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21.
Activity of aspartate transcarbamylase in uninfected and type 5 adenovirus-infected HeLa cells 总被引:2,自引:0,他引:2
Consigli, Richard A. (University of Pennsylvania, Philadelphia), and Harold S. Ginsberg. Activity of aspartate transcarbamylase in uninfected and type 5 adenovirus-infected HeLa cells. J. Bacteriol. 87:1034-1043. 1964.-A two- to three-fold increase in aspartate transcarbamylase (ATCase) activity was observed in type 5 adenovirus-infected HeLa cells 18 hr after infection. The enhanced enzyme activity was virus-specific and dependent on biosynthesis of deoxyribonucleic acid and protein. When various characteristics as well as the kinetics of the enzymes from uninfected and infected cells were compared, ATCase from adenovirus-infected cells was shown to have an altered pH optimum, greater heat stability, increased maximal velocity, and increased K(m) value for aspartate. 相似文献
22.
Mechanism by Which Fiber Antigen Inhibits Multiplication of Type 5 Adenovirus 总被引:29,自引:23,他引:6
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Purified fiber antigen of type 5 adenovirus inhibited the multiplication of type 5 adenovirus by 50% when 35 mug of fiber antigen protein was added to 10(6) KB cells in suspension culture. Although the fiber antigen reduced the number of virions adsorbed per cell when a multiplicity of infection of 50,000 plaque-forming units (PFU)/cell was employed, the number of cells infected was not diminished under these conditions. If a low multiplicity of infection (1.1 PFU/cell) was used, viral adsorption was not detectably decreased. The fiber antigen did not reduce the capability of virions to liberate their viral deoxyribonucleic acid (DNA). The biosyntheses of DNA, ribonucleic acid (RNA), and protein were blocked about 20 to 25 hr after the addition of fiber antigen to cultures of uninfected or type 5 adenovirus-infected KB cells. Most of the fiber antigen protein became cell-associated between 22 and 36 hr after it was added to cells. The hexon antigen neither inhibited viral multiplication nor blocked the biosynthesis of DNA, RNA, or protein. Moreover, the hexon did not attach to KB cells. The profound effects of the fiber antigen were not due to the induction of an interferon-like substance, for actinomycin D did not reduce the ability of the fiber to inhibit multiplication of type 1 poliovirus. 相似文献
23.
Characterization of a Tumorlike Antigen in Type 12 and Type 18 Adenovirus-Infected Cells. 总被引:11,自引:0,他引:11
Gilead, Zvee (University of Pennsylvania, Philadelphia), and Harold S. Ginsberg. Characterization of a tumor-like antigen in type 12 and type 18 adenovirus-infected cells. J. Bacteriol. 90:120-125. 1965.-An antigen that reacts with antibody from type 12 adenovirus tumor-bearing hamsters was identified in extracts of KB cells infected with type 12 or 18 adenovirus. In contrast, viral structural proteins separated by chromatography on diethylaminoethyl-cellulose did not react with the sera from tumorous hamsters. The tumorlike (T) antigen in infected cells was found to be smaller than the viral structural antigens and, therefore, could be separated from them by centrifugation in a linear sucrose gradient. Investigation of the production of the T antigen in virus-infected cells further distinguished it from viral structural proteins by the following properties: (i) the T antigen was first detected 3 to 4 hr after infection, whereas viral antigens were synthesized 17 to 20 hr after infection; and (ii) the T antigen was produced when deoxyribonucleic acid (DNA) biosynthesis was inhibited by 5-fluorodeoxyuridine (10(-6)m), but viral proteins were not synthesized in the absence of viral DNA replication. 相似文献
24.
Isolation and characterization of a platelet membrane protein related to the vitronectin receptor 总被引:7,自引:0,他引:7
S C Lam E F Plow S E D'Souza D A Cheresh A L Frelinger M H Ginsberg 《The Journal of biological chemistry》1989,264(7):3742-3749
Glycoprotein IIb-IIIa is the most prominent Arg-Gly-Asp (RGD)-binding adhesion receptor on platelets. By affinity chromatography on an immobilized RGD peptide, we have investigated the possible existence of other platelet-associated adhesion receptors that bind RGD peptides. When an octyl glucoside extract of surface-radioiodinated platelets was applied to an affinity matrix of KYGRGDS-coupled Sepharose 4B, a 160-kDa-labeled protein (P160) and GPIIb-IIIa bound and were specifically eluted by soluble GRGDSP peptide, but not by the variant GRGESP peptide. Furthermore, a dodecapeptide corresponding to fibrinogen gamma 400-411 eluted only GPIIb-IIIa but not P160 from the RGD affinity matrix. Characterization of P160 by two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by the O'Farrell gel electrophoresis system indicated that P160 is a component of platelet GPIc. GoH3, a monoclonal antibody recognizing the alpha subunit of the very late antigen-6, failed to immunoprecipitate P160 from the RGD eluate, indicating that it did not contain the very late antigen-6 alpha subunit. In immunoblots, P160 reacted specifically with a polyclonal anti-peptide antibody recognizing the alpha subunit of the vitronectin receptor (VnR), but not with the monoclonal anti-GPIIb antibody PMI-1, suggesting that P160 is the alpha subunit of platelet VnR. This possibility was further substantiated by the complete identity between the determined amino-terminal sequence of P160 and the known sequence of the VnR alpha subunit. Moreover, direct association of P160 with a beta subunit having an apparent molecular weight similar to that of GPIIIa was demonstrated by immunoprecipitation with LM609, an anti-VnR complex monoclonal antibody. These results indicate that the VnR complex is present on platelets and may play a functional role in platelet adhesive reactions. 相似文献
25.
Sheri L. Holmen Matt W. Vanbrocklin Robert R. Eversole Susan R. Stapleton Leonard C. Ginsberg 《In vitro cellular & developmental biology. Animal》1995,31(5):347-351
Cationic lipids are an effective means for transfecting nucleic acids into a variety of cell types. Very few of these lipids,
however, have been reported to be effective with primary cells. We report on the efficacy of several commercially available
cationic lipid reagents to transfect plasmid DNA into primary rat hepatocytes in culture. The reagents tested in this study
include TransfectAce, LipofectAmine, Lipofectin, N-[1-(2,3-dioleyloxy)propyl]-n,n,n-trimethylammoniumchloride (DOTMA), (N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethyl-ammonium
methylsulfate (DOTAP), and cetyltrimethyl-ammonium bromide/dioleoylphosphatidylethanol-amine (CTAB/DOPE). Electron micrographic
(EM) studies indicate that similar size Lipofectin and DOTAP vesicles contain DNA-like material internally and that these
vesicles attach to the cell membrane. DOTAP vesicles are multilamellar, appear as clusters, and have a high DNA-to-lipid ratio.
Lipofectin vesicles appear to attach to the cell surface as individual vesicles. The EM observations are consistent with current
theories on the mechanism of transfection by cationic lipids. While Lipofectin has proven to be effective in transfection
studies of primary cells in culture, we have found DOTAP to be a viable alternative. DOTAP yields transfection rates in hepatocytes
comparable to DOTMA and Lipofectin, however, at lower concentrations of reagent and at considerably less cost. Optimal conditions
for transfecting 5 μg of plasmid DNA with DOTAP were achieved by utilizing multilamellar (vortexed) vesicles at a concentration
of 15 μg DOTAP per 2 ml media in 60-mm plates for 2 h transfection time. In this study, DOTAP has proven to be economical,
easy to prepare, and very effective in transfecting DNA into primary rat hepatocytes. 相似文献
26.
27.
The inner world of cell adhesion: integrin cytoplasmic domains 总被引:3,自引:0,他引:3
Many of the interactions between cells and their environment are mediated by the integrin family of heterodimeric transmembrane receptors. The past decade has been a broad-based effort to decipher the rules by which integrins function. Integrins bind both intracellular and extracellular ligands and thus transfer signals across the membrane in both directions. The cytoplasmic domains of these receptors play a key role in this bidirectional flow of information and in the formation of direct physical linkages between protein structures on the inside and outside of the cell. 相似文献
28.
Pathogenesis of adenovirus type 5 pneumonia in cotton rats (Sigmodon hispidus). 总被引:18,自引:9,他引:9
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G A Prince D D Porter A B Jenson R L Horswood R M Chanock H S Ginsberg 《Journal of virology》1993,67(1):101-111
Cotton rats (Sigmodon hispidus) were inoculated intranasally with 10(2.0) to 10(10.0) PFU of human adenovirus type 5. The virus replicated to a high titer in pulmonary tissues, with the peak titer being proportional to the input dose. The 50% lethal dose was 10(9.4) PFU. Histopathologic changes were proportional to the infecting inoculum and included the infiltration of interstitial and intra-alveolar areas, moderate damage to bronchiolar epithelium, and cellular infiltration of peribronchiolar and perivascular regions. These changes could be divided into two phases: an early phase (affecting alveoli, bronchiolar epithelium, and peribronchiolar regions) with an infiltrate consisting primarily of monocytes-macrophages and neutrophils, with occasional lymphocytes, and a later phase (affecting peribronchiolar and perivascular regions) with an infiltrate consisting almost exclusively of lymphocytes. In both phases, the predominant process was the response of the host to infection, rather than direct viral damage to infected cells. An infecting inoculum of 10(8.0) PFU or larger caused severe damage to type II alveolar cells, which were swollen, showed a loss of lamellar bodies, and were surrounded by polymorphonuclear leukocytes and macrophages. No evidence of complete viral replication was found in type II alveolar cells. 相似文献
29.
A major difference between the divergence patterns within the lines-1 families in mice and voles 总被引:3,自引:0,他引:3
Vanlerberghe F; Bonhomme F; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1993,10(4):719-731
L1 retroposons are represented in mice by subfamilies of interspersed
sequences of varied abundance. Previous analyses have indicated that
subfamilies are generated by duplicative transposition of a small number of
members of the L1 family, the progeny of which then become a major
component of the murine L1 population, and are not due to any active
processes generating homology within preexisting groups of elements in a
particular species. In mice, more than a third of the L1 elements belong to
a clade that became active approximately 5 Mya and whose elements are >
or = 95% identical. We have collected sequence information from 13 L1
elements isolated from two species of voles (Rodentia: Microtinae: Microtus
and Arvicola) and have found that divergence within the vole L1 population
is quite different from that in mice, in that there is no abundant
subfamily of homologous elements. Individual L1 elements from voles are
very divergent from one another and belong to a clade that began a period
of elevated duplicative transposition approximately 13 Mya. Sequence
analyses of portions of these divergent L1 elements (approximately 250 bp
each) gave no evidence for concerted evolution having acted on the vole L1
elements since the split of the two vole lineages approximately 3.5 Mya;
that is, the observed interspecific divergence (6.7%-24.7%) is not larger
than the intraspecific divergence (7.9%-27.2%), and phylogenetic analyses
showed no clustering into Arvicola and Microtus clades.
相似文献
30.
J H Lazarus R John J Ginsberg I A Hughes G Shewring B R Smith J S Woodhead R Hall 《BMJ (Clinical research ed.)》1983,286(6365):592-594
In a screening programme for neonatal hypothyroidism an otherwise healthy female infant was found to have a high concentration of thyroid stimulating hormone in a filter paper blood spot and in serum. A high concentration was also found in the maternal serum. Mother and baby were both biochemically euthyroid with normal serum thyroxine concentrations. The apparently high concentration of thyroid stimulating hormone in the mother was due to the presence of an IgG antibody that bound to human but not bovine thyroid stimulating hormone. Maternal serum inhibited the action of human thyroid stimulating hormone in an in vitro bioassay for the hormone. It is suggested that the baby acquired the antibody transplacentally, especially as the concentration of thyroid stimulating hormone subsequently fell. It is concluded that maternal serum should be assayed for thyroid stimulating hormone when a neonate is found to have a high concentration of the hormone and a normal concentration of thyroxine to establish the incidence of this finding and to avoid inappropriate replacement treatment. 相似文献