全文获取类型
收费全文 | 71925篇 |
免费 | 6780篇 |
国内免费 | 4909篇 |
专业分类
耳鼻咽喉 | 662篇 |
儿科学 | 1156篇 |
妇产科学 | 1171篇 |
基础医学 | 8074篇 |
口腔科学 | 1128篇 |
临床医学 | 9075篇 |
内科学 | 10901篇 |
皮肤病学 | 772篇 |
神经病学 | 4089篇 |
特种医学 | 2345篇 |
外国民族医学 | 28篇 |
外科学 | 8204篇 |
综合类 | 12061篇 |
现状与发展 | 11篇 |
一般理论 | 9篇 |
预防医学 | 5071篇 |
眼科学 | 1678篇 |
药学 | 7364篇 |
64篇 | |
中国医学 | 3832篇 |
肿瘤学 | 5919篇 |
出版年
2024年 | 281篇 |
2023年 | 1203篇 |
2022年 | 2987篇 |
2021年 | 3869篇 |
2020年 | 2875篇 |
2019年 | 2544篇 |
2018年 | 2619篇 |
2017年 | 2427篇 |
2016年 | 2207篇 |
2015年 | 3363篇 |
2014年 | 4104篇 |
2013年 | 4017篇 |
2012年 | 5688篇 |
2011年 | 5933篇 |
2010年 | 3840篇 |
2009年 | 3084篇 |
2008年 | 3898篇 |
2007年 | 3786篇 |
2006年 | 3506篇 |
2005年 | 3357篇 |
2004年 | 2296篇 |
2003年 | 2230篇 |
2002年 | 1907篇 |
2001年 | 1619篇 |
2000年 | 1534篇 |
1999年 | 1549篇 |
1998年 | 787篇 |
1997年 | 877篇 |
1996年 | 643篇 |
1995年 | 582篇 |
1994年 | 511篇 |
1993年 | 348篇 |
1992年 | 471篇 |
1991年 | 422篇 |
1990年 | 359篇 |
1989年 | 313篇 |
1988年 | 296篇 |
1987年 | 252篇 |
1986年 | 221篇 |
1985年 | 160篇 |
1984年 | 94篇 |
1983年 | 98篇 |
1982年 | 56篇 |
1981年 | 63篇 |
1980年 | 47篇 |
1979年 | 60篇 |
1978年 | 33篇 |
1977年 | 27篇 |
1974年 | 26篇 |
1973年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
测定110例肝病的抗凝血酶Ⅲ(AT-Ⅲ)活性,62例低于正常(56.4%),均值为60.1±38.2%。50例正常对照为100.0±26.7%。重症肝炎、慢性活动性肝炎及失代偿期肝硬化活性显著下降,均值分别为12.9±13.0%、51.0±34.6%、43.3±29.6%.AT-Ⅲ活性在评价肝脏功能方面较凝血酶原时间敏感,具有一定的实用意义。 相似文献
52.
A general equation was derived, which directly describes the mathematical relationship between the allometrically predicted pharmacokinetic (PK) parameters in humans and the body weights of animal species (along with their corresponding measured PK parameters). It was shown, with use of the derived equation, that the predicted values in humans, based on combinations of animal species commonly used in allometry, are heavily dependent on certain species, for example, the dog. In contrast, parameter values from the rat made no contribution to the predicted human values, as long as the rat was not the smallest species used. Monte Carlo simulations were further performed to examine the species or weight dependence. The cost-effective combinations of animal species, in terms of number and species type, were theoretically examined through simulations. Finally, literature data demonstrated the species or weight dependence predicted from the equation and as illustrated through the Monte Carlo simulations. Appreciation of this species or weight dependence should guide researchers in selecting animal species and designing optimal experiments in the application of allometric scaling. 相似文献
53.
Toddlers who ingest the drug of abuse 3,4-methylenedioxymethamphetamine (MDMA; 'Ecstasy') are at particularly high risk of serious neurological and cardiovascular side effects. We report of a 20-month-old male toddler who accidentally ingested Ecstasy. He presented with fever and seizures, tachycardia, hypertension, and hyperthermia. Urine amphetamine level was 2111 ng/mL. Treatment included rapid cooling, hydration, and support measures. Vital signs were regularly monitored. His condition became stable on day 2 and urine amphetamine level returned to normal on day 3 of hospitalization. His behavior, activity, and appetite had returned to their usual levels upon follow-up at our outpatient clinic. The incidence of drug abuse with MDMA has increased dramatically over the last decade in developed countries. It can be expected that accidental Ecstasy poisoning in children will increase as well. This case illustrates the need to consider the possibility of accidental Ecstasy ingestion in the differential diagnosis of a child suffering from convulsions with fever. 相似文献
54.
55.
56.
N J Chao 《Current opinion in immunology》1992,4(5):571-576
Graft versus host disease is a major barrier in allogeneic bone marrow transplantation. The associated morbidity and mortality need to be understood and prevented if possible, as the potential indications for bone marrow transplantation continue to broaden. Areas of investigation include the cellular effector arm as well as the cytokines associated with the expression of the disease. 相似文献
57.
Rongnong Zhou Ligong Tang Kurt E. Geckeler Wolfgang Gpel 《Macromolecular chemistry and physics.》1994,195(7):2409-2421
Polystyrene-bound metal [2,9 or 2,10 (or 2,16 or 2,17) bis(3,4-dicarboxybenzoyl)]phthalocyaninates were synthesized by Friedel-Crafts reaction of polystyrene with the corresponding metal phthalocyaninates. Co(II) and Cu(II) [2,9 or 2,10 (or 2,16 or 2,17) bis(3,4-dicarboxybenzoyl)]-phthalocyaninate (PS-CodaPc and PS-CudaPc) contained 0,13 mmol · g?1 (12,4 wt.-%) and 0,13 mmol · g?1 (12,8 wt.-%) of CodaPc and CudaPc, respectively. They were soluble in N,N'-dimethylformamide, but only partially soluble in chloroform, tetrahydrofuran (THF), dimethyl sulfoxide, N-methyl-2-pyrrolidone, and pyridine. The THF extracts contained 0,12 mmol · g?1 (11,4 wt.-%) and 0,18 mmol ? g?1 (17,2 wt.-%) of PS-CodaPc and PS-CudaPc, respectively. The thermal stability of the polymers was studied using thermogravimetric and differential thermal analysis in nitrogen and synthetic air atmosphere. The contents of MdaPc(M: metal) in THF-extracted polymers calculated from the data of residue in thermogravimetric analysis are 0,12 mmol · g?1 for PS-CodaPc and 0,19 mmol · g?1 for PS-CudaPc. In addition, the sensitive properties of the polymers towards toxic gases were also investigated by quartz microbalance transducers. The results show that the quartz microbalance sensors coated with both polymers were sensitive to NO2 and chlorinated hydrocarbons, i.e. chloroform and perchloroethylene. The sensitivity to NO2 was 6,53 · 10?7 m3 · mL?1 · s?1 for PS-CodaPc and 1,90 · 10?6 m3 · mL?1 · s?1 for PS-CudaPc, and that to chloroform and perchloroethylene was 2,33 · 10?8 and 4,60 · 10?8 m3 · mL?1 · s?1, respectively, for PS-CodaPc and 4,79 · 10?8 and 9,51 · 10?7 m3 · mL?1 · s?1 for PS-CudaPc. 相似文献
58.
本文采用1:3病例对照研究方法,对甾体避孕药的使用与血栓栓塞性疾病(急性心肌梗塞、脑栓塞、脑血栓形成和深静脉血栓形成)间的关联进行多因素分析。结果提示在我国广泛应用的甾体避孕药(主要为国产Ⅰ号避孕药)并不增加血栓栓塞性疾病的危险性。用药和停药时间的长短与血栓栓塞性疾病的发生无关,并与高血压病之间亦不存在协同作用。 相似文献
59.
穿透性角膜移植术后角膜内皮细胞之命运 总被引:1,自引:0,他引:1
地2组猴行5。5→5.0mm穿透性角膜移植术,异种组4只,同种组4只,术前用冷冻创伤^3H-TdR标记法标记受生角膜内皮细胞,术后14周摘除眼球,用放射自显影法显示银颗粒的分布。 相似文献
60.
Monitoring the protective effects of minocycline treatment with radiolabeled annexin V in an experimental model of focal cerebral ischemia. 总被引:3,自引:0,他引:3
Xian Nan Tang Qing Wang Maya A Koike Danye Cheng Michael L Goris Francis G Blankenberg Midori A Yenari 《Journal of nuclear medicine》2007,48(11):1822-1828
Minocycline is an antibiotic now recognized to have antiapoptotic and antiinflammatory properties. Because of these properties, minocycline may be of benefit in reducing neuronal apoptosis from ischemia and subsequent postischemic inflammation if administered soon after a stroke. We now explore the feasibility of using (99m)Tc-annexin V, an in vivo marker of apoptosis, with SPECT to monitor the antiapoptotic effects of minocycline therapy. METHODS: CB6/F1 adult male mice underwent unilateral distal middle cerebral artery occlusion (dMCA) occlusion and were imaged and sacrificed at 1, 3, 7, or 30 d after injury. Animals were given minocycline (or vehicle) 30 min and 12 h after dMCA occlusion and then given 22.5 mg/kg twice daily for up to 7 d. Before imaging, behavioral tests were performed to evaluate the neurologic function. After imaging, brains were collected for histology and assessed for the degree of apoptosis and microglial activation. RESULTS: (99m)Tc-Annexin V uptake in injured hemispheres was significantly decreased 2- to 3-fold by minocycline at all time points. Minocyline reduced infarct size as seen histologically and improved behavioral indices as late as 30 d. Infarct volume as seen histologically correlated with radiolabeled annexin V uptake seen by SPECT. In situ fluorescent microscopy demonstrated that annexin V bound primarily to neurons at 1 and 3 d, with a shift toward microglia by 7 and 30 d. CONCLUSION: We found that minocycline significantly reduces neuronal apoptosis and infarct size and improves neurologic outcome in mice after acute focal cortical ischemia. 相似文献