首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2985篇
  免费   188篇
  国内免费   33篇
耳鼻咽喉   4篇
儿科学   9篇
妇产科学   14篇
基础医学   165篇
口腔科学   33篇
临床医学   104篇
内科学   37篇
皮肤病学   1325篇
神经病学   55篇
特种医学   49篇
外国民族医学   1篇
外科学   202篇
综合类   380篇
预防医学   80篇
眼科学   9篇
药学   321篇
  1篇
中国医学   400篇
肿瘤学   17篇
  2024年   10篇
  2023年   100篇
  2022年   51篇
  2021年   126篇
  2020年   151篇
  2019年   99篇
  2018年   78篇
  2017年   102篇
  2016年   133篇
  2015年   90篇
  2014年   214篇
  2013年   215篇
  2012年   201篇
  2011年   214篇
  2010年   183篇
  2009年   163篇
  2008年   116篇
  2007年   122篇
  2006年   108篇
  2005年   69篇
  2004年   72篇
  2003年   85篇
  2002年   67篇
  2001年   63篇
  2000年   40篇
  1999年   37篇
  1998年   25篇
  1997年   30篇
  1996年   30篇
  1995年   22篇
  1994年   24篇
  1993年   16篇
  1992年   13篇
  1991年   22篇
  1990年   18篇
  1989年   15篇
  1988年   8篇
  1987年   10篇
  1986年   5篇
  1985年   3篇
  1984年   12篇
  1983年   3篇
  1982年   8篇
  1981年   8篇
  1980年   4篇
  1979年   8篇
  1978年   3篇
  1976年   2篇
  1975年   1篇
  1972年   6篇
排序方式: 共有3206条查询结果,搜索用时 31 毫秒
31.
HLA-DRB1、DQB1基因与汉族人群寻常型天疱疮的相关性研究   总被引:4,自引:0,他引:4  
目的 探讨 HL A- DRB1、DQB1位点基因在汉族人群寻常型天疱疮易感性中的作用。方法用序列特异性引物 -聚合酶链反应方法 ,对 6 1例寻常型天疱疮 (pemphigus vulgaris,PV)患者和 5 7名正常对照进行了 HL A- DRB1、DQB1等位基因的分型 ,并分析了 DRB1、DQB1基因在两组中的分布。结果 与正常对照组比较 ,PV组 DR4、DRB1* 14 (* 14 0 1、* 14 0 4、* 14 0 5 )基因频率明显增高 (Pc分别 <0 .0 5及P<0 .0 1) ,差异有显著性 ;PV组 DQB1* 0 5 0 3、DQB1* 0 30 2基因频率明显增高 (Pc均 <0 .0 5 ) ,差异有显著性。对 DR4阳性样本的组内基因亚型分型结果发现 ,PV组中 DRB1* 0 4 0 3、DRB1* 0 4 0 6频率显著增高(Pc<0 .0 5 ) ,差异有显著性。 PV患者组单倍型 HL A- DRB1* 0 4 ,DQB1* 0 30 2和 HL A- DRB1* 14 ,DQB1* 0 5 0 3频率明显增高 (P<0 .0 5 )。结论 HL A- DRB1* 0 4 ,DQB1* 0 30 2和 HL A- DRB1* 14 ,DQB1* 0 5 0 3可能是汉族人 PV推测的易感单倍型。  相似文献   
32.
The expression of -GlcNAcβ1–6Man-(β1–6) branched oligosaccharides In carcinoma cells has been considered to influence their metastatic potentials. In the present paper, the lectin histochemistry of oral squamous cell carcinomas obtained in biopsy from 34 patients with Phaseolus vulgaris leukoagglutinin (L-PHA), which potentially binds to N-glycosidic carbohydrates with β1–6 linked lactosamin antennae, was studied in order to analyze the relationship between their staining patterns and metastases. The L-PHA-binding oligosaccharides of the carcinomas were expressed on the cell surface in the following patterns: (i) all cells were positive for the staining ('positive'); (ii) some cells were positive but the rest of the carcinoma cells were negative ('weakly positive'); and (iii) all were negative ('negative'). Statistical analysis revealed that the incidence of the metastasis to regional lymph nodes in the 'positive' cases was significantly higher than that in the 'negative' cases. Moreover, the number of the CD14 positive cells including macrophages in the Stroma adjacent to the cardnomas in the 'positive' cases was less than that in the 'negative' or 'weakly positive' cases. The expression of L-PHA-binding oligosaccharides in oral squamous cell carcinoma may be responsible for their metastatic potential to regional lymph nodes, possibly Including their ability to escape macrophage recognition.  相似文献   
33.
Lactobacillus plantarum CJLP55 has anti-pathogenic bacterial and anti-inflammatory activities in vitro. We investigated the dietary effect of CJLP55 supplement in patients with acne vulgaris, a prevalent inflammatory skin condition. Subjects ingested CJLP55 or placebo (n = 14 per group) supplements for 12 weeks in this double-blind, placebo-controlled randomized study. Acne lesion count and grade, skin sebum, hydration, pH and surface lipids were assessed. Metagenomic DNA analysis was performed on urine extracellular vesicles (EV), which indirectly reflect systemic bacterial flora. Compared to the placebo supplement, CJLP55 supplement improved acne lesion count and grade, decreased sebum triglycerides (TG), and increased hydration and ceramide 2, the major ceramide species that maintains the epidermal lipid barrier for hydration. In addition, CJLP55 supplement decreased the prevalence of Proteobacteria and increased Firmicutes, which were correlated with decreased TG, the major skin surface lipid of sebum origin. CJLP55 supplement further decreased the Bacteroidetes:Firmicutes ratio, a relevant marker of bacterial dysbiosis. No differences in skin pH, other skin surface lipids or urine bacterial EV phylum were noted between CJLP55 and placebo supplements. Dietary Lactobacillus plantarum CJLP55 was beneficial to clinical state, skin sebum, and hydration and urine bacterial EV phylum flora in patients with acne vulgaris.  相似文献   
34.
86例痤疮患者血清性激素水平分析   总被引:1,自引:0,他引:1  
目的 研究痤疮患者血清性激素水平与痤疮的关系。方法 对86例痤疮患者以放免法检测患者血清睾酮、卵泡刺激素(男性称精子生成素)、黄体生成素(男性称间质细胞刺激素)、孕酮和雌二醇;并对其中20例患者检测了泌乳素。结果 男性寻常痤疮、男和女聚合性痤疮和痤疮伴四肢或乳晕多毛(女性)63.89%患者血清睾酮增高,75%患者雌二醇增高;男性疮疮90.91%患者精子生成素低于正常。结论 血清性激素水平与痤疮类型有关,在痤疮的发生、发展和持续状态中起重要作用。  相似文献   
35.
IL-20在寻常型银屑病患者皮损和PBMC中表达的研究   总被引:1,自引:0,他引:1  
为了观察IL 2 0在寻常型银屑病患者皮损和外周血单个核细胞 (PBMC )中的表达情况 ,用免疫组化、免疫荧光和RT PCR方法检测IL 2 0在寻常型银屑病患者皮损处和正常人相应部位皮肤及PBMC中的表达。结果发现 ,用上述方法在正常人和银屑病患者皮肤中均不能检测到IL 2 0的表达。RT PCR检测发现 ,IL 2 0在寻常型银屑病患者PBMC中的阳性率为 2 5 % ,在正常人PBMC中的阳性率为 87 5 %。由此得出结论 ,虽然皮肤是IL 2 0作用的靶器官 ,但其本身并不表达IL 2 0。PBMC表达IL 2 0 ,但寻常型银屑病患者PBMC中IL 2 0的表达显著低于正常人 (P <0 0 1)。  相似文献   
36.
The results of electrical stimulation experiments [Bullier et al., (1988) Exp. Brain Res., 70, 90 - 98] demonstrated that afferents from areas 18 and 19 contact different functional types of neurons in area 17. We were therefore interested in examining whether these results could be explained by differences in the morphology of the terminals of these two groups of afferent connections to area 17. We also wanted to confirm, by a direct method, our earlier results [Salin et al. (1989) J. Comp. Neurol., 283, 486 - 512] that cortical afferents to area 17 in the cat present extensive divergences. We therefore placed small injections of anterograde tracers in areas 18 and 19 and examined the laminar distributions of terminals thus revealed and the extent of the surface of area 17 contacted by these terminals. Three tracers were used: wheat germ agglutinin - horseradish peroxidase (WGA - HRP), Phaseolus vulgaris leucoagglutinin (Pha-L) and biocytin. The results show that the divergence of these afferent connections are very extensive: 7 - 8 mm in the rotrocaudal direction and 3.5 - 6 mm in the mediolateral direction. In other words, neurons located in a region a few hundreds micron wide in areas 18 or 19 contact a region of area 17 covering several millimeters. Corticocortical connections are therefore not organized in a point-to-point fashion but are strongly divergent. The laminar distributions of terminals from areas 18 and 19 displayed a specific pattern. Area 19 projects most heavily to layers 5 and 6, also terminates in layers 1 - 3 and very little is present in layer 4. In contrast, the afferent terminals from area 18 are heaviest in layers 1, 2, 3, 4A and 5 and are rare in layer 6. Injections placed at different depths in area 18 revealed that upper layer neurons in that area mostly project to layers 1, 2, 3 and 5 in area 17, whereas lower layer neurons send their heaviest projections to layers 4A, 5 and 6 and hardly project to layers 1, 2 and 3.  相似文献   
37.
The prefrontal cortex (PFC) projections to the basal forebrain cholinergic cell groups in the medial septum (MS), vertical and horizontal limbs of the diagonal band of Broca (VDB and HDB), and the magnocellular basal nucleus (MBN) in the rat were investigated by anterograde transport of Phaseolus vulgaris leuco-agglutinin (PHA-L) combined with acetylcholinesterase (AChE) histochemistry or choline acetyltransferase (ChAT) immunocytochemistry. The experiments revealed rich PHA-L-labeled projections to discrete parts of the basal forebrain cholinergic system (BFChS) essentially originating from all prefrontal areas investigated. The PFC afferents to the BFChS display a topographic organization, such that medial prefrontal areas project to the MS, VDB, and the medial part of the HDB, whereas the orbital and agranular insular areas predominantly innervate the HDB and MBN, respectively. Since the recurrent BFChS projection to the prefrontal cortex is arranged according to a similar topography, the relationship between the BFChS and the prefrontal cortex is characterized by reciprocal connections. Furthermore, tracer injections in the PFC resulted in anterograde labeling of numerous "en passant" and terminal boutons apposing perikarya and proximal dendrites of neurons in the basal forebrain, which were stained for the cholinergic marker enzymes. These results indicate that prefrontal cortical afferents make direct synaptic contacts upon the cholinergic neurons in the basal forebrain, although further analysis at the electron microscopic level will be needed to provide conclusive evidence.  相似文献   
38.
中国芦荟治疗寻常痤疮临床研究   总被引:5,自引:0,他引:5  
目的:观察中国芦荟治疗寻常痊疮的疗效。方法:全叶组41例外用芦荟全叶,叶肉组40例外用芦荟叶肉,对照组30例外用达芙文凝胶治疗。结果:3组总有效率分别为73.2%,70.0%,76.7%,经统计学处理无显著性差异(P>0.05)。结论:中国芦荟全叶和叶肉外用治疗寻常痊疮疗效较好,但叶肉更安全,患者依从性好。  相似文献   
39.
夏枯草注射液为主治疗中晚期胃、大肠癌30例临床观察   总被引:17,自引:0,他引:17  
选符合入选条件的中晚期胃、大肠癌住院患者50例,随机分为治疗组30例、对照组20例。治疗组予夏枯草注射液静滴,对照组口服平消胶囊,疗程均为30天。结果:治疗组中医症侯综合疗效明显优于对照组(u=2.5200,P=0.0122);生存质量明显提高,且优于对照组(t=2.4776,P=0.0174);治疗组每治疗10人,可较对照组减少1例实体瘤进展(PD)患者(NNT=10);治疗组IFN—γ明显升高(t=2.3960,P=0.0204),IL12、IFN—γ升高优于对照组(t=2.9720,P=0.0047;t=2.1944,P=0.0361)。结论:夏枯草注射液对中晚期胃与大肠癌证属脾胃或大肠湿热证者有较好的应用价值,作用优于平消胶囊。  相似文献   
40.
中药愈银方治疗寻常型银屑病的临床研究   总被引:3,自引:0,他引:3  
目的:观察中药复方愈银方治疗寻常型银屑病的临床疗效及对红细胞、血小板指数的影响。方法:采用随机法将病人分为两组,治疗组44例,口服愈银方,日1剂,分2次水煎服;对照组25例,口服复方青黛丸,每次6g,每日3次。疗程8周。并检测治疗前后红细胞及血小板指数。结果:治疗组总有效率为93.18%,对照组总有效率为72.00%,两者相比有显著性差异(P<0.05)。且治疗前后的红细胞、血小板指数得到改善。结论:愈银方是治疗寻常型银屑病的有效方剂,值得进一步深入研究。其疗效机理可能与改善红细胞及血小板指数有关。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号