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201.
202.
We coupled Tn5 mutagenesis with a competition assay to isolate mutants of Rhizobium fredii USDA 257 that are defective in competition for nodulation of soybeans. Two mutants with single Tn5 inserts in the chromosome showed reduced competitiveness in vermiculite but were identical to the wild-type strain in symbiotic properties when inoculated alone. Recombination of Tn5 and flanking genomic regions cloned from the mutants into the parent strain showed that Tn5 was responsible for the mutant phenotype. 相似文献
203.
D. Mercanti A. Angelini MT. Ciotti ML. Eboli C. Galli L. Battistini D. Merlo P. Calissano 《Cytotechnology》1993,11(Z1):S117-S119
The neurite outgrowth and adhesion complex (NOAC), isolated from rabbit sera has been dissociated in its major components by reverse-phase chromatography in HPLC by using a C18 column. SDS-PAGE analisys of the active fractions revealed the presence of three major bands of approximately 100, 70 and 50 kDa. Studies on the biological activity of NOAC were carried out on rat cerebellar granule cells. NOAC-cultured cells exhibit a marked resistance to excitotoxic stimuli carried by glutamate. 相似文献
204.
Cinzia Volonté Daniela Merlo Maria Teresa Ciotti Pietro Calissano 《Journal of neurochemistry》1994,63(6):2028-2037
Abstract: Primary neuronal cultures from 8-day-old rat cerebellum were incubated in the presence of exogenously added 16 n M [γ-32 P]ATP. Phosphorylation of a 45-kDa endogenous protein was detected within 1 min and increased linearly for ∼20 min. Unlike what was seen with [γ-32 P]ATP, in the presence of [32 P] orthophosphate no visible phosphorylation of protein was detected after 10 min, but a different pattern of phosphorylation was obtained in 30 min. The phosphorylation of the 45-kDa protein was reduced by 80–90% in the presence of 1 µ M unlabeled ATP, 5 U/ml of apyrase, or 0.01% trypsin but not 1 m M PO4 3− . Phosphorylation was inversely proportional to cell density and was unaffected by addition to the cells of 56 m M KCl or 100 µ M glutamate for 3 min. The presence of exogenously added cellular protein extracts or pretreatment of the cells for up to 20 min in phosphorylation buffer also did not affect the observed phosphorylation of the 45-kDa protein. The phosphorylation was found to be insensitive to MgCl2 but inhibited in the presence of MnCl2 or NaF and in the absence of CaCl2 . Analogues of ATP suppressed phosphorylation of the 45-kDa protein by 80–90%. A similar inhibition was obtained in the presence of ADP or AMP. In this study, we establish via several different means that the phosphorylation of the 45-kDa protein in primary neuronal granule cultures occurs extracellularly through an ectokinase activity, which is furthermore distinguishable from a series of other presently characterized ecto-protein enzymes and intracellular kinases. 相似文献
205.
Howe GT; Bucciaglia PA; Hackett WP; Furnier GR; Cordonnier-Pratt MM; Gardner G 《Molecular biology and evolution》1998,15(2):160-175
The phytochrome photoreceptors play important roles in the photoperiodic
control of vegetative bud set, growth cessation, dormancy induction, and
cold-hardiness in trees. Interestingly, ecotypic differences in
photoperiodic responses are observed in many temperate- zone tree species.
Northern and southern ecotypes of black cottonwood (Populus trichocarpa
Torr. & Gray), for example, exhibit marked differences in the timing of
short-day-induced bud set and growth cessation, and these responses are
controlled by phytochrome. Therefore, as a first step toward determining
the molecular genetic basis of photoperiodic ecotypes in trees, we
characterized the phytochrome gene (PHY) family in black cottonwood. We
recovered fragments of one PHYA and two PHYB using PCR-based cloning and by
screening a genomic library. Results from Southern analyses confirmed that
black cottonwood has one PHYA locus and two PHYB loci, which we arbitrarily
designated PHYB1 and PHYB2. Phylogenetic analyses which included PHY from
black cottonwood, Arabidopsis thaliana and tomato (Solanum lycopersicum)
suggest that the PHYB/D duplications in these species occurred
independently. When Southern blots were probed with PHYC, PHYE, and PHYE
heterologous probes, the strongest bands that we detected were those of
black cottonwood PHYA and/or PHYB. These results suggest that black
cottonwood lacks members of the PHYC/F and PHYE subfamilies. Although black
cottonwood could contain additional PHY that are distantly related to known
angiosperm PHY, our results imply that the PHY family of black cottonwood
is less complex than that of other well-characterized dicot species such as
Arabidopsis and tomato. Based on Southern analyses of five black cottonwood
genotypes representing three photoperiodic ecotypes, substantial
polymorphism was detected for at least one of the PHYB loci but not for the
PHYA locus. The novel character of the PHY family in black cottonwood, as
well as the differences in polymorphism we observed between the PHYA and
PHYB subfamilies, indicates that a number of fundamental macro- and
microevolutionary questions remain to be answered about the PHY family in
dicots.
相似文献
206.
T Venesio D Taverna N E Hynes R Deed D MacAllan F Ciardiello E M Valverius D S Salomon R Callahan G Merlo 《Cell growth & differentiation》1992,3(1):63-71
We have investigated the effect of basic fibroblast growth factor (bFGF) and the related int-2 gene on the growth, transformation, and differentiation of HC11 mouse mammary epithelial cells. We show that in HC11 cells infected with int-2 retroviral expression vectors, the int-2 protein can function as a bFGF-like growth factor in stimulating: (a) HC11 cell proliferation in monolayer, (b) anchorage-independent growth in soft agar, and (c) soft agar growth of the bFGF-responsive SW13 tumor cell line. These effects are observed irrespective of whether the int-2 protein is expressed in its wild-type form or is linked to a signal peptide. A candidate bFGF receptor, which is the product of the flg gene and which may recognize the int-2 protein, is expressed at high levels in HC11 cells. Following epidermal growth factor or bFGF priming and subsequent treatment with lactogenic hormones, all of the int-2 infected and the parental HC11 cells synthesize similar levels of beta-casein. However, the autocrine expression of int-2 in HC11 cells abrogates their requirement for either exogenous epidermal growth factor or bFGF priming. These data suggest that, in HC11 cells, the growth factor activity of the int-2 gene is indistinguishable from that of bFGF and does not interfere with the mammary cell differentiation program associated with lactogenesis. 相似文献
207.
Luigi F. Agnati Michele Zoli Fabio Benfenati Emilio Merlo Pich Roberta Grimaldi Kjell Fuxe 《Neurochemistry international》1990,16(4):419-425
The possibility of using taxonomic techniques to classify neuronal populations was explored. In particular, coefficients of similarity such as the Canberra metric and the Shannon diversity index were examined. The theoretical work in the field of numerical classification was adapted to the aim of characterizing various brain areas in classes according to their transmitter contents. The study of neuropeptide distribution in 15 brain areas clearly demonstrated that, of these, the hypothalamus is particularly noteworthy due to its higher neuropeptide content. 相似文献
208.
Funmei Yang Donald J. Merlo Milton P. Gordon Eugene W. Nester 《Molecular & general genetics : MGG》1980,179(1):223-226
Summary Tabac anergié tissue has been used by many investigators as a habituated tobacco cell line. In this study, we have found sequences which are homologous to approximately 9 megadaltons of an Agrobacterium octopine-type plasmid in DNA isolated from Tabac anergié tissue. These T-DNA sequences were shown to be the same core DNA sequences found to be present in several other unorganized tumor lines which have been studied in our laboratory. The T-DNA was also shown to be integrated into plant DNA. Thus, the Tabac anergié tissue is a crown gall tumor induced by a strain of Agrobacterium tumefaciens containing an octopinetype plasmid. These results indicated that the plants regenerated from 40 clones of the Tabac anergié line by Sacristán and Melchers (1977) were actually reverted plants obtained from an unorganized crown gall tumor, kept in culture for more than 25 years. It is necessary to re-evaluate observations and conclusions which have been based upon Tabac anergié being a habituated tissue. 相似文献
209.
Ismael Cross Silvia Portela-Bens Aglaya García-Angulo Manuel A. Merlo María E. Rodríguez Thomas Liehr Laureana Rebordinos 《BMC genetics》2018,19(1):104
Background
The re-sequencing of C. angulata has revealed many polymorphisms in candidate genes related to adaptation to abiotic stress that are not present in C. gigas; these genes, therefore, are probably related to the ability of this oyster to retain high concentrations of toxic heavy metals. There is, in addition, an unresolved controversy as to whether or not C. angulata and C. gigas are the same species or subspecies. Both oysters have 20 metacentric chromosomes of similar size that are morphologically indistinguishable. From a genomic perspective, as a result of the great variation and selection for heterozygotes in C. gigas, the assembly of its draft genome was difficult: it is fragmented in more than seven thousand scaffolds.Results
In this work sixty BAC sequences of C. gigas downloaded from NCBI were assembled in BAC-contigs and assigned to BACs that were used as probes for mFISH in C. angulata and C. gigas. In addition, probes of H3, H4 histone, 18S and 5S rDNA genes were also used. Hence we obtained markers identifying 8 out the 10 chromosomes constituting the karyotype. Chromosomes 1 and 9 can be distinguished morphologically. The bioinformatic analysis carried out with the BAC-contigs annotated 88 genes. As a result, genes associated with abiotic adaptation, such as metallothioneins, have been positioned in the genome. The gene ontology analysis has also shown many molecular functions related to metal ion binding, a phenomenon associated with detoxification processes that are characteristic in oysters. Hence the provisional integrated map obtained in this study is a useful complementary tool for the study of oyster genomes.Conclusions
In this study 8 out of 10 chromosome pairs of Crassostrea angulata/gigas were identified using BAC clones as probes. As a result all chromosomes can now be distinguished. Moreover, FISH showed that H3 and H4 co-localized in two pairs of chromosomes different that those previously escribed. 88 genes were annotated in the BAC-contigs most of them related with Molecular Functions of protein binding, related to the resistance of the species to abiotic stress. An integrated genetic map anchored to the genome has been obtained in which the BAC-contigs structure were not concordant with the gene structure of the C. gigas scaffolds displayed in the Genomicus database.210.
Silvio Roncella Stefania Laurent Vincenzo Fontana Paola Ferro Maria Cristiana Franceschini Sandra Salvi Serena Varesano Simona Boccardo Antonella Vigani Anna Morabito Pier Aldo Canessa Ugo Giannoni Ilan Rosenberg Alessandro Valentino Franco Fedeli Domenico Franco Merlo Marcello Ceppi Salvatore Riggio Massimo Romani Daniele Saverino Alessandro Poggi Maria Pia Pistillo 《Cancer immunology, immunotherapy : CII》2016,65(8):909-917