全文获取类型
收费全文 | 2162篇 |
免费 | 88篇 |
国内免费 | 90篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 78篇 |
妇产科学 | 22篇 |
基础医学 | 183篇 |
口腔科学 | 76篇 |
临床医学 | 343篇 |
内科学 | 488篇 |
皮肤病学 | 33篇 |
神经病学 | 49篇 |
特种医学 | 332篇 |
外科学 | 336篇 |
综合类 | 30篇 |
预防医学 | 119篇 |
眼科学 | 6篇 |
药学 | 91篇 |
中国医学 | 1篇 |
肿瘤学 | 152篇 |
出版年
2022年 | 9篇 |
2021年 | 22篇 |
2020年 | 10篇 |
2019年 | 26篇 |
2018年 | 15篇 |
2017年 | 22篇 |
2016年 | 21篇 |
2015年 | 29篇 |
2014年 | 29篇 |
2013年 | 55篇 |
2012年 | 62篇 |
2011年 | 68篇 |
2010年 | 76篇 |
2009年 | 67篇 |
2008年 | 72篇 |
2007年 | 123篇 |
2006年 | 82篇 |
2005年 | 81篇 |
2004年 | 66篇 |
2003年 | 58篇 |
2002年 | 42篇 |
2001年 | 45篇 |
2000年 | 36篇 |
1999年 | 39篇 |
1998年 | 99篇 |
1997年 | 96篇 |
1996年 | 114篇 |
1995年 | 87篇 |
1994年 | 91篇 |
1993年 | 74篇 |
1992年 | 40篇 |
1991年 | 50篇 |
1990年 | 48篇 |
1989年 | 43篇 |
1988年 | 51篇 |
1987年 | 43篇 |
1986年 | 48篇 |
1985年 | 49篇 |
1984年 | 22篇 |
1983年 | 26篇 |
1982年 | 23篇 |
1981年 | 25篇 |
1980年 | 22篇 |
1979年 | 10篇 |
1978年 | 13篇 |
1977年 | 14篇 |
1976年 | 20篇 |
1975年 | 13篇 |
1973年 | 8篇 |
1969年 | 7篇 |
排序方式: 共有2340条查询结果,搜索用时 250 毫秒
21.
22.
WINOCOUR PH; KALUVYA S; BROWN L; FARRER M; MILLAR JP; NEIL HAW; ALBERTI KGMM 《QJM : monthly journal of the Association of Physicians》1991,79(3):539-560
Hyperinsulinaemia is said to be a risk factor for cardiovasculardisease, but the extent to which different insulinaemic measuresare associated with vascular risk factors in ostensibly healthyindividuals, and whether they operate independently in men andwomen, remains uncertain. The association between risk factors and various insulinaemicmeasures was examined in 148 men and 118 women who were normoglycaemic,normotensive, and non-obese (body mass index in men <27,in women <25). A 75 g glucose tolerance test was administeredafter blood sampling for fibrinogen, lipids, lipoproteins andinsulin. Insulin was also measured after 1 and 2 hours. Significantunivariate correlations (p<0.01) were most consistently recordedbetween insulinaemic measures and fasting serum triglyceridesin men and women, whilst systolic blood pressure only correlatedwith insulinaemia in women, and diastolic blood pressure correlatedwith fasting and 2 hour insulinaemic measures in men and women.Inconsistent associations were noted with total serum cholesterolin men and women, with high density lipoprotein cholesterol,body mass index, apoprotein B and A1 in men, and with fibrinogenin women. Age was not correlated with any insulinaemic measurein men or women. Differences in vascular risk factors between quintiles of theinsulinaemic measures were examined, after correction for bodymass index. The dominant association with fasting and post-glucoseload insulinaemic measures was with triglycerides, especiallyin women, with less frequent graded differences between quintilesobserved for total cholesterol, and diastolic and systolic bloodpressures in men and women. The incidence of other risk factors often only differed in thelowest or highest quintile in comparison to other quintiles,suggesting a threshold rather than a graded effect. Furthermore,differences in HDL cholesterol and apoprotein B were only recordedfor top quintiles of post-glucose challenge/integrated insulinaemicmeasures in men, whilst serum fibrinogen concentrations onlydiffered significantly in women in the top insulinaemic areaunder the curve quintile. In the absence of additional risk factors such as diabetes,hypertension and obesity, insulinaemic measures are not consistentlyrelated to blood pressure and measures of lipid metabolism andcoagulation, and are thus a weak predictor of other cardiovascularrisk factors. The vascular risk profile associated with insulinappears somewhat different in apparently healthy men and women. 相似文献
23.
Limited-field-of-view radio-frequency receiver antennas provide improved near-field sensitivity for magnetic resonance imaging by decreasing the antenna volume. The Helmholtz-type surface coil, consisting of two flat rings, is an organ-encompassing antenna that takes advantage of this principle to yield an improved signal-to-noise ratio (S/N). The coil was tested in a group of 50 patients and 16 healthy volunteers. Images obtained with the Helmholtz coil demonstrated quantitatively superior S/N of 2.2-fold or greater than that of comparison body coil images, as well as qualitatively superior anatomic resolution. 相似文献
24.
Because abnormalities of the autonomic nervous system have been described in several animal models of obesity, and because galanin has been proposed to be a sympathetic neurotransmitter in the endocrine pancreas, we hypothesized that the hyperinsulinemia observed in genetically obese (ob/ob) mice may result either from defective ability of galanin to inhibit insulin release or from a reduced degree of pancreatic galaninergic innervation. To address these possibilities, we examined the effect of exogenous galanin on immunoreactive insulin (IRI) levels in ob/ob mice and compared the pancreatic content of galaninlike immunoreactivity (GLIR) in ob/ob mice with that in lean littermates. Intravenous administration of synthetic porcine galanin significantly reduced basal IRI levels in ob/ob mice, suggesting that a defect in galanin action is unlikely to account for the hyperinsulinemia in this model. In contrast, reduced pancreatic galaninergic innervation was supported by findings that pancreatic content of GLIR in ob/ob mice was less than 10% of that in age- and sex-matched lean littermates. The reduction of pancreatic GLIR in ob/ob mice appeared organ specific; no such reduction was observed in adrenal GLIR content when comparing obese and lean mice. In addition, the relationship between pancreatic GLIR content and plasma IRI levels was examined in groups of obese and lean mice. It was found in young females, young males, and older mice of mixed sex that there was a significant negative correlation between pancreatic GLIR and plasma IRI in lean mice, whereas no such correlation was observed in obese mice.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
25.
26.
27.
28.
29.
Summary— Acidosis affects multiple steps in the excitation-contraction coupling pathway of myocardium, producing decreased calcium sensitivity of myofibrils and modification of the function of the sarcoplasmic reticulum. Our aim was to evaluate the effectiveness of three different classes of inotropic agents under acidotic conditions: 1) forskolin, an adenylate cyclase activator that enhances cellular cyclic AMP concentrations, 2) elevated extracellular Ca2+ and 3) endothelin-1, an activator of the inositol triphosphate, diacylglycerol pathway. Ferret papillary muscles were mounted in organ baths containing normal physiological solution (pH = 7.4). After baseline tension was measured, the muscles were bathed in an acidotic solution (pH = 6.98) that decreased tension to 40% of the control; subsequently, the muscles were washed with normal physiological solution until they returned to baseline. Each inotropic agent was added to the bathing solution in a concentration sufficient to increase tension by 40% above the baseline. Then the solution was made acidotic (pH = 6.98) in the continuous presence of that concentration of inotropic agent and the resultant steady-state developed tension measured. The increases in tension induced by each inotropic agent at normal pH were adjusted to be similar; in contrast, the response to each drug in acidosis was significantly different. Under acidotic conditions, endothelin-1 was the most effective inotropic agent in restoring the depressed developed tension. This was possibly due to enhancement of the myofilament sensitivity to Ca2+ , which was more effective than increasing [Ca2+ ]i through elevating extracellular Ca2+ or the addition of forskolin which increased [Ca2+ ]i but desensitized the myofilaments to Ca2+ . 相似文献
30.