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   4477403篇
  免费   356058篇
  国内免费   14761篇
耳鼻咽喉   62609篇
儿科学   144248篇
妇产科学   118396篇
基础医学   683422篇
口腔科学   122065篇
临床医学   408555篇
内科学   814529篇
皮肤病学   110435篇
神经病学   376882篇
特种医学   174668篇
外国民族医学   784篇
外科学   677218篇
综合类   125127篇
现状与发展   24篇
一般理论   2712篇
预防医学   368807篇
眼科学   104417篇
药学   316874篇
  25篇
中国医学   12266篇
肿瘤学   224159篇
  2021年   56412篇
  2020年   35988篇
  2019年   59003篇
  2018年   75043篇
  2017年   57145篇
  2016年   63333篇
  2015年   76106篇
  2014年   110475篇
  2013年   176169篇
  2012年   128101篇
  2011年   133704篇
  2010年   127463篇
  2009年   128601篇
  2008年   119550篇
  2007年   127600篇
  2006年   135980篇
  2005年   130022篇
  2004年   131225篇
  2003年   121299篇
  2002年   110358篇
  2001年   173053篇
  2000年   168371篇
  1999年   153818篇
  1998年   72356篇
  1997年   68049篇
  1996年   66076篇
  1995年   61442篇
  1994年   55397篇
  1993年   51387篇
  1992年   110651篇
  1991年   105654篇
  1990年   101558篇
  1989年   99035篇
  1988年   91151篇
  1987年   89138篇
  1986年   83872篇
  1985年   81846篇
  1984年   67809篇
  1983年   60179篇
  1982年   47992篇
  1981年   44544篇
  1980年   41733篇
  1979年   57706篇
  1978年   46404篇
  1977年   41319篇
  1976年   38110篇
  1975年   38419篇
  1974年   41632篇
  1973年   39855篇
  1972年   37435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