全文获取类型
收费全文 | 70478篇 |
免费 | 4641篇 |
国内免费 | 2986篇 |
专业分类
耳鼻咽喉 | 253篇 |
儿科学 | 1173篇 |
妇产科学 | 699篇 |
基础医学 | 6974篇 |
口腔科学 | 1412篇 |
临床医学 | 4169篇 |
内科学 | 8018篇 |
皮肤病学 | 1806篇 |
神经病学 | 6624篇 |
特种医学 | 1299篇 |
外国民族医学 | 5篇 |
外科学 | 3908篇 |
综合类 | 9217篇 |
现状与发展 | 3篇 |
预防医学 | 4970篇 |
眼科学 | 590篇 |
药学 | 17708篇 |
14篇 | |
中国医学 | 6878篇 |
肿瘤学 | 2385篇 |
出版年
2024年 | 204篇 |
2023年 | 961篇 |
2022年 | 1560篇 |
2021年 | 2182篇 |
2020年 | 2058篇 |
2019年 | 1756篇 |
2018年 | 1692篇 |
2017年 | 1982篇 |
2016年 | 2160篇 |
2015年 | 2278篇 |
2014年 | 4090篇 |
2013年 | 4939篇 |
2012年 | 4046篇 |
2011年 | 4443篇 |
2010年 | 3347篇 |
2009年 | 3222篇 |
2008年 | 3368篇 |
2007年 | 3420篇 |
2006年 | 3006篇 |
2005年 | 2693篇 |
2004年 | 2381篇 |
2003年 | 2042篇 |
2002年 | 1692篇 |
2001年 | 1469篇 |
2000年 | 1299篇 |
1999年 | 1153篇 |
1998年 | 1097篇 |
1997年 | 1038篇 |
1996年 | 1002篇 |
1995年 | 938篇 |
1994年 | 839篇 |
1993年 | 709篇 |
1992年 | 704篇 |
1991年 | 648篇 |
1990年 | 642篇 |
1989年 | 607篇 |
1988年 | 561篇 |
1987年 | 500篇 |
1986年 | 521篇 |
1985年 | 779篇 |
1984年 | 725篇 |
1983年 | 536篇 |
1982年 | 536篇 |
1981年 | 498篇 |
1980年 | 456篇 |
1979年 | 315篇 |
1978年 | 239篇 |
1977年 | 189篇 |
1976年 | 165篇 |
1975年 | 117篇 |
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
251.
252.
用差速离心方法分离提取荷Lewis肺癌小鼠癌组织和肝组织富含溶酶体部分,并以溶酶体标志酶酸性磷酸酶(ACP)的游离酶和总酶活性比值作为观察溶酶体膜稳定性变化的指标,观察了亚硒酸钠对两种组织ACP酶活性和膜稳定性的影响。发现硒对癌组织和肝组织ACP活性的异常升高有抑制作用、稳定溶酶体膜,在癌瘤增殖前期作用明显(P<0.05)。提示这种拮抗效应与硒直接和间接的抗脂质过氧化有关。 相似文献
253.
The present study investigated the specific ways by which cytotoxicity due to glutamate receptor stimulation could be attenuated by the administration of agonists and antagonists of the ionotropic and metabotropic glutamate receptors within the nucleus basalis magnocellularis (NBM) of rats as measured by cortical choline acetyltransferase activity. The results of these studies suggest that (1) the cytotoxicity of ibotenate to NBM cholinergic cells is not dependent upon stimulation of metabotropic glutamate receptors, but results from activation of
(NMDA) receptors, (2) the cytotoxicity of quisqualate to cholinergic cells within the NBM is not dependent upon stimulation of NMDA or metabotropic receptors, and (3) the cytotoxicity of NMDA was prevented by administration (i.p.) of the un-competitive NMDA antagonist memantine (30 mg/kg), resulting in plasma levels of 2.5 μg/ml, a concentration known to block efficiently NMDA receptors in vitro. Finally, performance of a food-motivated, delayed-alternation task on a T-maze was impaired by injections of NMDA into the NBM, but was prevented by co-administration of NMDA with memantine. 相似文献
254.
Excellent uricosuric efficacy of benzbromarone in cyclosporin-A-treated renal transplant patients: a prospective study 总被引:3,自引:1,他引:2
Patients on cyclosporin A (CsA) often develop hyperuricaemiaand gout. In transplant patients the use of uricosuric drugsfor treating hyperuricaemia may be preferable to allopurinolbecause of the known interaction of the latter with azathioprine.We therefore prospectively studied the uricosuric efficacy of100 mg benzbromarone (Bbr;Desuric®) daily in 25 CsA-treatedrenal transplant patients with stable graft function and hyperuricaemia(>359 µmol/l for females, >491 µmol/l formales). Benzbromarone decreased plasma uric acid from 579±18µmol/l to 313±24 µmol/l (mean±SEM;P<0.001) and thereby normalized plasma uric acid in 21 of25 patients. The remaining four patients had creatininc clearancesbetween 21 and 25 ml/min, the lowest of the entire study group.Mean fractional clearance of uric acid increased from 5.4±0.4%to 17.2±1.0% (P<0.001). The relative decrease of plasmauric acid closely correlated with baseline creatinine clearance(r=0.67; P<0.001). CsA trough values were not influenced.None of the patients experienced any significant side-effects.As an unexpected find-ing, urinary uric acid excretion increasedfrom 2082 ± 175 µmol7sol;24 h to 3233 ±232µmol/24 h after 4 weeks' treatment with benzbromarone. In conclusion, benzbromarone normalized plasma uric acid inall CsA-treated renal transplant recipients with a creatinineclearance >25 ml/min. Due to its excellent efficacy and lackof significant side-effects, benzbromarone appears to be preferableto allopurinol in CsA-treated renal transplant recipients witha creati nine clearance over 25 ml/min. 相似文献
255.
应用地高辛甙元标记人乳头瘤病毒(HPV)-6,11,16和18探针,通过核酸杂交法检测上海地区女性患者HPV的感染。计活检组织标本128例,阴道脱落细胞130例,同时取样34例。斑点杂交结果表明活检组织中四种类型HPV的总阳性率:宫颈癌44%,宫颈间变66.7%,有间变史28.6%,外阴尖锐湿疣63%和慢性宫颈炎5.6%。阴道脱落细胞的各阳性率与之相近,同时取样的检测符合率为91.2%。Southern转移杂交结果提示:宫颈癌以HPV-16型为主,尖锐湿疣中的HPV为6和11型 相似文献
256.
Consecutive survivors of a myocardial infarction from the Southern Hospital, below 70 years of age, were randomized into a Control group (n=276) and a Treatment group (n=279). The latter was openly prescribed the combination of clofibrate and nicotinic acid for serum lipid lowering. Each patient should remain in the study for 5 years and be seen regularly every 4 months at a special IHD outpatient clinic within the hospital. The concentration of serum cholesterol and triglyceride was lowered by 13% and 19%, respectively, in the Treatment group compared to the Control group. Total mortality was 82 cases in the Control group and 61 in the Treatment group, a 26% reduction (p<0.05). For patients above 60 years of age in the Treatment group the reduction in mortality was 28% (p<0.05). IHD mortality was reduced by 36% (p<0.01)in the Treatment group compared to the Control group. The beneficial effect of the serum lipid lowering treatment was related to the serum triglyceride concentration in two ways. First, it only occurred in patients with a triglyceride level >1.5 mmol/l (n=216). Secondly, it was most pronounced in the 44% of the treated patients who had a lowering of the serum triglyceride concentration by 30% or more, and in this subgroup the reduction of IHD mortality was 60% (p<0.01). For serum cholesterol there were no such relations. The difference between serum triglycerides and cholesterol concerning these relations to the treatment outcome may be due to the fact that hypertriglyceridaemia was the most common hyperlipidaemia among our patients, occurring in 50%, while hypercholesterolaemia only occurred in 13 %. Caution should be exercised in the interpretation of the results as the trial was not blind. However, the fact that the decrease in IHD deaths was directly related to the degree of serum triglyceride lowering indicates that it was the drug effect on serum lipids that was reponsible for the beneficial effect of the treatment. 相似文献
257.
本文介绍正常人113名,肺部恶性病变49例及肺部良性病变33例的血清LSA测定结果,正常人血清LSA含量平均值为0.1243±0.0358g/L。特异性97.40%,男女间无差异,48例肺癌血清LSA平均值0.2698±0.0915g/L,敏感性85.40%;33例良性病变LSA平均值0.1712±0.0767g/L,特异性78.79%。肺癌患者血清LSA较良性病变明显升高,故测定血清LSA对鉴别良恶性病变有一定价值。 相似文献
258.
The spinal cord dorsal horn contains neural mechanisms which can greatly facilitate pain. We have recently shown that ‘illness’-inducing agents, such as intraperitoneally administered lipopolysaccharide (LPS; bacterial endotoxin), can produce prolonged hyperalgesia. This hyperalgesic state is mediated at the level of the spinal cord via activation of the NMDA-nitric oxide cascade. However, prolonged neuronal depolarization is required before such a cascade can occur. The present series of experiments were aimed at identifying spinal neurotransmitters which might be responsible for creating such a depolarized state. These studies show that LPS hyperalgesia is mediated at the level of the spinal cord by substance P, cholecystokinin and excitatory amino acids acting at non-NMDA sites. No apparent role for serotonin or kappa opiate receptors was found. 相似文献
259.
未研究发现,经热休克处理的大鼠注油酸后,肺组织损伤明显减轻,Western印迹分析显示热休克使大鼠肺组织中HSP70含量明显增多;Northern印迹分析证实此乃由于HSP70mRNA转录增加所致。说明热休克处理使肺组织HSP70基因表达增强;提示热休克反应对大鼠油酸肺的保护作用与肺组织细胞中HSP70基因表达增强及与HSP70增多有关。 相似文献
260.
用低蛋白饮食方法建立豚鼠胆色素结石模型,共设对照、致石、维生素C修复、丹参修复和对照修复等5组,规定时间内处死动物,用放射免疫、固相酶联免疫、生物化学等方法检测肝细胞内环—磷酸腺甙(cAMP)、环—磷酸鸟嘌呤(cGMP)、钙调素(CaM)、钙,三磷酸腺甙酶(Ca2+-ATPase)、磷酸化酶a等水平。致石组豚鼠肝脏细胞内cAMP和磷酸化酶a升高,而cGMP,CaM和Ca2+-ATPase下降,表明肝细胞钙稳态呈失调状态。维生素C和丹参可调整肝细胞的上述改变,说明维生素C和丹参具有维持肝细胞钙稳态的作用。 相似文献