全文获取类型
收费全文 | 488907篇 |
免费 | 50975篇 |
国内免费 | 2915篇 |
专业分类
耳鼻咽喉 | 9849篇 |
儿科学 | 16726篇 |
妇产科学 | 13407篇 |
基础医学 | 53992篇 |
口腔科学 | 9579篇 |
临床医学 | 55168篇 |
内科学 | 111099篇 |
皮肤病学 | 14096篇 |
神经病学 | 39999篇 |
特种医学 | 19451篇 |
外国民族医学 | 43篇 |
外科学 | 94016篇 |
综合类 | 8890篇 |
现状与发展 | 74篇 |
一般理论 | 206篇 |
预防医学 | 30526篇 |
眼科学 | 10830篇 |
药学 | 25001篇 |
中国医学 | 844篇 |
肿瘤学 | 29001篇 |
出版年
2023年 | 5337篇 |
2021年 | 6328篇 |
2020年 | 7824篇 |
2019年 | 5366篇 |
2018年 | 12067篇 |
2017年 | 10666篇 |
2016年 | 12219篇 |
2015年 | 12804篇 |
2014年 | 21214篇 |
2013年 | 24503篇 |
2012年 | 17886篇 |
2011年 | 18381篇 |
2010年 | 18267篇 |
2009年 | 21199篇 |
2008年 | 17339篇 |
2007年 | 16533篇 |
2006年 | 18687篇 |
2005年 | 15656篇 |
2004年 | 14367篇 |
2003年 | 12722篇 |
2002年 | 12123篇 |
2001年 | 17484篇 |
2000年 | 16956篇 |
1999年 | 15024篇 |
1998年 | 7064篇 |
1997年 | 6601篇 |
1996年 | 6242篇 |
1995年 | 6018篇 |
1994年 | 4533篇 |
1993年 | 3995篇 |
1992年 | 9923篇 |
1991年 | 10080篇 |
1990年 | 9510篇 |
1989年 | 9433篇 |
1988年 | 8504篇 |
1987年 | 8070篇 |
1986年 | 7738篇 |
1985年 | 7383篇 |
1984年 | 5477篇 |
1983年 | 4779篇 |
1982年 | 3145篇 |
1979年 | 4848篇 |
1978年 | 3657篇 |
1977年 | 3231篇 |
1975年 | 3179篇 |
1974年 | 3632篇 |
1973年 | 3671篇 |
1972年 | 3456篇 |
1971年 | 3181篇 |
1970年 | 3132篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Christopher N. Cooley Tyler J. Beranek Matthew A. Warpinski Robert Alexander Amanda O. Esquivel 《The American journal of emergency medicine》2019,37(2):199-203
Introduction
In the United States there has been a large increase in participation in lacrosse for both males and females. The purpose of this study was to analyze the number of head injuries, injury rates (calculated using the reported number of participants) and types of head injuries that are seen in emergency departments in the United States.Methods
We compared injuries between male and female lacrosse participants. This was a retrospective study using a publicly available database produced by the US Consumer Product Safety Commission and information about lacrosse participation from US Lacrosse.Results
A linear regression was performed and showed a positive correlation between number of head injuries to males and time from 2002 to 2010 (R2?=?0.823; p?=?0.001). While the number of injuries to the head in female lacrosse participants was not significant. There was a negative correlation between the number of head injuries to males from 2010 to 2016 (R2?=?0.800; p?=?0.007), but again, there was no significance for female injury count (R2?=?0.417; p?=?0.117). Other significant differences between head injuries in males and females included the mechanism of injury and the type of injury recorded.Conclusion
The most recent data from 2010 to 2016, suggest that both males and females have had a decrease in injury rate. However the total number of female head injuries is not significantly decreasing and as the sport continues to grow there will likely be more total head injuries and visits to the emergency department. 相似文献13.
14.
15.
16.
17.
18.
19.
C F A Peralta P Cavoretto B Csapo O Falcon K H Nicolaides 《Ultrasound in obstetrics & gynecology》2006,27(2):128-133
OBJECTIVE: To establish reference intervals for the fetal right, left and total lung volumes and heart volume between 12 and 32 weeks of gestation. METHODS: Fetal lung and heart volumes were measured using three-dimensional (3D) ultrasound in 650 normal singleton pregnancies at 12-32 weeks. The VOCAL (Virtual Organ Computer-aided AnaLysis) technique was used to obtain a sequence of six sections of each lung and the heart around a fixed axis, each after a 30 degrees rotation from the previous one. The rotation axis for the lungs extended from the apex to the upper limit of the diaphragm dome, and the rotation axis for the heart extended from its apex to its connection to the great vessels. The contour of each of these organs was drawn manually in the six different rotation planes to obtain the 3D volume measurement. In 60 cases the fetal lungs and heart volumes were measured by the same sonographer twice and also by a second sonographer once in order to compare the measurements and calculate intra- and interobserver agreement. RESULTS: The total lung volume and heart volume increased with gestation, from respective mean values of 1.6 and 0.6 mL at 12 weeks to 10.9 and 4.3 mL at 20 weeks and 49.3 and 26.6 mL at 32 weeks. The right to left lung volume ratio did not change significantly with gestation (median, 0.7), whereas the heart to total lung volume ratio increased with gestation from about 0.3 at 12 weeks to 0.5 at 32 weeks. In the Bland-Altman plot, the difference between paired measurements by two sonographers was, in 95% of the cases, less than 0.05, 0.5 and 1.9 mL for each lung at 12-13, 19-22 and 29-32 weeks, respectively, and the corresponding values for the heart volumes were 0.04, 0.4 and 2.3 mL. CONCLUSIONS: In normal fetuses the lung and heart volumes increase between 12 and 32 weeks of gestation. The extent to which in pathological pregnancies possible deviations in these measurements from normal prove to be useful in the prediction of outcome remains to be determined. 相似文献
20.
K M Sarraf M Abdalla O Al-Omari M G Sarraf 《Ultrasound in obstetrics & gynecology》2006,27(2):220-221
We report the case of a 38-year-old woman who presented with chronic lower abdominal pain. Her past medical history included a splenectomy due to abdominal trauma. Ultrasound examination revealed four pelvic tumors which, upon laparotomy, were found to be the result of splenosis. Approximately 100 cases of splenosis have been reported but only a minority of them have been published in the gynecological literature. Our case indicates that those involved in pelvic scanning (even of asymptomatic women) and/or treating those complaining of lower abdominal pain or presenting with pelvic tumors should be aware of splenosis as a possible diagnosis. 相似文献