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   865篇
  免费   20篇
  国内免费   18篇
耳鼻咽喉   1篇
儿科学   6篇
基础医学   431篇
口腔科学   2篇
临床医学   105篇
内科学   105篇
皮肤病学   17篇
神经病学   10篇
特种医学   10篇
外科学   22篇
综合类   98篇
预防医学   20篇
眼科学   42篇
药学   24篇
中国医学   5篇
肿瘤学   5篇
  2024年   1篇
  2023年   6篇
  2022年   9篇
  2021年   9篇
  2020年   18篇
  2019年   8篇
  2018年   7篇
  2017年   6篇
  2016年   19篇
  2015年   10篇
  2014年   20篇
  2013年   49篇
  2012年   24篇
  2011年   34篇
  2010年   41篇
  2009年   62篇
  2008年   41篇
  2007年   65篇
  2006年   47篇
  2005年   43篇
  2004年   35篇
  2003年   23篇
  2002年   38篇
  2001年   36篇
  2000年   38篇
  1999年   25篇
  1998年   24篇
  1997年   36篇
  1996年   32篇
  1995年   27篇
  1994年   21篇
  1993年   8篇
  1992年   7篇
  1991年   6篇
  1990年   6篇
  1989年   4篇
  1988年   1篇
  1986年   2篇
  1985年   1篇
  1984年   4篇
  1983年   4篇
  1982年   3篇
  1981年   1篇
  1980年   1篇
  1978年   1篇
排序方式: 共有903条查询结果,搜索用时 15 毫秒
1.
Abstract: We describe the use of restriction analysis on PCR-amplified DNA for detecting all B*27 subtypes except B*2710 and B*2711 (i.e. from B*2701 to B*2709). After detecting B*27 by Sty I, double digestions consisting of Sty I plus another informative enzyme led to subtype assignment. We used mismatched primers to create restriction sites when necessary. The method avoids group-specific amplifications and other laborious optimization procedures. It was successfully tested on a panel of well characterized cell lines covering different B*27 subtypes. Then, we studied a group of 57 ankylosing spondyiitis patients and 746 controls from the south of Spain. B*27 showed a very strong association with the disease (OR=211.27, P=\0˜7). B*2702 and B*2705 distribution in controls (20% and 77.1%, respectively) differed from previously reported data in the Spanish population. We unexpectedly found the B*2707 allele in our population (one control).  相似文献   
2.
We have cloned and sequenced a genomic region centromeric of the HLA-B locus from different MHC ancestral haplotypes. These haplotypes are associated with several diseases. The sequences were analyzed for coding potential and their relevance to disease associations were assessed with respect to the level of polymorphism. Analysis of sequences located approximately 25kb centromeric of HLA-B reveals the existence of fibroblast growth factor receptor related sequences. These sequences designated PERB1 (FGFR6 ) reveal 80% homology, at both nucleic acid and amino acid level, to the immunoglobulin domain 1 (Ig-1) of the human fibroblast growth factor receptor 3 ( FGFR3 ) gene. Amino acid comparison of the Ig-1 domain of PERB1 to those of other FGFR molecules indicates that PERB1 is more closely related to FGFR3 and FGFR5 than to FGFR1 , FGFR2 or FGFR4 . Genomic sequence analysis, however, reveals no consensus splice sites and indicates the existence of inframe premature stop codons in the putative coding sequences. The results suggest that these sequences may represent FGFR gene fragments existing within the central MHC. Sequence analysis of the Mhc in 6 chimpanzee and one orangutan indicates that the existence of PERB 1 predates the spe-ciation of the three species. The fact that the MHC contains a mixture of functional and nonfunctional (pseudo) genes suggests that a functional copy of PERB1 (FGFR6 ) may exist within or in close proximity to the MHC.  相似文献   
3.
目的 :应用SSP PCR(Sequencespecialprime polymerasechainreaction)基因检定技术对急性前葡萄膜炎 (a cuteanterioruveitis ,AAU)患者HLA B2 7基因进行检测 ,并且对HLA B2 7阳性与阴性患者临床特征加以分析。方法 :采用SSP PCR基因检定技术检测 98例AAU患者及 82例正常人样本的HLA B2 7基因。并对HLA B2 7阳性与阴性患者临床特征进行观察。结果 :98例AAU患者样本中有 5 7例样本呈HLA B2 7阳性 ,82例正常人样本有 4例样本呈HLA B2 7阳性 ,阳性率分别为 5 8.2 %和 4 .9%。经 χ2 检验 ,χ2 =4 1.33,P <0 .0 0 5 ,二组间有显著差异。HLA B2 7阳性患者多见于男性 ,单眼多见 ,粉尘状KP ,发病时视力下降明显 ,易于复发 ,且并发症少为其特征 ,激素治疗效果佳。结论 :采用SSP PCR基因检定技术测定HLA B2 7快速、简单、准确性高、客观性强 ,值得推广和应用。HLA B2 7与急性前葡萄膜炎有着高度相关性。HLA B2 7阳性患者与阴性患者在临床特征上有着一定程度的差异。  相似文献   
4.
5.
HLA-B27相关的前葡萄膜炎眼后节并发症的临床特点   总被引:1,自引:0,他引:1  
目的探讨HLA—B27阳性的前葡萄膜炎眼后节并发症的临床特点及治疗。方法2002年1月至2005年10月就诊的前葡萄膜炎患者采用流式细胞术进行外周HLA-B27的检测,筛选出71-例82眼HLA-B27阳性前葡萄膜炎患者,分为两组:实验组为眼后节受累的患者24例31眼,对照组为眼后节未受累的患者47例51眼。另有HLA—B27阴性前葡萄膜炎患者74例116眼作参考。所有患者均进行裂隙灯、眼底镜等常规眼科查体,部分行眼底荧光血管造影。分析了HLA—B27相关的前葡萄膜炎眼后节并发症的临床特点。采用x^2检验及t检验进行统计学分析。结果71例82眼HLA—B27阳性前葡萄膜炎中有24例31眼占37.8%出现眼后节并发症者,包括:黄斑囊样水肿12例15眼占48.4%,视乳头水肿7例8眼占25.8%,而玻璃体炎最多见为21例27眼占87.1%,8例10眼占32.3%患者存在两种或两种以上的眼后节表现。74例116眼HLA—B27阴性者有8例12眼占10.3%有眼后节表现。实验组中发生前房成型纤维素渗出31眼中18眼占58.06%和积脓31眼中9眼占29.03%明显高于对照组(前房纤维素渗出51眼中3眼,5.88%,X^2=27.56,P〈0.01;前房积脓51眼中1眼,1.96%,X^2=13.20,P〈0.01);实验组中伴发相关全身性疾病24例中有16例占66.67%的几率高于对照组(47例中有17例,31.66%,X^2=5.94,P〈0.05)。出现眼后节并发症的患者经全身及局部应用糖皮质激素治疗,31眼中有11眼最佳矫正视力≥1.0。结论HLA-B27阳性前葡萄膜炎易出现眼后节并发症,HLA—B27相关的前葡萄膜炎眼后节受累的患者发生相关全身性疾病和前房纤维素渗出与积脓的几率较高。  相似文献   
6.
为了研究不同HLA B分子对NK细胞杀伤活性的影响 ,我们分别构建pcDNA3 HLA B 390 5 2、B 2 70 4、B 5 1 0 2 2基因真核表达载体 ;借助脂质体将各质粒转染入K5 6 2细胞 ,经G4 1 8筛选 ,分别获得阳性表达细胞株 ;并应用LDH法检测转染细胞对不同个体外周血NK细胞杀伤活性的抑制效应。结果显示 :与转染了空质粒的对照组相比 ,外周血NK细胞对K5 6 2 B39的杀伤率无明显影响 ,而对K5 6 2 B2 7,K5 6 2 B5 1的杀伤率降低。当使用针对NK细胞受体KIR3DL1的单抗DX9封闭NK细胞后 ,此抑制效应大部分消失。提示靶细胞表达HLA Bw4分子可明显抑制NK细胞的杀伤效应 ,而表达HLA Bw6分子对NK细胞杀伤功能无明显影响  相似文献   
7.
HLA-B44 is the most frequent HLA-B allele in Caucasian populations. Several B44 subtypes, B*4402-B*4406, have been identified in individuals with this ethnic origin. Mismatches among B44 subtypes have been described as major targets for allogeneic responses in bone marrow transplantation. We have developed a PCR-SSO method, based on a B12- specific DNA amplification of exon 2 through exon 3 and subsequent non radioactive hybridization with eight probes, which allow us to discriminate all B12 homozygous combinations. We applied this method to determine the frequency of B44 subtypes in a Spanish population, as well as their HLA-A.-C.-DRB1,-DRB3/DRB4/DRB5.-DQA1 and -DQB1 associated haplotypes. A total of 141 healthy unrelated Spanish individuals and 31 B44-bearing haplotypes were investigated. Four B44 alleles were identified, B*4402 (33%), B*4403 (66%), B*4404 (0.7%), and B*4405 (0.7%). Haplotype analysis showed a clear differentiated distribution pattern for the two major B44 subtypes. B*4402 is associated with Cw5 (11/13) and A2 antigens (10/13). In contrast, B*4403 is mainly found together with DRB1*0701 (14/16). An inverted B*4402/B*4403 frequency in comparison with other European and North American Caucasian populations, revealed the existence of an extended haplotype diversity between populations of the same ethnic origin. Apart from anthropological studies, high resolution typing for HLA class I antigens presenting molecular polymorphism will be of great relevance in unrelated bone marrow transplantation.  相似文献   
8.
Unrelated Bubi, native to the island of Bioko (Equatorial Guinea), were previously typed by low-resolution polymerase chain reaction using sequence-specific primers (PCR-SSP) and serology for HLA-A, -B and -C. HLA-B*44 was found frequently and associated with Cw*07. We have studied the HLA subtypes of 20 B*44pos/Cw*07pos Bubi individuals. HLA-B and -C were typed by sequencing exons 2 and 3. To distinguish the alleles Cw*1701/02/03, Cw*07011/012/06 and Cw*1801/02 additional sequencing of exon 1 or 5 was performed. All 20 B*44pos/Cw*07pos individuals of the Bubi population were typed Cw*0706 positive. Nineteen of them carried the B*44032 allele and one B*4407. In addition, 19 B*44neg/ Cw*07pos Bubi individuals were typed for HLA-C and none of them proved Cw*0706 positive. To determine whether the association between Cw*0706 and B*44032 was limited to the Bubi, 19 individuals from Dutch Caucasian families were typed in which B44 and Cw7 segregated on one haplotype. None of these individuals showed the presence of B*44032 or Cw*0706. The haplotypes found in the Dutch Caucasians were B*4402-Cw*0704, B*44031-Cw*07011 and B*44031-Cw*0702. The present observation indicates a strong association between B*44032 and Cw*0706 in the Bubi population.  相似文献   
9.
目的探讨皖籍汉族人群MICA基因(major histocompatibility complex class Ⅰchain-related gene A,MICA)第2、3、4外显子的多态性,及其与HLA-B抗原的连锁不平衡在强直性脊柱炎(ankylosing spondylitis,AS)发病中的作用。方法采用聚合酶链反应-序列特异性寡核苷酸探针杂交(polymerase chain reactionsequence-specific oligonucleotide probing,PCR-SS0)技术对56例AS患者和112名正常对照人群进行MICA基因第2、3、4外显子的多态性和HLA-B抗原的检测。结果AS患者和正常对照人群的MICA等位基因分布均以MICA*008占优势,频率分别为32.14%和30.36%。两组人群MICA*007等位基因的分布差异有统计学意义(X^2=10.18,P〈0.05,RR=2.50)。单倍型分析显示,AS患者和正常对照人群的MICA等位基因均显示出与多个HLA-B位点的连锁不平衡现象,两组间差异有统计学意义的单倍型为MICA*007-B27(X^2=18.46,P〈0.05,RR=7.47)。分层分析结果显示,HLA-B27阳性与AS的相关性有统计学意义(P〈0.05),但MICA*007基因与AS的相关性无统计学意义(P〉0.05)。结论AS患者中MICA*007等位基因频率的显著升高可能源于MICA基因与HLA-B位点间的广泛连锁不平衡。  相似文献   
10.
Seven new HLA-B locus alleles have been described. B*44022 and B*44032 are silent substitutions altering known alleles. B*4411 carries a unique Bw4-like epitope. B*4420, B*4421, and B*4424 carry new combinations of motifs previously observed in other alleles. B*8301 appears to be the result of the replacement of exon 2 from B*4402 with exon 2 from B*5603.  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