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   62821篇
  免费   4970篇
  国内免费   127篇
耳鼻咽喉   407篇
儿科学   2707篇
妇产科学   2017篇
基础医学   8023篇
口腔科学   708篇
临床医学   8699篇
内科学   11617篇
皮肤病学   1118篇
神经病学   6804篇
特种医学   1099篇
外科学   5697篇
综合类   690篇
现状与发展   1篇
一般理论   102篇
预防医学   8875篇
眼科学   948篇
药学   4031篇
中国医学   69篇
肿瘤学   4306篇
  2024年   101篇
  2023年   790篇
  2022年   1208篇
  2021年   2327篇
  2020年   1471篇
  2019年   2198篇
  2018年   2484篇
  2017年   1760篇
  2016年   1967篇
  2015年   2079篇
  2014年   2759篇
  2013年   3755篇
  2012年   5465篇
  2011年   5317篇
  2010年   2783篇
  2009年   2482篇
  2008年   3900篇
  2007年   4134篇
  2006年   3673篇
  2005年   3543篇
  2004年   3197篇
  2003年   2762篇
  2002年   2588篇
  2001年   367篇
  2000年   280篇
  1999年   374篇
  1998年   523篇
  1997年   350篇
  1996年   303篇
  1995年   314篇
  1994年   278篇
  1993年   243篇
  1992年   164篇
  1991年   141篇
  1990年   150篇
  1989年   123篇
  1988年   98篇
  1987年   95篇
  1986年   100篇
  1985年   120篇
  1984年   129篇
  1983年   94篇
  1982年   117篇
  1981年   103篇
  1980年   99篇
  1979年   66篇
  1978年   69篇
  1977年   51篇
  1975年   42篇
  1972年   43篇
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
81.
82.
PURPOSE: This study aims to determine the effect of loss of breast cancer metastasis suppressor 1 (BRMS1) protein expression on disease-free survival in breast cancer patients stratified by estrogen receptor (ER), progesterone receptor (PR), or HER2 status, and to determine whether loss of BRMS1 protein expression correlated with genomic copy number changes. EXPERIMENTAL DESIGN: A tissue microarray immunohistochemical analysis was done on tumors of 238 newly diagnosed breast cancer patients who underwent surgery at the Cleveland Clinic between January 1, 1995 and December 31, 1996, and a comparison was made with 5-year clinical follow-up data. Genomic copy number changes were determined by array-based comparative genomic hybridization in 47 breast cancer cases from this population and compared with BRMS1 staining. RESULTS: BRMS1 protein expression was lost in nearly 25% of cases. Patients with tumors that were PR negative (P=0.006) or HER2 positive (P=0.039) and <50 years old at diagnosis (P=0.02) were more likely to be BRMS1 negative. No overall correlation between BRMS1 staining and disease-free survival was observed. A significant correlation, however, was seen between loss of BRMS1 protein expression and reduced disease-free survival when stratified by either loss of ER (P=0.008) or PR (P=0.029) or HER2 overexpression (P=0.026). Overall, there was poor correlation between BRMS1 protein staining and copy number status. CONCLUSIONS: These data suggest a mechanistic relationship between BRMS1 expression, hormone receptor status, and HER2 growth factor. BRMS1 staining could potentially be used in patient stratification in conjunction with other prognostic markers. Further, mechanisms other than genomic deletion account for loss of BRMS1 gene expression in breast tumors.  相似文献   
83.
Triplet morbidity and mortality in a large case series.   总被引:1,自引:0,他引:1  
OBJECTIVE: A significant increase in the triplet birth rate has occurred recently. This rise is of concern, as these infants are historically reported to be at risk of adverse outcome. Thus, we examined the outcome of triplet births in a large contemporary case series. STUDY DESIGN: Since 1993, detailed clinical data have been collected on all patients admitted to our Neonatal Intensive Care Unit. We retrospectively analyzed this database to examine triplet outcome. RESULTS: A total of 51 consecutive sets of triplets were born over a 9-year period. The mean birth weight for triplets was 1789+/-505 g, mean gestational age was 32.6+/-2.7 weeks, with discordancy present in 17.6% of neonates. Complications of prematurity were infrequent. Triplet survival to discharge was 96%. CONCLUSIONS: This large contemporary case series of triplets demonstrates excellent survival with low associated morbidity. These data suggest that there may no longer be medical justification for offering selective fetal reduction to parents with triplet pregnancies.  相似文献   
84.
Lymphedema is an under-recognized, progressive, life-long condition estimated to impact 2-3 million people in the United States. The incidence of breast cancer related lymphedema varies greatly in the literature largely due to different measurement techniques, competing thresholds for defining lymphedema, and variation in length of follow-up. Multiple imaging techniques have become useful for diagnosis. Lymphoscintigraphy is one of the most commonly used, as it can identify pathways of lymphatic drainage, quantify extent of dermal backflow, and help determine functional and morphologic changes in the lymphatic system. Early detection and intervention hold the greatest promise of reducing the incidence of lymphedema. Health care providers involved with cancer patients need to become more educated about lymphedema, aware of current risk-reduction practices, and familiar with methods of diagnosis and assessment, so that patients with early swelling can be referred to lymphedema treatment specialists at a time when treatment is more effective.  相似文献   
85.
86.
87.

Background  

Colorectal cancer, if detected early, has greater than 90% 5-year survival. However, survival has been shown to vary across racial/ethnic groups in the United States, despite the availability of early detection methods.  相似文献   
88.
89.
This study examined the temporal concordance between the onset of childhood anxiety disorders and the points of onset and ending of child sexual abuse (CSA). Sexually abused children (N = 158) were assessed with structured diagnostic interviews. Onset ages for lifetime prevalence anxiety disorders were combined and sequenced with the onset and ending of sexual abuse. Hazard rates were calculated. Departures from the overall linear hazard trajectory for onsets were modeled using piecewise growth curve analyses. Increases from the overall trajectory were found around the point of sexual abuse onset for most childhood anxiety disorders. Decreases were found around the ending of sexual abuse. The risk for developing new anxiety disorders after the onset of sexual abuse showed a positive dose-effect relation with abuse severity. The findings add support to the idea that CSA can have a direct link to childhood anxiety disorders, apart from confounded vulnerability factors, postabuse events, or stable family background factors. The findings are contrasted with those from cross-sectional partial correlation studies that have suggested that there is little direct connection between sexual abuse and mental health outcomes.  相似文献   
90.
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