全文获取类型
收费全文 | 1882篇 |
免费 | 81篇 |
国内免费 | 29篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 150篇 |
妇产科学 | 15篇 |
基础医学 | 162篇 |
口腔科学 | 30篇 |
临床医学 | 122篇 |
内科学 | 394篇 |
皮肤病学 | 32篇 |
神经病学 | 99篇 |
特种医学 | 183篇 |
外科学 | 319篇 |
综合类 | 156篇 |
预防医学 | 86篇 |
眼科学 | 9篇 |
药学 | 136篇 |
1篇 | |
中国医学 | 2篇 |
肿瘤学 | 85篇 |
出版年
2023年 | 9篇 |
2021年 | 26篇 |
2020年 | 13篇 |
2019年 | 29篇 |
2018年 | 34篇 |
2017年 | 21篇 |
2016年 | 28篇 |
2015年 | 22篇 |
2014年 | 46篇 |
2013年 | 50篇 |
2012年 | 82篇 |
2011年 | 96篇 |
2010年 | 80篇 |
2009年 | 70篇 |
2008年 | 89篇 |
2007年 | 89篇 |
2006年 | 110篇 |
2005年 | 52篇 |
2004年 | 70篇 |
2003年 | 60篇 |
2002年 | 48篇 |
2001年 | 57篇 |
2000年 | 73篇 |
1999年 | 58篇 |
1998年 | 61篇 |
1997年 | 40篇 |
1996年 | 42篇 |
1995年 | 36篇 |
1994年 | 29篇 |
1993年 | 25篇 |
1992年 | 22篇 |
1991年 | 21篇 |
1990年 | 21篇 |
1989年 | 39篇 |
1988年 | 29篇 |
1987年 | 30篇 |
1986年 | 30篇 |
1985年 | 30篇 |
1984年 | 13篇 |
1983年 | 24篇 |
1982年 | 29篇 |
1981年 | 18篇 |
1980年 | 19篇 |
1979年 | 11篇 |
1978年 | 14篇 |
1977年 | 15篇 |
1976年 | 18篇 |
1975年 | 9篇 |
1974年 | 8篇 |
1973年 | 7篇 |
排序方式: 共有1992条查询结果,搜索用时 156 毫秒
21.
Vimala J Peter JV Jeyaseelan L Prabhakar S Cherian AM 《The Journal of the Association of Physicians of India》1998,46(11):930-932
Headache following lumbar puncture is a well known and well described complication. Various manoeuvres have been tried to prevent post lumbar puncture headache--the commonest being bed rest for 4 to 24 hours following lumbar puncture, though its value is questionable. Randomised controlled clinical trial was done to evaluate the effect of 24 hours bed rest on the incidence and severity of post lumbar puncture headaches. Two hundred and eight patients were randomly allocated to either the ambulant or the bed rest group. Patients were interviewed by a single investigator on days 0, 1, 2 and 7 about the presence and nature of headache. Other relevant clinical and laboratory data pertaining to the lumbar puncture was collected. The overall incidence of post lumbar puncture headache was 17%; 15% in the ambulant and 18% in the bed rest group. Of the patients who had headaches, severe headache was observed in 57% in the ambulant and 12% in the bed rest group (p = 0.02). Other variables did not alter the outcome of headaches. Bed rest does not appear to alter the incidence of post lumbar puncture headaches, but reduces the severity in those who get headaches, after a lumbar puncture. 相似文献
22.
Berry V; Ionides AC; Moore AT; Plant C; Bhattacharya SS; Shiels A 《Human molecular genetics》1996,5(3):415-419
Inherited cataract is a clinically and genetically heterogeneous disease.
Here we report the identification of a new locus for an autosomal dominant
anterior polar cataract on the short arm of chromosome 17. To map this new
locus we performed genetic linkage analysis with microsatellite markers in
a four-generation pedigree. After exclusion of seven candidate loci for
cataract, we obtained significant positive LOD scores for markers D17S849
(Z = 4.01 / theta = 0.05) and D17S796 (Z = 4.17 / theta = 0.05). Multipoint
analysis gave a maximum LOD score of 5.2 (theta max = 0.06) between these
two markers. From haplotype analysis, the cataract locus lies in the 13 cM
interval between markers D17S849 and D17S796. This study provides the first
genetic mapping of an autosomal dominant anterior polar cataract.
相似文献
23.
24.
25.
26.
PCR-Enzyme Immunoassay for Detection of Streptococcus pneumoniae DNA in Cerebrospinal Fluid Samples from Patients With Culture-Negative Meningitis 总被引:1,自引:0,他引:1 下载免费PDF全文
Thomas Cherian M. K. Lalitha Anand Manoharan Kurien Thomas Robert H. Yolken Mark C. Steinhoff 《Journal of clinical microbiology》1998,36(12):3605-3608
A PCR-based assay was developed to amplify a conserved region of the pneumococcal autolysin gene. The amplified product was labelled with digoxigenin-labelled dUTP and was detected with a biotin-labelled probe in an enzyme immunoassay (EIA). The assay was initially tested with suspensions of various serotypes of Streptococcus pneumoniae and other gram-positive and gram-negative bacteria and was then applied to cerebrospinal fluid (CSF) specimens from patients with meningitis and those with other neurological disorders. The assay detected all the serotypes of S. pneumoniae tested, whereas all the other bacterial strains tested were negative. Seven of the 8 CSF specimens positive for pneumococcus by culture or latex agglutination (LA) were positive by PCR-EIA, whereas all 10 specimens positive for other organisms were negative. Among 11 patients with clinically diagnosed meningitis but with negative culture and LA results, 5 were positive by PCR-EIA. The assay was negative for all but one patient without meningitis; it was positive with the CSF from a child with immunodeficiency and pneumococcal abscesses on the scalp. PCR-EIA is a useful tool for the diagnosis of meningitis, especially when culture and LA are negative because of prior antibiotic treatment. 相似文献
27.
Interaction of endothelin-1 with vasoactive factors in mediating glucose-induced increased permeability in endothelial cells 总被引:5,自引:0,他引:5
Chen S Apostolova MD Cherian MG Chakrabarti S 《Laboratory investigation; a journal of technical methods and pathology》2000,80(8):1311-1321
Alteration of endothelins (ET) and/or their receptors may be important in mediating vascular dysfunction in diabetes. We investigated mechanisms regulating ET-1 expression in human umbilical vein endothelial cells (HUVEC) in response to glucose and the functional significance of these mechanisms. Permeability across HUVEC, grown in medium containing either low (5 mmol/l) or high (25 mmol/l) D-glucose were investigated. L-glucose was used as a control. ET-1, ET(A), and ET(B) mRNA were assessed by semiquantitative RT-PCR. ET-1 immunoreactivity and F-actin microfilament assembly were investigated using confocal microscopy. Increased transendothelial permeability was noted in cells cultured in high glucose or when the cells grown in low (physiologic) glucose were incubated with ET-1, vascular endothelial growth factor (VEGF), or N (G) -nitro-L-arginine methyl ester but not when they were incubated with ET-3, N(G)-nitro-D-arginine methyl ester, or L-glucose. Increased permeability was associated with increased ET-1, ET(A), and ET(B) mRNA expression and augmented ET-1 immunoreactivity. High glucose induced increased permeability, increased ET-1, ET(A), and ET(B) mRNA expression. ET-1 immunoreactivity was blocked by the protein kinase C (PKC) inhibitor chelerythrine, the specific PKC isoform inhibitor 379196, VEGF-neutralizing antibody, or the ET(A) blocker TBC11251, but was not blocked by the specific ET(B) blocker BQ788 or by a VEGF-non-neutralizing antibody. Increased permeability was also associated with deranged F-actin assembly in the endothelial cells and by derangement of endothelial cell junctions as assessed by electron microscopy. Data from this study suggest that high glucose-induced increased permeability may be induced through increased ET-1 expression and disorganization of F-actin assembly. ET-1 expression and increased permeability may occur secondary to PKC isoform activation and may be modulated by VEGF and nitric oxide. 相似文献
28.
29.
0 引言 人类免疫缺陷病毒 (human immunodeficiencyvirus,HIV) - 1编码的反式激活蛋白 TAT具有独特的跨膜运转方式 ,而且有转导速度快 ,效率高的特点 ,被称为蛋白转导结构域 (protein transduction domain,PTD) [1 ,2 ] .本研究用PCR扩增了慢性粒细胞白血病慢粒 bcr/ abl融合蛋白的基因片段 ,在其 5′端融合 PTD结构域的编码区后在大肠杆菌中进行了表达 .表达产物经纯化后 ,加入培养的 HL 6 0细胞 ,表达的蛋白可直接进入细胞内 .这一结果为用外源蛋白负载(L oading)免疫细胞提供了新的途径 .1 材料和方法1.1 DNA重组 人工合… 相似文献
30.
Jebaraj R Cherian T Raghupathy P Brahmadathan KN Lalitha MK Thomas K Steinhoff MC 《Epidemiology and infection》1999,123(3):383-388
To investigate the dynamics of nasopharyngeal colonization with Streptococcus pneumoniae, and to determine the prevalent serogroups/types (SGT) and their antimicrobial susceptibility, we studied 100 infants attending our well-baby clinic. Nasopharyngeal swab specimens were obtained at 6, 10, 14, 18 and 22 weeks and at 9 and 18 months of age and submitted for culture, serotyping and antimicrobial susceptibility testing of S. pneumoniae. Colonization with pneumococcus was seen on at least one occasion in 81 infants. The median age of acquisition was 11 weeks and the median duration of carriage was 1 3 months. The common SGTs identified were 6, 19, 14 and 15. SGT 1, which was a common invasive isolate in children in our hospital during this period, was not isolated from these children. Sequential colonization by 2, 3 or 4 SGTs was observed in 18, 5 and 2 children, respectively. Resistance to penicillin, chloramphenicol, cotrimoxazole and erythromycin was observed in 0, 13 (6%) 11 (5 %) and 5 (3 %) isolates, respectively. There was a significant difference in susceptibility to cotrimoxazole between colonizing and invasive isolates (5 % vs. 40 %, P<0.0001). 相似文献