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   2777篇
  免费   209篇
  国内免费   16篇
耳鼻咽喉   33篇
儿科学   79篇
妇产科学   43篇
基础医学   379篇
口腔科学   103篇
临床医学   235篇
内科学   680篇
皮肤病学   109篇
神经病学   202篇
特种医学   131篇
外国民族医学   1篇
外科学   251篇
综合类   13篇
预防医学   121篇
眼科学   100篇
药学   222篇
中国医学   16篇
肿瘤学   284篇
  2024年   6篇
  2023年   46篇
  2022年   82篇
  2021年   147篇
  2020年   76篇
  2019年   109篇
  2018年   137篇
  2017年   109篇
  2016年   102篇
  2015年   99篇
  2014年   121篇
  2013年   141篇
  2012年   233篇
  2011年   266篇
  2010年   128篇
  2009年   98篇
  2008年   188篇
  2007年   156篇
  2006年   161篇
  2005年   139篇
  2004年   128篇
  2003年   116篇
  2002年   99篇
  2001年   14篇
  2000年   8篇
  1999年   13篇
  1998年   24篇
  1997年   10篇
  1996年   13篇
  1995年   11篇
  1994年   3篇
  1993年   5篇
  1992年   3篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1987年   4篇
  1985年   4篇
排序方式: 共有3002条查询结果,搜索用时 15 毫秒
91.
92.
Innate immunity plays an important role in host antiviral response to hepatitis C viral (HCV) infection. Recently, single nucleotide polymorphisms (SNPs) of IL28B and host response to peginterferon α (PEG-IFNα) and ribavirin (RBV) were shown to be strongly associated. We aimed to determine the gene expression involving innate immunity in IL28B genotypes and elucidate its relation to response to antiviral treatment. We genotyped IL28B SNPs (rs8099917 and rs12979860) in 88 chronic hepatitis C patients treated with PEG-IFNα-2b/RBV and quantified expressions of viral sensors (RIG-I, MDA5, and LGP2), adaptor molecule (IPS-1), related ubiquitin E3-ligase (RNF125), modulators (ISG15 and USP18), and IL28 (IFNλ). Both IL28B SNPs were 100% identical; 54 patients possessed rs8099917 TT/rs12979860 CC (IL28B major patients) and 34 possessed rs8099917 TG/rs12979860 CT (IL28B minor patients). Hepatic expressions of viral sensors and modulators in IL28B minor patients were significantly up-regulated compared with that in IL28B major patients (≈ 3.3-fold, P < 0.001). However, expression of IPS-1 was significantly lower in IL28B minor patients (1.2-fold, P = 0.028). Expressions of viral sensors and modulators were significantly higher in nonvirological responders (NVR) than that in others despite stratification by IL28B genotype (≈ 2.6-fold, P < 0.001). Multivariate and ROC analyses indicated that higher RIG-I and ISG15 expressions and RIG-I/IPS-1 expression ratio were independent factors for NVR. IPS-1 down-regulation in IL28B minor patients was confirmed by western blotting, and the extent of IPS-1 protein cleavage was associated with the variable treatment response. CONCLUSION: Gene expression involving innate immunity is strongly associated with IL28B genotype and response to PEG-IFNα/RBV. Both IL28B minor allele and higher RIG-I and ISG15 expressions and RIG-I/IPS-1 ratio are independent factors for NVR.  相似文献   
93.
94.
ABSTRACT

Topographical disorientation (TD) in novel environments is considered to be a part of anterograde amnesia. A 56-year-old woman presented with pure TD only in novel environments following limbic encephalitis. She could not remember directions inside the hospital on weekly outpatient visits; however, her verbal and visual anterograde memories were normal. In the test of learning photographs of scenes, faces, and objects, only her scores for landscapes were worse than those in healthy controls. These findings suggested that her TD specific to landscapes and directions in novel environments was caused by category-specific memory impairment related to bilateral hippocampal and parahippocampal dysfunction.  相似文献   
95.
We identified two afibrinogenemic girls in two Japanese families and performed molecular analysis to clarify the mechanisms of fibrinogen defects. Genetic analyses were performed by PCR amplification of the fibrinogen gene and DNA sequence analysis. To analyze the mechanisms of mature fibrinogen defects in plasma, we cloned minigenes from the proposita's PCR-amplified DNA, transfected them into CHO cells, and sequenced the cDNA amplified with the RT reaction followed by PCR. Sequence analyses indicated that one was caused by a homozygous 1238?bp deletion of the fibrinogen Aα-chain gene (FGAΔ1238) and the other was a compound heterozygous FGAΔ1238 and novel FGA c.54+3A>C substitution. The minigene corresponding to FGAΔ1238 generates two aberrant mRNAs, both of which may induce a frameshift and terminate prematurely. In contrast, the minigene corresponding to FGA c.54+3A>C generates two aberrant mRNAs, one of which may induce a frameshift and terminate prematurely, and the other uses a cryptic 5' splice site in exon 1, resulting in the deletion of six amino acids in signal peptides. Molecular analyses of both genetic variants suggest that the lack of a mature Aα-chain, impaired assembly, and/or secretion of the fibrinogen molecule may lead to afibrinogenemia.  相似文献   
96.
97.
Objective. Antibodies that recognize complexes formed by platelet factor 4 (PF4) and heparin are involved in the pathogenesis of heparin-induced thrombocytopenia (HIT). This study was undertaken to investigate the prevalence and clinical correlations of anti-PF4 autoantibodies in patients with SLE. Methods. We studied 118 patients with SLE, 78 with primary immune thrombocytopenia (ITP), 27 with primary APS, 2 with HIT (as positive controls) and 47 healthy controls. Heparin-dependent and -independent anti-PF4 antibodies were measured with an ELISA. Antibody binding was confirmed to be heparin-dependent when inhibited by the presence of a high concentration of heparin. Pathogenic anti-PF4 antibody was assessed by serotonin-release assay. Results. Heparin-dependent anti-PF4 antibodies were detected in 11 SLE (9%) and 2 primary ITP (3%) patients, but at much lower levels than in HIT patients. In serotonin-release assays, only the HIT sera induced platelet activation in vitro. Heparin-independent anti-PF4 antibodies were detected in 17 SLE patients (14%). There was no correlation between the levels of heparin-dependent and -independent anti-PF4 antibodies. Cross-reactivity between these two antibodies was not detectable by ELISA competitive assay. Heparin-dependent anti-PF4 antibodies were associated with thrombocytopenia and IgM aCLs (P?=?0.007 for both comparisons), while heparin-independent anti-PF4 antibody levels were correlated with SLE disease activity index (P?=?0.0005). None of the SLE patients with anti-PF4 antibodies had previous heparin exposure. Conclusion. PF4 is an autoimmune target in SLE patients. Heparin-dependent and -independent anti-PF4 autoantibodies may be involved in different aspects of pathophysiology of SLE.  相似文献   
98.
99.
100.
To identify fetuses at high risk of poor neurological outcomes using a novel ultrasound evaluation system. We assessed an ultrasound evaluation system based on our previous findings, consisting of screening for decreased or lack of fetal movements, abnormal patterns of fetal heart rate, congenital CNS malformations, polyhydramnios of unknown cause, and a “brief ultrasound evaluation” of fetal brain functions, including movement of extremities, breathing movements, ultradian rhythm, REM period, and NREM period. We then assessed the correlation between fetal brain functions and neurological outcomes in infancy (MR, CP, and low Developmental Quotient). During screening, we prospectively evaluated 4978 fetuses receiving prenatal and intrapartum management between January 2000 and December 2009 in our hospital that were later delivered between 32 and 41 weeks’ gestation and identified 93 cases as suspicious for impairment. Of the 93 fetuses, 26 underwent the second step of brief ultrasound examination at 35–40 weeks’ gestation. Our findings revealed that this method was adequately sensitive (80%) and specific (88%) in identifying neurological impairment. We concluded that this method was mainly useful in the clinical setting for establishing the first indication for fetal CNS examination for functional impairment, rendering it suitable for clinical application.  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