全文获取类型
收费全文 | 4330篇 |
免费 | 328篇 |
国内免费 | 108篇 |
专业分类
耳鼻咽喉 | 143篇 |
儿科学 | 62篇 |
妇产科学 | 25篇 |
基础医学 | 458篇 |
口腔科学 | 139篇 |
临床医学 | 433篇 |
内科学 | 804篇 |
皮肤病学 | 115篇 |
神经病学 | 623篇 |
特种医学 | 111篇 |
外科学 | 731篇 |
综合类 | 440篇 |
预防医学 | 186篇 |
眼科学 | 79篇 |
药学 | 240篇 |
3篇 | |
中国医学 | 66篇 |
肿瘤学 | 108篇 |
出版年
2024年 | 8篇 |
2023年 | 78篇 |
2022年 | 150篇 |
2021年 | 189篇 |
2020年 | 142篇 |
2019年 | 130篇 |
2018年 | 142篇 |
2017年 | 134篇 |
2016年 | 152篇 |
2015年 | 198篇 |
2014年 | 286篇 |
2013年 | 292篇 |
2012年 | 236篇 |
2011年 | 262篇 |
2010年 | 194篇 |
2009年 | 236篇 |
2008年 | 219篇 |
2007年 | 203篇 |
2006年 | 190篇 |
2005年 | 163篇 |
2004年 | 110篇 |
2003年 | 141篇 |
2002年 | 103篇 |
2001年 | 83篇 |
2000年 | 62篇 |
1999年 | 88篇 |
1998年 | 58篇 |
1997年 | 58篇 |
1996年 | 45篇 |
1995年 | 50篇 |
1994年 | 23篇 |
1993年 | 40篇 |
1992年 | 31篇 |
1991年 | 31篇 |
1990年 | 26篇 |
1989年 | 24篇 |
1988年 | 21篇 |
1987年 | 19篇 |
1986年 | 15篇 |
1985年 | 30篇 |
1984年 | 27篇 |
1983年 | 13篇 |
1982年 | 13篇 |
1981年 | 8篇 |
1980年 | 15篇 |
1979年 | 10篇 |
1978年 | 7篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1973年 | 3篇 |
排序方式: 共有4766条查询结果,搜索用时 0 毫秒
11.
12.
基底动脉缝隙连接蛋白的分布 总被引:3,自引:0,他引:3
目的:探讨正常脑血管缝隙连接蛋白的分布。方法:采用RT—PCR、免疫组化方法测定多种缝隙连接蛋白在大白兔基底动脉的表达。结果:(1)RT—PCR发现大白兔基底动脉血管组织中至少存在Xx45、Cx43、Cx40和Cx37四种缝隙连接蛋白mRNA表达;(2)免疫组化证实Cx45和Cx43主要分布于血管内皮,平滑肌细胞间末见Cx45和Cx43的染色。结论:大白兔基底动脉血管组织存在丰富的缝隙连接蛋白的表达,与体内其它弹力血管相比,缝隙连接蛋白的分布模式有其特殊性。 相似文献
13.
Gerhard Dahl 《Clinical and experimental pharmacology & physiology》1996,23(12):1047-1052
1. In the formation and function of gap junction channels two types of gates ought to be discriminated: the docking gate and the channel gates proper. The docking gate is involved in the transformation of a closed hemichannel to a patent gap junction channel. By definition the trigger mechanism for this gate and maybe even the gate itself is contained within the extracellular loops of the gap junction proteins, the connexins. The channel gates proper determine the open and closed states of the complete gap junction channels. 2. Probing the docking gate by mutagenesis of connexins and by synthetic peptides indicates that this gate is the consequence of complex interactions between a large fraction of the amino acids comprising the extracellular loops. Probably both inter- and intra-molecular interactions are involved, and disulfide exchange may be entailed in the stabilization of the open and closed states. 3. Of the various effectors on the channel gate(s) the voltage effects have obtained the most scrutiny to date. The response of gap junction channels and hemichannels is diverse, the various channels respond differently to transjunctional and membrane potential. No equivalent to the S4 segment representing the voltage sensor in other voltage dependent ion channels is present in the connexin sequences, instead mutations in various segments of connexins have been reported to affect the voltage dependence of gap junction channels. To understand the complexity of voltage effects on gap junction channels, non-connexin peptides may need to be considered as voltage sensors or as modifiers thereof. 相似文献
14.
In the Context of Risk: Supportive Adults and the School Engagement of Middle School Students* 总被引:1,自引:0,他引:1
Abstract: Many students in the United States, particularly those from lower income or racially/ethnically diverse families, are exposed to clusters of risk factors that have a negative impact on school success. This study examined the association between the number of supportive and caring adults in the home, school, and neighborhood and the school engagement of students in early adolescence. Results revealed that students who reported such supportive adults in their lives also reported higher levels of psychological and behavioral engagement with their schooling. Additionally, including measures of environmental risk factors in analytical models of the school engagement of middle school students reduced otherwise statistically significant race/ethnicity differences to nonsignificance. Implications for practice and policy are discussed. 相似文献
15.
糖尿病大鼠红细胞膜Band3蛋白的变化 总被引:1,自引:0,他引:1
目的:研究糖尿病时红细胞膜蛋白的变化。方法:注射STX诱发大鼠糖尿病,通过SDS-PAGE对糖尿病3个月大鼠红细胞膜蛋白进行电泳分析。结果:糖尿病大鼠红细胞膜Band3蛋白含量明显低于正常对照大鼠。结论:由于Band3蛋白是红细胞膜蛋白的主要成分,参与红细胞变形、物质通透等多方面的功能活动,其变化可能会直接影响红细胞的结构和功能,因此,糖尿病时Band3蛋白的变化值得进一步深入研究。 相似文献
16.
The present paper deals with a detailed analysis of cortical projections from the magnocellular basal nucleus (MBN) and horizontal limb of the diagonal band of Broca (HDB) in the rat. The MBN and HDB were injected iontophoretically with the anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L). After immunocytochemical visualization of labeled efferents, the distribution of projections over the cortical mantle, olfactory regions and amygdala were studied by light microscopy. Based on differences in cortical projection patterns, the MBN was subdivided in anterior, intermediate and posterior portions (MBNa, MBNi and MBNp). All subdivisions maintain neocortical projections and are subject to an anterior to posterior topographic arrangement. In the overall pattern, however, the frontal cortex is the chief target. Furthermore, all MBN parts project to various regions of meso- and allocortex, which are progressively more dense when the tracer injection is more anteriorly placed. The most conspicuous finding, however, was a ventrolateral to dorsomedial cortical projection pattern as the PHA-L injection site moved from posterior to anterior. Thus, the posterior MBN projects predominantly to lateral neo- and mesocortex while the anterior MBN sends more fibers to the medial cortical regions. Furthermore, the MBNa is a source of considerable afferent input to the olfactory nuclei and as such should be regarded as a transition to the HDB. The HDB, apart from projecting densely to olfactory bulb and related nuclei, maintains a substantial output to the medial prefrontal cortical regions and entorhinal cortex, as well. Comparison of young vs aged cases indicate that aging does not appear to have a profound influence on cortical innervation patterns, at least as studied with the PHA-L method. 相似文献
17.
目的:评价张力带固定法治疗锁骨远端骨折的临床效果。方法:对20例锁骨远端骨折行切开复位后张力带固定法治疗。术后随诊分析。结果:所有骨折均在半年内愈合。患侧肩关节功能恢复良好。无一例出现伤口感染。结论:张力带固定治疗锁骨远端骨折是一种简单可靠的手术方法。 相似文献
18.
19.
关节镜下经皮张力带钢丝固定治疗髌骨骨折 总被引:1,自引:0,他引:1
目的探索髌骨骨折错位在关节镜下复位、内固定的新方法。方法对56例新鲜闭合性横断型髌骨骨折病例,在关节镜下冲洗关节腔积血,清除骨折断端凝血块,去除小的骨碎片,进行髌骨复位,直接观察关节面复位对合情况。应用胥氏张力带钢丝固定原理,经皮穿入克氏针及钢丝,针孔做1cm小切口,完成内固定。结果术后2周绝大部分患者屈膝可达90°以上,骨折在6~10周达到临床愈合,出现针尾触痛者8例,克氏针松动上移2例,无钢丝断裂及脱落。治疗效果按膝关节损伤患者的功能评定法,优良率为96.4%。结论本术式两枚克氏针各有一根钢丝固定,在关节镜导引下,经皮穿针钢丝固定,不会因两根针位置不对称而产生扭距。操作方法简便、有效,有利于术后早期功能锻炼,为髌骨骨折提供了一种新的手术方法。 相似文献
20.
S. Iwamoto E. Kajii T. Omi T. Kamesaki Y. Akifuji S. Ikemoto 《European journal of haematology》1993,50(5):286-291
Abstract: A patient who represented acute hemolytic crisis was studied. Analysis of the erythrocyte membrane proteins by SDS-PAGE revealed a deficiency of band 4.2. In the family, the sister of the patient who had been clinically normal was also shown to be deficient in band 4.2. Binding studies showed that the propositus' membranes were able to bind normal band 4.2 protein as much as control. It was suggested that the binding sites for the protein were prepared on the membrane. We analyzed the band 4.2 cDNA of the propositus and detected a mutation that changes a codon for alanine to one for threonine at residue 142. Band 4.2 exon III of genomic DNA which included the mutation site was amplified and sequenced directly in the family members, and it was revealed that only the homozygotes of the mutation allele manifested band 4.2 deficiency and the parents, who were heterozygotes, showed normal amounts of band 4.2. Recently, the same mutation was reported as Protein 4.2NIPPON in another 4 cases (Bouhassira et al. Blood 1992: 79: 1846–1854). This study supports the hypothesis that this mutation is the pathogenetic cause of band 4.2 deficiency and not a polymorphism. 相似文献