全文获取类型
收费全文 | 74191篇 |
免费 | 6665篇 |
国内免费 | 158篇 |
专业分类
耳鼻咽喉 | 675篇 |
儿科学 | 2720篇 |
妇产科学 | 2466篇 |
基础医学 | 8918篇 |
口腔科学 | 882篇 |
临床医学 | 11378篇 |
内科学 | 13604篇 |
皮肤病学 | 1169篇 |
神经病学 | 7175篇 |
特种医学 | 1727篇 |
外科学 | 8341篇 |
综合类 | 787篇 |
现状与发展 | 1篇 |
一般理论 | 98篇 |
预防医学 | 9556篇 |
眼科学 | 1295篇 |
药学 | 4906篇 |
中国医学 | 86篇 |
肿瘤学 | 5230篇 |
出版年
2023年 | 757篇 |
2022年 | 961篇 |
2021年 | 2180篇 |
2020年 | 1403篇 |
2019年 | 2190篇 |
2018年 | 2439篇 |
2017年 | 1918篇 |
2016年 | 2117篇 |
2015年 | 2169篇 |
2014年 | 3102篇 |
2013年 | 4146篇 |
2012年 | 5719篇 |
2011年 | 5743篇 |
2010年 | 3243篇 |
2009年 | 2896篇 |
2008年 | 4700篇 |
2007年 | 4697篇 |
2006年 | 4369篇 |
2005年 | 4128篇 |
2004年 | 3715篇 |
2003年 | 3253篇 |
2002年 | 2962篇 |
2001年 | 774篇 |
2000年 | 675篇 |
1999年 | 756篇 |
1998年 | 672篇 |
1997年 | 546篇 |
1996年 | 517篇 |
1995年 | 488篇 |
1994年 | 408篇 |
1993年 | 365篇 |
1992年 | 484篇 |
1991年 | 406篇 |
1990年 | 437篇 |
1989年 | 420篇 |
1988年 | 336篇 |
1987年 | 332篇 |
1986年 | 352篇 |
1985年 | 335篇 |
1984年 | 307篇 |
1983年 | 300篇 |
1982年 | 219篇 |
1981年 | 234篇 |
1980年 | 187篇 |
1979年 | 236篇 |
1978年 | 219篇 |
1976年 | 173篇 |
1975年 | 159篇 |
1974年 | 153篇 |
1973年 | 164篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
141.
Christopher D Wells Russell I Heigh Virender K Sharma Michael D Crowell Suryakanth R Gurudu Jonathan A Leighton Nora Mattek David E Fleischer 《BMC gastroenterology》2007,7(1):19
Background
Many factors impacting cecal intubation rates have been examined in detail; however, little information exists regarding the effect of the timing of the procedure. We sought to examine any difference in cecal intubation rates between morning and afternoon colonoscopies and identify factors contributing to a discrepancy. 相似文献142.
This study examined the impact of implementing a rotating dissection schedule on the attitudes and performance of first-year dental students in the gross anatomy laboratory at the University of Kentucky. In 2002-2003, half of the students assigned to each cadaver dissected the assigned objectives during the first 90 min of the laboratory session. During the last 30 min, the non-dissecting group members came into the laboratory and had the day's dissection demonstrated and explained to them via peer instruction. Dissection responsibilities rotated with each laboratory session. Eighty-eight percent of student participants were satisfied with the rotating dissection approach according to a mid-term survey, and this satisfaction level remained unchanged at the end of the semester for most students. Students' perceptions of the quality of peer laboratory presentations varied, with only 44% rating them as good or better. Eighty percent of students perceived that rotating dissection did not impede their performance, and this was confirmed by analysis of grade data. Student satisfaction and the ability to devote additional weekly curriculum time to studying anatomy in a very compressed curriculum were the main student-described benefits. 相似文献
143.
144.
145.
A new decontaminated hassles measure for adults, the Survey of Recent Life Experiences, was developed and validated. An initial pool of 92 items was administered to 100 subjects along with the Perceived Stress Scale. Fifty-one items were selected, based on significant correlations with the latter scale. The alpha reliability of the resultant final form of the Survey of Recent Life Experiences and its correlation with perceived stress were both high. In a separate cross-replication sample of 136 adults, the alpha reliability of the Survey and its correlation against the Perceived Stress Scale remained acceptably high. Moreover, separate-sex analyses supported the reliability and validity of the Survey of Recent Life Experiences across gender. Factor analysis of the Survey yielded six interpretable factors. Intercorrelations among subscales based on these factors were generally modest, suggesting that the scale is relatively free from contamination by psychological distress.The work reported was facilitated by a grant from the Social Sciences and Humanities Research Council of Canada's Small Grant Program, administered by the Office of Research Administration, York University. The authors appreciate the cooperation of staff at the Ontario Science Centre, Toronto, and the assistance of Maria Gurevich in verifying the data. 相似文献
146.
Michael Lefevre Author Vitae Penny M. Kris-EthertonAuthor Vitae Guixiang ZhaoAuthor Vitae Russell P. TracyAuthor Vitae 《Journal of the American Dietetic Association》2004,104(3):410-419
The cause of many myocardial infarctions is occlusive thrombosis, or a blood clot that stops blood flow in a coronary artery. Hemostasis involves a complex system of factors, which normally form and degrade blood clots, that work within a delicate balance. Emerging evidence suggests that some hemostatic factors, including factor VII, fibrinogen, and plasminogen activator inhibitor-1, are associated with increased risk for cardiovascular disease (CVD). Accumulating evidence suggests a relationship between dietary fatty acids and emerging hemostatic CVD risk factors, although much of this evidence is incomplete or conflicting. Dietary supplementation with marine n-3 fatty acids prolongs bleeding time and may decrease risk for thrombosis. Factor VII coagulant activity modestly decreases with reductions in saturated fatty acid (SFA) intake and thereby may contribute to the beneficial effects of low SFA diets. Large triglyceride-rich particles formed during postprandial lipemia can support the assembly and function of coagulation complexes and seem to play a role in the activation of factor VII, and thus may partially explain increased CVD risk associated with increased postprandial triglyceridemia. As our understanding of the role of dietary fatty acids and hemostasis evolves, it is likely that we will be able to make specific dietary recommendations to further decrease CVD risk. At this juncture, however, increasing marine n-3 fatty acids and decreasing certain SFAs are leading strategies to reduce hemostatic CVD risk factors. An array of dietary strategies that target multiple CVD risk factors could have a greater impact on CVD than a single risk factor intervention strategy. 相似文献
147.
Robert M. Russell M.D. 《Nutrition reviews》1992,50(12):463-466
148.
This study evaluates the microvascular reperfusion of ischemic skin flaps with and without acute hyperbaric oxygen (HBO) treatment. Thirty-two axial pattern epigastric skin flaps (3 x 6 cm) in male Wistar rats were subjected to 8 hours of global ischemia by pedicle clamp occlusion. The rats were divided into the following control and two experimental groups: Control (n = 12) with ischemia, no HBO; Group 1 (n = 11) with HBO treatment (three 1.75-hour dives, 2.5 absolute atm, 100% O2) during ischemia; and Group 2 (n = 9) with HBO treatment (two 1.75-hour dives) immediately after ischemia. Laser Doppler flows were recorded in two distal standardized flap locations at 0.5, 2, 4, and 18 hours after reperfusion in control rats and Group 1 rats and at 18 hours only in Group 2 rats, using a Med-Pacific 6000 laser Doppler unit. Mean distal flap laser Doppler flows (mV) were Control: 0.5 hours = 23.2 +/- 11.9, 2 hours = 52.8 +/- 27.3, 4 hours = 53.6 +/- 32.1, 18 hours = 40.2 +/- 36.2; Group 1: 0.5 hours = 71.8 +/- 30.9 (p less than 0.05 vs. control), 2 hours = 74.3 +/- 27.3, 4 hours = 67.4 +/- 20.6, 18 hours = 79.1 +/- 40.3 (p less than 0.05 vs. control); and Group 2: 18 hours = 90.3 +/- 47.9 (p less than 0.05 vs. control). It is concluded that acute HBO treatment of ischemic rat skin flaps improves distal microvascular perfusion as measured by laser Doppler flowmetry. This effect is observed for HBO treatment given either during or immediately after prolonged global ischemia.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
149.
150.