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排序方式: 共有87条查询结果,搜索用时 8 毫秒
71.
Rachel IM van Haaften Blanche Schroen Ben JA Janssen Arie van Erk Jacques JM Debets Hubert JM Smeets Jos FM Smits Arthur van den Wijngaard Yigal M Pinto Chris TA Evelo 《BMC bioinformatics》2006,7(1):200-15
Background
Gene expression microarray technology permits the analysis of global gene expression profiles. The amount of sample needed limits the use of small excision biopsies and/or needle biopsies from human or animal tissues. Linear amplification techniques have been developed to increase the amount of sample derived cDNA. These amplified samples can be hybridised on microarrays. However, little information is available whether microarrays based on amplified and unamplified material yield comparable results. 相似文献72.
Oliver Hoeller Jared E. Toettcher Huaqing Cai Yaohui Sun Chuan-Hsiang Huang Mariel Freyre Min Zhao Peter N. Devreotes Orion D. Weiner 《PLoS biology》2016,14(2)
For directional movement, eukaryotic cells depend on the proper organization of their actin cytoskeleton. This engine of motility is made up of highly dynamic nonequilibrium actin structures such as flashes, oscillations, and traveling waves. In Dictyostelium, oscillatory actin foci interact with signals such as Ras and phosphatidylinositol 3,4,5-trisphosphate (PIP3) to form protrusions. However, how signaling cues tame actin dynamics to produce a pseudopod and guide cellular motility is a critical open question in eukaryotic chemotaxis. Here, we demonstrate that the strength of coupling between individual actin oscillators controls cell polarization and directional movement. We implement an inducible sequestration system to inactivate the heterotrimeric G protein subunit Gβ and find that this acute perturbation triggers persistent, high-amplitude cortical oscillations of F-actin. Actin oscillators that are normally weakly coupled to one another in wild-type cells become strongly synchronized following acute inactivation of Gβ. This global coupling impairs sensing of internal cues during spontaneous polarization and sensing of external cues during directional motility. A simple mathematical model of coupled actin oscillators reveals the importance of appropriate coupling strength for chemotaxis: moderate coupling can increase sensitivity to noisy inputs. Taken together, our data suggest that Gβ regulates the strength of coupling between actin oscillators for efficient polarity and directional migration. As these observations are only possible following acute inhibition of Gβ and are masked by slow compensation in genetic knockouts, our work also shows that acute loss-of-function approaches can complement and extend the reach of classical genetics in Dictyostelium and likely other systems as well. 相似文献
73.
Marcelo Filonzi Laís C Cardoso Maristela T Pimenta Daniel BC Queiróz Maria CW Avellar Catarina S Porto Maria FM Lazari 《Reproductive biology and endocrinology : RB&E》2007,5(1):29
Background
Relaxin is the endogenous ligand of the G-protein coupled receptor RXFP1, previously known as LGR7. In humans relaxin can also activate, but with lower affinity, the closely related receptor for the insulin-like peptide from Leydig cells, RXFP2, previously known as LGR8. The lack of relaxin impairs male fertility but the precise distribution and the function of relaxin receptors in the male reproductive tract is not known. We investigated the distribution of Rxfp1 and Rxfp2 in the reproductive tract of the male rat and the function of relaxin in the vas deferens, a tissue with high expression of both receptors. 相似文献74.
D. S. Douches K. Ludlam R. Freyre 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,82(2):195-200
Summary Isozyme and ctDNA RFLP patterns were determined for ten historically important potato cultivars (Solanum tuberosum ssp. tuberosuni) in order to relate and confirm their pedigrees. Isozyme polymorphism was detected at 11 of 13 loci examined, whereas only T-type cytoplasm, the predominant ctDNA of S. tuberosum ssp. tuberosum, was observed. Isozyme analysis indicated that potato cultivars previously presumed to be derived from open-pollinated berries of Garnet Chili and Early Rose were in fact the result of hybridizations. In addition, putative pedigrees of Irish Cobbler, White Rose, and Bliss Triumph were not supported. Garnet Chili, the first derivative of Rough Purple Chili, carries allozmyes at Mdh-1 and Pgm-2, which supports the Chilean origin of Rough Purple Chili. The identical ctDNA pattern among the cultivars may indicate a common maternal lineage that traces through Garnet Chili to Rough Purple Chili. The allozyme frequencies estimated from these cultivars provide a base from which subsequent introductions of Solanum species into the ssp. tuberosum gene pool can be assessed.Journal Article No. 000123 相似文献
75.
Rodomiro Ortiz Stanley J. Peloquin Rosanna Freyre Masaru Iwanaga 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1991,82(5):602-608
Summary The objective of this research was to compare the efficiency of the 4x×2x breeding scheme with the traditional 4x×4x method with respect to potato improvement. The basis for such a comparison was the parental value of four 2x and four 4x male parents from the International Potato Center (CIP) as measured by multitrait selection and progeny testing. The 2x parents produced 2n pollen by parallel spindles at anaphase II, which is genetically equivalent to a first division restitution (FDR) mechanism. Both 2x and 4x parents were crossed with four common 4x female parents. Thus, 32 families were evaluated over 2 years at four Peruvian locations. A selection index which considered tuber yield, tuber number, average tuber weight and specific gravity was used for multitrait selection. Three FDR 2x parents had better selection index scores than the 4x parents over the four locations. Estimates of broad-sense heritability for total yield using different number of replications and locations were calculated by using the variance components. The 4x × 2x breeding scheme was found to be better than the traditional 4x × 4x method since fewer replications and locations are required to evaluate tuber yield in 4x × 2x progenies than in 4x × 4x progenies. The FDR 2x parents were also better material than the 4x parents for testing combining ability for tuber yield of the 4x progenitors. This could be the result of the mode of FDR 2n pollen formation. The pollen of FDR 2x parents is more heterozygous, but more homogenous than n pollen from 4x parents.Paper from the Laboratory of Genetics. Research supported by the College of Agricultural and Life Sciences; International Potato Center; USDA-CRGO-88-37234 3619, and Frito-Lay, Inc., USA 相似文献
76.
R. Freyre P. W. Skroch V. Geffroy A.-F. Adam-Blondon A. Shirmohamadali W. C. Johnson V. Llaca R. O. Nodari P. A. Pereira S.-M. Tsai J. Tohme M. Dron J. Nienhuis C. E. Vallejos P. Gepts 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(5-6):847-856
Three RFLP maps, as well as several RAPD maps have been developed in common bean (Phaseolus vulgaris L.). In order to align these maps, a core linkage map was established in the recombinant inbred population BAT93×Jalo EEP558
(BJ). This map has a total length of 1226 cM and comprises 563 markers, including some 120 RFLP and 430 RAPD markers, in addition
to a few isozyme and phenotypic marker loci. Among the RFLPs mapped were markers from the University of California, Davis
(established in the F2 of the BJ cross), University of Paris-Orsay, and University of Florida maps. These shared markers allowed us to establish
a correspondence between the linkage groups of these three RFLP linkage maps. In total, the general map location (i.e., the
linkage group membership and approximate location within linkage groups) has been determined for some 1070 markers. Approaches
to align this core map with other current or future maps are discussed.
Received: 10 March 1998 / Accepted: 22 April 1998 相似文献
77.
The objective was to test immune protection against the formation of Toxoplasma gondii tissue cysts in rats. It has been previously shown that 50 T. gondii tissue cysts of strain Me49 are not pathogenic for CF-1 mice, whereas 1 T. gondii tissue cyst of strain M-7741, can be lethal for mice 11-13 days after subcutaneous or oral administration. In the present study, ten rats were fed T. gondii oocysts of strain Me49 and after a further 30 days they were each orally challenged with T. gondii oocysts of strain M-7741. Thirty days after this, they were euthanased and brain and muscle samples inoculated subcutaneously or orally dosed, respectively, to mice for bioassay. None of the mice died, whereas all the mice that were inoculated with brain homogenates or were fed muscle samples from four non-immunized rats that had been inoculated with T. gondii oocysts of strain M-7741, died. These results encourage further research towards achieving vaccinal protection against the formation of T. gondii tissue cysts in meat animals and people. 相似文献
78.
Very high expression of an anti-carcinoembryonic antigen single chain Fv antibody fragment in the yeast Pichia pastoris 总被引:8,自引:0,他引:8
Freyre FM Vázquez JE Ayala M Canaán-Haden L Bell H Rodríguez I González A Cintado A Gavilondo JV 《Journal of biotechnology》2000,76(2-3):157-163
In this paper we report the development of a recombinant strain of the yeast Pichia pastoris, which secretes an anti-carcinoembryonic antigen single chain Fv (scFv) antibody fragment to the culture supernatant as a biologically active protein, at levels of 1.2 g l(-1). The yeast scFv was purified by IMAC, with a final yield of approximately 0.440 g of 93% pure scFv per liter of culture supernatant. The specific activity in ELISA of the yeast scFv was almost three times higher than that of a bacterial periplasmic counterpart. These results reaffirm that the yeast P. pastoris is a suitable host for high level production of scFv antibody fragments with potential in vivo diagnostic and therapeutic applications. 相似文献
79.
C Jewell AD Papineau R Freyre LC Moyle 《Evolution; international journal of organic evolution》2012,66(8):2628-2636
We examined reproductive isolating barriers at four postmating stages among 11 species from the morphologically diverse genus Nolana (Solanaceae). At least one stage was positively correlated with both genetic and geographic distance between species. Postzygotic isolation was generally stronger and faster evolving than postmating prezygotic isolation. In addition, there was no evidence for mechanical isolation, or for reproductive character displacement in floral traits that can influence pollinator isolation. In general, among the potential isolating stages examined here, postzygotic barriers appear to be more effective contributors to reducing gene flow, including between sympatric species. 相似文献
80.