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61.
Sabine Lhernould Yannis Karamanos Sylvain Bourgerie Gerard Strecker Raymond Julien Henri Morvan 《Glycoconjugate journal》1992,9(4):191-197
We have previously isolated mannoside and xylomannoside oligosaccharides with one or two terminal reducingN-acetylglucosamine residues from the extracellular medium of white campion (Silene alba) suspension culture. We have now demonstrated the presence of peptide-N
4-(N-acetylglucosaminyl)asparagine amidase (PNGase) activity in cell extracts as well in the culture medium that could explain the production of those compounds. An additional xylomannoside, (GlcNAc)Man3(Xyl)GlcNAc(Fuc)GlcNAc, was characterized, and1H- and13C-NMR assignments for the oligosaccharide Man3(Xyl)GlcNAc(Fuc)GlcNAc were obtained using homonuclear and heteronuclear spectroscopy (COSY).Abbreviations Endo
endo--N-acetylglucosaminidase
- Fuc
fucose
- GlcNAc
N-acetylglucosamine
- Man
mannose
- NMR
nuclear magnetic resonance
- PNGase
peptide-N
4-(N-acetylglucosaminyl)asparagine amidase
- Xyl
xylose 相似文献
62.
Alba Vecchini Luciano Binaglia Paolo Di Nardo Marilena Minieri Giuseppe Tallarida 《Molecular and cellular biochemistry》1992,110(1):47-54
The activity of phospholipid base exchange enzymes has been evaluated in cardiac sarcolemmal membranes from Syrian Golden
hamsters and from a hamster strain (UM-X7.1) characterized by a genetic form of hypertrophic cardiomyopathy. No choline base
exchange activity and only a little serine base exchange activity were detected, whereas the ethanolamine base exchange enzyme
was found highly active in membranes from both strains. For this reason, the present study is focussed on the ethanolamine
base exchange enzyme. The apparent Km for ethanolamine of ethanolamine base exchange enzyme from Syrian Golden membranes and
from UM-X7.1 strain membranes are 18 and 32 μM, respectively. The specific activity of the sarcolemmal ethanolamine base exchange
enzyme is lower in the UM-X7.1 strain than in Syrian Golden hamsters. The calcium-dependence of the enzyme appears different
when the membranes from the two strains are compared. Indeed, after removal of the membrane-bound divalent cations, comparable
activities are found in both membrane preparations, whereas, upon addition of Ca2+ to the incubation mixtures, the activity of the enzyme is enhanced in the membranes from Syrian Golden strain more than in
those from UM-X7.1 strain. The cholesterol content of sarcolemmal membranes is higher in the cardiomyopathic strain than in
the Syrian Golden hamsters. A possible relation between changes of the membrane lipid composition and of the ethanolamine
base exchange activity is discussed. 相似文献
63.
Genomic potential of erythroid and leukocytic cells of Rana pipiens analyzed by nuclear transfer into diplotene and maturing oocytes 总被引:3,自引:0,他引:3
Marie A. Di Berardino Nancy Hoffner Orr 《Differentiation; research in biological diversity》1992,50(1):1-13
In order to determine whether differentiated somatic cells maintain genetic totipotency, nuclear transplantations from several differentiated somatic cell types into eggs and oocytes were performed previously in Rana pipiens and Xenopus laevis. The formation of postneurula embryos and tadpoles under the direction of the test nuclei demonstrated their genetic multipotency. In addition, Rana erythrocyte nuclei transplanted to oocytes directed more extensive tadpole development than those injected into eggs. We have extended our studies of the genomic potential of differentiated somatic nuclei from the peripheral blood of Rana pipiens. First, we show that the developmental potential of erythrocyte nuclei injected into oocytes at first meiotic metaphase was greater than those injected into diplotene oocytes. Second, we demonstrate that erythroblast and leukocyte nuclei transplanted to oocytes at first meiotic metaphase promoted more advanced tadpole development than those previously injected into Xenopus eggs. Third, erythrocyte nuclei were more successful in promoting advanced tadpole development compared with erythroblast and leukocyte nuclei. The results show that differentiated somatic nuclei transferred to the cytoplasm of oocytes at first meiotic metaphase display enhanced genomic and developmental potential over those transplanted to diplotene oocytes and eggs, at least for the three nuclear cell types tested from the peripheral blood. 相似文献
64.
R C de Oliveira D T Ribeiro R G Nigro P Di Mascio C F Menck 《Nucleic acids research》1992,20(16):4319-4323
In order to characterize the molecular nature of singlet oxygen (1O2) induced mutations in mammalian cells, a SV40-based shuttle vector (pi SVPC13) was treated with singlet oxygen arising from the thermal decomposition of the water-soluble endoperoxide of 3,3'-(1,4-naphthylidene) dipropionate (NDPO2). After the passage of damaged plasmid through monkey COS7 cells, the vector was shuffled into E. coli cells, allowing the screening of supF mutants. The mutation spectrum analysis shows that single and multiple base substitutions arose in 82.5% of the mutants, the others being rearrangements. The distribution of mutations within the supF gene is not random and some hotspots are evident. Most of the point mutations (98.4%) involve G:C base pairs and G:C to T:A transversion was the most frequent mutation (50.8%), followed by G:C to C:G transversion (32.8%). These results indicate that mutagenesis in mammalian cells, mediated by 1O2-induced DNA damage, is targeted selectively at guanine residues. 相似文献
65.
Identification of regulatory elements within the minimal promoter region of the human endogenous ERV9 proviruses: accurate transcription initiation is controlled by an Inr-like element. 下载免费PDF全文
G La Mantia B Majello A Di Cristofano M Strazzullo G Minchiotti L Lania 《Nucleic acids research》1992,20(16):4129-4136
66.
67.
Y Ma B I Wilson S Bijvoet H E Henderson E Cramb G Roederer M R Ven Murthy P Julien H D Bakker J J Kastelein 《Genomics》1992,13(3):649-653
We have previously reported two common lipoprotein lipase (LPL) gene mutations underlying LPL deficiency in the majority of 37 French Canadians (Monsalve et al., 1990. J. Clin. Invest. 86: 728-734; Ma et al., 1991. N. Engl. J. Med. 324: 1761-1766). By examining the 10 coding exons of the LPL gene in another French Canadian patient, we have identified a third missense mutation that is found in two of the three remaining patients for whom mutations are undefined. This is a G to A transition in exon 6 that results in a substitution of asparagine for aspartic acid at residue 250. Using in vitro site-directed mutagenesis, we have confirmed that this mutation causes a catalytically defective LPL protein. In addition, the Asp250----Asn mutation was also found on the same haplotype in an LPL-deficient patient of Dutch ancestry, suggesting a common origin. This mutation alters a TaqI restriction site in exon 6 and will allow for rapid screening in patients with LPL deficiency. 相似文献
68.
Regional expression of the homeobox gene Nkx-2.2 in the developing mammalian forebrain. 总被引:11,自引:0,他引:11
M Price D Lazzaro T Pohl M G Mattei U Rüther J C Olivo D Duboule R Di Lauro 《Neuron》1992,8(2):241-255
69.
70.
M Bernardi B Di Sarra G Montecchiani L Re L Rossini C Tonnini 《Bollettino della Società italiana di biologia sperimentale》1991,67(1):47-54
Spontaneous fluctuations in heart rate were analyzed by spectral analysis in the ether anesthetized and pithed adult rat. In order to investigate the changes in the spectral pattern of the fluctuations, the selective 5HT-2 and -3 isoreceptor blockers ritanserin and BRL 43694A were used. In both the experimental conditions, ritanserin blockade led to dose-dependent increased fluctuations in HR low and high frequencies. In both the anesthetized and pithed rats, the low frequency range HR fluctuations were drastically reduced by BRL 43694A. 相似文献