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561.
562.
Cytotoxic effect of multinucleation in HeLa cell cultures associated with the presence of Vir plasmid in Escherichia coli strains 总被引:6,自引:0,他引:6
Eric Oswald Jean De Rycke Jean François Guillot Roger Boivin 《FEMS microbiology letters》1989,58(1):95-99
The occurrence activity and localization of calmodulin in three heterocystous cyanobacteria of the genus Anabaena were studied. Boiled crude extracts caused a Ca2+-dependent stimulation of NAD kinase. Such a stimulation was blocked by EGTA and chlorpromazine, SDS-PAGE and Western blot analysis using antiserum against eukaryotic spinach calmodulin, revealed a polypeptide of about 17 kDa. Immunogold localization of calmodulin gave a dense gold label in both vegetative cells and heterocysts. The label was mainly confined to the centroplasm in vegetative cells, while it was evenly distributed in the cytoplasm of mature heterocysts. 相似文献
563.
564.
Nathalie Isabel Rodolphe Boivin Caroline Levasseur Pierre-M. Charest Jean Bousquet Francine M. Tremblay 《American journal of botany》1996,83(9):1121-1130
Four different variegata phenotypes were identified among 2270 white spruce plants [Picea glauca (Moench.) Voss.] produced over a period of 2 yr from the time of induction of embryogenic tissues. The four variegated plants differed from each other in the extent and distribution of chlorophyll-deficient needles. Light microscopy showed that variegated leaves of a selected variant consisted of a chimeral mixture of green and white cells. Electron microscopy showed that cells in completely white needles had large nuclei with predominant euchromatin, lacked large cytoplasmic vacuoles, and harbored vacuolized plastids with aberrant morphologies. Various observations suggest that the recovered variegata phenotypes reflect some kind of genetic instability of either chloroplastic or nuclear genomes. To elucidate the genetic basis of these variegata phenotypes in white spruce, three out of the four variants were subjected to randomly amplified polymorphic DNA (RAPD) analysis. Out of more than 250 RAPD markers screened, only one correlated with white needles of variegated plants. The nucleotide sequence of this DNA fragment showed no homology with any known gene, but the amplified sequence appears most likely of nuclear origin. 相似文献
565.
Ethanol, at high concentrations, produced a dose-dependent contraction of male rat aortic rings, . Mechanical removal of endothelial cells from aortic rings of control rats resulted in a small, but significant, shift of the ethanol dose-response curve to the right without a change in the maximal contraction. Removing the endothelial cells of aortic rings obtained from rats intoxicated with ethanol for two days significantly shifted the ethanol dose-response curve to the left and significantly increased the maximal contraction induced by ethanol. A comparison of the ethanol dose-response curves in aortic rings with endothelium obtained from control rats with those obtained from intoxicated rats indicated a significant shift to the right with no change in maximal response. No significant changes were observed when the responses of aortic rings without endothelium obtained from control and intoxicated rats were compared. These observations confirm that tolerance to ethanol can be demonstrated in vascular smooth muscle. In addition, they demonstrate that the endothelium is required for the development of tolerance to ethanol in the aorta. 相似文献
566.
567.
The synthesis and accumulation of membrane protein 4.1 in Friend erythroleukemia cells 总被引:1,自引:0,他引:1
K Benabdallah P Boivin D Dhermy 《Biology of the cell / under the auspices of the European Cell Biology Organization》1991,71(3):273-280
The effect of extensive differentiation on the synthesis and accumulation of protein 4.1 were studied on Friend erythroleukemia cells grown in suspension and on fibronectin coated dishes. Whole membranes of Friend erythroleukemia cells (FELC) contained a protein 4.1a and 4.1b doublet of Mr 76 and 74 kDa and two minor bands of Mr 105 and 43 kDa that cross-reacted with anti-human protein 4.1 IgG. These proteins were present even in uninduced cells. The synthesis of protein 4.1 was maximal after 4 days of induction in both suspension culture and in fibronectin-coated dishes whereas the protein 4.1 continued to accumulate until the seventh day. More protein 4.1 accumulated in cells grown on fibronectin-coated dishes, at each stage of differentiation, than in cells grown in suspension. The protein 4.1a/4.1b ratio changed during differentiation. The amounts of protein 4.1b increased progressively after induction until the protein 4.1a/4.1b ratio was similar to that of mouse mature erythrocyte. The protein 4.1a/4.1b ratio appears to be an internal marker of erythroid differentiation. 相似文献