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991.
Evidence is presented indicating that Lichanura roseofusca and Lichanura trivirgata are conspecific. Data include the report of an intermediate specimen from El Arco, Baja California Norte, a site midway between the previously known peninsular ranges of the two species; captive hybridization provides additional support for the conclusion. 相似文献
992.
Identification of the gene altered in Berardinelli-Seip congenital lipodystrophy on chromosome 11q13
Magré J Delépine M Khallouf E Gedde-Dahl T Van Maldergem L Sobel E Papp J Meier M Mégarbané A Bachy A Verloes A d'Abronzo FH Seemanova E Assan R Baudic N Bourut C Czernichow P Huet F Grigorescu F de Kerdanet M Lacombe D Labrune P Lanza M Loret H Matsuda F Navarro J Nivelon-Chevalier A Polak M Robert JJ Tric P Tubiana-Rufi N Vigouroux C Weissenbach J Savasta S Maassen JA Trygstad O Bogalho P Freitas P Medina JL Bonnicci F Joffe BI Loyson G Panz VR Raal FJ O'Rahilly S Stephenson T Kahn CR 《Nature genetics》2001,28(4):365-370
Congenital generalized lipodystrophy, or Berardinelli-Seip syndrome (BSCL), is a rare autosomal recessive disease characterized by a near-absence of adipose tissue from birth or early infancy and severe insulin resistance. Other clinical and biological features include acanthosis nigricans, hyperandrogenism, muscular hypertrophy, hepatomegaly, altered glucose tolerance or diabetes mellitus, and hypertriglyceridemia. A locus (BSCL1) has been mapped to 9q34 with evidence of heterogeneity. Here, we report a genome screen of nine BSCL families from two geographical clusters (in Lebanon and Norway). We identified a new disease locus, designated BSCL2, within the 2.5-Mb interval flanked by markers D11S4076 and D11S480 on chromosome 11q13. Analysis of 20 additional families of various ethnic origins led to the identification of 11 families in which the disease cosegregates with the 11q13 locus; the remaining families provide confirmation of linkage to 9q34. Sequence analysis of genes located in the 11q13 interval disclosed mutations in a gene homologous to the murine guanine nucleotide-binding protein (G protein), gamma3-linked gene (Gng3lg) in all BSCL2-linked families. BSCL2 is most highly expressed in brain and testis and encodes a protein (which we have called seipin) of unknown function. Most of the variants are null mutations and probably result in a severe disruption of the protein. These findings are of general importance for understanding the molecular mechanisms underlying regulation of body fat distribution and insulin resistance. 相似文献
993.
The evolution of 'thunniform' body shapes in several different groups of vertebrates, including whales, ichthyosaurs and several species of large pelagic fishes supports the view that physical and hydromechanical demands provided important selection pressures to optimize body design for locomotion during vertebrate evolution. Recognition of morphological similarities between lamnid sharks (the most well known being the great white and the mako) and tunas has led to a general expectation that they also have converged in their functional design; however, no quantitative data exist on the mechanical performance of the locomotor system in lamnid sharks. Here we examine the swimming kinematics, in vivo muscle dynamics and functional morphology of the force-transmission system in a lamnid shark, and show that the evolutionary convergence in body shape and mechanical design between the distantly related lamnids and tunas is much more than skin deep; it extends to the depths of the myotendinous architecture and the mechanical basis for propulsive movements. We demonstrate that not only have lamnids and tunas converged to a much greater extent than previously known, but they have also developed morphological and functional adaptations in their locomotor systems that are unlike virtually all other fishes. 相似文献
994.
BubR1 insufficiency causes early onset of aging-associated phenotypes and infertility in mice 总被引:17,自引:0,他引:17
Baker DJ Jeganathan KB Cameron JD Thompson M Juneja S Kopecka A Kumar R Jenkins RB de Groen PC Roche P van Deursen JM 《Nature genetics》2004,36(7):744-749
Faithful segregation of replicated chromosomes is essential for maintenance of genetic stability and seems to be monitored by several mitotic checkpoints. Various components of these checkpoints have been identified in mammals, but their physiological relevance is largely unknown. Here we show that mutant mice with low levels of the spindle assembly checkpoint protein BubR1 develop progressive aneuploidy along with a variety of progeroid features, including short lifespan, cachectic dwarfism, lordokyphosis, cataracts, loss of subcutaneous fat and impaired wound healing. Graded reduction of BubR1 expression in mouse embryonic fibroblasts causes increased aneuploidy and senescence. Male and female mutant mice have defects in meiotic chromosome segregation and are infertile. Natural aging of wild-type mice is marked by decreased expression of BubR1 in multiple tissues, including testis and ovary. These results suggest a role for BubR1 in regulating aging and infertility. 相似文献
995.
A transcriptomic analysis of the phylum Nematoda 总被引:1,自引:0,他引:1
Parkinson J Mitreva M Whitton C Thomson M Daub J Martin J Schmid R Hall N Barrell B Waterston RH McCarter JP Blaxter ML 《Nature genetics》2004,36(12):1259-1267
The phylum Nematoda occupies a huge range of ecological niches, from free-living microbivores to human parasites. We analyzed the genomic biology of the phylum using 265,494 expressed-sequence tag sequences, corresponding to 93,645 putative genes, from 30 species, including 28 parasites. From 35% to 70% of each species' genes had significant similarity to proteins from the model nematode Caenorhabditis elegans. More than half of the putative genes were unique to the phylum, and 23% were unique to the species from which they were derived. We have not yet come close to exhausting the genomic diversity of the phylum. We identified more than 2,600 different known protein domains, some of which had differential abundances between major taxonomic groups of nematodes. We also defined 4,228 nematode-specific protein families from nematode-restricted genes: this class of genes probably underpins species- and higher-level taxonomic disparity. Nematode-specific families are particularly interesting as drug and vaccine targets. 相似文献
996.
Kleta R Romeo E Ristic Z Ohura T Stuart C Arcos-Burgos M Dave MH Wagner CA Camargo SR Inoue S Matsuura N Helip-Wooley A Bockenhauer D Warth R Bernardini I Visser G Eggermann T Lee P Chairoungdua A Jutabha P Babu E Nilwarangkoon S Anzai N Kanai Y Verrey F Gahl WA Koizumi A 《Nature genetics》2004,36(9):999-1002
Hartnup disorder, an autosomal recessive defect named after an English family described in 1956 (ref. 1), results from impaired transport of neutral amino acids across epithelial cells in renal proximal tubules and intestinal mucosa. Symptoms include transient manifestations of pellagra (rashes), cerebellar ataxia and psychosis. Using homozygosity mapping in the original family in whom Hartnup disorder was discovered, we confirmed that the critical region for one causative gene was located on chromosome 5p15 (ref. 3). This region is homologous to the area of mouse chromosome 13 that encodes the sodium-dependent amino acid transporter B(0)AT1 (ref. 4). We isolated the human homolog of B(0)AT1, called SLC6A19, and determined its size and molecular organization. We then identified mutations in SLC6A19 in members of the original family in whom Hartnup disorder was discovered and of three Japanese families. The protein product of SLC6A19, the Hartnup transporter, is expressed primarily in intestine and renal proximal tubule and functions as a neutral amino acid transporter. 相似文献
997.
Churchill GA Airey DC Allayee H Angel JM Attie AD Beatty J Beavis WD Belknap JK Bennett B Berrettini W Bleich A Bogue M Broman KW Buck KJ Buckler E Burmeister M Chesler EJ Cheverud JM Clapcote S Cook MN Cox RD Crabbe JC Crusio WE Darvasi A Deschepper CF Doerge RW Farber CR Forejt J Gaile D Garlow SJ Geiger H Gershenfeld H Gordon T Gu J Gu W de Haan G Hayes NL Heller C Himmelbauer H Hitzemann R Hunter K Hsu HC Iraqi FA Ivandic B Jacob HJ Jansen RC Jepsen KJ Johnson DK Johnson TE Kempermann G 《Nature genetics》2004,36(11):1133-1137
The goal of the Complex Trait Consortium is to promote the development of resources that can be used to understand, treat and ultimately prevent pervasive human diseases. Existing and proposed mouse resources that are optimized to study the actions of isolated genetic loci on a fixed background are less effective for studying intact polygenic networks and interactions among genes, environments, pathogens and other factors. The Collaborative Cross will provide a common reference panel specifically designed for the integrative analysis of complex systems and will change the way we approach human health and disease. 相似文献
998.
999.
1000.
Spicules are dynamic jets propelled upwards (at speeds of approximately 20 km s(-1)) from the solar 'surface' (photosphere) into the magnetized low atmosphere of the Sun. They carry a mass flux of 100 times that of the solar wind into the low solar corona. With diameters close to observational limits (< 500 km), spicules have been largely unexplained since their discovery in 1877: none of the existing models can account simultaneously for their ubiquity, evolution, energetics and recently discovered periodicity. Here we report a synthesis of modelling and high-spatial-resolution observations in which numerical simulations driven by observed photospheric velocities directly reproduce the observed occurrence and properties of individual spicules. Photospheric velocities are dominated by convective granulation (which has been considered before for spicule formation) and by p-modes (which are solar global resonant acoustic oscillations visible in the photosphere as quasi-sinusoidal velocity and intensity pulsations). We show that the previously ignored p-modes are crucial: on inclined magnetic flux tubes, the p-modes leak sufficient energy from the global resonant cavity into the chromosphere to power shocks that drive upward flows and form spicules. 相似文献