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   4925439篇
  免费   387609篇
  国内免费   15384篇
耳鼻咽喉   69597篇
儿科学   159876篇
妇产科学   131357篇
基础医学   738620篇
口腔科学   135379篇
临床医学   450985篇
内科学   902418篇
皮肤病学   118160篇
神经病学   410481篇
特种医学   192700篇
外国民族医学   1299篇
外科学   741982篇
综合类   136410篇
现状与发展   24篇
一般理论   2791篇
预防医学   408375篇
眼科学   116594篇
药学   352049篇
  26篇
中国医学   13078篇
肿瘤学   246231篇
  2021年   56809篇
  2019年   59333篇
  2018年   76106篇
  2017年   58315篇
  2016年   64630篇
  2015年   77154篇
  2014年   111466篇
  2013年   177246篇
  2012年   139511篇
  2011年   147329篇
  2010年   130828篇
  2009年   130876篇
  2008年   133290篇
  2007年   143194篇
  2006年   150654篇
  2005年   144760篇
  2004年   145779篇
  2003年   135745篇
  2002年   124902篇
  2001年   196370篇
  2000年   193243篇
  1999年   174338篇
  1998年   75672篇
  1997年   70250篇
  1996年   68276篇
  1995年   63652篇
  1994年   57705篇
  1993年   53497篇
  1992年   128172篇
  1991年   123074篇
  1990年   118805篇
  1989年   115409篇
  1988年   106383篇
  1987年   104293篇
  1986年   98066篇
  1985年   95411篇
  1984年   77417篇
  1983年   68241篇
  1982年   51220篇
  1981年   47512篇
  1980年   44386篇
  1979年   67203篇
  1978年   52459篇
  1977年   46429篇
  1976年   43024篇
  1975年   43939篇
  1974年   48459篇
  1973年   46444篇
  1972年   43475篇
  1971年   40111篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Background  Machine learning (ML) has captured the attention of many clinicians who may not have formal training in this area but are otherwise increasingly exposed to ML literature that may be relevant to their clinical specialties. ML papers that follow an outcomes-based research format can be assessed using clinical research appraisal frameworks such as PICO (Population, Intervention, Comparison, Outcome). However, the PICO frameworks strain when applied to ML papers that create new ML models, which are akin to diagnostic tests. There is a need for a new framework to help assess such papers. Objective  We propose a new framework to help clinicians systematically read and evaluate medical ML papers whose aim is to create a new ML model: ML-PICO (Machine Learning, Population, Identification, Crosscheck, Outcomes). We describe how the ML-PICO framework can be applied toward appraising literature describing ML models for health care. Conclusion  The relevance of ML to practitioners of clinical medicine is steadily increasing with a growing body of literature. Therefore, it is increasingly important for clinicians to be familiar with how to assess and best utilize these tools. In this paper we have described a practical framework on how to read ML papers that create a new ML model (or diagnostic test): ML-PICO. We hope that this can be used by clinicians to better evaluate the quality and utility of ML papers.  相似文献   
992.
993.
994.
995.
996.
997.
998.
999.
Inbred mouse strains are the most widely used mammalian model organism in biomedical research owing to ease of genetic manipulation and short lifespan; however, each inbred strain possesses a unique repertoire of deleterious homozygous alleles that can make a specific strain more susceptible to a particular disease. In the current study, we report dystrophic cardiac calcinosis (DCC) in C.B‐17 SCID male mice at 10 weeks of age with no significant change in cardiac function. Acquisition of DCC was characterized by myocardial injury, fibrosis, calcification, and necrosis of the tissue. At 10 weeks of age, 38% of the C.B‐17 SCID mice from two different commercial colonies exhibited significant calcinosis on the ventricular epicardium, predominantly on the right ventricle. The frequency of calcinosis was more than 50% for mice obtained from Taconic's Cambridge City colony and 25% for mice obtained from Taconic's German Town colony. Interestingly, the DCC phenotype did not affect cardiac function at 10 weeks of age. No differences in echocardiography or electrocardiography were observed between the calcinotic and non‐calcinotic mice from either colony. Our findings suggest that C.B‐17 SCID mice exhibit DCC as early as 10 weeks of age with no significant impact on cardiac function. This strain of mice should be cautiously considered for the study of cardiac physiology.  相似文献   
1000.

Objective

To discover the experiences of end-of-life patients attended by the emergency services, through the discourse of the family caregivers who accompanied the family member in this care transit.

Method

A qualitative approach study, based on the paradigm of hermeneutical phenomenology. In total, 81 family caregivers participated. The techniques used were the in-depth interview and the discussion group, with a total of 5 discussion groups and 41 interviews. The period of data collection was carried out between January 2013 and June 2014.

Results

In the network of discourses obtained with respect to “Urgent Care”, all the codes were grouped in relation to a single argumentative line: deficiencies in urgent care. Among them, we found different dimensions that are established depending on the different times of care, or the different determinant aspects of these deficiencies: disorganization of the care received, lack of experience of the professionals in emergencies, application of general protocols in the emergency services, inadequate care in the treatment received, delays in emergency care.

Conclusions

In general, we highlight the dissatisfaction of the family members with respect to the care received from the emergency services. The needs of these types of situation are not covered from these services and are of low quality. Therefore, it is necessary to reorient the care protocols for these 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