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81.
uPA binding increases UPAR localization to lipid rafts and modifies the receptor microdomain composition 总被引:1,自引:0,他引:1
Sahores M Prinetti A Chiabrando G Blasi F Sonnino S 《Biochimica et biophysica acta》2008,1778(1):250-259
UPAR is a GPI anchored protein, which is found in both lipid rafts and in more fluid regions of the plasma membrane. We have studied the role of the ligand uPA on uPAR localization and on the composition of the lipid membrane microdomains. We have analyzed the glycosphingolipid environment of uPAR in detergent resistant membrane (DRM) fractions prepared by cell lysis with 1% Triton X-100 and fractionated by sucrose gradient centrifugation obtained from HEK293-uPAR cells. The uPAR specific lipid membrane microdomain has been separated from the total DRM fraction by immunoprecipitation with an anti-uPAR specific antibody under conditions that preserve membrane integrity. We have also tested uPA-induced ERK phosphorylation in the presence of methyl-beta-cyclodextrin, which is known to disrupt lipid rafts by sequestering cholesterol from such domains. Our results show that uPAR is partially associated with DRM and this association is increased by ligands, is independent of the catalytic activity of uPA, and is required for intracellular signalling. In the absence of ligands, uPAR experiences a lipid environment very similar to that of total DRM, enriched in sphingomyelin and glycosphingolipids. However, after treatment of cells with uPA or ATF the lipid environment is strongly impoverished of neutral glycosphingolipids. 相似文献
82.
Carlos E. Aragón Maritza Escalona Iris Capote Danilo Pina Inaudis Cejas Roberto Rodriguez Maria Jesus Cañal Jorge Sandoval Sophe Roels Pierre Debergh Justo Gonzalez-Olmedo 《In vitro cellular & developmental biology. Plant》2005,41(4):550-554
Summary The photosynthetic capacity changes and the main enzymatic systems related to carbon metabolism were investigated during the
in vitro culture of plantain shoots (Musa AAB cv. CEMSA 3/4) in temporary immersion bioreactors (TIB) and their subsequent acclimatization.
The maximal rate of photosynthesis (Pn), transpiration, and the activity of the carbon metabolism enzymes phosphoenolpyruvate
carboxylase (PEPC), acid invertase (AI), pyruvate kinase (PK) and sucrose phosphate synthase (SPS) were measured every 7 d
during the 21 d of elongation in TIB, and the following 42 d of acclimatization. Sucrose content in the liquid medium and
in the leaves was also determined. The most significant changes in plant growth were observed during acclimatization. During
the in vitro stage photosynthesis was limited (4–6 μmol CO2m−2s−1); the photosynthetic rate however increases rapidly and significantly as soon as in vitro culture is over during acclimatization. PEPC activity increased during the whole evaluation period. The highest levels were
achieved around days 42 and 56. PK and SPS activities were optimal during the first weeks in acclimatization (28–35 d), while
AI increased at the beginning of the elongation phase (7 d), and later at the end of the acclimatization (49–63 d). The relationships
between morphological parameters, photosynthetic capacity of the plantlets and the carbon metabolism enzymes during both phases
of the culture are discussed. 相似文献
83.
Strategy for Cloning Large Gene Assemblages as Illustrated Using the Phenylacetate and Polyhydroxyalkanoate Gene Clusters 下载免费PDF全文
Beln García Elías R. Olivera ngel Sandoval Elsa Arias-Barrau Sagrario Arias Germn Naharro Jos M. Luengo 《Applied microbiology》2004,70(8):5019-5025
We report an easy procedure for isolating chromosome-clustered genes. By following this methodology, the entire set of genes belonging to the phenylacetic acid (PhAc; 18-kb) pathway as well as those required for the synthesis and mobilization of different polyhydroxyalkanoates (PHAs; 6.4 kb) in Pseudomonas putida U were recovered directly from the bacterial chromosome and cloned into a plasmid for the first time. The transformation of different bacteria with these genetic constructions conferred on them the ability to either degrade PhAc or synthesize bioplastics (PHAs). 相似文献
84.
Macarena Sahores Alessandro Prinetti Francesco Blasi Sandro Sonnino 《生物化学与生物物理学报:生物膜》2008,1778(1):250-259
UPAR is a GPI anchored protein, which is found in both lipid rafts and in more fluid regions of the plasma membrane. We have studied the role of the ligand uPA on uPAR localization and on the composition of the lipid membrane microdomains. We have analyzed the glycosphingolipid environment of uPAR in detergent resistant membrane (DRM) fractions prepared by cell lysis with 1% Triton X-100 and fractionated by sucrose gradient centrifugation obtained from HEK293-uPAR cells. The uPAR specific lipid membrane microdomain has been separated from the total DRM fraction by immunoprecipitation with an anti-uPAR specific antibody under conditions that preserve membrane integrity. We have also tested uPA-induced ERK phosphorylation in the presence of methyl-β-cyclodextrin, which is known to disrupt lipid rafts by sequestering cholesterol from such domains. Our results show that uPAR is partially associated with DRM and this association is increased by ligands, is independent of the catalytic activity of uPA, and is required for intracellular signalling. In the absence of ligands, uPAR experiences a lipid environment very similar to that of total DRM, enriched in sphingomyelin and glycosphingolipids. However, after treatment of cells with uPA or ATF the lipid environment is strongly impoverished of neutral glycosphingolipids. 相似文献
85.
Alfredo Téllez-Valencia Ada A. Sandoval Mario Pedraza-Reyes 《Current microbiology》2003,46(4):0307-0310
The modular endocellulase Cel9 of the bicistronic operon cel9-cel48 of Myxobacter sp. AL-1 shares not only amino acid sequence similarity but also biochemical properties similar to those of Thermobifida fusca endo/exocellulase E4. Amino acid alignments of a T. fusca E4 cellulase subfamily of family 9 cellulases revealed that Asp446 of Myxobacter sp. AL-1 Cel9, a putatively noncatalytic residue, is highly conserved in one of the catalytic domains of this subfamily.
Directed mutagenesis of residue aspartate (Asp446) to alanine generated a Cel9 mutant that lost more than 99% of its activity, suggesting that Asp446 plays an essential structural role in Cel9 during cellulose degradation. Owing to its high degree of conservation and essential
role, we propose that Asp446 of Myxobacter sp. AL-1 Cel9 is a good landmark that distinguishes members of the E4 subfamily of family 9 cellulases.
Received: 4 May 2002 / Accepted: 5 July 2002 相似文献
86.
C G Zamorano M C Contreras A Sánchez M A Bahamondes L Sandoval 《Boletín chileno de parasitología》1991,46(3-4):82-84
San Juan de la Costa County (40 degrees 45' South lat., 73 degrees 19' West long.) is located in the Osorno province, South of Chile. Its population is 8,486 inhabitants. The basic economic activities are agriculture, cattle raising, timber production and manufacture of wood and coal. According to official reports, the incidence of human hydatidosis and trichinosis in this locality in 1989 were 24 and 59 per 100,000 respectively. In order to contribute to a better knowledge of the epidemiology of human hydatidosis and trichinosis in San Juan de la Costa County, an indirect hemagglutination test (IHAT) for these parasitoses was performed to 511 randomized people. Nine (1.8%) individuals resulted positive for hydatidosis and twenty four (4.7%) were positive for trichinosis. Some considerations on the corresponding prophylactic measures are proposed. 相似文献
87.
The experiments were conducted to explore the possibility that formic acid could serve as a reducing agent for carbonyl compounds on the prebiotic earth, since it has been shown that formic acid is a product of numerous chemical evolution experiments. The photoreduction of solutions 0.33 M in acetaldehyde or acetone at 2537 Å in 0.167 M formic acid, sodium formate, or both formic acid and sodium formate in a nitrogen atmosphere has been conducted. The formation of the corresponding reduction product, ethanol or isopropyl alcohol, and the disappearance of the reactant were followed as a function of irradiation time by using gas chromatography. Product confirmation was done by NMR analysis and mass spectrometry. 相似文献
88.
Graciela E. Santillán Marisa J. Sandoval Yuti Chernajovsky Patricia L. Orchansky 《Molecular and cellular biochemistry》1992,110(2):181-191
A number of cell-surface proteins are anchored in plasma membranes by a glycosylated phosphatidylinositol (PI) moiety that
is covalently attached to the carboxyl-terminal amino acid of the mature protein. We have previously reported the construction
of a cDNA clone of a truncated Platelet-derived growth factor (PDGF) receptor that consists of the extracellular domain without
the transmembrane and cytoplasmic domains. In the construction of the vector, a sequence of 51 base pairs (bp) from the 3′-untranslated
region of the receptor cDNA was linked in frame with the external domain coding sequence. The truncated receptor protein with
the peptide VTSGHCHEERVDRHDGE fused to its carboxyl terminus was covalently attached to the membrane by a PI linkage and it
was released by phosphatidylinositol specific-phospholipase C (PI-PLC). When the 51 bp sequence was deleted, the external
domain receptor protein was secreted into the media. To determine whether the PI linkage of the protein was due to the 17
amino acids added, the peptide was fused to the carboxyl terminus of the secreted protein human Interferon-β (hu-IFN-β). Chinese
hamster ovary (CHO) cells transfected with the hu-IFN-β cDNA secreted the protein to theconditioned media, whereas CHO cells
transfected with the carboxyl terminus modified-hu-IFN-β cDNA did not secrete detectable levels of protein. CHO cells expressing
the carboxyl terminus modified-hu-IFN-β were treated with PI-PLC, the media and cell lysates were analyzed by SDS-PAGE after
immunoprecipitation with antibodies against hu-IFN-β. The modified protein is anchored to the plasma membrane by a PI linkage
and it is specifically released by PI-PLC, whereas a control preparation of CHO cells expressing wild type hu-IFN-β does not
show the same pattern. The 17 amino acid peptide fused to the carboxyl terminus of IFN-β directs attachment of a PI anchor
and targets the fusion protein to the plasma membrane. 相似文献
89.
Juan A. Godoy Macarena S. Arrázola Daniela Ordenes Carmen Silva-Alvarez Nady Braidy Nibaldo C. Inestrosa 《The Journal of biological chemistry》2014,289(52):36179-36193
The Wnt signaling pathway plays an important role in developmental processes, including embryonic patterning, cell specification, and cell polarity. Wnt components participate in the development of the central nervous system, and growing evidence indicates that this pathway also regulates the function of the adult nervous system. In this study, we report that Wnt-5a, a noncanonical Wnt ligand, is a potent activator of mitochondrial dynamics and induces acute fission and fusion events in the mitochondria of rat hippocampal neurons. The effect of Wnt-5a was inhibited in the presence of sFRP, a Wnt scavenger. Similarly, the canonical Wnt-3a ligand had no effect on mitochondrial fission-fusion events, suggesting that this effect is specific for Wnt-5a alone. We also show that the Wnt-5a effects on mitochondrial dynamics occur with an increase in both intracellular and mitochondrial calcium (Ca2+), which was correlated with an increased phosphorylation of Drp1(Ser-616) and a decrease of Ser-637 phosphorylation, both indicators of mitochondrial dynamics. Electron microscope analysis of hippocampal tissues in the CA1 region showed an increase in the number of mitochondria present in the postsynaptic region, and this finding correlated with a change in mitochondrial morphology. We conclude that Wnt-5a/Ca2+ signaling regulates the mitochondrial fission-fusion process in hippocampal neurons, a feature that might help to further understand the role of Wnt-related pathologies, including neurodegenerative diseases associated with mitochondrial dysfunction, and represents a potentially important link between impaired metabolic function and degenerative disorders. 相似文献
90.