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31.
Takeshi Yoshida Lanxi Song Yun Bai Fumi Kinose Jiannong Li Kim C. Ohaegbulam Teresita Mu?oz-Antonia Xiaotao Qu Steven Eschrich Hidetaka Uramoto Fumihiro Tanaka Patrick Nasarre Robert M. Gemmill Jo?lle Roche Harry A. Drabkin Eric B. Haura 《PloS one》2016,11(1)
Epithelial-mesenchymal transition (EMT) is one mechanism of acquired resistance to inhibitors of the epidermal growth factor receptor-tyrosine kinases (EGFR-TKIs) in non-small cell lung cancer (NSCLC). The precise mechanisms of EMT-related acquired resistance to EGFR-TKIs in NSCLC remain unclear. We generated erlotinib-resistant HCC4006 cells (HCC4006ER) by chronic exposure of EGFR-mutant HCC4006 cells to increasing concentrations of erlotinib. HCC4006ER cells acquired an EMT phenotype and activation of the TGF-β/SMAD pathway, while lacking both T790M secondary EGFR mutation and MET gene amplification. We employed gene expression microarrays in HCC4006 and HCC4006ER cells to better understand the mechanism of acquired EGFR-TKI resistance with EMT. At the mRNA level, ZEB1 (TCF8), a known regulator of EMT, was >20-fold higher in HCC4006ER cells than in HCC4006 cells, and increased ZEB1 protein level was also detected. Furthermore, numerous ZEB1 responsive genes, such as CDH1 (E-cadherin), ST14, and vimentin, were coordinately regulated along with increased ZEB1 in HCC4006ER cells. We also identified ZEB1 overexpression and an EMT phenotype in several NSCLC cells and human NSCLC samples with acquired EGFR-TKI resistance. Short-interfering RNA against ZEB1 reversed the EMT phenotype and, importantly, restored erlotinib sensitivity in HCC4006ER cells. The level of micro-RNA-200c, which can negatively regulate ZEB1, was significantly reduced in HCC4006ER cells. Our results suggest that increased ZEB1 can drive EMT-related acquired resistance to EGFR-TKIs in NSCLC. Attempts should be made to explore targeting ZEB1 to resensitize TKI-resistant tumors. 相似文献
32.
Agnes Kenessey Miriam Banay-Schwartz Teresita De Guzman Abel Lajtha 《Neurochemical research》1991,16(9):1001-1007
Changes in the activity of proteases (cathepsin D and calpains) caused by 48-h food withdrawal were studied in the brain, liver, kidney, spleen, and heart of 3-, 12-, and 24-month-old Fischer rats. Cathepsin D activity was similar in brain, liver, and heart of control animals; in kidney it was 5-fold higher and in spleen about 10-fold higher. With age, activity increased in all organs tested except spleen. Brief starvation caused no change of cathepsin D activity in brain, but caused an increase in liver and a decrease in spleen. Neutral proteolytic activity in control was highest in the pons-medulla-cerebellum fraction of brain, and activity in liver and heart was below that in brain. Activity increased with age in brain and decreased in other organs. Brief starvation in young animals caused an increase in activity in brain, and a decrease in liver and spleen. Isolated calpain II activity was high in control brain. It increased with age in the cerebrum. Brief starvation resulted in a decrease in the brain. The results indicate that the protease content of the brain is altered with age and in malnutrition, with changes not being the same for all proteases, and changes in brain being different from those in other organs.Special issue dedicated to Dr. Louis Sokoloff. 相似文献
33.
Mónica N. Garrido Teresita A. Lisa Carlos E. Domenech 《Molecular and cellular biochemistry》1988,84(1):41-49
Summary In this work the action of the following compounds upon Ps. aeruginosa acid phosphatase has been studied: 1) alkylammonium compounds; 2) aminoalcohols and aminoacids with different substituents (–H, –CH3OH and –CH3) attached to the nitrogen atom; 3) alcohols analogous to some compounds of the above series, but without the amino group.It was found that the enzyme inhibition was more effective with N-trimethylated compounds than with the triethylated ones. The degree of inhibition depended on the number of methyl groups bound to the nitrogen atom. Taking into account the choline and betaine series the hydroxyl derivatives showed more affinity for the enzyme than the carboxylated ones. In each series the Ki values increased with the decrease of methyl groups bound to the nitrogen atom. The presence of a positively charged nitrogen atom in the molecule of the effector was essential. These results enable us to confirm that in the molecule of Ps. aeruginosa acid phosphatase there exists an anionic site with one subsite with affinity for methyl groups. 相似文献
34.
Choline and betaine as inducer agents of Pseudomonas aeruginosa phospholipase C activity in high phosphate medium 总被引:3,自引:1,他引:2
Gloria I. Lucchesi Teresita A. Lisa Carlos E. Domenech 《FEMS microbiology letters》1989,57(3):335-338
In Pseudomonas aeruginosa, choline or betaine employed as the sole carbon and nitrogen source in a high phosphate medium induced a phospholipase C and an acid phosphatase activity but not an alkaline phosphatase activity. The P. aeruginosa strain utilized in this work does not possess a constitutive phospholipase C, since under culture conditions identical to those utilized by other authors (J. Bacteriol. 93, 670-674 (1967) and J. Bacteriol. 150, 730-738 (1982), our phospholipase C proved to be an inorganic phosphate-repressible enzyme. These findings enable us to conclude that although the phosphate control for the synthesis of phospholipase C may exist, it is expressed only under certain favorable culture conditions. 相似文献
35.
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37.
Emiliano David Primo Maricel Valeria Santoro Walter Fabin Giordano ngela Teresita Lisa 《Journal of Phytopathology》2019,167(3):146-155
The genus Pseudomonas includes pathogenic species P. syringae, which can be found in various agricultural environments and which can affect a wide variety of plants, causing significant economic losses when the environmental conditions for its proliferation are optimal. Comprehensive characterizations of phytopathogenic bacteria belonging to the genus Pseudomonas are scarce in Argentina. In this work, the tabtoxin‐producing strain Pseudomonas S5, isolated from oat, was identi?ed as a P. syringae through biochemical tests such as the LOPAT test, and genetic tests such as the analysis of the small subunit ribosomal RNA gene (16S rRNA) sequence and repetitive elements, using BOX and ERIC primers. It was also determined that this phytopathogen is potentially capable of infecting other crops of agricultural importance for our region, such as soybean. This ability to infect different hosts gives it an adaptive advantage that allows it to endure seasonal changes in the environment where it lives. Our work contributes to the physiological classification of the phytopathogen P. syringae S5 isolated from our region, as well as to the knowledge about its range of potential hosts. 相似文献
38.
Jamilis Martín Garelli Fabricio Mozumder Md Salatul Islam Castañeda Teresita De Battista Hernán 《Bioprocess and biosystems engineering》2015,38(10):1903-1914
Bioprocess and Biosystems Engineering - This paper addresses the estimation of the specific production rate of intracellular products and the modeling of the bioreactor volume dynamics in high cell... 相似文献
39.
Maria Lourdes J.A.J. Jacinto Carlos Primo C. David Teresita R. Perez Benjamin R. De Jesus 《Ecological Engineering》2009,35(5):856-860
The performance of a macroalgae (Sargassum sp.), a laboratory-cultivated microalgae (Chlorococcum sp.) and a commercially available granulated activated carbon (GAC) for the removal of copper (Cu) and chromium (Cr) from aqueous solutions was evaluated using batch experiments. Kinetic and isotherm experiments were done at the optimal pH of 4.5 ± 0.1 for Cu (II) and 2.0 ± 0.1 for Cr (total). The equilibrium isotherms were determined and the results were analyzed using the Langmuir and Freundlich models. The best Cu removal performance was observed on Sargassum at a maximum removal of 87.3% obtained for an initial concentration of 20 mg L?1 Cu. The maximum uptake capacities for Cu (II) were 71.4, 19.3 and 11.4 mg g?1 of Sargassum, Chlorococcum and GAC, respectively. The biosorbents were also able to remove appreciable amounts of Cr, again with Sargassum showing maximum uptake capacity over the other materials. Kinetic studies also reveal that the removal rate is faster for both metals in Sargassum. Tests with an actual wastewater confirm the maximum uptake capacity of Cu by Sargassum. In all experiments the Sargassum biofilter outperformed GAC, which makes it a promising low-cost alternative to conventional filtration materials for wastewater treatment. 相似文献
40.
Carlos A. Nagle Monica M. Lahoz Maria M. Porta Marta Torres Teresita Manzur & Zulema Farinati 《Journal of medical primatology》2009,38(5):340-346
Background From the limited research in New World monkeys it is not clear whether they are as sensitive to the antiovulatory effects of synthetic progestins as noted in human beings. We examined whether levonorgestrel prevented ovulation in the capuchin monkey.
Methods Cebus apella monkeys were treated orally with two doses of 2 mg of levonorgestrel, 8–9 hours apart, in four periovulatory stages assessed by laparoscopy.
Results Levonorgestrel-induced luteinization of the follicle prevented oocyte release up to 8 hours before ovulation. Unhealthy oocytes were recovered from 46% of unruptured follicles. Luteal progesterone was reduced by 55%, 35%, and 25% according to when levonorgestrel was given −2, −1, and 0 day from estradiol peak respectively.
Conclusion The capuchin monkey, a neotropical primate in which progesterone circulates at levels much higher than in Old World primates and human beings, is sensitive to the antiovulatory effects of synthetic progestins. 相似文献
Methods Cebus apella monkeys were treated orally with two doses of 2 mg of levonorgestrel, 8–9 hours apart, in four periovulatory stages assessed by laparoscopy.
Results Levonorgestrel-induced luteinization of the follicle prevented oocyte release up to 8 hours before ovulation. Unhealthy oocytes were recovered from 46% of unruptured follicles. Luteal progesterone was reduced by 55%, 35%, and 25% according to when levonorgestrel was given −2, −1, and 0 day from estradiol peak respectively.
Conclusion The capuchin monkey, a neotropical primate in which progesterone circulates at levels much higher than in Old World primates and human beings, is sensitive to the antiovulatory effects of synthetic progestins. 相似文献