全文获取类型
收费全文 | 26867篇 |
免费 | 2107篇 |
国内免费 | 970篇 |
出版年
2023年 | 261篇 |
2022年 | 523篇 |
2021年 | 1066篇 |
2020年 | 704篇 |
2019年 | 935篇 |
2018年 | 956篇 |
2017年 | 725篇 |
2016年 | 1037篇 |
2015年 | 1449篇 |
2014年 | 1647篇 |
2013年 | 1993篇 |
2012年 | 2178篇 |
2011年 | 2020篇 |
2010年 | 1160篇 |
2009年 | 1051篇 |
2008年 | 1190篇 |
2007年 | 1103篇 |
2006年 | 1015篇 |
2005年 | 893篇 |
2004年 | 792篇 |
2003年 | 684篇 |
2002年 | 597篇 |
2001年 | 454篇 |
2000年 | 473篇 |
1999年 | 414篇 |
1998年 | 250篇 |
1997年 | 233篇 |
1996年 | 243篇 |
1995年 | 227篇 |
1994年 | 200篇 |
1993年 | 163篇 |
1992年 | 245篇 |
1991年 | 258篇 |
1990年 | 233篇 |
1989年 | 178篇 |
1988年 | 189篇 |
1987年 | 194篇 |
1986年 | 133篇 |
1985年 | 159篇 |
1984年 | 133篇 |
1983年 | 116篇 |
1982年 | 90篇 |
1981年 | 94篇 |
1979年 | 116篇 |
1978年 | 97篇 |
1977年 | 77篇 |
1976年 | 73篇 |
1975年 | 86篇 |
1974年 | 81篇 |
1973年 | 83篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
961.
A variety of epidemiologic studies have focused on the association between macrophage migration inhibitory factor (MIF) gene − 173G/C polymorphism and inflammatory bowel disease (IBD). However, results in different studies have been inconsistent. In order to derive a more precise estimation of the associations, we performed this meta-analysis and systematic searches of electronic databases PubMed and Web of Science (up to April 30, 2013). Based on our search criteria, a total of seven eligible studies concerning the MIF − 173G/C polymorphism and IBD risk were included in the final meta-analysis, comprising 2162 IBD cases and 2134 controls. Significant association was found between MIF − 173G/C polymorphism and the risk of IBD when all studies were pooled into the meta-analysis (for C allele vs. G allele: OR = 1.25, 95% CI = 1.12–1.41, p = 0.000; for C/C vs. G/G: OR = 1.71, 95% CI = 1.23–2.39, p = 0.002; for C/C + G/C vs. G/G: OR = 1.24, 95% CI = 1.09–1.42, p = 0.002; for C/C vs. G/C + G/G: OR = 1.67, 95% CI = 1.20–2.33, p = 0.002). Heterogeneity and publication bias did not exist in the overall comparisons. The present meta-analysis suggests an association between the MIF − 173G/C polymorphism and IBD risk. However, due to few studies and the selection bias existed in some studies, the results should be interpreted with caution. 相似文献
962.
963.
Luz Ma. González-Huerta Olga Messina-Baas Héctor Urueta Jaime Toral-López Sergio A. Cuevas-Covarrubias 《Gene》2013
Purpose
To describe at molecular level a family with pulverulent congenital cataract associated with a CRYGC gene mutation.Methods
One family with several affected members with pulverulent congenital cataract and 230 healthy controls were examined. Genomic DNA from leukocytes was isolated to analyze the CRYGA-D cluster, CX46, CX50 and MIP genes through high-resolution melting curve and DNA sequencing.Results
DNA sequencing in the affected members revealed the c.143G>A mutation (p.R48H) in exon 2 of the CRYGC gene; 230 healthy controls and ten healthy relatives were also analyzed and none of them showed the c.143G>A mutation. No other polymorphisms or mutations were found to be present.Conclusion
In the present study, we described a family with pulverulent congenital cataract that segregated the c.143G>A mutation (p.R48H) in the CRYGC gene. A few mutations have been described in the CRYGC gene in autosomal dominant cataract, none of them with pulverulent cataract making clear the clinical heterogeneity of congenital cataract. This mutation has been associated with the phenotype of congenital cataract but also is considered an SNP in the NCBI data base. Our data and previous report suggest that p.R48H could be a disease-causing mutation and not an SNP. 相似文献964.
To investigate the influence of the interleukin-10 gene promoter polymorphisms on the susceptibility of endometriosis, we examined the association by performing a meta-analysis. The PubMed, Embase, HuGE Navigator and CNKI were searched to identify eligible studies. We then conducted a meta-analysis to examine the association between interleukin-10 gene promoter polymorphisms and endometriosis. Eight case–control studies which examined the association between the IL-10 gene promoter polymorphisms and the susceptibility to endometriosis were finally included in the meta-analysis. Meta-analysis of the IL-10 − 592 A/C polymorphisms showed a significant increased risk of endometriosis in the overall and Asian population in all genetic models and allele contrast. However, meta-analysis of the IL-10 − 1082 A/G and IL-10 − 819 T/C polymorphisms showed no association with endometriosis in all genetic models and allele contrast in the overall and Asian population samples. In addition, there was not a significant association between the IL-10 − 592 A/C gene promoter polymorphisms with the severity of endometriosis. 相似文献
965.
Song Xu Yuan Zhou Wei-Dong Du Gang Chen Fu-Sheng Zhou Marion Schneider Xue-Ling Ma Hong-Yuan Xu Xue-Jun Zhang 《Gene》2013
Human DOC-2/DAB2 interactive protein (hDAB2IP) gene is a novel member of the Ras GTPase-activating family and has been demonstrated to be a tumor-suppressor gene that inhibits cell survival and proliferation and induces cell apoptosis. It was reported that the expression level of hDAB2IP in gastric cancer tissue was highly correlated with tumor progression, however, whether hDAB2IP genetic variants are associated with the risk of gastric cancer remains yet unknown. In this case–control study, we conducted a genetic analysis for hDAB2IP variants in 311 patients with gastric cancer and 425 controls from the Chinese Han population. We found that the SNP rs2243421 of hDAB2IP gene with the minor allele C significantly revealed strong association with decreased gastric cancer susceptibility (P = 0.007, adjusted odds ratio [OR] = 0.734, 95%CI = 0.586–0.919). Haplotypes rs2243421 and rs10985332 (HaploType: CC, P = 0.012, aOR = 0.760) and haplotypes rs2243421 and rs555996 (HaploType: CG, P = 0.034, aOR = 0.788) represented the decreased risk of gastric cancer, respectively. On the contrary, rs2243421 and rs555996 showed an elevated susceptibility (HaploType: TG, P = 0.010, aOR = 1.320). Our results for the first time provided new insight into susceptibility factors of hDAB2IP gene variants in carcinogenesis of gastric cancer. 相似文献
966.
Yujing Huang Ying Qi Yanping Ma Rong He Yaohua Ji Zhengrong Sun Qiang Ruan 《Journal of biosciences》2013,38(3):479-485
MicroRNAs (miRNAs) are small RNAs, 19–23 nucleotides in length, which regulate a variety of cellular processes. Human cytomegalovirus (HCMV) encodes only one intronic miRNA: human cytomegalovirus microRNA UL36 (hcmv-miR-UL36). In this study, we found that over-expression of hcmv-miR-UL36 resulted in a more than threefold increase in HCMV DNA synthesis at 24 h post infection. Fifteen putative targets of hcmv-miR-UL36 were identified using hybrid PCR, one being the HCMV UL138 gene that has previously been identified as a novel latency-associated determinant of HCMV infection. Down-regulation of UL138 expression by hcmv-miR-UL36 was validated using luciferase reporter assays and Western blot analysis in HEK293 cells. In the presence of hcmv-miR-UL36, we observed a 74.6% decrease in luciferase activity and a 46.2% decrease in HCMV UL138 protein expression. Our results indicate that hcmv-miR-UL36 may be a viral miRNA contributing to HCMV replication. 相似文献
967.
包括过氧化氢(Hzoz)在内的活性氧通过引起细胞内钙的变化而造成细胞损伤。然而,不同浓度的H202可以导致细胞内不同的钙变化,并激活不同的信号通路。细胞内钙振荡是其中的一种钙信号变化形式,钙振荡可以调控转录因子NF—KB的活性。该研究探讨可以诱导支气管上皮细胞内钙振苏发生的H2o2浓度。体外培养人支气管上皮细胞,采取钙离子荧光探针Fura_2标记细胞。并使用离子成像系统,观测不同浓度的H:0:(0~1000μmol/L)作用下细胞内钙浓度的变化。结果发现,低于50μmol/L的H202仅仅引起“钙火花”;50~500μmol/L的H202导致细胞内钙振荡的发生;而1000μmol/L的H202引起细胞内持续的高钙;同时也证实150μmol/L的H202诱发明显的钙振荡,而钙振荡随后引起了NF—KB活性的升高。该研究提示,适当浓度的H:0:可以诱发支气管上皮细胞内钙振荡的发生,推测可能是活性氧导致慢性气道炎症损伤的一个机制。 相似文献
968.
969.
Yun Kong Malene B Vester‐Christensen Katrine T‐B G Schjoldager Kirstine Lavrsen Sally Dabelsteen Nis B Pedersen Lara Marcos‐Silva Ramneek Gupta Eric Paul Bennett Ulla Mandel Søren Brunak Hans H Wandall Steven B Levery Henrik Clausen 《The EMBO journal》2013,32(10):1478-1488
Glycosylation is the most abundant and diverse posttranslational modification of proteins. While several types of glycosylation can be predicted by the protein sequence context, and substantial knowledge of these glycoproteomes is available, our knowledge of the GalNAc‐type O‐glycosylation is highly limited. This type of glycosylation is unique in being regulated by 20 polypeptide GalNAc‐transferases attaching the initiating GalNAc monosaccharides to Ser and Thr (and likely some Tyr) residues. We have developed a genetic engineering approach using human cell lines to simplify O‐glycosylation (SimpleCells) that enables proteome‐wide discovery of O‐glycan sites using ‘bottom‐up’ ETD‐based mass spectrometric analysis. We implemented this on 12 human cell lines from different organs, and present a first map of the human O‐glycoproteome with almost 3000 glycosites in over 600 O‐glycoproteins as well as an improved NetOGlyc4.0 model for prediction of O‐glycosylation. The finding of unique subsets of O‐glycoproteins in each cell line provides evidence that the O‐glycoproteome is differentially regulated and dynamic. The greatly expanded view of the O‐glycoproteome should facilitate the exploration of how site‐specific O‐glycosylation regulates protein function. 相似文献