全文获取类型
收费全文 | 195565篇 |
免费 | 34167篇 |
国内免费 | 2567篇 |
专业分类
耳鼻咽喉 | 5642篇 |
儿科学 | 6310篇 |
妇产科学 | 3328篇 |
基础医学 | 9497篇 |
口腔科学 | 2488篇 |
临床医学 | 31017篇 |
内科学 | 56496篇 |
皮肤病学 | 8446篇 |
神经病学 | 18925篇 |
特种医学 | 8204篇 |
外国民族医学 | 2篇 |
外科学 | 48898篇 |
综合类 | 714篇 |
现状与发展 | 72篇 |
一般理论 | 76篇 |
预防医学 | 9557篇 |
眼科学 | 4245篇 |
药学 | 3643篇 |
中国医学 | 83篇 |
肿瘤学 | 14656篇 |
出版年
2024年 | 716篇 |
2023年 | 5138篇 |
2022年 | 2057篇 |
2021年 | 4697篇 |
2020年 | 6892篇 |
2019年 | 3430篇 |
2018年 | 8762篇 |
2017年 | 8231篇 |
2016年 | 9425篇 |
2015年 | 9624篇 |
2014年 | 17123篇 |
2013年 | 17587篇 |
2012年 | 8834篇 |
2011年 | 8786篇 |
2010年 | 12115篇 |
2009年 | 15757篇 |
2008年 | 8348篇 |
2007年 | 6652篇 |
2006年 | 8916篇 |
2005年 | 6022篇 |
2004年 | 5144篇 |
2003年 | 3926篇 |
2002年 | 3860篇 |
2001年 | 4284篇 |
2000年 | 3491篇 |
1999年 | 3712篇 |
1998年 | 4045篇 |
1997年 | 3776篇 |
1996年 | 3585篇 |
1995年 | 3429篇 |
1994年 | 2134篇 |
1993年 | 1762篇 |
1992年 | 1733篇 |
1991年 | 1732篇 |
1990年 | 1362篇 |
1989年 | 1447篇 |
1988年 | 1274篇 |
1987年 | 1091篇 |
1986年 | 1118篇 |
1985年 | 970篇 |
1984年 | 764篇 |
1983年 | 722篇 |
1982年 | 680篇 |
1981年 | 557篇 |
1980年 | 523篇 |
1979年 | 488篇 |
1978年 | 478篇 |
1977年 | 531篇 |
1975年 | 392篇 |
1972年 | 424篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
ABSTRACT: Background: Although increases in perinatal mortality risk associated with fetal macrosomia are well documented, the optimal route of delivery for fetuses with suspected macrosomia remains controversial. The objective of this investigation was to assess the risk of neonatal death among macrosomic infants delivered vaginally compared with those delivered by cesarean section. Methods: Data were derived from the U.S. 1995–1999 Linked Live Birth‐Infant Death Cohort files and term (37–44 wk), single live births to United States resident mothers selected. A proportional hazards model was used to analyze the risk of neonatal death associated with cesarean delivery among 3 categories of macrosomic infants (infants weighing 4,000–4,499 g; 4,500–4,999 g; and 5,000+ g). Results: After controlling for maternal characteristics and complications, the adjusted hazard ratio for neonatal death associated with cesarean delivery among the 3 categories of macrosomic infants was 1.40, 1.30, and 0.85. Conclusions: Although cesarean delivery may reduce the risk of death for the heaviest infants (5,000+ g), the relative benefit of this intervention for macrosomic infants weighing 4,000–4,999 g remains debatable. Thus, policies in support of prophylactic cesarean delivery for suspected fetal macrosomia may need to be reevaluated. (BIRTH 33:4 December 2006) 相似文献
12.
13.
14.
15.
Timothy C. Evans MD PhD ; Keren H. Wick PhD ; Douglas M. Brock PhD ; Douglas C. Schaad PhD ; Ruth Ballweg MPA PA-C 《The Journal of rural health》2006,22(3):212-219
CONTEXT: The physician assistant profession has been moving toward requiring master's degrees for new practitioners, but some argue this could change the face of the discipline. PURPOSE: To see if there is an association between physician assistants' academic degrees and practice in primary care, in rural areas, and with the medically underserved. METHODS: Surveys were sent to 880 graduates of the first 32 University of Washington physician assistant classes through 2000. Respondents noted their academic degree at program entry and the highest degree attained at any time up to the time of survey. Relationships between practice characteristics and academic degree levels were tested by unadjusted odds ratios and logistic regression after controlling for year of graduation and sex. RESULTS: Of the 478 respondents, 54% worked in primary care, about 30% practiced in nonmetropolitan communities, and 42% reported providing care for the medically underserved. Respondents with no degree (33% of total at entry, 24% at survey) were significantly more likely than degree holders to work in primary care and nonmetropolitan areas. Respondents with no degree at program entry were significantly more likely, and those with no degree at the time of the survey were marginally more likely, to self-report work with the medically underserved. CONCLUSION: Respondents with no academic degree are significantly more likely to demonstrate a commitment to primary, rural, and underserved health care. These findings may inform the national debate about the impact of required advanced degrees on the practice patterns of nonphysician providers. 相似文献
16.
17.
18.
19.
20.
Angiotensin Converting Enzyme Inhibitors: Animal Experiments Suggest a New Pharmacological Treatment for Alcohol Abuse in Humans 总被引:1,自引:0,他引:1
G. Spinosa MSc E. Perlanski Dipl Tech. F. H. H. Leenen MD R. B. Stewart MSc L. A. Grupp DSc 《Alcoholism, clinical and experimental research》1988,12(1):65-70
The prevalence of heavy alcohol consumption is a major problem of increasing proportions throughout the world. Although alcohol sensitizing drugs and more recently serotonin uptake inhibitors are drug interventions with some following, their long term beneficial consequences have yet to be demonstrated. In recent years, we have demonstrated that manipulating activity in the renin-angiotensin system will dramatically alter voluntary alcohol consumption in rats. Based on these findings, the present study evaluated the ability of a class of drugs known as the angiotensin converting enzyme inhibitors to reduce voluntary alcohol drinking in laboratory animals. These drugs prevent the conversion of angiotensin I to angiotensin II. They have been licensed for use in Europe and North America and are indicated in the treatment of hypertension. Our experiments showed that both captopril (Capoten, Squibb) and enalapril (Vasotec, Merck Sharpe & Dohme) can reduce alcohol drinking in both normotensive and hypertensive animals regardless of whether the pattern of intake is in a bout or of a less exaggerated nature. Furthermore, this change in alcohol intake can occur without concomitant changes in blood pressure, plasma renin activity, overall fluid balance, or the distribution and metabolism of alcohol. Taken together these findings suggest that the angiotensin converting enzyme inhibitors should be evaluated in a clinical setting for they may prove to be a useful new treatment or treatment adjunct for alcohol abuse in humans. 相似文献