全文获取类型
收费全文 | 4454篇 |
免费 | 314篇 |
国内免费 | 74篇 |
专业分类
耳鼻咽喉 | 57篇 |
儿科学 | 169篇 |
妇产科学 | 14篇 |
基础医学 | 510篇 |
口腔科学 | 42篇 |
临床医学 | 916篇 |
内科学 | 470篇 |
皮肤病学 | 168篇 |
神经病学 | 9篇 |
特种医学 | 73篇 |
外科学 | 275篇 |
综合类 | 609篇 |
预防医学 | 740篇 |
眼科学 | 48篇 |
药学 | 573篇 |
中国医学 | 113篇 |
肿瘤学 | 56篇 |
出版年
2023年 | 49篇 |
2022年 | 101篇 |
2021年 | 137篇 |
2020年 | 141篇 |
2019年 | 81篇 |
2018年 | 110篇 |
2017年 | 99篇 |
2016年 | 127篇 |
2015年 | 153篇 |
2014年 | 230篇 |
2013年 | 402篇 |
2012年 | 341篇 |
2011年 | 355篇 |
2010年 | 252篇 |
2009年 | 251篇 |
2008年 | 273篇 |
2007年 | 230篇 |
2006年 | 233篇 |
2005年 | 211篇 |
2004年 | 156篇 |
2003年 | 142篇 |
2002年 | 120篇 |
2001年 | 106篇 |
2000年 | 92篇 |
1999年 | 70篇 |
1998年 | 52篇 |
1997年 | 51篇 |
1996年 | 28篇 |
1995年 | 22篇 |
1994年 | 28篇 |
1993年 | 21篇 |
1992年 | 26篇 |
1991年 | 16篇 |
1990年 | 21篇 |
1989年 | 15篇 |
1988年 | 15篇 |
1987年 | 13篇 |
1986年 | 7篇 |
1985年 | 23篇 |
1984年 | 10篇 |
1983年 | 3篇 |
1982年 | 10篇 |
1981年 | 1篇 |
1980年 | 7篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有4842条查询结果,搜索用时 15 毫秒
991.
我们成功地建立了一个新的层析等电点聚焦的三步程序.细菌培养液首先以CG-50吸附,洗脱出的粗毒素溶液在PBE_(94)柱上进行层析等电点聚焦.分别用5mMTris-Base pH9.4和Buffalyte_(8-4) pH5.4缓冲液洗脱,出现多个洗脱峰,即刻测定pH值.收集pH6.8~7.1的洗脱液,混合、浓缩,最后通过Sephacryl s-200过滤,以0.05M PBS pH6.8洗脱,出现3个峰,毒素在第1峰.毒素纯度为98%,回收率89%,p17.6,MW28500,SDS-PAGE上1条带.以~(125)I标记SED作探针的电泳转移和放射自显影均证明了提纯SED的免疫学特异性.免疫扩散试验,即使200μg/ml SED与不产毒素的FRI-184抗血清,也未有可见沉淀线. 相似文献
992.
应用聚合酶链反应检测临床分离的产TSST—1金黄色葡萄球菌 总被引:3,自引:0,他引:3
中毒休克综合征(TSS)是由产毒素金黄色葡萄球菌引起的累及多器官系统的严重临床综合征。中毒休克综合征毒素1(TSST-1)在TSS发病中起重要作用。本研究应用聚合酶链反应技术,对产毒素金黄色葡萄球菌染色体编码TSST-1的tst基因进行体外扩增,建立了快速、特异、灵敏的检测产TSST-1金葡菌的方法。本研究还对天津市1986 ̄1995年10年间临床分离的金葡菌进行了tst基因检测,在112株受检菌 相似文献
993.
Histamine release from human basophil leukocytes from allergic patients or controls was induced by specific antigens, anti-IgE or calcium ionophore A23187. Influenza A virus, S. aureus and lipopolysaccharide from S. typhimurium increased the maximum release of histamine and caused a shift to the left of the dose-response curves showing increased cell sensitivity and lowering of the threshold to these stimuli. The mechanism of action was elucidated by examining the mediator release as a function of increasing extracellular concentration of calcium. In these experiments the dose-response curves were changed by the microorganisms and lipopolysaccharide as before. This indicates that the microorganisms and lipopolysaccharide change the basophil cell response to IgE-dependent and non-immunological stimuli by causing a change in the subcellular handling of calcium. 相似文献
994.
房室瓣手术和金葡菌菌血症后心室组织细胞黏附分子和炎症因子的基因表达 总被引:2,自引:0,他引:2
目的初步观察房室瓣手术和金黄色葡萄球菌菌血症对左、右心室组织细胞黏附分子和炎症因子基因表达的影响,探讨感染性心内膜炎的发病机制。方法26只家兔分别行二尖瓣、三尖瓣手术和经静脉注射金葡菌,术后早期分别提取左、右心室组织RNA,RT—PCR技术检测内皮白细胞黏附分子(ELAM—1),巨噬细胞集落刺激因子(MCSF—1)和血小板内皮细胞黏附分子(PECAM-1)基因表达水平,并与健康对照组比较。结果二尖瓣和三尖瓣手术后,左、右心室组织的ELAM—1和MCSF—1 mRNA表达水平均明显增高,左室ELAM—1 mRNA表达水平高于右室;PECAM—1 mRNA表达水平无明显变化。菌血症组仅左心室ELAM-1 mRNA表达水平明显增高。结论感染性心内膜炎的发病中左、右心室组织的细胞黏附分子和炎症因子存在着不同的变化特点。 相似文献
995.
ABSTRACT. Forty-five cases of neonatal subcutaneous gangrene were admitted between Nov. 1985 and Feb. 1987, with a mortality of 6.6%. This paper presents the first epidemiologic study of 20 cases of this disease caused by multi-resistant Staphylococcus aureus. Eight of 20 cases were caused by an epidemic strain belonging to phage 29 (group I) and carrying 2.8, 3.3, 4.2 and 28.5–34.0 kb plasmid DNA. The restriction endonudease analysis confirmed that the plas-mid DNA of approximately similar size in different isolates were identical or highly homologous. According to the results of an epidemiologic study the source of infection of one patient who died was her grandmother and the other one was her mother, so the family members can also be the source of neonatal infection caused by multi-resistant S. aureus. 相似文献
996.
bcl-2、p16、nm23基因在金黄色葡萄球菌L型感染小鼠肿瘤中的表达 总被引:4,自引:1,他引:3
目的 探讨bcl- 2凋亡抑制基因、p16抑癌基因和nm2 3 转移抑制基因在金黄色葡萄球菌 (金葡菌 )L型感染C57小鼠致瘤中的表达及意义。方法 动物实验观察金葡菌L型感染C57小鼠后肿瘤的发生情况 ;免疫组化及核酸原位杂交检测小鼠肿瘤和癌前病变中bcl- 2、p16、nm2 3 基因的表达。结果 金葡菌L型感染后 10只小鼠发生肿瘤 ,13只出现癌前病变。小鼠肿瘤中bcl- 2、p16、nm2 3 蛋白表达阳性率分别为 6 0 0 %、30 0 %和 2 0 0 % ;癌前病变中分别为 30 8%、5 3 1%和 6 1 1%。小鼠肿瘤中bcl- 2、p16、nm2 3 mRNA表达阳性率分别为 6 0 0 %、2 0 0 %和 2 0 0 % ;癌前病变中分别为 2 3 1%、5 3 1%和 6 1 1%。其蛋白和mRNA表达具一致性 ,且与正常对照有显著性差异。结论 金葡菌L型感染可能引起bcl- 2、p16、nm2 3 基因的异常表达 ,进而导致体细胞的恶性转化 ,故金葡菌L型感染在小鼠肿瘤发生中起重要作用 相似文献
997.
Michael S. Marriott 《Clinical microbiology and infection》1998,4(S1):S9-S14
Grepafloxacin is a new broad-spectrum fluoroquinolone characterized by having a methyl-substituted piperazine at the 7 position. It is a water-soluble racemate with both stereoisomers having the same activity. Its mode of action involves inhibition of topoisomerases II and IV. Grepafloxacin is not recognized by the NorA efflux mechanism in Staphylococcus aureus and, thus, some strains of Staphylococcus aureus that are resistant to other fluoroquinolones remain susceptible to grepafloxacin.
Grepafloxacin has potent in vitro activity against streptococci and staphylococci, respiratory Gram-negative pathogens, atypical respiratory pathogens and sexually transmitted disease pathogens. It combines the positive properties of the β-lactams against conventional Gram-positive and Gram-negative respiratory pathogens with the activity of the macrolides against the atypical pathogens. Unlike macrolides, it is bactericidal at concentrations close to the MIC. Its in vitro activity has been reflected in animal models of respiratory tract infections. Concentrations above MICs are maintained throughout nearly all of the 24-h dosing interval. Grepafloxacin provides important improvements over older quinolones and over other classes of antibiotics. 相似文献
Grepafloxacin has potent in vitro activity against streptococci and staphylococci, respiratory Gram-negative pathogens, atypical respiratory pathogens and sexually transmitted disease pathogens. It combines the positive properties of the β-lactams against conventional Gram-positive and Gram-negative respiratory pathogens with the activity of the macrolides against the atypical pathogens. Unlike macrolides, it is bactericidal at concentrations close to the MIC. Its in vitro activity has been reflected in animal models of respiratory tract infections. Concentrations above MICs are maintained throughout nearly all of the 24-h dosing interval. Grepafloxacin provides important improvements over older quinolones and over other classes of antibiotics. 相似文献
998.
999.
K. McCLELLAN fraco fracs D. J. COSTER fraco fracs P. R. BADENOCH BSc R. SANDERS fracog E. CHANDRARATNAM frcpa A. KUPA fracp 《Clinical & experimental ophthalmology》1987,15(1):19-23
We describe a case of bacterial endophthalmitis complicating routine cataract extraction and intraocular lens implantation in a 97-year-old woman. The ocular and systemic factors that may have predisposed to intraocular infection in this case, and the possibility of predicting these pre-operatively, are discussed. 相似文献
1000.
Professor G.A.J. Ayliffe Chairman Ms A Buckles M.W. Casewell Professor B.D. Cookson Dr R.A. Cox Dr G.J. Duckworth Dr Honorary Secretary G.L. French Professor Ms A. Griffiths-Jones R. Heathcock Dr H. Humphreys Dr C.T. Keane Professor R.R. Marples Dr D.C. Shanson Dr R. Slack Dr E. Tebbs Dr observer 《The Journal of hospital infection》1998,39(4):253-290