全文获取类型
收费全文 | 11225篇 |
免费 | 1002篇 |
国内免费 | 910篇 |
专业分类
耳鼻咽喉 | 89篇 |
儿科学 | 161篇 |
妇产科学 | 162篇 |
基础医学 | 1345篇 |
口腔科学 | 158篇 |
临床医学 | 1487篇 |
内科学 | 1733篇 |
皮肤病学 | 135篇 |
神经病学 | 604篇 |
特种医学 | 486篇 |
外国民族医学 | 10篇 |
外科学 | 1013篇 |
综合类 | 1741篇 |
现状与发展 | 4篇 |
一般理论 | 1篇 |
预防医学 | 771篇 |
眼科学 | 469篇 |
药学 | 1175篇 |
8篇 | |
中国医学 | 593篇 |
肿瘤学 | 992篇 |
出版年
2024年 | 30篇 |
2023年 | 158篇 |
2022年 | 433篇 |
2021年 | 547篇 |
2020年 | 388篇 |
2019年 | 367篇 |
2018年 | 408篇 |
2017年 | 341篇 |
2016年 | 346篇 |
2015年 | 492篇 |
2014年 | 604篇 |
2013年 | 547篇 |
2012年 | 824篇 |
2011年 | 935篇 |
2010年 | 627篇 |
2009年 | 449篇 |
2008年 | 634篇 |
2007年 | 568篇 |
2006年 | 538篇 |
2005年 | 562篇 |
2004年 | 348篇 |
2003年 | 308篇 |
2002年 | 267篇 |
2001年 | 225篇 |
2000年 | 293篇 |
1999年 | 278篇 |
1998年 | 215篇 |
1997年 | 191篇 |
1996年 | 199篇 |
1995年 | 151篇 |
1994年 | 124篇 |
1993年 | 85篇 |
1992年 | 73篇 |
1991年 | 75篇 |
1990年 | 80篇 |
1989年 | 55篇 |
1988年 | 67篇 |
1987年 | 57篇 |
1986年 | 48篇 |
1985年 | 40篇 |
1984年 | 19篇 |
1983年 | 17篇 |
1982年 | 12篇 |
1981年 | 14篇 |
1980年 | 17篇 |
1977年 | 13篇 |
1976年 | 7篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1973年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
Photic evoked responses were recorded from the striate cortex of Long-Evans hooded intact, monocular visual deprivation (MD) and MD treated with NGF rats. The averaged visual evoked responses (AVER) were obtained from both hemispheres and provided comparison after binocular photic stimuli between the contralateral and the ipsilateral striate cortex with relation to the MD eye. One month of monocular visual deprivation at the critical period of development resulted in marked reduction of the amplitudes of AVER components as compared to the control recordings (P < 0.001). These changes of the AVER could be prevented by NGF infusion to lateral ventricle at the dosage of 2.0–2.4 μg/day for four weeks during the monocular deprivation. In conclusion, the change of AVER amplitudes induced by monocular visual deprivation during the critical period of development can be prevented by NGF infusion to lateral ventricle. 相似文献
52.
吡那地尔对高血压心脏结构和功能重构的影响 总被引:5,自引:0,他引:5
在等降压剂量下吡那地尔和赖诺普利可使4月龄自发性高血压大鼠的血压下降6.0 ̄8.0kPa,并接近同种属正常血压大刀瓣血压水平。 相似文献
53.
目的 分析儿童急性白血病伴侵袭性肺部真菌感染(IPFI)的临床特点、真菌分布及影响因素。方法 回顾性分析2018年1月—2022年12月安徽省儿童医院82例急性白血病患儿的临床资料,按照是否合并IPFI分为IPFI组(18例)和非IPFI组(64例)。比较两组患儿的一般临床资料;采用多因素一般Logistic回归模型分析儿童急性白血病伴IPFI的危险因素;分析IPFI组患儿的临床特征、真菌菌种分布。结果 18例IPFI患儿均有不同程度的发热,体温>38.5℃占比72.22%,咳嗽咳痰/白色黏痰占比83.33%;18例IPFI患儿中5例表现为结节实变影,7例表现为多发斑片状阴影,8例表现为散在斑片状阴影合并小结节,2例表现多发云雾状毛玻璃样高密度影、间质病变为主。16例获得真菌微生物学证据,血培养2例,肺泡灌洗液涂片1例,血或者肺泡灌洗液NGS检测13例,其中以毛霉菌(31.25%)、曲霉菌(25.00%)、近平滑假丝酵母菌(18.75%)为主;多因素一般Logistic回归分析结果显示,化疗方案含激素■、中性粒细胞缺乏时间≥10 d[■]、抗菌药物使用种类≥2种■均是儿童急性白血... 相似文献
54.
55.
胸腰脊神经根鞘形态观测及其临床意义 总被引:9,自引:1,他引:9
目的:为了探讨腰腿疼痛等疾病与脊神经根鞘的关系。方法:用巨视解剖和游标卡尺测量法对15具尸体的胸腰脊神经根鞘进行了解剖学观察与测量。结果:①左、右胸腰脊神经根鞘长度和横径基本对称;②T1根鞘长度和横径大于其它胸神经根鞘,接近L2水平,L3~L5根鞘长度和横径大于其它胸腰神经根鞘,尤其L5更为突出;③胸腰脊神经根鞘开口式,由上向下,由2~3孔逐渐减至1孔。结论:①T1、L2~L5脊神经根鞘既长又粗,与周围接触范围大,受损危险增大;②根鞘开口式孔数由上向下减少,发生在鞘内的炎症和肿瘤引起前、后根同时受累的机会增多。 相似文献
56.
Steffen Dietzel Anna Jauch Dirk Kienle Guoquiong Qu Heidi Holtgreve-Grez Roland Eils Christian Munkel Michael Bittner Paul S. Meltzer Jeffrey M. Trent Thomas Cremer 《Chromosome research》1998,6(1):25-33
Fluorescence in situ hybridization (FISH) with microdissection probes from human chromosomes 3 and 6 was applied to visualize arm and subregional band domains in human amniotic fluid cell nuclei. Confocal laser scanning microscopy and quantitative three-dimensional image analysis showed a pronounced variability of p- and q-arm domain arrangements and shapes. Apparent intermingling of neighbouring arm domains was limited to the domain surface. Three-dimensional distance measurements with pter and qter probes supported a high variability of chromosome territory folding. 相似文献
57.
Molecular epidemiology of Vibrio cholerae O139 in China: polymorphism of ribotypes and CTX elements 总被引:5,自引:0,他引:5 下载免费PDF全文
Qu M Xu J Ding Y Wang R Liu P Kan B Qi G Liu Y Gao S 《Journal of clinical microbiology》2003,41(6):2306-2310
Vibrio cholerae O139, the second etiological serogroup of cholera, triggered the first outbreak of O139 cholera in China in 1993. To analyze the clone polymorphism of O139 isolates in China, 117 strains of V. cholerae O139, isolated from different areas in China between 1993 and 1999, were selected to characterize the phylogenetic relationships by molecular techniques. Analysis of restriction fragment length polymorphism in the conserved 16S rRNA gene revealed seven different ribotypes within the 117 strains. Among these strains, there were eight that lacked the cholera toxin gene (ctxAB), zot, and the repetitive sequence (RS); these eight strains belonged to three individual ribotypes. Our results suggested that V. cholerae O139 strains in China had clone diversity in phylogeny. The results of our hybridization patterns for CTX genetic elements (ctxAB, zot, and RS) showed that CTXPhi genomes in most V. cholerae O139 strains had two or more copies and had extensive restriction patterns even for the strains which belong to the same ribotype. For 22 (20.1%) strains, the copies of ctxAB were different from those of zot, suggesting that a ctxAB-negative CTXPhi genome may exist in O139 strains. This ctxAB-negative CTXPhi genome may coexist with the intact CTXPhi genome in a strain. In addition, the dendrogram for I-CeuI-generated pulsed-field gel electrophoresis patterns showed that V. cholerae serogroup O139 has a closer relationship with one strain of serogroup O22 than with the strains of serogroup O1. The results of this study showed the clonal diversity and the distribution of O139 strains in China, suggesting multiple origins of the O139 cholera epidemic or sporadic events. 相似文献
58.
Monosomy for the short arm of chromosome 18 is one of the most frequent autosomal deletions observed. While most cases result from terminal deletion of 18p, 16% of cases reported were as a result of an unbalanced whole arm translocation resulting in monosomy 18p. The origin and structure of these derivative chromosomes were reported in only a few cases. We report the prenatal diagnosis and characterization of a new case of monosomy 18p as a result of an unbalanced whole arm translocation. Amniocentesis was performed at 15 weeks of gestation on a 34-year-old woman initially referred for advanced maternal age. Holoprosencephaly was identified by ultrasound at the time of amniocentesis. Karyotype analysis showed an unbalanced whole arm translocation between the long arm of one chromosome 18 and the long arm of one chromosome 22, 45,XX,der(18;22)(q10;q10), in all metaphases. In effect, the fetus had monosomy for 18p. Parental karyotypes were normal, suggesting a de novo origin for the der(18;22). Fluorescence in situ hybridization (FISH) analysis was performed with alpha-satellite probes D18Z1 and D14Z1/D22Z1 to identify the origin of the centromere on the der(18;22). Signal was observed with both probes, indicating that the centromere was composed of alpha-satellite DNA from both constituent chromosomes. Genotyping of the fetus and her parents with chromosome 18p STS marker D18S391 showed only the paternal 187 bp allele was present in the fetus, indicating that it was the maternal chromosome 18 involved in the der(18;22). This case and previous reports show that de novo unbalanced whole arm translocations are more likely to retain alpha-satellite sequences from the two chromosomes involved. 相似文献
59.
树突状细胞负载肝癌抗原肽疫苗体外诱导特异性免疫学反应的研究 总被引:1,自引:1,他引:1
目的:研究树突状细胞(dendritic cell,DC)负载肝癌抗原肽EPVTKAEML体外诱导特异性CTL的能力及其抑癌效果。方法:用顺序特异引物聚合酶链反应技术(PCR—SSP)选择HLA—B7表型供者,从脾组织中分离、培养DC-EPVTKAEML特异性CTL。用^51Cr释放法检测CTL的杀伤活性,并用抗HLA-1分子单抗(mAb)进行杀伤抑制实验。结果:找到4例HLA-B7杂合子供者,用DC负载HLA-B7限制的抗原肽EPVTKAEML可诱导特异性CTL反应,对肝癌细胞HHCC有较强的杀伤作用。结论:DC负载抗原肽EPVTKAEML在体外可诱发较强的特异性免疫反应。 相似文献
60.
黄皮酰胺促钾通道开放 总被引:1,自引:0,他引:1
一种新发现的具有促智作用的药物——黄皮酰胺能抑制去甲肾上腺素(NE)或KCl引起的血管平滑肌收缩。本研究旨在应用膜片钳(patch clamp)技术探讨黄皮酰胺对Wistar大鼠尾动脉平滑肌细胞膜钾离子通道的作用。单个平滑肌细胞用酶法分离,以细胞封接方式记录离子通道活动。在细胞池内注入2μM黄皮酰胺后,钾离子通道活动明显增强。用本实验室开发的计算机软件(patch clamp analysis system,Version 1.0)计算分析通道活动的特征参数。 相似文献