiac failure. The majority had small left ventricular volumes. The hypothesis that clinically silent myocardial ischemia impairing left ventricular function during stress may contribute to IC limb symptomatology was not supported.

Trial registration: ClinicalTrials.gov identifier: NCT01219842.  相似文献   
4.
5.
6.
Background

The impact of obesity on patient-reported outcome (PRO) after total knee arthroplasty (TKA) surgery has demonstrated varying results. We evaluated knee pain, Activity in Daily Life function (ADL), and satisfaction after TKA surgery in patients with and without prior bariatric surgery (BS).

Methods

Scandinavian Obesity Surgery Registry (SOReg) and the Swedish Knee Arthroplasty Register (SKAR) were used to identify patients operated on with primary TKA for osteoarthritis (OA) between 2009 and 2019 that had a BS within 2 years before the TKA (BS group). These patients were compared to patients with TKA without prior BS (no BS group). The patients filled in the Knee injury and Osteoarthritis Outcome Score (KOOS) preoperatively and one year postoperatively as well as satisfaction with the surgery one year postoperatively. Multiple linear regression analysis was used to evaluate 1-year postoperative KOOS pain and ADL function between the 2 groups. Adjustments were made for sex, age, and preoperative KOOS pain and ADL function respectively.

Results

Forty-four patients were included in the BS group and 3,525 patients in the no BS group. We found no statistically or clinically significant difference in one-year postoperative KOOS pain and ADL function between the BS group and the no BS group. The majority of the patients in both groups were classified as satisfied or very satisfied one year postoperatively to the TKA.

Conclusions

Our results indicate that patients without BS prior to the TKA gain similar 1-year outcome in pain, ADL function and satisfaction as patients with prior BS.

Graphical abstract
  相似文献   
7.
8.
9.
10.
Similar family-based cancer and genealogy data from Norway and Utah allowed comparisons of the incidence of testicular cancer (TC), and exploration of the role of Scandinavian ancestry and family history of TC in TC risk. Our study utilizes data from the Utah Population Database and Norwegian Population Registers. All males born during 1951–2015 were followed for TC until the age of 29 years. A total of 1,974,287 and 832,836 males were born in Norway and Utah, respectively, of whom 2,686 individuals were diagnosed with TC in Norway and 531 in Utah. The incidence per year of TC in Norway (10.6) was twice that observed in Utah (5.1) for males born in the last period (1980–1984). The incidence rates of TC in Utah did not differ according to the presence or absence of Scandinavian ancestry (p = 0.669). Having a brother diagnosed with TC was a strong risk factor for TC among children born in Norway and Utah, with HR = 9.87 (95% CI 5.68–17.16) and 6.02 (95% CI 4.80–7.55), respectively; with even higher HR observed among the subset of children in Utah with Scandinavian ancestry (HR = 12.30, 95% CI 6.78–22.31). A clear difference in TC incidence among individuals born in Norway and descendants of Scandinavian people born in Utah was observed. These differences in TC rates point to the possibility of environmental influence. Family history of TC is a strong risk factor for developing TC in both populations.  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