全文获取类型
收费全文 | 3209258篇 |
免费 | 233046篇 |
国内免费 | 7146篇 |
专业分类
耳鼻咽喉 | 43857篇 |
儿科学 | 104414篇 |
妇产科学 | 86950篇 |
基础医学 | 470057篇 |
口腔科学 | 89528篇 |
临床医学 | 299400篇 |
内科学 | 613988篇 |
皮肤病学 | 68640篇 |
神经病学 | 258233篇 |
特种医学 | 118316篇 |
外国民族医学 | 810篇 |
外科学 | 470528篇 |
综合类 | 69734篇 |
现状与发展 | 13篇 |
一般理论 | 1224篇 |
预防医学 | 261604篇 |
眼科学 | 74159篇 |
药学 | 238295篇 |
16篇 | |
中国医学 | 6828篇 |
肿瘤学 | 172856篇 |
出版年
2021年 | 25831篇 |
2019年 | 26718篇 |
2018年 | 37055篇 |
2017年 | 27949篇 |
2016年 | 30934篇 |
2015年 | 35098篇 |
2014年 | 49157篇 |
2013年 | 75005篇 |
2012年 | 102861篇 |
2011年 | 109595篇 |
2010年 | 64826篇 |
2009年 | 60595篇 |
2008年 | 101971篇 |
2007年 | 108433篇 |
2006年 | 109286篇 |
2005年 | 105811篇 |
2004年 | 101056篇 |
2003年 | 96948篇 |
2002年 | 93739篇 |
2001年 | 142450篇 |
2000年 | 146411篇 |
1999年 | 123265篇 |
1998年 | 36564篇 |
1997年 | 32170篇 |
1996年 | 32174篇 |
1995年 | 30434篇 |
1994年 | 28257篇 |
1993年 | 26579篇 |
1992年 | 96768篇 |
1991年 | 94939篇 |
1990年 | 92385篇 |
1989年 | 88568篇 |
1988年 | 81724篇 |
1987年 | 80159篇 |
1986年 | 75683篇 |
1985年 | 72549篇 |
1984年 | 54229篇 |
1983年 | 46349篇 |
1982年 | 27758篇 |
1979年 | 49987篇 |
1978年 | 35722篇 |
1977年 | 29574篇 |
1976年 | 28577篇 |
1975年 | 30254篇 |
1974年 | 36535篇 |
1973年 | 35210篇 |
1972年 | 32854篇 |
1971年 | 30981篇 |
1970年 | 28701篇 |
1969年 | 26906篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
S J Graafsma L J van Tits P van Heijst J Reyenga J F Rodrigues de Miranda T Thien 《Journal of cardiovascular pharmacology》1989,14(4):598-602
The effect of handgrip (HG) isometric exercise on plasma catecholamines, alpha 2-adrenoceptors on platelets and beta 2-adrenoceptors on lymphocytes was studied in normotensive subjects (NT) and essential hypertensive subjects (HT). Whereas systolic blood pressure (SBP) increases were similar in NT and HT subjects, diastolic blood pressure (DBP) and heart rate (HR) increased more in the former group. Baseline values and changes in plasma epinephrine (E) and norepinephrine (NE) did not differ between both groups. No differences were apparent in alpha 2-adrenoceptor density and affinity between NT and HT subjects before or after the test. HG isometric exercise induced a similar increase in beta 2-adrenoceptors on lymphocytes of 22 +/- 7 and 13 +/- 5% in NT and HT subjects, respectively. Affinity to the beta 2-adrenoceptors under baseline conditions was somewhat lower in HT (8.1 +/- 0.4 pM) than in NT subjects (6.5 +/- 0.5 pM), and this difference persisted during the test. Our results indicate that there are no differences in alpha 2- and beta 2-adrenoceptor densities either at baseline conditions or after HG isometric exercise between NT and HT subjects. Small differences noted in affinity to the beta 2-adrenoceptors require further investigation. 相似文献
995.
This article examines the distribution of positive blood alcohol levels (BALs) among emergency room patients and the relationship between intoxication and other variables. Approximately one-quarter of the 640 subjects had positive blood alcohol levels and 16.3% had BAL readings above 0.10%, the legal limit for operating a motor vehicle in most states. Chi-square tests and logistic regression analysis indicated a significant relationship between employment status, gender, educational attainment, age and BAL. There were no significant racial differences. Analysis of the role of the presenting problem with BAL revealed that being involved in an accident was significantly predictive of a high BAL in a multivariate context. However, patients presenting with psychiatric problems had overall higher levels of intoxication than other patients. These findings have major implications for public policy formulation vis-à-vis public health delivery. 相似文献
996.
L F Edwards 《Hospital practice (Office ed.)》1989,24(6):185-7, 191-2, 200-1 passim
997.
Using a 31P-NMR spectroscopy, we monitored the metabolic kinetics of energy organophosphate compound in rat lens during the process of generating galactose cataract. The most remarkable metabolic change in the earlier phase of galactose cataract formation was found in alpha-glycerophosphate. This increased significantly, as compared to controls, since the day 3 of giving feed containing 25% galactose. The high level lasted for up to three weeks, decrease followed by a gradual decrease and subsequently a significant decrease at five weeks. Adenosine triphosphate (ATP) showed a significant decrease in the galactose group compared to the controls from two weeks after beginning of the experiment and the decrease continued. Inorganic orthophosphate increased gradually in the galactose group as compared to the controls, the increase being of significance at one week reading a maximum at two weeks followed by a subsegment decrease. Our basic study suggests that 31P-NMR spectroscopy is a useful technique in lens of the metabolic kinetics, to noninvasively determine the pathophysiology of galactose cataract, which has been studied biochemically and histologically. 相似文献
998.
The epidemiology of viral hepatitis in US Navy enlisted personnel was reviewed for the years 1975-1984. Hospital discharge summaries of all active duty enlisted personnel admitted to a US Navy treatment facility were used for the study. From 1975 to 1984, total first hospitalizations for viral hepatitis declined from 128 per 100,000 personnel (95% confidence interval (Cl) 118-139) to 56 per 100,000 personnel (95% Cl 50-63). The highest incidence of acute viral hepatitis (115 per 100,000 personnel) was found in the youngest age groups aged 24 years and less. Risk factors for acute hepatitis included a previous hospitalization with either drug abuse (relative risk = 363) or a sexually transmitted disease (relative risk = 25) listed among the discharge diagnoses. Having a medical job classification was also associated with an increased risk of acute hepatitis. The steep decline in the incidence of viral hepatitis during this 10-year period may have been due to decreasing drug abuse in the US Navy. Immunization of high-risk groups in the US Navy with hepatitis B vaccine could be an effective policy for the prevention of acute viral hepatitis. 相似文献
999.
1000.