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排序方式: 共有502条查询结果,搜索用时 93 毫秒
71.
F W Perrino R R Meyer A M Bobst D C Rein 《The Journal of biological chemistry》1988,263(24):11833-11839
A single-stranded DNA-binding protein (SSB) affinity column was prepared by optimizing the coupling of Escherichia coli single-stranded DNA-binding protein to Affi-Gel 10. The bound SSB retained its ability to specifically bind single-stranded DNA. When nuclease-treated cell extracts were incubated with the SSB beads overnight at 4 degrees C, a major protein of Mr = 25,000 was bound. At shorter incubation times, two additional proteins of Mr = 32,000 and 36,000 were also detected. In the absence of nuclease treatment, eight additional proteins ranging from Mr = 14,000 to 160,000 also bound to the affinity column. The major Mr = 25,000 protein has been shown to be a folded chromosome-associated protein. Its binding to SSB is strongly enhanced by the addition of DNA polymerase III or DNA polymerase III holoenzyme. 相似文献
72.
Abstract Adaptor properties of linear hairpin helices have been examined. The analysis suggests that neither right nor left handed hairpin helices can simultaneously read a comma free messenger and align aminoacyl residues for peptide condensation. Comparison of these studies with the model of the present day peptidyl transfer intermediate suggests that the “L” shaped folding of the present day tRNAs may be a prerequisite for adaptor function. Therefore, the three-dimensional organization of the ancestral adaptor molecule must have had structural features similar to its present day counterpart. 相似文献
73.
A Rein 《Biochimica et biophysica acta》1971,232(2):306-313
74.
Richard P. Shefferson Tiiu Kull Michael J. Hutchings Marc‐André Selosse Hans Jacquemyn Kimberly M. Kellett Eric S. Menges Richard B. Primack Juha Tuomi Kirsi Alahuhta Sonja Hurskainen Helen M. Alexander Derek S. Anderson Rein Brys Emilia Brzosko Slavomir Dostálik Katharine Gregg Zdeněk Ipser Anne Jäkäläniemi Jana Jersáková W. Dean Kettle Melissa K. McCormick Ana Mendoza Michael T. Miller Asbjørn Moen Dag‐Inge Øien Ülle Püttsepp Mélanie Roy Nancy Sather Nina Sletvold Zuzana Štípková Kadri Tali Robert J. Warren II Dennis F. Whigham 《Ecology letters》2018,21(5):724-733
Vegetative dormancy, that is the temporary absence of aboveground growth for ≥ 1 year, is paradoxical, because plants cannot photosynthesise or flower during dormant periods. We test ecological and evolutionary hypotheses for its widespread persistence. We show that dormancy has evolved numerous times. Most species displaying dormancy exhibit life‐history costs of sprouting, and of dormancy. Short‐lived and mycoheterotrophic species have higher proportions of dormant plants than long‐lived species and species with other nutritional modes. Foliage loss is associated with higher future dormancy levels, suggesting that carbon limitation promotes dormancy. Maximum dormancy duration is shorter under higher precipitation and at higher latitudes, the latter suggesting an important role for competition or herbivory. Study length affects estimates of some demographic parameters. Our results identify life historical and environmental drivers of dormancy. We also highlight the evolutionary importance of the little understood costs of sprouting and growth, latitudinal stress gradients and mixed nutritional modes. 相似文献
75.
Evidence for Cooperation between Murine Leukemia Virus Env Molecules in Mixed Oligomers 总被引:2,自引:2,他引:0
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Alan Rein Chinglai Yang Jacqueline A. Haynes Jane Mirro Richard W. Compans 《Journal of virology》1998,72(4):3432-3435
A retroviral Env molecule consists of a surface glycoprotein (SU) complexed with a transmembrane protein (TM). In turn, these complexes are grouped into oligomers on the surfaces of the cell and of the virion. In the case of murine leukemia viruses (MuLVs), the SU moieties are polymorphic, with SU proteins of different viral isolates directed towards different cell surface receptors. During maturation of the released virus particle, the 16 C-terminal residues of TM (the R peptide or p2E) are removed from the protein by the viral protease; this cleavage is believed to activate the membrane-fusing potential of MuLV Env. We have tested the possibility that different MuLV Env proteins in the same cell can interact with each other, both physically and functionally, in mixed oligomers. We found that coexpressed Env molecules can be precipitated out of cell lysates by antiserum which reacts with only one of them. Furthermore, they can evidently cooperate with each other: if one Env species lacks the R peptide, then it can apparently induce fusion if the SU protein of the other Env species encounters its cognate receptor on the surface of another cell. This functional interaction between different Env molecules has a number of implications with respect to the mechanism of induction of membrane fusion, for the genetic analysis of Env function, and for the design of targeted retroviral vectors for gene therapy. 相似文献
76.
Simian virus 40 rapidly lowers cAMP levels in mouse cells 总被引:4,自引:0,他引:4
A Rein R A Carchman G S Johnson I Pastan 《Biochemical and biophysical research communications》1973,52(3):899-904
The addition of SV40 to contact inhibited cells causes a 2-fold decrease in intracellular cAMP levels. The levels reach a minimum 3 hours after virus addition, and after a few hours begin to rise toward normal. No significant changes in cAMP levels are observed after cells are exposed to UV-inactivated virus or are mock-infected. This is the earliest known effect of SV40 infection. We propose that SV40 induces host DNA synthesis by lowering cAMP levels. 相似文献
77.
Tandekile Lubelwana Hafver Kjetil Hodne Pimthanya Wanichawan Jan Magnus Aronsen Bj?rn Dalhus Per Kristian Lunde Marianne Lunde Marita Martinsen Ulla Helene Enger William Fuller Ivar Sjaastad William Edward Louch Ole Mathias Sejersted Cathrine Rein Carlson 《The Journal of biological chemistry》2016,291(9):4561-4579
The sodium (Na+)-calcium (Ca2+) exchanger 1 (NCX1) is an important regulator of intracellular Ca2+ homeostasis. Serine 68-phosphorylated phospholemman (pSer-68-PLM) inhibits NCX1 activity. In the context of Na+/K+-ATPase (NKA) regulation, pSer-68-PLM is dephosphorylated by protein phosphatase 1 (PP1). PP1 also associates with NCX1; however, the molecular basis of this association is unknown. In this study, we aimed to analyze the mechanisms of PP1 targeting to the NCX1-pSer-68-PLM complex and hypothesized that a direct and functional NCX1-PP1 interaction is a prerequisite for pSer-68-PLM dephosphorylation. Using a variety of molecular techniques, we show that PP1 catalytic subunit (PP1c) co-localized, co-fractionated, and co-immunoprecipitated with NCX1 in rat cardiomyocytes, left ventricle lysates, and HEK293 cells. Bioinformatic analysis, immunoprecipitations, mutagenesis, pulldown experiments, and peptide arrays constrained PP1c anchoring to the K(I/V)FF motif in the first Ca2+ binding domain (CBD) 1 in NCX1. This binding site is also partially in agreement with the extended PP1-binding motif K(V/I)FF-X5–8Φ1Φ2-X8–9-R. The cytosolic loop of NCX1, containing the K(I/V)FF motif, had no effect on PP1 activity in an in vitro assay. Dephosphorylation of pSer-68-PLM in HEK293 cells was not observed when NCX1 was absent, when the K(I/V)FF motif was mutated, or when the PLM- and PP1c-binding sites were separated (mimicking calpain cleavage of NCX1). Co-expression of PLM and NCX1 inhibited NCX1 current (both modes). Moreover, co-expression of PLM with NCX1(F407P) (mutated K(I/V)FF motif) resulted in the current being completely abolished. In conclusion, NCX1 is a substrate-specifying PP1c regulator protein, indirectly regulating NCX1 activity through pSer-68-PLM dephosphorylation. 相似文献
78.
The present study is an attempt to investigate the pattern of morphological variability of the short roots of Norway spruce
(Picea abies (L.) Karst.) growing in different soils. Five root parameters – diameter, length and dry weight of the root tip,
root density (dry weight per water-saturated volume) and specific root area (absorbing area of dry weight unit) were studied
with respect to 11 soil characteristics using CANOCO RDA analysis. The investigation was conducted in seven study areas in
Estonia differing in site quality class and soil type. Ten root samples per study area were collected randomly from the forest
floor and from the 20 cm soil surface layer. Eleven soil parameters were included in the study: humus content, specific soil
surface area, field capacity, soil bulk density, pH (KCl and H2O dilution's), N and Ca concentrations, Ca/Al and C/N ratios, and the decomposition rate of fine roots (<2 mm dia.). Root
morphological characteristics most strongly related to the measured soil characteristics in the different sites were specific
root area, root density and diameter of the short roots, the means varying from 29 to 42 m2 kg−1, from 310 to 540 kg m−3 and from 0.26 to 0.32 mm, respectively; root density being most sensitive. The most favourable site and soil types resulting
in fine roots with morphological characteristics for optimizing nutrient uptake (e.g. low short root density and high specific
root area) were Umbric Luvisol (Oxalis), Dystric Gleysol (Oxalis) and Gleyic Luvisol (Hepatica). These soil types correspond
to highly productive natural forest stands of Norway spruce in Estonia. All measured soil variables explained 28% of total
variance of the root characteristics. The most important variables related to root morphology were the humus content, field
capacity and specific soil surface area.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
79.
J. Ruff T. Hitzler U. Rein A. Ritter A. M. Cook 《Applied microbiology and biotechnology》1999,52(3):446-450
Highly substituted arenesulfonates are chemically stable compounds with a range of industrial applications, and they are
widely regarded as being poorly degradable. We did enrichment cultures for bacteria able to utilise the sulfonate moiety of
14 compounds, and we obtained mixed cultures that were able to desulfonate each compound. The products formed were usually
identified as the corresponding phenol, but because we could not obtain pure cultures, we followed up these findings with
quantitative work in pure cultures of, e.g., Pseudomonas putida S-313, which generated the same phenols from the compounds studied. Many of these phenols are known to be biodegradable,
or to be subject to binding to soil components. We thus presume that the capacity to degrade aromatic sulfonates extensively
is widespread in the environment, even though the degradative capacity is spread over several organisms and conditions.
Received: 9 February 1999 / Revision received: 7 April 1999 / Accepted: 9 April 1999 相似文献
80.