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   1469600篇
  免费   117853篇
  国内免费   6236篇
耳鼻咽喉   18978篇
儿科学   47208篇
妇产科学   42065篇
基础医学   208879篇
口腔科学   39078篇
临床医学   132049篇
内科学   294458篇
皮肤病学   34284篇
神经病学   120450篇
特种医学   55778篇
外国民族医学   485篇
外科学   217806篇
综合类   39701篇
现状与发展   7篇
一般理论   492篇
预防医学   113408篇
眼科学   33257篇
药学   104308篇
  24篇
中国医学   5041篇
肿瘤学   85933篇
  2021年   12352篇
  2019年   12747篇
  2018年   18049篇
  2017年   13990篇
  2016年   15501篇
  2015年   17698篇
  2014年   24700篇
  2013年   35568篇
  2012年   48446篇
  2011年   51137篇
  2010年   30101篇
  2009年   28739篇
  2008年   46657篇
  2007年   49264篇
  2006年   49789篇
  2005年   47858篇
  2004年   45418篇
  2003年   43320篇
  2002年   41653篇
  2001年   76604篇
  2000年   78105篇
  1999年   64807篇
  1998年   18460篇
  1997年   16529篇
  1996年   16255篇
  1995年   15360篇
  1994年   13927篇
  1993年   12984篇
  1992年   47392篇
  1991年   44844篇
  1990年   42763篇
  1989年   40738篇
  1988年   37218篇
  1987年   36304篇
  1986年   33693篇
  1985年   32002篇
  1984年   24297篇
  1983年   20400篇
  1982年   12388篇
  1981年   10919篇
  1979年   20930篇
  1978年   14635篇
  1977年   12132篇
  1976年   11419篇
  1975年   11676篇
  1974年   14052篇
  1973年   13617篇
  1972年   12693篇
  1971年   11526篇
  1970年   10969篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
患者女,40岁,因"咳嗽10个月余,咳绿色浓痰伴发热5 d"就诊本院。体格检查:神志清,一般情况可。2018年10月26日外院胸部CT平扫及增强(图1)示右肺上叶肺门旁直径约2.2 cm类圆形结节影,边缘光整,无毛刺及卫星灶,密度尚均匀;增强后明显强化,动脉期CT值约107 HU,静脉期CT值约89 HU,考虑为硬化性肺细胞瘤。于外院行抗炎、止咳、化痰等治疗,症状无缓解。  相似文献   
72.
73.
First described in 1955 in New Jersey, epizootic haemorrhagic disease (EHD) causes a severe clinical disease in wild and domestic ruminants worldwide. Epizootic haemorrhagic disease outbreaks occur in deer populations each year from summer to late autumn. The etiological agent is EHD virus (EHDV) which is a double‐stranded segmented icosahedral RNA virus. EHD virus utilizes point mutations and reassortment strategies to maintain viral fitness during infection. In 2018, EHDV serotype 2 was predominantly detected in deer in Illinois. Whole genome sequencing was conducted for two 2018 EHDV2 isolates (IL41747 and IL42218) and the sequence analyses indicated that IL42218 was a reassortant between different serotypes whereas IL41747 was a genetically stable strain. Our data suggest that multiple strains contribute to outbreaks each year.  相似文献   
74.
75.
76.

Background Context

Low back pain (LBP) is a common complaint in clinical practice of multifactorial origin. Although obesity has been thought to contribute to LBP primarily by altering the distribution of mechanical loads on the spine, the additional contribution of obesity-related conditions such as diabetes mellitus (DM) to LBP has not been thoroughly examined.

Purpose

To determine if there is a relationship between DM and LBP that is independent of body mass index (BMI) in a large cohort of adult survey participants.

Study Design

Retrospective analysis of prospectively collected National Health and Nutrition Examination Survey (NHANES) data to characterize associations between LBP, DM, and BMI in adults subdivided into 6 subpopulations: normal weight (BMI 18.5–25), overweight (BMI 25–30), and obese (BMI >30) diabetics and nondiabetics. Diabetes was defined with glycohemoglobin A1c (HbA1c) 6.5%.

Patient Sample

11,756 participants from NHANES cohort.

Outcome Measures

Percentage of LBP reported.

Methods

LBP reported in the 1999-2004 miscellaneous pain NHANES questionnaire was the dependent variable examined. Covariates included HbA1c, BMI, age, and family income ratio to poverty as continuous variables as well as race, gender, and smoking as binary variables. Individuals were further subdivided by weight class and diabetes status. Regression and graphical analyses were performed on the study population as a whole and also on subpopulations.

Results

Increasing HbA1c did not increase the odds of reporting LBP in the full cohort. However, multivariate logistic regression of the 6 subpopulations revealed that the odds of LBP significantly increased with increasing HbA1c levels in normal weight diabetics. No other subpopulations reported significant relationships between LBP and HbA1c. LBP was also significantly associated with BMI for normal weight diabetics and also for obese subjects regardless of their DM status.

Conclusions

LBP is significantly related to DM status, but this relationship is complex and may interact with BMI. These results support the concept that LBP may be improved in normal weight diabetic subjects with improved glycemic control and weight loss, and that all obese LBP subjects may benefit from improved weight loss alone.  相似文献   
77.
Affinity peptide and protein‐ (APP) based radiotracers are an increasingly popular class of radiotracer in positron emission tomography (PET), which was once dominated by the use of small molecule radiotracers. Radiolabelled monoclonal antibodies (mAbs) are important examples of APPs, yet a preference for smaller APPs, which exhibit fast pharmacokinetics and permit rapid PET aided diagnosis, has become apparent. 18F exhibits favourable physical characteristics for APP radiolabelling and has been described as an ideal PET radionuclide. Notwithstanding, 18F radiolabelling of APP is challenging, and this is echoed in the literature where a number of diverse approaches have been adopted. This review seeks to assess and compare the approaches taken to 18F APP radiolabelling with the intention of highlighting trends within this expanding field. Generic themes have emerged in the literature, namely the use of mild radiolabelling conditions, a preference of site‐specific methodologies with an impetus for short, automated procedures which produce high‐yielding [18F]APPs.  相似文献   
78.
79.

Introduction

Physician communication impacts patient outcomes. However, communication skills, especially around difficult conversations, remain suboptimal, and there is no clear way to determine the validity of entrustment decisions. The aims of this study were to 1) describe the development of a simulation-based mastery learning (SBML) curriculum for breaking bad news (BBN) conversation skills and 2) set a defensible minimum passing standard (MPS) to ensure uniform skill acquisition among learners.

Innovation

An SBML BBN curriculum was developed for fourth-year medical students. An assessment tool was created to evaluate the acquisition of skills involved in a BBN conversation. Pilot testing was completed to confirm improvement in skill acquisition and set the MPS.

Outcomes

A BBN assessment tool containing a 15-item checklist and six scaled items was developed. Students' checklist performance improved significantly at post-test compared to baseline (mean 65.33%, SD = 12.09% vs mean 88.67%, SD = 9.45%, P < 0.001). Students were also significantly more likely to have at least a score of 4 (on a five-point scale) for the six scaled questions at post-test. The MPS was set at 80%, requiring a score of 12 items on the checklist and at least 4 of 5 for each scaled item. Using the MPS, 30% of students would require additional training after post-testing.

Comments

We developed a SBML curriculum with a comprehensive assessment of BBN skills and a defensible competency standard. Future efforts will expand the mastery model to larger cohorts and assess the impact of rigorous education on patient care outcomes.  相似文献   
80.
Brian C. Werner 《Arthroscopy》2019,35(4):1072-1073
Achieving tendon-bone healing continues to be challenging after arthroscopic rotator cuff repair, particularly for larger tears, despite significant improvements in repair techniques and implants. Considerable effort has been invested in research to identify methods to improve healing, including patches and injectable biologics. Parathyroid hormone improves tendon-to-bone healing. Teriparatide is osteogenic, stimulating bone growth, and chondrogenic, promoting cartilage formation at the enthesis. However, it could be difficult to justify the expense and potential risk of systemic administration of a recombinant hormone to improve structural healing until improvement in clinical outcomes can be shown.  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