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91.
Mg isotope evidence for contemporaneous formation of chondrules and refractory inclusions 总被引:2,自引:0,他引:2
Primitive or undifferentiated meteorites (chondrites) date back to the origin of the Solar System, and thus preserve a record of the physical and chemical processes that occurred during the earliest evolution of the accretion disk surrounding the young Sun. The oldest Solar System materials present within these meteorites are millimetre- to centimetre-sized calcium-aluminium-rich inclusions (CAIs) and ferromagnesian silicate spherules (chondrules), which probably originated by thermal processing of pre-existing nebula solids. Chondrules are currently believed to have formed approximately 2-3 million years (Myr) after CAIs (refs 5-10)--a timescale inconsistent with the dynamical lifespan of small particles in the early Solar System. Here, we report the presence of excess (26)Mg resulting from in situ decay of the short-lived (26)Al nuclide in CAIs and chondrules from the Allende meteorite. Six CAIs define an isochron corresponding to an initial (26)Al/(27)Al ratio of (5.25 +/- 0.10) x 10(-5), and individual model ages with uncertainties as low as +/- 30,000 years, suggesting that these objects possibly formed over a period as short as 50,000 years. In contrast, the chondrules record a range of initial (26)Al/(27)Al ratios from (5.66 +/- 0.80) to (1.36 +/- 0.52) x 10(-5), indicating that Allende chondrule formation began contemporaneously with the formation of CAIs, and continued for at least 1.4 Myr. Chondrule formation processes recorded by Allende and other chondrites may have persisted for at least 2-3 Myr in the young Solar System. 相似文献
92.
Recurrent de novo point mutations in lamin A cause Hutchinson-Gilford progeria syndrome 总被引:36,自引:0,他引:36
Eriksson M Brown WT Gordon LB Glynn MW Singer J Scott L Erdos MR Robbins CM Moses TY Berglund P Dutra A Pak E Durkin S Csoka AB Boehnke M Glover TW Collins FS 《Nature》2003,423(6937):293-298
Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disorder characterized by features reminiscent of marked premature ageing. Here, we present evidence of mutations in lamin A (LMNA) as the cause of this disorder. The HGPS gene was initially localized to chromosome 1q by observing two cases of uniparental isodisomy of 1q-the inheritance of both copies of this material from one parent-and one case with a 6-megabase paternal interstitial deletion. Sequencing of LMNA, located in this interval and previously implicated in several other heritable disorders, revealed that 18 out of 20 classical cases of HGPS harboured an identical de novo (that is, newly arisen and not inherited) single-base substitution, G608G(GGC > GGT), within exon 11. One additional case was identified with a different substitution within the same codon. Both of these mutations result in activation of a cryptic splice site within exon 11, resulting in production of a protein product that deletes 50 amino acids near the carboxy terminus. Immunofluorescence of HGPS fibroblasts with antibodies directed against lamin A revealed that many cells show visible abnormalities of the nuclear membrane. The discovery of the molecular basis of this disease may shed light on the general phenomenon of human ageing. 相似文献
93.
To ensure cell survival, it is essential that the ubiquitous pro-apoptotic machinery is kept quiescent. As death is irreversible, cells must continually integrate developmental information with regulatory inputs to control the switch between repressing and activating apoptosis. Inappropriate activation or suppression of apoptosis can lead to degenerative pathologies or tumorigenesis, respectively. Here we report that Caenorhabditis elegans inhibitor of cell death-1 (ICD-1) is necessary and sufficient to prevent apoptosis. Loss of ICD-1 leads to inappropriate apoptosis in developing and differentiated cells in various tissues. Although this apoptosis requires CED-4, it occurs independently of CED-3--the caspase essential for developmental apoptosis--showing that these core pro-apoptotic proteins have separable roles. Overexpressing ICD-1 inhibits the apoptosis of cells that are normally programmed to die. ICD-1 is the beta-subunit of the nascent polypeptide-associated complex (betaNAC) and contains a putative caspase-cleavage site and caspase recruitment domain. It localizes primarily to mitochondria, underscoring the role of mitochondria in coordinating apoptosis. Human betaNAC is a caspase substrate that is rapidly eliminated in dying cells, suggesting that ICD-1 apoptosis-suppressing activity may be inactivated by caspases. 相似文献
94.
Sanna S Jackson AU Nagaraja R Willer CJ Chen WM Bonnycastle LL Shen H Timpson N Lettre G Usala G Chines PS Stringham HM Scott LJ Dei M Lai S Albai G Crisponi L Naitza S Doheny KF Pugh EW Ben-Shlomo Y Ebrahim S Lawlor DA Bergman RN Watanabe RM Uda M Tuomilehto J Coresh J Hirschhorn JN Shuldiner AR Schlessinger D Collins FS Davey Smith G Boerwinkle E Cao A Boehnke M Abecasis GR Mohlke KL 《Nature genetics》2008,40(2):198-203
95.
International Consortium for Systemic Lupus Erythematosus Genetics 《Nature genetics》2008,40(2):204-210
Systemic lupus erythematosus (SLE) is a common systemic autoimmune disease with complex etiology but strong clustering in families (lambda(S) = approximately 30). We performed a genome-wide association scan using 317,501 SNPs in 720 women of European ancestry with SLE and in 2,337 controls, and we genotyped consistently associated SNPs in two additional independent sample sets totaling 1,846 affected women and 1,825 controls. Aside from the expected strong association between SLE and the HLA region on chromosome 6p21 and the previously confirmed non-HLA locus IRF5 on chromosome 7q32, we found evidence of association with replication (1.1 x 10(-7) < P(overall) < 1.6 x 10(-23); odds ratio = 0.82-1.62) in four regions: 16p11.2 (ITGAM), 11p15.5 (KIAA1542), 3p14.3 (PXK) and 1q25.1 (rs10798269). We also found evidence for association (P < 1 x 10(-5)) at FCGR2A, PTPN22 and STAT4, regions previously associated with SLE and other autoimmune diseases, as well as at > or =9 other loci (P < 2 x 10(-7)). Our results show that numerous genes, some with known immune-related functions, predispose to SLE. 相似文献
96.
Nath SK Han S Kim-Howard X Kelly JA Viswanathan P Gilkeson GS Chen W Zhu C McEver RP Kimberly RP Alarcón-Riquelme ME Vyse TJ Li QZ Wakeland EK Merrill JT James JA Kaufman KM Guthridge JM Harley JB 《Nature genetics》2008,40(2):152-154
We identified and replicated an association between ITGAM (CD11b) at 16p11.2 and risk of systemic lupus erythematosus (SLE) in 3,818 individuals of European descent. The strongest association was at a nonsynonymous SNP, rs1143679 (P = 1.7 x 10(-17), odds ratio = 1.78). We further replicated this association in two independent samples of individuals of African descent (P = 0.0002 and 0.003; overall meta-analysis P = 6.9 x 10(-22)). The genetic association between ITGAM and SLE implicates the alpha(M)beta2-integrin adhesion pathway in disease development. 相似文献
97.
98.
Adrianto I Wen F Templeton A Wiley G King JB Lessard CJ Bates JS Hu Y Kelly JA Kaufman KM Guthridge JM Alarcón-Riquelme ME;BIOLUPUS GENLES Networks Anaya JM Bae SC Bang SY Boackle SA Brown EE Petri MA Gallant C Ramsey-Goldman R Reveille JD Vila LM Criswell LA Edberg JC Freedman BI Gregersen PK Gilkeson GS Jacob CO James JA Kamen DL Kimberly RP Martin J Merrill JT Niewold TB Park SY Pons-Estel BA Scofield RH Stevens AM Tsao BP Vyse TJ Langefeld CD Harley JB Moser KL Webb CF Humphrey MB 《Nature genetics》2011,43(3):253-258
Systemic lupus erythematosus (SLE, MIM152700) is an autoimmune disease characterized by self-reactive antibodies resulting in systemic inflammation and organ failure. TNFAIP3, encoding the ubiquitin-modifying enzyme A20, is an established susceptibility locus for SLE. By fine mapping and genomic re-sequencing in ethnically diverse populations, we fully characterized the TNFAIP3 risk haplotype and identified a TT>A polymorphic dinucleotide (deletion T followed by a T to A transversion) associated with SLE in subjects of European (P = 1.58 × 10(-8), odds ratio = 1.70) and Korean (P = 8.33 × 10(-10), odds ratio = 2.54) ancestry. This variant, located in a region of high conservation and regulatory potential, bound a nuclear protein complex composed of NF-κB subunits with reduced avidity. Further, compared with the non-risk haplotype, the haplotype carrying this variant resulted in reduced TNFAIP3 mRNA and A20 protein expression. These results establish this TT>A variant as the most likely functional polymorphism responsible for the association between TNFAIP3 and SLE. 相似文献
99.
The value of data 总被引:1,自引:0,他引:1
Mons B van Haagen H Chichester C Hoen PB den Dunnen JT van Ommen G van Mulligen E Singh B Hooft R Roos M Hammond J Kiesel B Giardine B Velterop J Groth P Schultes E 《Nature genetics》2011,43(4):281-283
Data citation and the derivation of semantic constructs directly from datasets have now both found their place in scientific communication. The social challenge facing us is to maintain the value of traditional narrative publications and their relationship to the datasets they report upon while at the same time developing appropriate metrics for citation of data and data constructs. 相似文献
100.