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181.
Mutations in a member of the Ras superfamily of small GTP-binding proteins causes Bardet-Biedl syndrome 总被引:10,自引:0,他引:10
Fan Y Esmail MA Ansley SJ Blacque OE Boroevich K Ross AJ Moore SJ Badano JL May-Simera H Compton DS Green JS Lewis RA van Haelst MM Parfrey PS Baillie DL Beales PL Katsanis N Davidson WS Leroux MR 《Nature genetics》2004,36(9):989-993
RAB, ADP-ribosylation factors (ARFs) and ARF-like (ARL) proteins belong to the Ras superfamily of small GTP-binding proteins and are essential for various membrane-associated intracellular trafficking processes. None of the approximately 50 known members of this family are linked to human disease. Using a bioinformatic screen for ciliary genes in combination with mutational analyses, we identified ARL6 as the gene underlying Bardet-Biedl syndrome type 3, a multisystemic disorder characterized by obesity, blindness, polydactyly, renal abnormalities and cognitive impairment. We uncovered four different homozygous substitutions in ARL6 in four unrelated families affected with Bardet-Biedl syndrome, two of which disrupt a threonine residue important for GTP binding and function of several related small GTP-binding proteins. Analysis of the Caenorhabditis elegans ARL6 homolog indicates that it is specifically expressed in ciliated cells, and that, in addition to the postulated cytoplasmic functions of ARL proteins, it undergoes intraflagellar transport. These findings implicate a small GTP-binding protein in ciliary transport and the pathogenesis of a pleiotropic disorder. 相似文献
182.
Moreira MC Klur S Watanabe M Németh AH Le Ber I Moniz JC Tranchant C Aubourg P Tazir M Schöls L Pandolfo M Schulz JB Pouget J Calvas P Shizuka-Ikeda M Shoji M Tanaka M Izatt L Shaw CE M'Zahem A Dunne E Bomont P Benhassine T Bouslam N Stevanin G Brice A Guimarães J Mendonça P Barbot C Coutinho P Sequeiros J Dürr A Warter JM Koenig M 《Nature genetics》2004,36(3):225-227
Ataxia-ocular apraxia 2 (AOA2) was recently identified as a new autosomal recessive ataxia. We have now identified causative mutations in 15 families, which allows us to clinically define this entity by onset between 10 and 22 years, cerebellar atrophy, axonal sensorimotor neuropathy, oculomotor apraxia and elevated alpha-fetoprotein (AFP). Ten of the fifteen mutations cause premature termination of a large DEAxQ-box helicase, the human ortholog of yeast Sen1p, involved in RNA maturation and termination. 相似文献
183.
During spermatogenesis in the mammalian testis, stem cells (spermatogonia) differentiate into spermatocytes, which subsequently undergo two consecutive meiotic divisions to give rise to haploid spermatids. These cells are initially round but progressively elongate, condense their nuclei, acquire flagellar and acrosomal structures, and shed a significant amount of their cytoplasm to form spermatozoa (the sperm cells) in a developmental cascade termed spermiogenesis. Defects in these processes will lead to a lack of mature sperm cells (azoospermia), which is a major cause of male infertility in the human population. Here we report that a cell-surface protein of the immunoglobulin superfamily, junctional adhesion molecule-C (JAM-C), is critically required for the differentiation of round spermatids into spermatozoa in mice. We found that Jam-C is essential for the polarization of round spermatids, a function that we attribute to its role in the assembly of a cell polarity complex. 相似文献
184.
The transcription factor Engrailed-2 guides retinal axons 总被引:1,自引:0,他引:1
Brunet I Weinl C Piper M Trembleau A Volovitch M Harris W Prochiantz A Holt C 《Nature》2005,438(7064):94-98
185.
Aubin I Adams CP Opsahl S Septier D Bishop CE Auge N Salvayre R Negre-Salvayre A Goldberg M Guénet JL Poirier C 《Nature genetics》2005,37(8):803-805
The mouse mutation fragilitas ossium (fro) leads to a syndrome of severe osteogenesis and dentinogenesis imperfecta with no detectable collagen defect. Positional cloning of the locus identified a deletion in the gene encoding neutral sphingomyelin phosphodiesterase 3 (Smpd3) that led to complete loss of enzymatic activity. Our knowledge of SMPD3 function is consistent with the pathology observed in mutant mice and provides new insight into human pathologies. 相似文献
186.
Zollikofer CP Ponce de León MS Lieberman DE Guy F Pilbeam D Likius A Mackaye HT Vignaud P Brunet M 《Nature》2005,434(7034):755-759
Previous research in Chad at the Toros-Menalla 266 fossiliferous locality (about 7 million years old) uncovered a nearly complete cranium (TM 266-01-60-1), three mandibular fragments and several isolated teeth attributed to Sahelanthropus tchadensis. Of this material, the cranium is especially important for testing hypotheses about the systematics and behavioural characteristics of this species, but is partly distorted from fracturing, displacement and plastic deformation. Here we present a detailed virtual reconstruction of the TM 266 cranium that corrects these distortions. The reconstruction confirms that S. tchadensis is a hominid and is not more closely related to the African great apes. Analysis of the basicranium further indicates that S. tchadensis might have been an upright biped, suggesting that bipedalism was present in the earliest known hominids, and probably arose soon after the divergence of the chimpanzee and human lineages. 相似文献
187.
Summary Incorporation of linoleic acid14C by human erythrocyte membranes at different stades of blood conservation was studied for evaluating the metabolic state of these membranes. The incorporation was found to increase during the first two weeks of conservation for female and male blood, with important individual variation. However, this increase was more important for male blood. Then the incorporation decreased until the end of experimentation, after 6 weeks of conservation.
Chercheur du Centre de Transfusion Sanguine de Lyon, Service du DrA. Jouvenceaux. 相似文献
Chercheur du Centre de Transfusion Sanguine de Lyon, Service du DrA. Jouvenceaux. 相似文献
188.
Van Laere AS Nguyen M Braunschweig M Nezer C Collette C Moreau L Archibald AL Haley CS Buys N Tally M Andersson G Georges M Andersson L 《Nature》2003,425(6960):832-836
Most traits and disorders have a multifactorial background indicating that they are controlled by environmental factors as well as an unknown number of quantitative trait loci (QTLs). The identification of mutations underlying QTLs is a challenge because each locus explains only a fraction of the phenotypic variation. A paternally expressed QTL affecting muscle growth, fat deposition and size of the heart in pigs maps to the IGF2 (insulin-like growth factor 2) region. Here we show that this QTL is caused by a nucleotide substitution in intron 3 of IGF2. The mutation occurs in an evolutionarily conserved CpG island that is hypomethylated in skeletal muscle. The mutation abrogates in vitro interaction with a nuclear factor, probably a repressor, and pigs inheriting the mutation from their sire have a threefold increase in IGF2 messenger RNA expression in postnatal muscle. Our study establishes a causal relationship between a single-base-pair substitution in a non-coding region and a QTL effect. The result supports the long-held view that regulatory mutations are important for controlling phenotypic variation. 相似文献
189.
Cytochrome c oxidase, the terminal enzyme of cellular respiration in mitochondria and many bacteria, reduces O(2) to water. This four-electron reduction process is coupled to translocation (pumping) of four protons across the mitochondrial or bacterial membrane; however, proton pumping is poorly understood. Proton pumping was thought to be linked exclusively to the oxidative phase, that is, to the transfer of the third and fourth electron. Upon re-evaluation of these data, however, this proposal has been questioned, and a transport mechanism including proton pumping in the reductive phase--that is, during the transfer of the first two electrons--was suggested. Subsequently, additional studies reported that proton pumping during the reductive phase can occur, but only when it is immediately preceded by an oxidative phase. To help clarify the issue we have measured the generation of the electric potential across the membrane, starting from a defined one-electron reduced state. Here we show that a second electron transfer into the enzyme leads to charge translocation corresponding to pumping of one proton without necessity for a preceding turnover. 相似文献
190.
Mutations in IRF6 cause Van der Woude and popliteal pterygium syndromes 总被引:25,自引:0,他引:25
Kondo S Schutte BC Richardson RJ Bjork BC Knight AS Watanabe Y Howard E de Lima RL Daack-Hirsch S Sander A McDonald-McGinn DM Zackai EH Lammer EJ Aylsworth AS Ardinger HH Lidral AC Pober BR Moreno L Arcos-Burgos M Valencia C Houdayer C Bahuau M Moretti-Ferreira D Richieri-Costa A Dixon MJ Murray JC 《Nature genetics》2002,32(2):285-289