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991.
Jeffrey J. Wine Damjan Glavač Gregory Hurlock Clare Robinson Margaret Lee Uros Potočnik Metka Ravnik-Glavač Michael Dean 《Mammalian genome》1998,9(4):301-305
Cystic fibrosis is a common human genetic disease caused by mutations in CFTR, a gene that codes for a chloride channel that
is regulated by phosphorylation and cytosolic nucleotides. As part of a program to discover natural animal models for human
genetic diseases, we have determined the genomic sequence of CFTR in the Rhesus monkey, Macaca mulatta. The coding region of rhesus CFTR is 98.3% identical to human CFTR at the nucleotide level and 98.2% identical and 99.7% similar at the amino acid level. Partial
sequences of flanking introns (5582 base pair positions analyzed) revealed 91.1% identity with human introns. Relative to
rhesus intronic sequence, the human sequences had 27 insertions and 22 deletions. Primer sequences for amplification of rhesus
genomic CFTR sequences are provided. The accession number is AF013753 (all 27 exons and some flanking intronic sequence).
Received: 27 August 1992 / Accepted: 5 December 1997 相似文献
992.
Ulrike Teichmann Michael E. Ray Jane Ellison Caroline Graham Graeme Wistow Paul S. Meltzer Jeffrey M. Trent William J. Pavan 《Mammalian genome》1998,9(9):715-720
We report the isolation of the murine ortholog of AIM1, a human gene whose expression is associated with the reversal of
tumorigenicity in an experimental model of melanoma. Mouse and human AIM1 are more than 90% identical in amino acid sequence
in the βγ-crystallin repeats and the C-terminal domain, and more than 75% identical in the extended N-terminal domain. Consistent
with the isolated cDNA representing the authentic AIM1 ortholog, linkage analysis localized mouse Aim1 to proximal mouse Chromosome (Chr) 10 in a conserved linkage group with genes localized to human Chr band 6q21. Searches
of EST databases identified a second AIM1-like gene in both mouse and human, suggesting the existence of a gene family. Northern
analysis demonstrates Aim1 is expressed most abundantly in adult skin, lung, heart, liver, and kidney and is temporally regulated during embryogenesis.
Aim1 is expressed highly in the shaft region of the hair follicles and the presumptive ectoderm, but not at detectable levels
in melanocytes or melanocyte precursor cells.
Received: 18 February 1998 / Accepted: 8 May 1998 相似文献
993.
Notes from some crypt watchers: regulation of renewal in the mouse intestinal epithelium 总被引:1,自引:0,他引:1
Thaddeus S Stappenbeck Melissa H Wong Jennifer R Saam Indira U Mysorekar Jeffrey I Gordon 《Current opinion in cell biology》1998,10(6):702-709
The mouse intestinal epithelium undergoes rapid renewal throughout life, thereby requiring continuous coordination of its cellular proliferation, differentiation, and death programs. Recent advances in our understanding of this process have highlighted some of the molecules that regulate renewal and their potential roles in gut neoplasia. 相似文献
994.
Yajue Huang Qinshi Jiang Kristine M. Debolt Jeffrey M. Voigt Howard D. Colby 《The Journal of steroid biochemistry and molecular biology》1998,64(5-6):305-311
We recently reported that CYP2D16, a xenobiotic-metabolizing P450 isozyme, was expressed at higher levels in adrenal microsomes from inbred Strain 13 guinea pigs than in those from outbred English Short Hair (ESH) animals. Studies were done to determine if there also were strain differences in adrenal microsomal steroid metabolism. In both inner (zona reticularis) and outer (zona fasciculata plus zona glomerulosa) zone preparations of the adrenal cortex, 21-hydroxylase activities were greater in microsomes from ESH than from Strain 13 guinea pigs. By contrast, 17-hydroxylase activities were similar in the two strains. In both strains, 21-hydroxylase activities were greater in inner than outer zone microsomes, but the opposite was found for 17-hydroxylase activities (outer>inner). Northern and Western analyses revealed higher levels of CYP21 mRNA and protein in adrenals from ESH than Strain 13 guinea pigs, but there were no strain differences in CYP17 mRNA or protein concentrations. Despite the zonal differences in adrenal 17-hydroxylase and 21-hydroxylase activities, CYP17 and CYP21 mRNA and protein levels were similar in the inner and outer zones within each strain of guinea pig. The results demonstrate strain differences in microsomal steroid metabolism that are explained by differences in CYP21 expression. By contrast, the zonal differences in steroid hydroxylase activities may be attributable to post-translational mechanisms. 相似文献
995.
996.
Jeffrey M. Leonard Steven J. Knapp Mary B. Slabaugh 《The Plant journal : for cell and molecular biology》1998,13(5):621-628
Acyl–acyl carrier protein (ACP) thioesterases with specificities on medium chain substrates (C8–C14) are requisite enzymes in plants that produce 8:0, 10:0, 12:0 and 14:0 seed oils, but they may not be the sole enzymatic determinants of chain length. The contribution to chain length regulation of a β-ketoacyl-ACP synthase, Cw KAS A1, derived from Cuphea wrightii, a species that accumulates 30% 10:0 and 54% 12:0 in seed oils, was investigated. Expression of Cw KAS A1 in Arabidopsis seeds reduced 16:0 from 8.2 to 6.2 mol%, suggesting a KAS II-type activity. In the presence of the KAS I inhibitor cerulenin, however, transgenic seed extracts extended 6:0- and 8:0-ACP at a rate four- to fivefold greater than extracts from untransformed plants, whereas no difference was observed in extension of 14:0- and 16:0-ACP. The effect of KAS A1 on seed oils was tested by combining it with the C. wrightii medium chain-specific thioesterases, Cw FatB1 and Cw FatB2, in crosses of transformed plants. Fatty acid synthesis shifted towards shorter chains in progeny expressing both classes of enzymes. KasA1/FatB1 homozygotes produced threefold more 12:0 than the FatB1 parent while 14:0 and 16:0 were reduced by one-third and one-half, respectively. F2 progeny expressing KasA1 and FatB2 produced twofold more 10:0 and 1.4-fold more 12:0 than the FatB2 parent, and the double-transgenic progeny produced one-quarter less 14:0 and one-half less 16:0 than the FatB2 parent. It is hypothesized that the shift towards production of shorter chains resulted from increased pools of medium chain acyl-ACP resulting from KAS A1 activity. The combined activities of KAS A1 and FatB thioesterases appear to determine the C. wrightii phenotype. 相似文献
997.
Intraspecific brood mixing and reduced polyandry in a maternal mouth-brooding cichlid 总被引:3,自引:1,他引:2
Kellogg Karen A.; Markert Jeffrey A.; Stauffer Jay R. Jr.; Kocher Thomas D. 《Behavioral ecology》1998,9(3):309-312
Microsatellite loci were used to evaluate the level of polyandryand intraspecific brood mixing in Protomelas c.f. spilopterus,a paedophagous, maternal mouth-brooding cichlid from Lake MakaiAfrica. We found that broods were fertilized by one to threemales, which was a reduced level of multiple paternity comparedto other mouth-brooding cichlids. Low density of breeding malesand the risk of intraspecific predation are likely explanationsfor reduced polyandry. Intraspecific brood-mixing was foundin four out of the six broods examined, with the proportionsof foreign fry ranging from 6% to 65%. The potential originsof brood mixing are discussed, although no firm conclusionscan be drawn given the limited behavioral observations for thisspecies. 相似文献
998.
Ihab A. Abumuhor Paula H. Spencer Jeffrey A. Cohlberg 《Journal of structural biology》1998,123(3):187-198
The pathway of filament assembly from the neuronal intermediate filament α-intermexin was investigated. Optimal assembly occurred in solutions of pH 6.5 to 7 and moderate ionic strength at 37°C. Short filaments formed upon dialysis at 24°C, which elongated further when incubated at 37°C. Soluble forms of α-internexin were characterized by analytical ultracentrifugation and electron microscopy. In 10 mM Tris, pH 8, conditions that favor formation of tetramers and other small oligomers for other intermediate filament proteins, α-internexin formed 10.5 S particles, apparently unit-length half-filaments in the form of rods 10.6 nm in diameter and 68 nm long. Dialysis vs the same buffer with added 10 mM NaCl yielded 16 S rods, probably unit-length filaments, of the same length but 13.0 nm in diameter. At 50 mM NaCl, rods about 13 nm in diameter and heterogeneous in length were observed in electron micrographs, apparently formed from longitudinal annealing of unit-length rods. The results favor a model of assembly in which coiled coil dimers aggregate laterally to form first “unit-length half-filaments” (Herrmann, H., and Aebi, U. (1998)Curr. Opin. Struct. Biol.8, 177–185) and then “unit-length filaments,” which subsequently elongate by annealing. 相似文献
999.
Biolistic transfer of large DNA fragments to tobacco cells using YACs retrofitted for plant transformation 总被引:1,自引:0,他引:1
Mullen Jeffrey Adam Gerhard Blowers Alan Earle Elizabeth 《Molecular breeding : new strategies in plant improvement》1998,4(5):449-457
To determine whether large DNA molecules could be transferred and integrated intact into the genome of plant cells, we bombarded tobacco suspension cells with yeast DNA containing artificial chromosomes (YACs) having sizes of 80, 150, 210, or 550 kilobases (kb). Plant selectable markers were retrofitted on both YAC arms so that recovery of each arm in transgenic calli could be monitored. Stably transformed calli resistant to kanamycin (300 mg/L) were recovered for each size of YAC tested. Two of 12 kanamycin-resistant transformants for the 80 kb YAC and 8 of 29 kanamycin-resistant transformants for the 150 kb YAC also contained a functional hygromycin gene derived from the opposite YAC arm. Southern analyses using probes that spanned the entire 55 kb insert region of the 80 kb YAC confirmed that one of the two double-resistant lines had integrated a fully intact single copy of the YAC DNA while the other contained a major portion of the insert. Transgenic lines that contained only one selectable marker gene from the 80 kb YAC incorporated relatively small portions of the YAC insert DNA distal to the selectable marker. Our data suggest genomic DNA cloned in artificial chromosomes up to 150 kb in size have a reasonable likelihood of being transferred by biolistic methods and integrated intact into the genome of plant cells. Biolistic transfer of YAC DNA may accelerate the isolation of agronomically useful plant genes using map-based cloning strategies. 相似文献
1000.
Myelin sheath formation depends on appropriate axo-glial interactions that are mediated by myelin-specific surface molecules. In this study, we have used quantitative morphological analysis to determine the roles of the prominent myelin lipids galactocerebroside (GalC) and sulfatide in both central and peripheral myelin formation, exploiting mutant mice incapable of synthesizing these lipids. Our results demonstrate a significant increase in uncompacted myelin sheaths, the frequency of multiple cytoplasmic loops, redundant myelin profiles, and Schmidt-Lanterman incisures in the CNS of these mutant mice. In contrast, PNS myelin appeared structurally normal in these animals; however, at post-natal day 10, greater than 10% of the axons withered and pulled away from their myelin sheaths. These results indicate that GalC and sulfatide are critical to the formation of CNS myelin. In contrast, PNS myelin formation is not dependent on these lipids; however, GalC and sulfatide appear to be instrumental in maintaining Schwann cell-axon contact during a specific developmental window. 相似文献