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   6237篇
  免费   424篇
  国内免费   23篇
耳鼻咽喉   51篇
儿科学   265篇
妇产科学   130篇
基础医学   690篇
口腔科学   115篇
临床医学   541篇
内科学   1750篇
皮肤病学   65篇
神经病学   317篇
特种医学   156篇
外科学   807篇
综合类   142篇
一般理论   4篇
预防医学   350篇
眼科学   258篇
药学   513篇
中国医学   56篇
肿瘤学   474篇
  2023年   55篇
  2022年   148篇
  2021年   223篇
  2020年   118篇
  2019年   157篇
  2018年   201篇
  2017年   151篇
  2016年   136篇
  2015年   154篇
  2014年   249篇
  2013年   285篇
  2012年   414篇
  2011年   424篇
  2010年   219篇
  2009年   195篇
  2008年   317篇
  2007年   341篇
  2006年   268篇
  2005年   276篇
  2004年   269篇
  2003年   259篇
  2002年   249篇
  2001年   130篇
  2000年   145篇
  1999年   136篇
  1998年   52篇
  1997年   50篇
  1996年   47篇
  1995年   29篇
  1994年   26篇
  1993年   18篇
  1992年   103篇
  1991年   60篇
  1990年   72篇
  1989年   62篇
  1988年   80篇
  1987年   59篇
  1986年   62篇
  1985年   64篇
  1984年   37篇
  1983年   22篇
  1982年   18篇
  1981年   19篇
  1979年   50篇
  1978年   18篇
  1975年   16篇
  1974年   18篇
  1973年   19篇
  1972年   19篇
  1969年   23篇
排序方式: 共有6684条查询结果,搜索用时 15 毫秒
71.
We investigated an outbreak of Middle East respiratory syndrome (MERS) at King Fahad Medical City (KFMC), Riyadh, Saudi Arabia, during March 29–May 21, 2014. This outbreak involved 45 patients: 8 infected outside KFMC, 13 long-term patients at KFMC, 23 health care workers, and 1 who had an indeterminate source of infection. Sequences of full-length MERS coronavirus (MERS-CoV) from 10 patients and a partial sequence of MERS-CoV from another patient, when compared with other MERS-CoV sequences, demonstrated that this outbreak was part of a larger outbreak that affected multiple health care facilities in Riyadh and possibly arose from a single zoonotic transmission event that occurred in December 2013 (95% highest posterior density interval November 8, 2013–February 10, 2014). This finding suggested continued health care–associated transmission for 5 months. Molecular epidemiology documented multiple external introductions in a seemingly contiguous outbreak and helped support or refute transmission pathways suspected through epidemiologic investigation.  相似文献   
72.
The patency of a polytetrafluoroethylene (Gortex®) graft 9½ years after coronary artery bypass graft surgery (CABG) is demonstrated. While this material is not commonly used as a conduit because of limited success in the past, this case demonstrates that, given the right circumstances, longterm patency is possible. Since available conduits for CABG are quite often limited, viable alternatives may be lifesaving and require further evaluation. In addition to mechanical considerations such as size, length, and material, anticoagulation and strict management of hyperlipidemia may be critical.  相似文献   
73.
74.
The tropism of influenza viruses for the human respiratory tract is a key determinant of host-range, and consequently, of pathogenesis and transmission. Insights can be obtained from clinical and autopsy studies of human disease and relevant animal models. Ex vivo cultures of the human respiratory tract and in vitro cultures of primary human cells can provide complementary information provided they are physiologically comparable in relevant characteristics to human tissues in vivo, e.g. virus receptor distribution, state of differentiation. We review different experimental models for their physiological relevance and summarize available data using these cultures in relation to highly pathogenic avian influenza H5N1, in comparison where relevant, with other influenza viruses. Transformed continuous cell-lines often differ in important ways to the corresponding tissues in vivo.  相似文献   
75.
Introduction: Fetal kidney length vs biparietal diameter (BPD) and femur length (FL) were comparatively evaluated and the role of fetal kidney length in estimating gestational age was determined in the second and third trimesters. Materials and methods: The study was carried out on 199 women with singleton uncomplicated pregnancies attending the outdoor patient department (OPD) for routine ultrasound fetal biometry. Fetal kidney length was measured biweekly, between 18 weeks and 38 weeks of gestation. Linear regression models for estimation of gestational age were derived from biometric indices (BPD and FL) and kidney length. Result: The earliest age at which fetal kidney could be seen sonographically was the 18th week of gestation with the mean kidney length of 12 ± 1.31 mm. The mean sonographic kidney length at the 38th week of gestation was 40.4 ± 1.71 mm, indicating that the mean fetal kidney length increases as pregnancy progresses from 18 weeks to 38 weeks of gestation. Conclusion: The best linear regression model for estimating fetal gestational age is femur length, kidney length, and biparietal diameter in that order, with standard error of ±3.85 days, ±8.04 days, and ±8.75 days, respectively.  相似文献   
76.
Sport Sciences for Health - Social isolation due to the coronavirus disease 2019 (COVID-19) pandemic has reduced physical activity levels in both men and women. The identification of barriers to...  相似文献   
77.
The coronavirus disease 2019 (COVID-19) pandemic presents a significant global public health challenge. One in five individuals with COVID-19 presents with symptoms that last for weeks after hospital discharge, a condition termed “long COVID”. Thus, efficient follow-up of patients is needed to assess the resolution of lung pathologies and systemic involvement. Thoracic imaging is multimodal and involves using different forms of waves to produce images of the organs within the thorax. In general, it includes chest X-ray, computed tomography, lung ultrasound and magnetic resonance imaging techniques. Such modalities have been useful in the diagnosis and prognosis of COVID-19. These tools have also allowed for the follow-up and assessment of long COVID. This review provides insights on the effectiveness of thoracic imaging techniques in the follow-up of COVID-19 survivors who had long COVID.  相似文献   
78.
Patel  Urvish  Malik  Preeti  Shah  Dhaivat  Patel  Achint  Dhamoon  Mandip  Jani  Vishal 《Journal of neurology》2021,268(1):240-247
Journal of Neurology - Due to pro-inflammatory and hypercoagulation states, COVID-19 infection is believed to increase the risk of stroke and worsen the outcomes of the patients having pre-existing...  相似文献   
79.
Rodin et al.'s study (2020) on the belief, knowledge and attitudes about tics amongst health professionals in Uganda is a preliminary yet an important step towards challenging the current thinking amongst clinicians and academics working with tics, which is that tics are hardly seen in or are absent in the sub-Saharan African population and it has been psotulated that this phenomenon is considered to be explained by genetics.  相似文献   
80.
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