全文获取类型
收费全文 | 924434篇 |
免费 | 59099篇 |
国内免费 | 1679篇 |
专业分类
耳鼻咽喉 | 12052篇 |
儿科学 | 29973篇 |
妇产科学 | 22073篇 |
基础医学 | 141641篇 |
口腔科学 | 25057篇 |
临床医学 | 81172篇 |
内科学 | 182409篇 |
皮肤病学 | 21956篇 |
神经病学 | 69018篇 |
特种医学 | 32292篇 |
外国民族医学 | 171篇 |
外科学 | 131824篇 |
综合类 | 15744篇 |
现状与发展 | 2篇 |
一般理论 | 221篇 |
预防医学 | 71276篇 |
眼科学 | 20564篇 |
药学 | 69251篇 |
3篇 | |
中国医学 | 2996篇 |
肿瘤学 | 55517篇 |
出版年
2021年 | 8667篇 |
2019年 | 9053篇 |
2018年 | 14814篇 |
2017年 | 10677篇 |
2016年 | 11374篇 |
2015年 | 12671篇 |
2014年 | 15593篇 |
2013年 | 23997篇 |
2012年 | 35652篇 |
2011年 | 36635篇 |
2010年 | 20145篇 |
2009年 | 17511篇 |
2008年 | 32972篇 |
2007年 | 35467篇 |
2006年 | 34681篇 |
2005年 | 33115篇 |
2004年 | 31876篇 |
2003年 | 29773篇 |
2002年 | 28687篇 |
2001年 | 41636篇 |
2000年 | 42322篇 |
1999年 | 35182篇 |
1998年 | 8690篇 |
1997年 | 7324篇 |
1996年 | 7599篇 |
1995年 | 7210篇 |
1994年 | 6605篇 |
1992年 | 25842篇 |
1991年 | 25547篇 |
1990年 | 24773篇 |
1989年 | 24336篇 |
1988年 | 22187篇 |
1987年 | 21434篇 |
1986年 | 20376篇 |
1985年 | 19031篇 |
1984年 | 13984篇 |
1983年 | 11831篇 |
1982年 | 6555篇 |
1979年 | 12651篇 |
1978年 | 8909篇 |
1977年 | 7571篇 |
1976年 | 7177篇 |
1975年 | 8013篇 |
1974年 | 9404篇 |
1973年 | 9064篇 |
1972年 | 8522篇 |
1971年 | 7991篇 |
1970年 | 7694篇 |
1969年 | 7160篇 |
1968年 | 6525篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Adilson Cunha Ferreira Edward Araujo Júnior Wellington P. Martins João Francisco Jordão Antônio Hélio Oliani Simon E. Meagher 《The journal of maternal-fetal & neonatal medicine》2015,28(14):1706-1710
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality. 相似文献
12.
13.
14.
15.
I. Fouzas C. Papanikolaou G. Katsanos N. Antoniadis N. Salveridis K. Karakasi S. Vasileiadou A. Fouza E. Mouloudi G. Imvrios V. Papanikolaou 《Transplantation proceedings》2019,51(2):416-420
Aims
Variations of the anatomy of donor hepatic arteries increase the number of arterial anastomoses during liver transplantation and, possibly, the incidence of hepatic artery thrombosis (HAT). In this study, we describe the arterial anatomic variations in liver grafts procured and transplanted by a single center in Greece, the techniques of arterial anastomosis, and their effect on the incidence of early HAT.Materials and Methods
From January 2013 to December 2017, the arterial anatomy of 116 grafts procured for liver transplantation were recorded, as well as the technique of arterial anastomosis and the incidence of early hepatic artery thrombosis (HAT <30 days).Results
A single hepatic artery was recorded in 72.41% of the procured grafts, an aberrant left hepatic artery (accessory or replaced) in 18 grafts (15.52%), and an aberrant right hepatic artery (accessory or replaced) in 17 grafts (14.66%), while other variations were observed in less than 1% of the procured livers. Of the 116 primary liver transplantations, 6 patients (5.17%) developed early HAT <30 days. Two of these patients (1.72%) had 1 anastomosis of the hepatic artery and 4 (3.45%) had 2 anastomoses due to anatomic variations.Conclusions
Anatomic variations of the hepatic artery in liver grafts is a common finding and increase the incidence of early HAT but not to a degree to make these grafts unusable. 相似文献16.
17.
N. V. Bashmakova G. N. Chistiakova I. A. Gazieva Y. M. Trapeznikova D. O. Mazurov 《Gynecological endocrinology》2015,31(10):31-33
AbstractThis study was undertaken to compare the concentrations of pro- and anti-angiogenic growth factors, nitric oxide (NO) stable metabolites in maternal serum and embryonic left ventricular (LV) isovolumic relaxation time (IRT, ms) during the first trimester in two groups of women: with pregnancy conceived by assisted reproductive technologies (ART, n?=?39) and normally conceived (control group, n?=?68) pregnancy. The concentration of vasoconstrictor endothelin 1 was 45.5 times more in ART than in control group. On the contrary, the concentrations of NO stable metabolites in ART were 1.9 times less than in control women. The assessment of angiogenic suppressors in ART women demonstrates the decrease in s-endoglin concentration was 1.6 times and in soluble receptor to vascular endothelial growth factor concentration was 2.0 times in comparison with control group. There was a significant increase in LV IRT in ART embryos in comparison to control ones. These data suggest significant changes in pro- anti-angiogenic factors balance and increase in vascular impedance in ART-conceived embryos. 相似文献
18.
María Cabrerizo Gloria Trallero María José Pena Amaia Cilla Gregoria Megias Carmen Mu?oz-Almagro Eva Del Amo Diana Roda Ana Isabel Mensalvas Antonio Moreno-Docón Juan García-Costa Nuria Rabella Manuel Ome?aca María Pilar Romero Sara Sanbonmatsu-Gámez Mercedes Pérez-Ruiz María José Santos-Mu?oz Cristina Calvo And the study group of “Enterovirus parechovirus infections in children under ?years-old Spain” PI- 《European journal of pediatrics》2015,174(11):1511-1516
19.
20.