全文获取类型
收费全文 | 1594篇 |
免费 | 93篇 |
国内免费 | 113篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 70篇 |
妇产科学 | 15篇 |
基础医学 | 201篇 |
口腔科学 | 30篇 |
临床医学 | 203篇 |
内科学 | 393篇 |
皮肤病学 | 43篇 |
神经病学 | 53篇 |
特种医学 | 367篇 |
外国民族医学 | 1篇 |
外科学 | 70篇 |
综合类 | 43篇 |
预防医学 | 116篇 |
眼科学 | 15篇 |
药学 | 103篇 |
中国医学 | 1篇 |
肿瘤学 | 75篇 |
出版年
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 12篇 |
2018年 | 21篇 |
2017年 | 7篇 |
2016年 | 20篇 |
2015年 | 25篇 |
2014年 | 28篇 |
2013年 | 40篇 |
2012年 | 23篇 |
2011年 | 38篇 |
2010年 | 58篇 |
2009年 | 53篇 |
2008年 | 37篇 |
2007年 | 81篇 |
2006年 | 40篇 |
2005年 | 66篇 |
2004年 | 20篇 |
2003年 | 17篇 |
2002年 | 23篇 |
2001年 | 21篇 |
2000年 | 28篇 |
1999年 | 24篇 |
1998年 | 97篇 |
1997年 | 99篇 |
1996年 | 108篇 |
1995年 | 66篇 |
1994年 | 64篇 |
1993年 | 64篇 |
1992年 | 16篇 |
1991年 | 34篇 |
1990年 | 27篇 |
1989年 | 53篇 |
1988年 | 47篇 |
1987年 | 67篇 |
1986年 | 35篇 |
1985年 | 47篇 |
1984年 | 23篇 |
1983年 | 17篇 |
1982年 | 27篇 |
1981年 | 24篇 |
1980年 | 35篇 |
1979年 | 14篇 |
1978年 | 17篇 |
1977年 | 19篇 |
1976年 | 27篇 |
1975年 | 18篇 |
1972年 | 8篇 |
1969年 | 5篇 |
1967年 | 6篇 |
排序方式: 共有1800条查询结果,搜索用时 15 毫秒
1.
ARH missense polymorphisms and plasma cholesterol levels. 总被引:1,自引:0,他引:1
Mutations in a putative low-density lipoprotein (LDL) receptor adaptor protein called ARH have been recently described in patients with autosomal recessive hypercholesterolemia (ARH). ARH plays a tissue-specific role in determination of LDL receptor function. In the ARH gene three mismatched polymorphisms have been detected: Pro202Ser, Pro202His and Arg238Trp. These are of putative interest in plasma cholesterol level determination. To evaluate the effect of polymorphisms on plasma cholesterol levels, all polymorphisms were analyzed by PCR and restriction enzyme analysis by MnII, HpyCH4IV and SacII in 100 Caucasian males with high (>90%, 6.29 +/- 0.89 mmol/l), and 100 males with low (<10%, 3.60 +/- 0.57 mmol/l), total plasma cholesterol levels. No significant differences were observed in frequencies of ARH genotypes or alleles between these two extreme groups. These results suggest that ARH polymorphisms are unlikely to be important genetic determinants of plasma cholesterol levels. 相似文献
2.
Summary— To investigate if the functional alterations observed in resistance arteries of spontaneously hypertensive rats (SHRs) were also present at the coronary level, in vitro experiments were performed in mesenteric resistance arteries (MRA) and in right (RIC) and left interventricular coronary (LIC) arteries taken from 15–25-week-old SHR and age-matched Wistar Kyoto rats WKYs. Using a passive extension protocol, internal diameters corresponding to 100 mmHg intraluminal pressure (D100) were determined and vessels were set up to a normalized internal diameter (0.9 D100). SHR mesenteric resistance arteries had a significantly smaller diameter compared to WKY arteries, whereas both types of SHR coronary arteries had a greater diameter compared to those of WKY rats. In arteries in the absence of contracting agonist, nitro-L-arginine (NOLA, 100 μM) induced a progressive rise in basal tone, which could be reversed by subsequent addition of L-arginine (100 μM) but not D-arginine (100 μM). When expressed as percent of maximal contractions induced by agonists (noradrenaline, NA [10 μM] in MRA; serotonin, 5-HT [10 μM], in RIC and LIC), these contractions were significantly stronger in WKY compared to SHR coronary and mesenteric resistance arteries. In NA-precontracted MRA and 5HT-precontracted coronary arteries in the presence of indomethacin (10 μM), the magnitude of acetylcholine-induced maximal relaxations (expressed as percent of maximal contractions induced by agonists) was greater in WKY compared to SHR arteries. After a 30-min incubation period, NOLA (100 μM) completely inhibited relaxations induced by acetylcholine (0.01–10 μM) in all types of precontracted arteries. Subsequent additions of sodium nitroprusside, (SNP, 10 μM) induced complete relaxations in all preparations. These results show that a basal release of NO or NO-like compound by endothelial cells is present in isolated mesenteric resistance and coronary arteries of WKY rats and SHRs. The contribution of endothelium-derived relaxing factor-nitric oxide (EDRF-NO) to arterial tone was lower in MRA compared to coronary arteries in both strains and in SHR compared to WKY arteries. In the SHR preparations, the impaired relaxation induced by acetylcholine appeared to be due to a functional alteration of the endothelium in the presence of normal reactivity of the smooth muscle cells. 相似文献
3.
4.
5.
表小檗碱对α受体的作用 总被引:2,自引:0,他引:2
表小檗碱(epiberberine,EB)是从湖北产黄连(Coptis chinensis Franch)中提取的一种生物碱,属苯喹嗪类原小檗碱,对其药理作用的研究资料甚少,未见其对α肾上腺素体作用的报道。资料表明,许多原小檗碱类化合物有α受体阻滞作用,为从该类化合物中选择 相似文献
6.
7.
8.
E. A. Mowat S. Thomas R. Hyatt J. D. Maxwell M. N. Whitelaw 《Journal of human nutrition and dietetics》1992,5(1):35-51
Two sample groups of elderly were compared from a population living in South London. One group attended a local day centre (a socially orientated establishment), and the other attended a local day hospital (a therapeutically orientated establishment).
The aim of the study was to compare nutritional intake, functional status and muscle strength between these two groups.
The mean nutritional intakes of the day hospital and day centre attenders were similar. Intake of macronutrients, with the exception of fibre, met Recommended Daily Allowances (RDAs) in both groups. In take of folic acid, vitamin D and zinc fell below recommendations in both groups.
Low intake of folic acid was improved by supplementation, and some individual blood levels of folate reflected this. Blood folate levels were generally within normal limits. Low intake of vitamin D was improved by supplementation, but blood levels were generally normal anyway. There was, however, a tendency for the more dependent day hospital patients to have lower vitamin D levels. This group also had less sunshine exposure.
Communal dining, whether in the setting of day hospital or day centre, may have been an essential means of bolstering nutritional intake for many 'at risk' elderly.
There were significant differences in functional status and muscle strength in favour of the day centre group and these indicate that anthropometric indices rather than nutritional or biochemical indices were the most reliable markers of disease and disability in this study.
The effect of fortifying local meals-on-wheels was also highlighted, and suggests that this may be one means of preventing nutritional deficiencies in the vulnerable, house-bound elderly.
Alcohol intake was reported as being modest. However, discrepancies were noted on review of biochemical indices known to be influenced by alcohol intake. 相似文献
The aim of the study was to compare nutritional intake, functional status and muscle strength between these two groups.
The mean nutritional intakes of the day hospital and day centre attenders were similar. Intake of macronutrients, with the exception of fibre, met Recommended Daily Allowances (RDAs) in both groups. In take of folic acid, vitamin D and zinc fell below recommendations in both groups.
Low intake of folic acid was improved by supplementation, and some individual blood levels of folate reflected this. Blood folate levels were generally within normal limits. Low intake of vitamin D was improved by supplementation, but blood levels were generally normal anyway. There was, however, a tendency for the more dependent day hospital patients to have lower vitamin D levels. This group also had less sunshine exposure.
Communal dining, whether in the setting of day hospital or day centre, may have been an essential means of bolstering nutritional intake for many 'at risk' elderly.
There were significant differences in functional status and muscle strength in favour of the day centre group and these indicate that anthropometric indices rather than nutritional or biochemical indices were the most reliable markers of disease and disability in this study.
The effect of fortifying local meals-on-wheels was also highlighted, and suggests that this may be one means of preventing nutritional deficiencies in the vulnerable, house-bound elderly.
Alcohol intake was reported as being modest. However, discrepancies were noted on review of biochemical indices known to be influenced by alcohol intake. 相似文献
9.
10.
Pernes JM; Vitoux JF; Brenoit P; Raynaud A; Parola JL; Roth JP; Angel CY; Fiessinger JN; Roncato M; Gaux JC 《Radiology》1986,158(2):481-485
Thirty-five patients hospitalized for recent angiographically documented arterial occlusion in the legs (27 femoropopliteal arteries and eight grafts) benefited from local fibrinolytic therapy delivered at the site of the occlusion with a 4- or 5-F catheter. This therapy combined a continuous urokinase (UK) infusion of 1,000 U/kg/hour and a lysyl plasminogen (LYS-PLG) infusion of 15 microkatals every 30 minutes. Angiographically confirmed lysis was obtained in 85% of the cases. Only 3% of the patients had major and 6% had minor groin hematomas. Only two patients had concentrations of fibrinogen as low as 100 mg/dl. Intravascular infusion of UK-LYS-PLG is as effective as streptokinase. Its excellent tolerance makes it a good alternative in the treatment of acute ischemia in the lower limbs. 相似文献