全文获取类型
收费全文 | 49876篇 |
免费 | 3797篇 |
国内免费 | 1447篇 |
专业分类
耳鼻咽喉 | 201篇 |
儿科学 | 972篇 |
妇产科学 | 1033篇 |
基础医学 | 4824篇 |
口腔科学 | 953篇 |
临床医学 | 5790篇 |
内科学 | 10542篇 |
皮肤病学 | 330篇 |
神经病学 | 806篇 |
特种医学 | 615篇 |
外国民族医学 | 11篇 |
外科学 | 2249篇 |
综合类 | 7424篇 |
现状与发展 | 9篇 |
预防医学 | 6566篇 |
眼科学 | 185篇 |
药学 | 6717篇 |
15篇 | |
中国医学 | 1547篇 |
肿瘤学 | 4331篇 |
出版年
2024年 | 139篇 |
2023年 | 703篇 |
2022年 | 1782篇 |
2021年 | 2171篇 |
2020年 | 1690篇 |
2019年 | 1644篇 |
2018年 | 1667篇 |
2017年 | 1576篇 |
2016年 | 1884篇 |
2015年 | 2103篇 |
2014年 | 3336篇 |
2013年 | 4055篇 |
2012年 | 3468篇 |
2011年 | 3688篇 |
2010年 | 2824篇 |
2009年 | 2586篇 |
2008年 | 2740篇 |
2007年 | 2696篇 |
2006年 | 2310篇 |
2005年 | 1983篇 |
2004年 | 1658篇 |
2003年 | 1257篇 |
2002年 | 1013篇 |
2001年 | 911篇 |
2000年 | 716篇 |
1999年 | 622篇 |
1998年 | 500篇 |
1997年 | 470篇 |
1996年 | 401篇 |
1995年 | 329篇 |
1994年 | 305篇 |
1993年 | 234篇 |
1992年 | 222篇 |
1991年 | 186篇 |
1990年 | 137篇 |
1989年 | 136篇 |
1988年 | 98篇 |
1987年 | 108篇 |
1986年 | 71篇 |
1985年 | 124篇 |
1984年 | 78篇 |
1983年 | 48篇 |
1982年 | 79篇 |
1981年 | 62篇 |
1980年 | 54篇 |
1979年 | 41篇 |
1978年 | 31篇 |
1977年 | 42篇 |
1976年 | 38篇 |
1975年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
医院感染常见细菌分布与耐药性分析 总被引:6,自引:0,他引:6
目的了解细菌分布及常见细菌的耐药性。方法回顾性分析某院2000—2004年临床标本分离的细菌及其耐药性监测结果。结果1439株细菌中,革兰阳性菌456株(31.69%),以凝固酶阴性表皮葡萄球菌为多,达206株(45.18%),其次为金黄色葡萄球菌92株(20.18%);两种葡萄球菌的耐药率相似,对万古霉素耐药率均为0。革兰阴性菌983株,前5位依次为肠杆菌属346株(35.20%),克雷伯菌属164株(16,68%),铜绿假单胞菌155株(15.77%),埃希菌属101株(10.27%),变形杆菌属94株(9.56%);前5位革兰阴性菌对常用抗菌药物的耐药性以半合成青霉索较明显,铜绿假单胞菌的耐药性较突出。结论应高度重视细菌变迁和耐药性监测,提高抗菌药物合理应用水平。 相似文献
72.
73.
随着医药工业的发展,新药层出不穷。以抗生素为例,20世纪50年代临床用的抗生素只有青、链、红、氯四大素,现在常用临床的抗生素以有100多种,临床医生长期来忙与医疗任务,如何掌握新药信息,做到合理选药,合理用药,使药物的药理作用转化为治疗效应,已成为临床医生日益关心的问题。1抗生素在临床应用中存在问题1.1常规固定方案长期以来根据以往的经验或资料,正式或非正式采用抗生素治疗方案。如:氨苄西林+庆大霉素、青霉素+庆大霉素、红霉素+氯霉素。由于对致病菌针对性不强,以致延误治疗。1.2抗生素在选择中存在问题随着医药工业的发展,抗生素… 相似文献
74.
Wilke , W. Lee & Person , A. E. G. 1992. Captopril and time dependent changes in post- to pre-glomerular resistance ratios in remnant kidneys of pre-hypertensive rats. Acta Physiol Scand 144 , 253–261. Received 26 June 1991, accepted 8 October 1991. ISSN 0001–6772. Department of Physiology, Colorado State University, Fort Collins, Colorado, USA and Department of Physiology and Biophysics, University of Lund, Sweden. Micropuncture experiments were performed on intact and remnant kidneys of male Sprague-Dawley rats before and after angiotensin converting enzyme inhibition with captopril (0.5 mg kg-1 iv). Partially nephrectomized rats were studied at 2 and 8 weeks post-surgery before the development of systemic hypertension. At 2 weeks, nephrectomized rats had a numerically higher tubular stop-flow pressure than controls (43 ± 2 mmHg vs. 38 ± 2 mmHg; P = 0.08) and a higher post- to pre-glomerular resistance ratio (Re/Ra) (0.40 ± 0.03 vs. 0.31± 0.03; P = 0.08). At 8 weeks, stop-flow pressure and post- to pre-glomerular resistance ratios were similar in remnant and intact kidneys. Captopril had no effect on stop-flow pressure in 2 week post-surgery nephrectomized rats or either control group, but it increased stop-flow pressure in 8 week post-surgery nephrectomized rats (40 ± 2 to 44 ± 2 mmHg, P= 0.04). This increase in stop-flow pressure was associated with an increase in the post- to pre-glomerular resistance ratio (0.33 ± 0.02–0.42 ±0.02, P = 0.009). Stop-flow pressure was positively correlated with the post- to pre-glomerular resistance ratio in 2-week post-surgery nephrectomized rats and their respective controls when combined (r = 0.89, P= 0.0001) and 8-week post-surgery nephrectomized rats and their respective controls combined (r= 0.78, P = 0.0001). Stop-flow pressure was not significantly correlated with mean arterial pressures or welling-point pressures in these groups. We conclude that stop-flow pressure in remnant kidneys of pre-hypertensive rats is primarily determined by the post- to pre-glomerular resistance ratio, and increases in stop-flow pressure and post- to pre-glomerular resistance ratios in remnant kidneys are transient in the absence of systemic hypertension. The role of the renin-angiotensin system in determining the ratio and stop-flow pressure is dependent on time post-nephrectomy. Captopril-induced increases in stop-flow pressure and post- to pre-glomerular resistance ratio at 8 weeks, suggests that its primary effect at that time is not a preferential post-gIomerular vasodilation subsequent to reductions in intrarenal angiotensin II. 相似文献
75.
老年患者尿路感染菌群分布及其耐药性分析 总被引:3,自引:0,他引:3
目的 :了解老年患者尿路感染致病菌的菌群分布及其对抗生素的耐药情况 ,为临床合理使用抗生素提供依据。方法 :收集湖北省 15所三级甲等医院 2 0 0 2年尿路感染老年患者清洁中段尿细菌培养分离的 5 34株致病菌 ,对其进行耐药性监测。药敏采用K B法 ,用WHONET 5软件进行数据分析。结果 :共收集致病菌 5 34株 ,其中革兰阴性菌 4 0 9株 (76 .6 % ) ,革兰阳性菌 12 5株(2 3.4 % )。革兰阴性菌中大肠埃希菌检出率最高 (2 6 4株 ,4 9.4 % ) ,其次为克雷白杆菌 (44株 ,8.2 % )。 16 .7%的大肠埃希菌和 2 2 .7%的克雷白杆菌产超广谱 β 内酰胺酶。亚胺培南、阿米卡星、头孢他啶对革兰阴性菌的抗菌活性最强 ,而革兰阴性菌对环丙沙星、庆大霉素、哌拉西林的耐药率均在 5 0 %以上。革兰阳性菌以肠球菌最多见 (6 4株 ,12 % ) ,其次为葡萄球菌属 (43株 ,8.1% )。革兰阳性菌对SMZco、红霉素等的耐药率均在 4 0 %以上 ,但对万古霉素均敏感。结论 :老年患者尿路感染以革兰阴性菌为优势菌株 ,且耐药性日益严重 ,对亚胺培南、阿米卡星、头孢他啶最为敏感。革兰阳性菌宜以万古霉素为首选。 相似文献
76.
P. A. da Silva M. M. S. Boffo I. G. de Mattos A. B. S. Silva J. C. Palomino A. Martin H. E. Takiff 《Clinical microbiology and infection》2006,12(3):293-296
Rapid, accurate and inexpensive methods are essential to detect drug-resistant Mycobacterium tuberculosis and allow timely application of effective treatment and precautions to prevent transmission. The proportion method, the MTT and Alamar Blue redox methods, and the D29 mycobacteriophage assay, were compared for their ability to detect resistance to isoniazid and rifampicin. When tested against a panel of known M. tuberculosis strains, the redox methods and the D29 assay showed good sensitivity and specificity compared to the proportion method, suggesting that they could be useful alternatives for identifying multidrug resistance in M. tuberculosis. 相似文献
77.
PCR-SSCP法检测结核分枝杆菌耐药性 总被引:10,自引:0,他引:10
目的:探讨耐多药结核分枝杆菌耐药基因突变与耐药性的关系以及聚合酶链反应-单链构象多态性分析(poly merase chain reaction-single strand cinfomlation polymorphism,PCR-SSCP)方法的临床应用价值。方法:用PCR-SSCP方法检测58株结核分枝杆菌临床分离株katG,rpoB,rpsL基因突变并与常规药敏试验检测结果进行对比。结果:经常规药敏试验检测,58株结核分枝杆菌临床分离株中共有41株耐药,其中,耐异烟肼(INH)为35株,高耐药株27株;耐利福平(RFP)为31株,高耐药株24株;耐链霉素(SM)有31株,高耐药株26株。同时耐3种药物的有21株(51.2%),耐2种药物的14株(34.1%),单耐药株6株(14.6%).PCR-SSCP方法对58株临床分离株katG,rpoB,rpsL基因突变的检测率为40%(23/58),45%(26/58),38%(22/58),其中检出3个基因同时突变的有13株(32%),2种基因突变的12株(29%),1种基因突变的有10株(23.8%).常规药敏试验与PCR-SSCP法检出结核分枝杆菌同时耐3种药物的符合率为61.9%(13/21),检出耐2种药物的符合率为85.70k,(12/14),检出耐1种药物的符合率为50%(3/6).高耐药株中突变率为80.5%(62/77),低耐药株中突变率为60%(12/20).结论:PCR-SS-CP方法对耐2种以上药物的结核杆菌检出率较高,且耐药基因突变率随着耐药浓度增高而增高。将PCR-SSCP法与药敏试验联合应用可互相弥补,已成为临床指导用药的好方法。 相似文献
78.
Tuberculosis remained a very significant cause of death in Ireland until the mid-20th century and still occupies a prominent position in the folk memory. As I show with reference to recent Irish media coverage, the global resurgence of tuberculosis is therefore viewed with concern in Ireland. Using data collated by the Health Protection Surveillance Centre between 1998 and 2005 however, I show that the recent increase in tuberculosis incidence in Ireland is less than is popularly perceived. This increase is largely associated with economic immigrants attracted to Ireland by the ‘Celtic Tiger’ economic boom, but there is little evidence to suggest that this has had a negative impact on the Irish-born population. Drug resistance is still a small but growing problem. Whilst vigilance is required, it is argued that the recent increase does not at present indicate a likely return to the situation in the mid-20th century. 相似文献
79.
由聚酯二元醇、异佛尔酮二异氰酸酯和二羟甲基丙酸合成聚氨酯预聚体,以氨乙基氨丙基聚二甲基硅氧(AEAPS)为扩链剂,制备了AEAPS改性聚氨酯水分散液。与未改性的聚氨酯水分散液相比,AEAPS改性聚氨酯水分散液的粒径增大,但粒径分布和表面张力基本不变,说明疏水的聚二甲基硅氧烷侧链被包裹于分散颗粒的内部;此外,改性聚氨酯水分散液的冻融稳定性显著增强。AEAPS改性聚氨酯水分散液成膜后,吸水率明显下降,水在膜表面的接触角增加,400℃时热失重下降,具有良好的疏水性和耐热性。 相似文献
80.
穹窿体是真核细胞中的核糖核蛋白颗粒,由肺耐药蛋白、穹窿体多聚腺苷二磷酸聚合酶、端粒酶相关蛋白和穹窿体RNA构成,其主要成分为肺耐药蛋白。肺耐药蛋白是介导肿瘤多药耐药的蛋白之一,可能与肿瘤的治疗效果和临床预后相关。穹窿体可能通过介导药物转运或者信号转导引起肿瘤的多药耐药。文章介绍了穹窿体的结构、成分及其介导多药耐药机制研究的新进展。 相似文献