全文获取类型
收费全文 | 3633篇 |
免费 | 453篇 |
专业分类
4086篇 |
出版年
2021年 | 39篇 |
2019年 | 34篇 |
2017年 | 38篇 |
2016年 | 59篇 |
2015年 | 86篇 |
2014年 | 101篇 |
2013年 | 137篇 |
2012年 | 169篇 |
2011年 | 178篇 |
2010年 | 80篇 |
2009年 | 83篇 |
2008年 | 130篇 |
2007年 | 147篇 |
2006年 | 145篇 |
2005年 | 138篇 |
2004年 | 116篇 |
2003年 | 127篇 |
2002年 | 114篇 |
2001年 | 98篇 |
2000年 | 128篇 |
1999年 | 108篇 |
1998年 | 35篇 |
1997年 | 57篇 |
1996年 | 44篇 |
1995年 | 39篇 |
1994年 | 42篇 |
1993年 | 41篇 |
1992年 | 71篇 |
1991年 | 58篇 |
1990年 | 65篇 |
1989年 | 76篇 |
1988年 | 75篇 |
1987年 | 80篇 |
1986年 | 71篇 |
1985年 | 73篇 |
1984年 | 63篇 |
1983年 | 50篇 |
1982年 | 39篇 |
1981年 | 41篇 |
1980年 | 42篇 |
1979年 | 57篇 |
1978年 | 41篇 |
1977年 | 45篇 |
1976年 | 47篇 |
1975年 | 53篇 |
1974年 | 57篇 |
1973年 | 49篇 |
1971年 | 42篇 |
1970年 | 40篇 |
1967年 | 31篇 |
排序方式: 共有4086条查询结果,搜索用时 15 毫秒
991.
992.
993.
994.
The association of a SNP upstream of INSIG2 with body mass index is reproduced in several but not all cohorts 总被引:1,自引:0,他引:1 下载免费PDF全文
Lyon HN Emilsson V Hinney A Heid IM Lasky-Su J Zhu X Thorleifsson G Gunnarsdottir S Walters GB Thorsteinsdottir U Kong A Gulcher J Nguyen TT Scherag A Pfeufer A Meitinger T Brönner G Rief W Soto-Quiros ME Avila L Klanderman B Raby BA Silverman EK Weiss ST Laird N Ding X Groop L Tuomi T Isomaa B Bengtsson K Butler JL Cooper RS Fox CS O'Donnell CJ Vollmert C Celedón JC Wichmann HE Hebebrand J Stefansson K Lange C Hirschhorn JN 《PLoS genetics》2007,3(4):e61
A SNP upstream of the INSIG2 gene, rs7566605, was recently found to be associated with obesity as measured by body mass index (BMI) by Herbert and colleagues. The association between increased BMI and homozygosity for the minor allele was first observed in data from a genome-wide association scan of 86,604 SNPs in 923 related individuals from the Framingham Heart Study offspring cohort. The association was reproduced in four additional cohorts, but was not seen in a fifth cohort. To further assess the general reproducibility of this association, we genotyped rs7566605 in nine large cohorts from eight populations across multiple ethnicities (total n = 16,969). We tested this variant for association with BMI in each sample under a recessive model using family-based, population-based, and case-control designs. We observed a significant (p < 0.05) association in five cohorts but saw no association in three other cohorts. There was variability in the strength of association evidence across examination cycles in longitudinal data from unrelated individuals in the Framingham Heart Study Offspring cohort. A combined analysis revealed significant independent validation of this association in both unrelated (p = 0.046) and family-based (p = 0.004) samples. The estimated risk conferred by this allele is small, and could easily be masked by small sample size, population stratification, or other confounders. These validation studies suggest that the original association is less likely to be spurious, but the failure to observe an association in every data set suggests that the effect of SNP rs7566605 on BMI may be heterogeneous across population samples. 相似文献
995.
996.
Phillips GN Fox BG Markley JL Volkman BF Bae E Bitto E Bingman CA Frederick RO McCoy JG Lytle BL Pierce BS Song J Twigger SN 《Journal of structural and functional genomics》2007,8(2-3):73-84
The Center for Eukaryotic Structural Genomics (CESG) produces and solves the structures of proteins from eukaryotes. We have
developed and operate a pipeline to both solve structures and to test new methodologies. Both NMR and X-ray crystallography
methods are used for structure solution. CESG chooses targets based on sequence dissimilarity to known structures, medical
relevance, and nominations from members of the scientific community. Many times proteins qualify in more than one of these
categories. Here we review some of the structures that have connections to human health and disease. 相似文献
997.
Recent findings have substantiated the importance of T lymphocytes to the pathogenesis of rheumatoid arthritis (RA). Here,
we review emerging data regarding genetic predisposition, spontaneous animal models of arthritis, and cell-cell interactions
that implicate T cells as driving synovial inflammation and joint destruction. Information regarding the proinflammatory role
of interleukin-17-producing T cells and the functional state of regulatory T cells both in animal models and in patients with
RA is also discussed. In light of the overwhelming evidence that disrupted T-cell homeostasis greatly contributes to joint
pathology in RA, the therapeutic potential of targeting activators of pro-inflammatory T cells or their products is compelling. 相似文献
998.
999.
2'-o-dimethylaminoethoxyuridine and 5-dimethylaminopropargyl deoxyuridine for at base pair recognition in triple helices 总被引:1,自引:0,他引:1
Brennan L Peng G Srinivasan N Fox KR Brown T 《Nucleosides, nucleotides & nucleic acids》2007,26(10-12):1283-1286
The nucleoside analogues 2'-O-dimethylaminoethoxy uridine and 5-dimethylaminopropargyl deoxyuridine have been synthesised and incorporated into oligonucleotides. Their triplex-stabilising properties have been determined in fluorescence melting experiments. 相似文献
1000.
Tessa B. Francis Daniel E. Schindler Justin M. Fox Elizabeth Seminet-Reneau 《Ecosystems》2007,10(7):1057-1068
Residential development of lakeshores affects the structure and function of riparian and littoral habitats. Organic detritus
in sediments is a critical component of littoral food webs, but the effects of urbanization on sediment characteristics are
unexplored. We characterized the quantity of organic sediments in Pacific Northwest lakes along a development gradient and
found a 10-fold decline in the proportion of detritus in littoral sediments associated with density of lakeshore dwellings.
In a comparison between two fully developed lakes and two undeveloped reference lakes, we examined several possible controls
on sedimentary organic content, including terrestrial inputs, decomposition rates and associated macroinvertebrate communities,
and physical retention by coarse wood. The littoral sediments of undeveloped lakes ranged from 34 to 77% organic by mass,
whereas the range on urban lakes was an order of magnitude less, ranging from 1 to 3% organic. We found no significant differences
in terrestrial litter inputs between the two sets of lakes. Leaf litter decomposition rates did not vary significantly between
the two sets of lakes, and we found higher densities of shredder macroinvertebrate taxa in the littoral zones of undeveloped
lakes. Sedimentary organic matter on undeveloped lakes accumulated in shallow waters and declined with distance from shore,
whereas the opposite pattern existed on urban lakes. Our results suggest that coarse wood physically retains organic matter
in littoral zones where it can enter the detrital energy pathway, and the loss of this feature on urban lakes alters littoral
sediment characteristics, with potentially far-reaching consequences for lake food webs. 相似文献