全文获取类型
收费全文 | 2023篇 |
免费 | 140篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 32篇 |
妇产科学 | 63篇 |
基础医学 | 338篇 |
口腔科学 | 21篇 |
临床医学 | 254篇 |
内科学 | 305篇 |
皮肤病学 | 27篇 |
神经病学 | 164篇 |
特种医学 | 81篇 |
外科学 | 235篇 |
综合类 | 17篇 |
一般理论 | 1篇 |
预防医学 | 261篇 |
眼科学 | 16篇 |
药学 | 134篇 |
肿瘤学 | 199篇 |
出版年
2021年 | 25篇 |
2020年 | 21篇 |
2019年 | 25篇 |
2018年 | 41篇 |
2017年 | 35篇 |
2016年 | 29篇 |
2015年 | 39篇 |
2014年 | 29篇 |
2013年 | 50篇 |
2012年 | 88篇 |
2011年 | 114篇 |
2010年 | 58篇 |
2009年 | 41篇 |
2008年 | 94篇 |
2007年 | 75篇 |
2006年 | 99篇 |
2005年 | 83篇 |
2004年 | 98篇 |
2003年 | 88篇 |
2002年 | 101篇 |
2001年 | 42篇 |
2000年 | 40篇 |
1999年 | 46篇 |
1997年 | 19篇 |
1992年 | 21篇 |
1991年 | 25篇 |
1990年 | 39篇 |
1989年 | 29篇 |
1988年 | 21篇 |
1987年 | 40篇 |
1986年 | 27篇 |
1985年 | 25篇 |
1984年 | 29篇 |
1983年 | 37篇 |
1982年 | 20篇 |
1981年 | 19篇 |
1980年 | 14篇 |
1979年 | 42篇 |
1978年 | 26篇 |
1977年 | 27篇 |
1976年 | 19篇 |
1975年 | 25篇 |
1974年 | 29篇 |
1973年 | 20篇 |
1972年 | 33篇 |
1971年 | 19篇 |
1970年 | 19篇 |
1969年 | 14篇 |
1968年 | 16篇 |
1967年 | 21篇 |
排序方式: 共有2165条查询结果,搜索用时 15 毫秒
1.
Unemployment causes ill health: the wrong track 总被引:1,自引:0,他引:1
A R Kagan 《Social science & medicine (1982)》1987,25(2):217-218
It is not unemployment per se that causes ill health. It can be a very desirable state. There are no diseases specific to unemployment. Contrast this with employment. Unemployment shares with all other socio-environmental situations risk of exposure to common physical, social and psychological stressors that predispose to disease. Focus for action and research should be on reducing such stressors and not on provision of full employment. The former is likely to be possible and beneficial. The latter is likely to be impossible and carries a risk of making matters worse. As an immediate first step, that will reduce 'cratogenic' disease, people in authority should stop misleading the public into believing that unemployment is the cause of ill health. 相似文献
2.
Padmaja Yalamanchili Eric Wexler Megan Hayes Ming Yu Jody Bozek Mikhail Kagan Heike S. Radeke Michael Azure Ajay Purohit David S. Casebier Simon P. Robinson 《Journal of nuclear cardiology》2007,14(6):782-788
Background
BMS-747158-02 is a novel fluorine 18-labeled pyridazinone derivative designed for cardiac imaging. The uptake and retention
mechanisms of F-18 BMS-747158-02 in cardiac myocytes were studied in vitro, and the biodistribution of F-18 BMS-747158-02
was studied in vivo in mice.
Methods and Results
Fluorine 19 BMS-747158-01 inhibited mitochondrial complex I (MC-I) in bovine heart submitochondrial particles with an IC50 of 16.6±3 nmol/L that was comparable to the reference inhibitors of MC-1, rotenone, pyridaben, and deguelin (IC50 of 18.2±6.7 nmol/L, 19.8±2.6 nmol/L, and 23.1±1.5 nmol/L, respectively). F-18 BMS-747158-02 had high uptake in monolayers
of neonatal rat cardiomyocytes (10.3%±0.7% of incubated drug at 60 minutes) that was inhibited by 200 nmol/L of rotenone (91%±2%)
and deguelin (89%±3%). In contrast, an inactive pyridaben analog, P-0 (IC50 value>4 μmol/L in MC-1 assay), did not inhibit the binding of F-18 BMS-747158-02 in cardiomyocytes. Uptake and washout kinetics
for F-18 BMS-747158-02 in rat cardiomyocytes indicated that the time to half-maximal (t1/2) uptake was very rapid (approximately 35 seconds), and washout t1/2 for efflux of F-18 BMS-747158-02 was greater than 120 minutes. In vivo biodistribution studies in mice showed that F-18 BMS-747158-02
had substatial myocardial uptake (9.5%±0.5% of injected dose per gram) at 60 minutes and heart-to-lung and heart-to-liver
ratios of 14.1±2.5 and 8.3±0.5, respectively. Positron emission tomography imaging in the mouse allowed clear cardiac visualization
and demonstrated sustained myocardial uptake through 55 minutes.
Conclusions
F-18 BMS-747158-02 is a novel positron emission tomography cardiac tracer targeting MC-I in cardiomyocytes with rapid uptake
and slow washout. These characteristics allow fast and sustained accumulation in the heart. 相似文献
3.
4.
J Jacobsson L Cheng K Lyke M Kuwahara E Kagan P W Ramwell M L Foegh 《The Journal of heart and lung transplantation》1992,11(6):1188-1193
Migration and proliferation of vascular smooth muscle cells are early and major events in the formation of atherosclerotic lesions. We report on an aorta transplant model in rabbits wherein myointimal proliferation is inhibited by 17-beta-estradiol. The abdominal aortas of outbred white New Zealand rabbits were harvested and allografted to the carotid artery of the recipient. The animals, which were fed either a normal or a high-cholesterol (0.5%) diet, were killed 3 weeks later. The degree of myointimal proliferation was measured with a digitized system attached to a light microscope. The myointimal hyperplasia was expressed as the cross section area of the intima/the area of the intima + the area of the media x 100. Transmission electron micrographs were obtained for all vessels. Intimal thickening was shown mainly to consist of proliferating smooth muscle cells. The cholesterol diet resulted in significantly higher serum total cholesterol levels compared to animals on a normal diet (p < 0.0001) but did not affect serum high-density lipoprotein-cholesterol or serum triglyceride levels. The cholesterol diet was also associated with a greater but not significant amount of intimal thickening. Treatment with 17-beta-estradiol significantly decreased both serum triglyceride concentration (p < 0.05) and myointimal thickening (p < 0.01) in cholesterol-fed animals. Transmission electron microscopy showed that the endothelial cells appeared structurally normal in the estradiol-treated animals. Further, estradiol prevented the appearance of vacuolized macrophages. Thus estradiol may decrease myointimal thickening by preserving the endothelium and preventing macrophage appearance in the intima.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
5.
6.
The development and maintenance of the normal functional integrity of the mammalian central nervous system is under the influence of a number of growth and trophic factors. One such growth factor, epidermal growth factor, has been detected in the mammalian brain and found to be associated with various brain regions and cell types. This small ubiquitous polypeptide can influence the proliferation, Metabolism, and differentiation of both glia and neurons in the central nervous system. We discuss the effects of epidermal growth factor on glial and neuronal cell function in an attempt to understand its role in development and maintenance of normal brain integrity. In addition, we review its possible implications in several pathological states in the central nervous system and speculate on therapeutic applications for this growth factor. © 1992 Wiley-Liss, Inc. 相似文献
7.
8.
K O Kagan A Gazzoni G Sepulveda-Gonzalez A Sotiriadis K H Nicolaides 《Ultrasound in obstetrics & gynecology》2007,29(5):527-532
OBJECTIVE: To examine in monochorionic pregnancies the possible value of intertwin discordance in nuchal translucency (NT) thickness in the prediction of early fetal death or severe twin-twin transfusion syndrome (TTTS). METHODS: In 512 monochorionic twin pregnancies NT was measured at 11 to 13 + 6 weeks' gestation and regression analysis was used to determine the significance of the association between the intertwin discordance in NT and subsequent early fetal death or development of severe TTTS requiring endoscopic laser surgery. RESULTS: In 412 (80.5%) pregnancies there was a normal outcome, in 58 (11.3%) there was severe TTTS requiring endoscopic laser surgery at 18-24 weeks, in 19 (3.7%) there was death of one or both fetuses at 13-18 weeks and in 23 (4.5%) there was fetal death at 21-38 weeks. In the four outcome groups the median discordance in NT was 11%, 22%, 35% and 7%, respectively. Significant prediction of early fetal death and severe TTTS was provided by the discordance in fetal NT, which was not significantly improved by including the discordance in crown-rump length. If the discordance in NT was 20% or more, the false positive rate was 20%, the detection rate of early fetal death was 63% and the detection rate of severe TTTS was 52%. CONCLUSIONS: Discordance in NT of 20% or more is found in about 25% of monochorionic twins and in this group the risk of early fetal death or development of severe TTTS is more than 30%. If the discordance is less than 20% the risk of complications is less than 10%. 相似文献
9.
V. A. Gotlib V. A. Tyurin M. P. Rychkova A. L. Berman A. A. Lev V. E. Kagan 《Bulletin of experimental biology and medicine》1989,108(2):1104-1107
Institute of Cytology, Academy of Sciences of the USSR. I. M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Academy of Sciences of the USSR, Leningrad. Institute of Physiology, Bulgarian Academy of Sciences, Sofia. (Presented by Academician of the Academy of Medical Sciences of the USSR Yu. A. Vladimirov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 108, No. 8, pp. 160–171, August, 1989. 相似文献
10.
Performance of a commercial, type-specific enzyme-linked immunosorbent assay for detection of herpes simplex virus type 2-specific antibodies in Ugandans 下载免费PDF全文
Laeyendecker O Henson C Gray RH Nguyen RH Horne BJ Wawer MJ Serwadda D Kiwanuka N Morrow RA Hogrefe W Quinn TC 《Journal of clinical microbiology》2004,42(4):1794-1796
Two hundred forty-eight human immunodeficiency virus (HIV)-positive and 496 HIV-negative subjects in Uganda were tested by HerpeSelect herpes simplex virus type 2 enzyme-linked immunosorbent assay (ELISA) and Western blotting to optimize the ELISA for use in this population. A higher index cutoff value was required for optimal sensitivity and specificity, and overall performance of the assay was not affected by HIV status. 相似文献