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排序方式: 共有111条查询结果,搜索用时 62 毫秒
101.
Aharonian FA Akhperjanian AG Aye KM Bazer-Bachi AR Beilicke M Benbow W Berge D Berghaus P Bernlöhr K Bolz O Boisson C Borgmeier C Breitling F Brown AM Gordo JB Chadwick PM Chitnis VR Chounet LM Cornils R Costamante L Degrange B Djannati-Ataï A Drury LO Ergin T Espigat P Feinstein F Fleury P Fontaine G Funk S Gallant YA Giebels B Gillessen S Goret P Guy J Hadjichristidis C Hauser M Heinzelmann G Henri G Hermann G Hinton JA Hofmann W Holleran M Horns D De Jager OC Jung I Khélifi B Komin N 《Nature》2004,432(7013):75-77
A significant fraction of the energy density of the interstellar medium is in the form of high-energy charged particles (cosmic rays). The origin of these particles remains uncertain. Although it is generally accepted that the only sources capable of supplying the energy required to accelerate the bulk of Galactic cosmic rays are supernova explosions, and even though the mechanism of particle acceleration in expanding supernova remnant (SNR) shocks is thought to be well understood theoretically, unequivocal evidence for the production of high-energy particles in supernova shells has proven remarkably hard to find. Here we report on observations of the SNR RX J1713.7 - 3946 (G347.3 - 0.5), which was discovered by ROSAT in the X-ray spectrum and later claimed as a source of high-energy gamma-rays of TeV energies (1 TeV = 10(12) eV). We present a TeV gamma-ray image of the SNR: the spatially resolved remnant has a shell morphology similar to that seen in X-rays, which demonstrates that very-high-energy particles are accelerated there. The energy spectrum indicates efficient acceleration of charged particles to energies beyond 100 TeV, consistent with current ideas of particle acceleration in young SNR shocks. 相似文献
102.
Extinction risk from climate change 总被引:20,自引:0,他引:20
Thomas CD Cameron A Green RE Bakkenes M Beaumont LJ Collingham YC Erasmus BF De Siqueira MF Grainger A Hannah L Hughes L Huntley B Van Jaarsveld AS Midgley GF Miles L Ortega-Huerta MA Peterson AT Phillips OL Williams SE 《Nature》2004,427(6970):145-148
Climate change over the past approximately 30 years has produced numerous shifts in the distributions and abundances of species and has been implicated in one species-level extinction. Using projections of species' distributions for future climate scenarios, we assess extinction risks for sample regions that cover some 20% of the Earth's terrestrial surface. Exploring three approaches in which the estimated probability of extinction shows a power-law relationship with geographical range size, we predict, on the basis of mid-range climate-warming scenarios for 2050, that 15-37% of species in our sample of regions and taxa will be 'committed to extinction'. When the average of the three methods and two dispersal scenarios is taken, minimal climate-warming scenarios produce lower projections of species committed to extinction ( approximately 18%) than mid-range ( approximately 24%) and maximum-change ( approximately 35%) scenarios. These estimates show the importance of rapid implementation of technologies to decrease greenhouse gas emissions and strategies for carbon sequestration. 相似文献
103.
Interdecadal variation in the extent of South Pacific tropical waters during the Younger Dryas event
During the Younger Dryas event, about 12,000 years ago, the Northern Hemisphere cooled by between 2 and 10 degrees C (refs 1, 2) whereas East Antarctica experienced warming. But the spatial signature of the event in the southern mid-latitudes and tropics is less well known, as records are sparse and inconclusive. Here we present high-resolution analyses of skeletal Sr/Ca and 18O/16O ratios for a giant fossil Diploastrea heliopora coral that was preserved in growth position on the raised reef terraces of Espiritu Santo Island, Vanuatu, in the southwestern tropical Pacific Ocean. Our data indicate that sea surface temperatures in Vanuatu were on average 4.5 +/- 1.3 degrees C cooler during the Younger Dryas event than today, with a significant interdecadal modulation. The amplified annual cycle of sea surface temperatures, relative to today, indicates that cooling was caused by the compression of tropical waters towards the Equator. The positive correlation in our record between the oxygen isotope ratios of sea water and sea surface temperatures suggests that the South Pacific convergence zone, which brings 18O-depleted precipitation to the area today, was not active during the Younger Dryas period. 相似文献
104.
Gene expression as a drug discovery tool 总被引:1,自引:0,他引:1
105.
Eeles RA Kote-Jarai Z Giles GG Olama AA Guy M Jugurnauth SK Mulholland S Leongamornlert DA Edwards SM Morrison J Field HI Southey MC Severi G Donovan JL Hamdy FC Dearnaley DP Muir KR Smith C Bagnato M Ardern-Jones AT Hall AL O'Brien LT Gehr-Swain BN Wilkinson RA Cox A Lewis S Brown PM Jhavar SG Tymrakiewicz M Lophatananon A Bryant SL;UK Genetic Prostate Cancer Study Collaborators;British Association of Urological Surgeons' Section of Oncology;UK ProtecT Study Collaborators Horwich A Huddart RA 《Nature genetics》2008,40(3):316-321
Prostate cancer is the most common cancer affecting males in developed countries. It shows consistent evidence of familial aggregation, but the causes of this aggregation are mostly unknown. To identify common alleles associated with prostate cancer risk, we conducted a genome-wide association study (GWAS) using blood DNA samples from 1,854 individuals with clinically detected prostate cancer diagnosed at =60 years or with a family history of disease, and 1,894 population-screened controls with a low prostate-specific antigen (PSA) concentration (<0.5 ng/ml). We analyzed these samples for 541,129 SNPs using the Illumina Infinium platform. Initial putative associations were confirmed using a further 3,268 cases and 3,366 controls. We identified seven loci associated with prostate cancer on chromosomes 3, 6, 7, 10, 11, 19 and X (P = 2.7 x 10(-8) to P = 8.7 x 10(-29)). We confirmed previous reports of common loci associated with prostate cancer at 8q24 and 17q. Moreover, we found that three of the newly identified loci contain candidate susceptibility genes: MSMB, LMTK2 and KLK3. 相似文献
106.
Merveille AC Davis EE Becker-Heck A Legendre M Amirav I Bataille G Belmont J Beydon N Billen F Clément A Clercx C Coste A Crosbie R de Blic J Deleuze S Duquesnoy P Escalier D Escudier E Fliegauf M Horvath J Hill K Jorissen M Just J Kispert A Lathrop M Loges NT Marthin JK Momozawa Y Montantin G Nielsen KG Olbrich H Papon JF Rayet I Roger G Schmidts M Tenreiro H Towbin JA Zelenika D Zentgraf H Georges M Lequarré AS Katsanis N Omran H Amselem S 《Nature genetics》2011,43(1):72-78
Primary ciliary dyskinesia (PCD) is an inherited disorder characterized by recurrent infections of the upper and lower respiratory tract, reduced fertility in males and situs inversus in about 50% of affected individuals (Kartagener syndrome). It is caused by motility defects in the respiratory cilia that are responsible for airway clearance, the flagella that propel sperm cells and the nodal monocilia that determine left-right asymmetry. Recessive mutations that cause PCD have been identified in genes encoding components of the outer dynein arms, radial spokes and cytoplasmic pre-assembly factors of axonemal dyneins, but these mutations account for only about 50% of cases of PCD. We exploited the unique properties of dog populations to positionally clone a new PCD gene, CCDC39. We found that loss-of-function mutations in the human ortholog underlie a substantial fraction of PCD cases with axonemal disorganization and abnormal ciliary beating. Functional analyses indicated that CCDC39 localizes to ciliary axonemes and is essential for assembly of inner dynein arms and the dynein regulatory complex. 相似文献
107.
Conrad DF Keebler JE DePristo MA Lindsay SJ Zhang Y Casals F Idaghdour Y Hartl CL Torroja C Garimella KV Zilversmit M Cartwright R Rouleau GA Daly M Stone EA Hurles ME Awadalla P; Genomes Project 《Nature genetics》2011,43(7):712-714
J.B.S. Haldane proposed in 1947 that the male germline may be more mutagenic than the female germline. Diverse studies have supported Haldane's contention of a higher average mutation rate in the male germline in a variety of mammals, including humans. Here we present, to our knowledge, the first direct comparative analysis of male and female germline mutation rates from the complete genome sequences of two parent-offspring trios. Through extensive validation, we identified 49 and 35 germline de novo mutations (DNMs) in two trio offspring, as well as 1,586 non-germline DNMs arising either somatically or in the cell lines from which the DNA was derived. Most strikingly, in one family, we observed that 92% of germline DNMs were from the paternal germline, whereas, in contrast, in the other family, 64% of DNMs were from the maternal germline. These observations suggest considerable variation in mutation rates within and between families. 相似文献
108.
Girard SL Gauthier J Noreau A Xiong L Zhou S Jouan L Dionne-Laporte A Spiegelman D Henrion E Diallo O Thibodeau P Bachand I Bao JY Tong AH Lin CH Millet B Jaafari N Joober R Dion PA Lok S Krebs MO Rouleau GA 《Nature genetics》2011,43(9):860-863
Schizophrenia is a severe psychiatric disorder that profoundly affects cognitive, behavioral and emotional processes. The wide spectrum of symptoms and clinical variability in schizophrenia suggest a complex genetic etiology, which is consistent with the numerous loci thus far identified by linkage, copy number variation and association studies. Although schizophrenia heritability may be as high as ~80%, the genes responsible for much of this heritability remain to be identified. Here we sequenced the exomes of 14 schizophrenia probands and their parents. We identified 15 de novo mutations (DNMs) in eight probands, which is significantly more than expected considering the previously reported DNM rate. In addition, 4 of the 15 identified DNMs are nonsense mutations, which is more than what is expected by chance. Our study supports the notion that DNMs may account for some of the heritability reported for schizophrenia while providing a list of genes possibly involved in disease pathogenesis. 相似文献
109.
Helgadottir A Thorleifsson G Magnusson KP Grétarsdottir S Steinthorsdottir V Manolescu A Jones GT Rinkel GJ Blankensteijn JD Ronkainen A Jääskeläinen JE Kyo Y Lenk GM Sakalihasan N Kostulas K Gottsäter A Flex A Stefansson H Hansen T Andersen G Weinsheimer S Borch-Johnsen K Jorgensen T Shah SH Quyyumi AA Granger CB Reilly MP Austin H Levey AI Vaccarino V Palsdottir E Walters GB Jonsdottir T Snorradottir S Magnusdottir D Gudmundsson G Ferrell RE Sveinbjornsdottir S Hernesniemi J Niemelä M Limet R 《Nature genetics》2008,40(2):217-224
Recently, two common sequence variants on 9p21, tagged by rs10757278-G and rs10811661-T, were reported to be associated with coronary artery disease (CAD) and type 2 diabetes (T2D), respectively. We proceeded to further investigate the contributions of these variants to arterial diseases and T2D. Here we report that rs10757278-G is associated with, in addition to CAD, abdominal aortic aneurysm (AAA; odds ratio (OR) = 1.31, P = 1.2 x 10(-12)) and intracranial aneurysm (OR = 1.29, P = 2.5 x 10(-6)), but not with T2D. This variant is the first to be described that affects the risk of AAA and intracranial aneurysm in many populations. The association of rs10811661-T to T2D replicates in our samples, but the variant does not associate with any of the five arterial diseases examined. These findings extend our insight into the role of the sequence variant tagged by rs10757278-G and show that it is not confined to atherosclerotic diseases. 相似文献
110.
Gros-Louis F Dupré N Dion P Fox MA Laurent S Verreault S Sanes JR Bouchard JP Rouleau GA 《Nature genetics》2007,39(1):80-85
The past decade has seen great advances in unraveling the biological basis of hereditary ataxias. Molecular studies of spinocerebellar ataxias (SCA) have extended our understanding of dominant ataxias. Causative genes have been identified for a few autosomal recessive ataxias: Friedreich's ataxia, ataxia with vitamin E deficiency, ataxia telangiectasia, recessive spastic ataxia of Charlevoix-Saguenay and ataxia with oculomotor apraxia type 1 (refs. 6,7) and type 2 (ref. 8). Nonetheless, genes remain unidentified for most recessive ataxias. Additionally, pure cerebellar ataxias, which represent up to 20% of all ataxias, remain poorly studied with only two causative dominant genes being described: CACNA1A (ref. 9) and SPTBN2 (ref. 10). Here, we report a newly discovered form of recessive ataxia in a French-Canadian cohort and show that SYNE1 mutations are causative in all of our kindreds, making SYNE1 the first identified gene responsible for a recessively inherited pure cerebellar ataxia. 相似文献