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1.
Retinol and extracellular collagen matrices modulate hepatic Ito cell collagen phenotype and cellular retinol binding protein levels 总被引:8,自引:0,他引:8
The hepatic vitamin A-storing Ito cell has been implicated as a causative cell in hepatic fibrogenesis. Using a modification of a recent method (Friedman, S. L., Roll, F. J., Boyles, J., and Bissell, D. M. (1985) Proc. Natl. Acad. Sci. U. S. A. 82, 8681-8685), rat Ito cells were isolated and passaged in vitro on collagen-coated plastic dishes through cell generation 40-50. The collagen synthetic phenotype for Ito cells grown on various extracellular matrices was demonstrated by immunofluorescence and quantitated by competition enzyme-linked immunosorbent assays. When grown on a type I collagen matrix, Ito cells produced type IV greater than type III greater than type I collagen. When grown on a type IV collagen matrix, the cells produced relatively equal amounts of types I and III collagen. The absolute amounts of type I collagen produced were greater when cells were grown on type IV versus type I matrix. When 10(-5) M retinol was added to cell cultures, there was a uniform increase in type III collagen regardless of matrix type but a decrease in type I collagen when cells were grown on a type IV matrix and a large increase in type I collagen when cells were grown on a type I collagen matrix. The levels of cellular retinol binding protein, a key cytosolic retinol transport protein, were quantitated by high performance liquid chromatography and compared for cells grown on type I versus type IV collagen matrices. It was found that cells on a type I matrix contain 4.96 +/- 2.8 times more cellular retinol binding protein than do cells grown on a type IV matrix. In conclusion, Ito cell collagen synthesis may be altered by underlying extracellular matrix and exogenous retinol. This in vitro culture system should allow the study of regulatory factors and possible therapeutic anti-fibrogenic mediators. 相似文献
2.
Summary Alpha-smooth muscle actin is currently considered a marker of smooth muscle cell differentiation. However, during various
physiologic and pathologic conditions, it can be expressed, sometimes only transiently, in a variety of other cell types,
such as cardiac and skeletal muscle cells, as well as in nonmuscle cells. In this report, the expression of actin mRNAs in
cultured rat capillary endothelial cells (RFCs) and aortic smooth muscle cells (SMCs) has been studied by Northern hybridization
in two-dimensional cultures seeded on individual extracellular matrix proteins and in three-dimensional type I collagen gels.
In two-dimensional cultures, in addition to cytoplasmic actin mRNAs which are normally found in endothelial cell populations,
RFCs expressed α-smooth muscle (SM) actin mRNA at low levels. α-SM actin mRNA expression is dramatically enhanced by TGF-β1. In addition, double immunofluorescence staining with anti-vWF and anti-α-SM-1 (a monoclonal antibody to α-SM actin) shows
that RFCs co-express the two proteins. In three dimensional cultures, RFCs still expressed vWF, but lost staining for α-SM
actin, whereas α-SM actin mRNA became barely detectable. In contrast to two-dimensional cultures, the addition of TGF-β1 to the culture media did not enhance α-SM actin mRNA in three-dimensional cultures, whereas it induced rapid capillary tube
formation. Actin mRNA expression was modulated in SMCs by extracellular matrix components and TGF-β1 with a pattern very different from that of RFCs. Namely, the comparison of RFCs with other cell types such as bovine aortic
endothelial cells shows that co-expression of endothelial and smooth muscle cell markers is very unique to RFCs and occurs
only in particular culture conditions. This could be related to the capacity of these microvascular endothelial cells to modulate
their phenotype in physiologic and pathologic conditions, particularly during angiogenesis, and could reflect different embryologic
origins for endothelial cell populations.
Supported by a Post-Doctoral Fellowship from the Swiss National Science Foundation (OK) and grant HL-RO1-28373 (JAM) from
the Department of Human Services, Public Health Service, Washington, D.C. 相似文献
3.
A 48 kDa collagen-binding phosphoprotein isolated from bovine aortic endothelial cells interacts with the collagenous domain, but not the globular domain, of collagen type IV. 下载免费PDF全文
We have identified collagen-binding proteins in detergent extracts of metabolically labelled bovine aortic endothelial cells (BAEC) by collagen type IV-Sepharose affinity chromatography. The major collagen type IV-binding protein identified by SDS/PAGE had a molecular mass of 48 kDa, which we term the 'collagen-binding 48 kDa protein' (CB48). The pI of CB48 was 8.0-8.3 in a two-dimensional gel system, running non-equilibrium pH gel electrophoresis in the first dimension and SDS/PAGE in the second dimension. Under these conditions CB48 separated into two major (a and b) and one minor isoform (c); a was the most basic of the three isoforms. Two-dimensional chymotryptic peptide maps derived from each individual isoform were virtually identical. The charge differences between the isoforms were due in part to differential H3(32)PO4 incorporation by the protein. CB48 bound to intact collagen type IV and the collagenous region of collagen type IV, but not to the globular NC1 domain. Cell-surface labelling and indirect immunofluorescence experiments localized the bulk of CB48 intracellularly in the endoplasmic reticulum Golgi region, with a minor population of molecules on the cell surface. A specific rabbit polyclonal anti-CB48 serum did not inhibit the attachment or spreading of BAEC to collagen type IV in an 'in vitro' adhesion assay, suggesting that the cell-surface population of CB48 is not involved in BAEC adhesion. We conclude that CB48 is a collagen-binding phosphoprotein that interacts with the collagenous domain of collagen type IV and may be involved in intracellular transport of collagen molecules. 相似文献
4.
An Ustilago maydis ergosterol biosynthesis mutant (A14) which is partially blocked in sterol 14alpha-demethylase (P45014DM) activity is described. This mutant accumulated the abnormal 14alpha-methyl sterols, eburicol, 14alpha-methylfecosterol, and obtusifoliol, along with significant amounts of ergosterol. Although the A14 mutant grew nearly as well as the wild type, it was impaired in cell extension growth, which indicated a dysfunction in apical cell wall synthesis. The mutant was also found to be hypersensitive to the azole fungicides penconazole and tebuconazole. 相似文献
5.
6.
J R Merwin A Tucker L Madisen A Purchio J Madri 《Biochemical and biophysical research communications》1991,175(2):589-595
Functional biological assays were performed using a hybrid molecule of Transforming Growth Factor-Beta (TGF-5 beta) where nine amino acids near the cleavage site of TGF-beta 1 were substituted with nine amino acids located in the identical position of TGF-beta 2. Bovine aortic endothelial and smooth muscle cells as well as rat epididymal fat pad microvascular endothelia were studied in three distinct bioassays examining proliferation, migration and angiogenesis. The data suggested TGF-5 beta elicited results that do not differ significantly from the TGF-beta 1 isoform, while TGF-beta 2 expressed unique characteristics. We have also shown that these amino acid substitutions to TGF-beta 1 do not, in fact, alter the biological functions of the growth factor. 相似文献
7.
JA Kiernan 《Biotechnic & histochemistry》2013,88(5-6):203-210
Hexazonium pararosaniline is a valuable reagent that has been used in enzyme activity histochemistry for 50 years. It is an aqueous solution containing the tris-diazonium ion derived from pararosaniline, an aminotriarylmethane dye, and it contains an excess of nitrous acid that was not consumed in the diazotization reaction. Other investigators have found that immersion for 2 min in an acidic (pH 3.5) 0.0015 M hexazonium pararosaniline solution can protect cryostat sections of unfixed animal tissues from the deleterious effects of aqueous reagents such as buffered solutions used in immunohistochemistry, while preserving specific affinities for antibodies. In the present investigation hexazonium pararosaniline protected lymphoid tissue and striated muscle against the damaging effects of water or saline. The same protection was conferred on unfixed sections treated with dilute nitrous or hydrochloric acid in concentrations similar to those in hexazonium pararosaniline solutions. Model tissues (solutions, gels or films containing gelatin and/or bovine albumin) responded predictably to well known cross-linking (formaldehyde) or coagulant (mercuric chloride) fixatives. Hexazonium pararosaniline solutions prevented the dissolution of protein gels in water only after 9 or more days of contact, during which time considerable swelling occurred. It is concluded that there is no evidence for a “fixative” action of hexazonium pararosaniline. The protective effect on frozen sections of unfixed tissue is attributable probably to the low pH of the solution. 相似文献
8.
Water hyacinth Eichhornia crassipes is considered the most damaging aquatic weed in the world. However, few studies have quantified the impact of this weed economically and ecologically, and even fewer studies have quantified the benefits of its control. This paper focuses on water loss saving as the benefit derived from biological control of this plant between 1990 and 2013 at New Year’s Dam, Alicedale, Eastern Cape, South Africa. Estimates of water loss due to evapotranspiration from water hyacinth vary significantly; therefore, the study used three different rates, high, medium and low. A conservative raw agriculture value of R 0.26 per m3 was used to calculate the benefits derived by the water saved. The present benefit and cost values were determined using 10% and 5% discount rates. The benefit/cost ratio at the low evapotranspiration rate was less than one, implying that biological control was not economically viable but, at the higher evapotranspiration rates, the return justified the costs of biological control. However, at the marginal value product of water, the inclusion of the costs of damage to infrastructure, or the adverse effects of water hyacinth on biodiversity, would justify the use of biological control, even at the low transpiration rate. 相似文献
9.
The Tau/A152T mutation,a risk factor for frontotemporal‐spectrum disorders,leads to NR2B receptor‐mediated excitotoxicity 下载免费PDF全文
Astrid Sydow Frank JA Dennissen Zuzana Siskova Eckhard Mandelkow Eva‐Maria Mandelkow 《EMBO reports》2016,17(4):552-569
We report on a novel transgenic mouse model expressing human full‐length Tau with the Tau mutation A152T (hTauAT), a risk factor for FTD‐spectrum disorders including PSP and CBD. Brain neurons reveal pathological Tau conformation, hyperphosphorylation, mis‐sorting, aggregation, neuronal degeneration, and progressive loss, most prominently in area CA3 of the hippocampus. The mossy fiber pathway shows enhanced basal synaptic transmission without changes in short‐ or long‐term plasticity. In organotypic hippocampal slices, extracellular glutamate increases early above control levels, followed by a rise in neurotoxicity. These changes are normalized by inhibiting neurotransmitter release or by blocking voltage‐gated sodium channels. CA3 neurons show elevated intracellular calcium during rest and after activity induction which is sensitive to NR2B antagonizing drugs, demonstrating a pivotal role of extrasynaptic NMDA receptors. Slices show pronounced epileptiform activity and axonal sprouting of mossy fibers. Excitotoxic neuronal death is ameliorated by ceftriaxone, which stimulates astrocytic glutamate uptake via the transporter EAAT2/GLT1. In summary, hTauAT causes excitotoxicity mediated by NR2B‐containing NMDA receptors due to enhanced extracellular glutamate. 相似文献
10.
Hernandez-Trejo A B Estrada-Drouaillet JA López-Santillán C Rios-Velasco SE Varela-Fuentes R Rodríguez-Herrera E Osorio-Hernández 《Phyton》2019,88(1):47-54
The control of Spodoptera frugiperda is based
on synthetic insecticides, so some alternatives are the use of
entomopathogenic fungi (EF) and neem extract. The objective of
the study was to evaluate in vitro effectiveness of native EF and
neem extracts on S. frugiperda larvae. Six EF were identified by
DNA sequencing of ITS regions from three EF (Fusarium solani,
Metarrhizium robertsii, Nigrospora spherica and Penicillium
citrinum). They were evaluated in concentrations of 1 × 10⁸ spores/
mL. In addition, a second bioassay was carried out evaluating
only F. solani, M. robertsii and N. sphaerica and the addition
of vegetable oil. On the other hand, extraction of secondary
metabolites from neem seed (Azadirachta indica) was carried
out by performing, mass (g) and solvent volume (mL ethanol
and water) combinations, which were subjected to microwaves
and ultrasound. Subsequently, these extracts were evaluated
in concentrations of 3%, 4% and 5%. A survival analysis was
performed for each of the bioassays. With respect to the results
of the first bioassay, F. solani obtained a probability of survival of
0.476 on the seventh day, while in the second bioassay, M. robertsii
obtained 0.488 survival probability. This suggests that the expected
percentage of larvae that stay alive on the sixth day is 48.8%.
However, in the evaluation of the neem extract the combination
1:12/70% to 4% caused 84% mortality of larvae. The use of native
HE and neem extracts has potential for the control of S. frugiperda. 相似文献