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51.
Sucrose-inducible expression of hepatitis B surface antigen using potato granule-bound starch synthase promoter 总被引:2,自引:0,他引:2
U. K. S. Shekhawat T. R. Ganapathi G. B. Sunil Kumar L. Srinivas 《Plant biotechnology reports》2007,1(4):199-206
NT-1 cells of tobacco (Nicotiana tabacum L.) were transformed with pGBSSHBS and pGBSSHER expression cassettes wherein expression of hepatitis B surface antigen (HBsAg)
was driven by potato granule-bound starch synthase (GBSS) promoter. The transformed nature of the cells was confirmed by PCR
analysis. Expression of HBsAg was confirmed by RT-PCR and Western blotting and levels of expression were assayed by ELISA.
Transformed cell lines exhibited a sucrose-inducible pattern of HBsAg expression. NT-1 medium supplemented with 175 mmol L−1 sucrose gave the highest HBsAg expression of 198 ng g−1 FW after 8 days of induction. Different sugars, for example glucose, fructose, and palatinose, were also tested to study
the inducible nature of GBSS promoter. The results demonstrate that potato GBSS promoter can be used in heterologous host
systems like tobacco NT-1 cell suspension cultures for sucrose-inducible expression of recombinant proteins. 相似文献
52.
An Internet hosting center hosts services on its server ensemble. The center must allocate servers dynamically amongst services to maximize revenue earned from hosting fees. The finite server ensemble, unpredictable request arrival behavior and server reallocation cost make server allocation optimization difficult. Server allocation closely resembles honeybee forager allocation amongst flower patches to optimize nectar influx. The resemblance inspires a honeybee biomimetic algorithm. This paper describes details of the honeybee self-organizing model in terms of information flow and feedback, analyzes the homology between the two problems and derives the resulting biomimetic algorithm for hosting centers. The algorithm is assessed for effectiveness and adaptiveness by comparative testing against benchmark and conventional algorithms. Computational results indicate that the new algorithm is highly adaptive to widely varying external environments and quite competitive against benchmark assessment algorithms. Other swarm intelligence applications are briefly surveyed, and some general speculations are offered regarding their various degrees of success. 相似文献
53.
Chhatre S Francis R Titchener-Hooker NJ Newcombe AR Keshavarz-Moore E 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2007,860(2):209-217
This paper evaluates a prototype agarose-based affinity adsorbent utilizing a bound synthetic ligand designed to replace Protein A as an IgG-affinity capture resin and compares its purification characteristics with four commercially available matrices for the recovery of polyclonal antibodies from crude hyperimmune ovine serum. The novel adsorbent was found to show the highest dynamic capacity (29.2 mg/mL) of all matrices under evaluation--30% higher than the other commercial adsorbents evaluated. When using a post-load caprylic acid wash, IgG yields of over 85% and purities of over 90% were achieved consistently over multiple loading cycles. To evaluate bead diffusion, inverted confocal microscopy was used to visualise fluorescent antibody binding on to individual adsorbent beads in real time. The results indicate that the binding characteristics of the prototype adsorbent are similar to those obtained with Protein G Sepharose. This study indicates that the high-capacity prototype matrix is a feasible and potentially cost-effective alternative for the direct capture of antibodies from crude ovine serum and may therefore also be applicable to the purification of other complex industrial feedstocks such as transgenic milk or monoclonal antibodies expressed using recombinant technologies. 相似文献
54.
Segregation distortion genes are widespread in plants and animals and function by their effect on competition among gametes
for preferential fertilization. In this study, we evaluated the segregation distortion of molecular markers in multiple reciprocal
backcross populations derived from unique cytogenetic stocks involving the durum cultivar Langdon (LDN) and wild emmer accessions
that allowed us to study the effects of chromosome 5B in isolation. No segregation distortion of female gametes was observed,
but three populations developed to analyze segregation of male gametes had genomic regions containing markers with skewed
segregation ratios. One region of distortion was due to preferential transmission of LDN alleles over wild emmer alleles through
male gametes. Another region required the presence of LDN 5B chromosomes in the female for preferential fertilization by male
gametes harboring LDN alleles indicating that the corresponding genes in the female gametes can govern genes affecting segregation
distortion of male gametes. A third region of distortion was the result of preferential transmission of wild emmer alleles
over LDN alleles through male gametes. These results indicate the existence of different distorter/meiotic drive elements
among different genotypes and show that distortion factors along wheat chromosome 5B differ in chromosomal location as well
as underlying mechanisms. 相似文献
55.
Prabhu AD Karim RA Thazhkuni IE Rajendran S Thamaran RA Vellachamy KA Sridharan V Vettath MP 《Innovations (Philadelphia, Pa.)》2007,2(4):213-214
SUMMARY:: Suprahepatic inferior vena caval (IVC) injuries are rare but carry nearly a 100% mortality rate. The main problem with its surgical management is the technical difficulty in draining the IVC during cardiopulmonary bypass. In this report, an efficient method of IVC drainage for repair of the IVC on cardiopulmonary bypass is described. 相似文献
56.
Nutritional metabonomics: applications and perspectives 总被引:1,自引:0,他引:1
Nowadays, nutrition focuses on improving health of individuals through diet. Current nutritional research aims at health promotion, disease prevention, and performance improvement. Modern analytical platforms allow the simultaneous measurement of multiple metabolites providing new insights in the understanding of the functionalities of cells and whole organisms. Metabonomics, "the quantitative measurement of the dynamic multiparametric metabolic response of living systems to pathophysiological stimuli or genetic modifications", provides a systems approach to understanding global metabolic regulations of organisms. This concept has arisen from various applications of NMR and MS spectroscopies to study the multicomponent metabolic composition of biological fluids, cells, and tissues. The generated metabolic profiles are processed by multivariate statistics to maximize the recovery of information to be correlated with well-determined stimuli such as dietary intervention or with any phenotypic data or diet habits. Metabonomics is thus uniquely suited to assess metabolic responses to deficiencies or excesses of nutrients and bioactive components. Furthermore, metabonomics is used to characterize the metabolic phenotype of individuals integrating genetic polymorphism, metabolic interactions with commensal and symbiotic partners such as gut microflora, as well as environmental and behavioral factors including dietary preferences. This paper reports several experimental key aspects in nutritional metabonomics, reviews its applications employing targeted and holistic approach analysis for the study of the metabolic responses following dietary interventions. It also reports the assessment of intra- and inter-individual variability in animal and human populations. The potentialities of nutritional metabonomics for the discovery of new biomarkers and the characterization of metabolic phenotypes are discussed in a context of their possible utilizations for personalized nutrition to provide health maintenance at the individual level. 相似文献
57.
Human metabolic phenotypes link directly to specific dietary preferences in healthy individuals 总被引:1,自引:0,他引:1
Rezzi S Ramadan Z Martin FP Fay LB van Bladeren P Lindon JC Nicholson JK Kochhar S 《Journal of proteome research》2007,6(11):4469-4477
Individual human health is determined by a complex interplay between genes, environment, diet, lifestyle, and symbiotic gut microbial activity. Here, we demonstrate a new "nutrimetabonomic" approach in which spectroscopically generated metabolic phenotypes are correlated with behavioral/psychological dietary preference, namely, "chocolate desiring" or "chocolate indifferent". Urinary and plasma metabolic phenotypes are characterized by differential metabolic biomarkers, measured using 1H NMR spectroscopy, including the postprandial lipoprotein profile and gut microbial co-metabolism. These data suggest that specific dietary preferences can influence basal metabolic state and gut microbiome activity that in turn may have long-term health consequences to the host. Nutrimetabonomics appears as a promising approach for the classification of dietary responses in populations and personalized nutritional management. 相似文献
58.
Cofilin is an actin-binding protein of low molecular weight which is widely distributed in eukaryotes and is deeply involved in the dynamics of actin assembly in the cytoplasm. The actin-binding ability of cofilin is inhibited by inositol phosphates (PIP2), and the PIP2- and actin-binding site(s) has been localized in residues W104 - M115 of the cofilin primary sequence (Yonezawa et al. 1991). In the present study, in order to further clarify the functional domains in cofilin molecule, we constructed expression vectors containing cDNAs of different size with deletion at the 3-region of the open reading frame. The truncated cofilin molecules produced in E. coli were purified and examined for their actin-binding and PIP2-binding ability. We found that the truncated cofilin molecule without C-terminal residues #100-#166 including the previously-described actin-binding site could be cross-linked with actin by EDC, a zero-length cross-linker. In addition, these truncated peptides as well as synthetic peptides corresponding to the N-terminal sequence of cofilin suppressed the inhibitory action of PIP2 on actin-cofilin interaction. These results strongly suggest that additional actin- and PIP2-binding sites exist in the N-terminal region of cofilin. 相似文献
59.
Bailey JP Nieport KM Herbst MP Srivastava S Serra RA Horseman ND 《Molecular endocrinology (Baltimore, Md.)》2004,18(5):1171-1184
Both prolactin (PRL) and TGF-beta regulate cell survival in mammary epithelial cells, but their mechanisms of interactions are not known. In primary mammary epithelial cells and the HC11 mouse mammary epithelial cell line, PRL prevented TGF-beta-induced apoptosis, as measured by terminal deoxynucleotidyltransferase dUTP nick-end labeling staining and caspase-3 activation. This effect depended on phosphatidyl inositol triphosphate kinase (PI3K). PI3K activates a downstream serine/threonine kinase, Akt; therefore, we investigated the role of Akt in the interaction between PRL and TGF-beta signaling. Akt activity was inhibited by TGF-beta over a 20- to 60-min time course. In TGF-beta-treated cells, PRL disinhibited Akt in a PI3K-dependent manner. Expression of dominant negative Akt blocked the protective effect of PRL in TGF-beta-induced apoptosis. Transgenic mice overexpressing a dominant-negative TGF-beta type II receptor (DNIIR) in the mammary epithelium undergo hyperplastic alveolar development, and this effect was PRL dependent. Involution in response to teat sealing was slowed by overexpression of DNIIR; furthermore, Akt and forkhead phosphorylation increased in the sealed mammary glands of DNIIR mice. Thus, Akt appears to be an essential component of the interaction between PRL and TGF-beta signaling in mammary epithelial cells both in vitro and in vivo. 相似文献
60.
Bettoun DJ Lu J Khalifa B Yee Y Chin WW Nagpal S 《The Journal of steroid biochemistry and molecular biology》2004,(1-5):195-198
We have recently shown that in colon cancer cells, Vitamin D receptor (VDR) interacts with the catalytic subunit of Ser/Thr protein phosphatases, PP1c and PP2Ac, and induces their enzymatic activity in a ligand-dependent manner. The VDR-PP1c and VDR-PP2Ac interactions were ligand independent in vivo, and 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3))-mediated increase in VDR-associated phosphatase activity resulted in dephosphorylation and inactivation of p70S6 kinase in colon cancer cells. Here, we demonstrate that in myeloid leukemia cells, 1,25(OH)(2)D(3) treatment increased the Thr389 phosphorylation of p70S6 kinase. Accordingly, 1,25(OH)(2)D(3) decreased VDR-associated Ser/Thr protein phosphatase activity by dissociating VDR-PP1c and VDR-PP2Ac interactions. Further, 1,25(OH)(2)D(3) increased the association between VDR and Thr389 phosphorylated p70S6 kinase. Finally, by using non-secosteroidal VDR ligands, we demonstrate a separation between transactivation and p70S6 kinase phosphorylation activities of VDR and show pharmacologically that p70S6 kinase phosphorylation correlates with HL-60 cell differentiation. 相似文献