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171.
A. Maldotti Leonardo Andreotti Alessandra Molinari Vittorio Carassiti 《Journal of biological inorganic chemistry》1999,4(2):154-161
Photoexcited iron porphyrins can be used to mimic the catalytic activity of cytochrome P-450 oxygenases both in the reduction of halogenated alkanes and in the oxidation of hydrocarbons by O2 itself at room temperature and atmospheric pressure. The results reported indicate that there is a similarity and a complementarity of photonic activation with other more conventional methods of activation of model systems of oxygenases. In fact, by irradiating at suitable wavelengths, it is possible to induce redox reactions which mimic those of natural oxygenases, avoiding the difficulties caused by parallel processes which could be expected when chemical reagents are used. These processes occur with good turnover values of the photocatalyst and in mild temperature and pressure conditions. By controlling the reaction environment, it is possible to address the selectivity of the process. In this regard, the very recent results obtained after heterogenization of the photocatalysts inside membranes of Nafion® are particularly promising for the development of new biomimetic photocatalysts in heterogeneous or organized systems. 相似文献
172.
Ricardo Andreotti Siqueira Andre Mario Doi Paulo Petrus de Petrus Crossara Paula Celia Mariko Koga Alexandre Gimenes Marques Fabiane Gomes Nunes Jacyr Pasternak Marines Dalla Valle Martino 《Revista iberoamericana de micología》2018,35(2):83-87
Background
An increased incidence of fungal infections caused by Candida species, especially Candida glabrata and Candida krusei, which are less susceptible to azoles, has been observed. Standardized susceptibility testing is essential for clinical management and for monitoring the epidemiology of resistance.Aims
We evaluated the performance of two different susceptibility testing commercial methods, Vitek 2® and Sensititre YeastOne®, and compared them with the standard broth microdilution method (CLSI).Methods
A total of 80 isolates of several Candida species (Candida albicans, Candida parapsilosis complex, Candida tropicalis, C. glabrata and C. krusei) were selected for this study.Results
We analyzed the categorical agreement (CA) between the methods, stratifying the disagreements. The average CA between the methods was 96.3% for Vitek 2® and 84% for Sensititre YeastOne®. No very major errors were observed. Major errors and minor errors were found for all the isolates tested. With the azoles, both Vitek 2® and Sensititre YeastOne® had good and similar performance levels, except for C. tropicalis and C. krusei (Sensititre YeastOne® showed low CA, 56.2%). With the echinocandins, both methods showed good performance for C. albicans, C. parapsilosis and C. tropicalis. However, we observed important discrepancies for C. krusei with caspofungin: Vitek 2® had 100% CA while Sensititre YeastOne® had only 25%. With amphotericin B, both Vitek 2® and Sensititre YeastOne® had good performance with high CA.Conclusions
Despite the limited isolates tested, we concluded that both methods have good performance and are reliable for antifungal susceptibility testing. However, caspofungin activity against C. krusei and C. glabrata should be interpreted carefully when using Sensititre YeastOne® because we observed a low CA. 相似文献173.
Rasha AH Attia Abeer E Mahmoud Haiam Mohammed Mahmoud Farrag Rania Makboul Mona Embarek Mohamed Zedan Ibraheim 《Memórias do Instituto Oswaldo Cruz》2015,110(8):1035-1041
Trichinellosis is a serious disease with no satisfactory treatment. We aimed to
assess the effect of myrrh (Commiphora molmol) and, for the first
time, thyme (Thymus vulgaris L.) against enteral
and encysted (parenteral) phases of Trichinella spiralis in mice
compared with albendazole, and detect their effect on inducible nitric oxide synthase
(iNOS) expression. Oral administration of 500 mg/kg of myrrh and thyme led to adult
reduction (90.9%, 79.4%), while 1,000 mg/kg led to larvae reduction (79.6%, 71.3%),
respectively. Administration of 50 mg/kg of albendazole resulted in adult and larvae
reduction (94.2%, 90.9%). Positive immunostaining of inflammatory cells infiltrating
intestinal mucosa and submucosa of all treated groups was detected. Myrrh-treated
mice showed the highest iNOS expression followed by albendazole, then thyme. On the
other hand, both myrrh and thyme-treated groups showed stronger iNOS expression of
inflammatory cells infiltrating and surrounding encapsulated T.
spiralis larvae than albendazole treated group. In conclusion, myrrh and
thyme extracts are highly effective against both phases of T.
spiralis and showed strong iNOS expressions, especially myrrh which could
be a promising alternative drug. This experiment provides a basis for further
exploration of this plant by isolation and retesting the active principles of both
extracts against different stages of T. spiralis. 相似文献
174.
Julhiany de Fátima da Silva Juliana Vicentim Haroldo Cesar de Oliveira Caroline Maria Marcos Patricia Akemi Assato Patrícia Ferrari Andreotti Juliana Leal Monteiro da Silva Christiane Pienna Soares Gil Benard Ana Marisa Fusco Almeida Maria José Soares Mendes-Giannini 《Memórias do Instituto Oswaldo Cruz》2015,110(4):476-484
The fungal strain Paracoccidioides brasiliensis remains viable
inside of epithelial cells and can induce apoptosis in this population. However,
until now, the molecules that participate in this process remained unknown. Thus,
this study evaluated the contribution of two P. brasiliensis
molecules, the 14-3-3 and glycoprotein of 43 kDa proteins, which had been previously
described as extracellular matrix adhesins and apoptosis inductors in human
pneumocytes. Accordingly, epithelial cells were treated with these molecules for
different periods of time and the expression of the apoptosis regulating-proteins
Bak, Bax, Bcl-2, p53 and caspases were evaluated by terminal deoxynucleotidyl
transferase dUTP nick end labelling, flow cytometry and real-time polymerase chain
reaction analysis. Our results demonstrated that treatment with these molecules
induces apoptosis signalling in pulmonary epithelial cells, showing the same pattern
of programmed cell-death as that observed during infection with P.
brasiliensis. Thus, we could conclude that P.
brasiliensis uses these molecules as virulence factors that participate
not only in the fungal adhesion process to host cells, but also in other important
cellular mechanisms such as apoptosis. 相似文献
175.
Blocking the QB‐binding site of photosystem II by tenuazonic acid,a non–host‐specific toxin of Alternaria alternata,activates singlet oxygen‐mediated and EXECUTER‐dependent signalling in Arabidopsis 下载免费PDF全文
SHIGUO CHEN CHANHONG KIM JE MIN LEE HYUN‐AH LEE ZHANGJUN FEI LIANGSHENG WANG KLAUS APEL 《Plant, cell & environment》2015,38(6):1069-1080
Necrotrophic fungal pathogens produce toxic compounds that induce cell death in infected plants. Often, the primary targets of these toxins and the way a plant responds to them are not known. In the present work, the effect of tenuazonic acid (TeA), a non–host‐specific toxin of Alternaria alternata, on Arabidopsis thaliana has been analysed. TeA blocks the QB‐binding site at the acceptor side of photosystem II (PSII). As a result, charge recombination at the reaction centre (RC) of PSII is expected to enhance the formation of the excited triplet state of the RC chlorophyll that promotes generation of singlet oxygen (1O2). 1O2 activates a signalling pathway that depends on the two EXECUTER (EX) proteins EX1 and EX2 and triggers a programmed cell death response. In seedlings treated with TeA at half‐inhibition concentration 1O2‐mediated and EX‐dependent signalling is activated as indicated by the rapid and transient up‐regulation of 1O2‐responsive genes in wild type, and its suppression in ex1/ex2 mutants. Lesion formation occurs when seedlings are exposed to higher concentrations of TeA for a longer period of time. Under these conditions, the programmed cell death response triggered by 1O2‐mediated and EX‐dependent signalling is superimposed by other events that also contribute to lesion formation. 相似文献
176.
Fonseca-Alaniz MH Brito LC Borges-Silva CN Takada J Andreotti S Lima FB 《Obesity (Silver Spring, Md.)》2007,15(9):2200-2208
Objective: Salt restriction has been reported to increase white adipose tissue (WAT) mass in rodents. The objective of this study was to investigate the effect of different sodium content diets on the lipogenic and lipolytic activities of WAT. Research Methods and Procedures: Male Wistar rats were fed on normal‐sodium (NS; 0.5% Na+), high‐sodium (HS; 3.12% Na+), or low‐sodium (LS; 0.06% Na+) diets for 3, 6, and 9 weeks after weaning. Blood pressure (BP) was measured using a computerized tail‐cuff system. At the end of each period, rats were killed and blood samples were collected for leptin determinations. The WAT from abdominal and inguinal subcutaneous (SC), periepididymal (PE) and retroperitoneal (RP) depots was weighed and processed for adipocyte isolation, rate measurement of lipolysis and d ‐[U‐14C]‐glucose incorporation into lipids, glucose‐6‐phosphate dehydrogenase (G6PDH) and malic enzyme activity evaluation, and determination of G6PDH and leptin mRNA expression. Results: After 6 weeks, HS diet significantly increased BP; SC, PE, and RP WAT masses; PE adipocyte size; plasma leptin concentration; G6PDH activity in SC WAT; and PE depots and malic activity only in SC WAT. The leptin levels correlated positively with WAT masses and adipocyte size. An increase in the basal and isoproterenol‐stimulated lipolysis and in the ability to incorporate glucose into lipids was observed in isolated adipocytes from HS rats. Discussion: HS diet induced higher adiposity characterized by high plasma leptin concentration and adipocyte hypertrophy, probably due to an increased lipogenic capacity of WAT. 相似文献
177.
Monteiro da Silva JL Andreotti PF Benard G Soares CP Miranda ET Mendes-Giannini MJ 《Antonie van Leeuwenhoek》2007,92(1):129-135
Paracoccidioidomycosis is caused by Paracoccidioides brasiliensis, which although not formally considered an intracellular pathogen, can be internalized by epithelial cells in vitro and in
vivo. The mechanisms used by P. brasiliensis to adhere to and invade non-professional phagocytes have not been identified. The signal-transduction networks, involving
protein tyrosine kinase (PTK) and protein phosphatase activities, can modulate crucial events during fungal infections. In
this study, the involvement of PTK has been investigated in P. brasiliensis adherence and invasion in mammalian epithelial cells. A significant inhibition of the fungal invasion occurred after the
pre-treatment of the epithelial cells with genistein, a specific tyrosine kinase inhibitor, indicating that the tyrosine kinase
pathway is involved in P. brasiliensis internalization. In contrast, when the fungus was treated, a slight (not significant) inhibition of PTK was observed, suggesting
that PTK might not be the fungus’ transduction signal pathway during the invasion process of epithelial cells. An intense
PTK immunofluorescence labeling was observed in the periphery of the P. brasiliensis infected cells, little PTK labeling was found in both uninfected cells and yeast cells, at later infection times (8 and 24 h).
Moreover, when the epithelial cells were treated with genistein and infected with P. brasiliensis, no labeling was observed, suggesting the importance of the PTK in the infectious process. These results suggest that PTK
pathway participates in the transduction signal during the initial events of the adhesion and invasion processes of P. brasiliensis to mammalian epithelial cells. 相似文献
178.
Saravana R. K. Murthy Tessi Sherrin Chad Jansen Ingrid Nijholt Michael Robles Amalia M. Dolga Nicolas Andreotti Jean-Marc Sabatier Hans-Guenther Knaus Reinhold Penner Cedomir Todorovic Thomas Blank 《PloS one》2015,10(5)
Small-conductance, Ca2+ activated K+ channels (SK channels) are expressed at high levels in brain regions responsible for learning and memory. In the current study we characterized the contribution of SK2 channels to synaptic plasticity and to different phases of hippocampal memory formation. Selective SK2 antisense-treatment facilitated basal synaptic transmission and theta-burst induced LTP in hippocampal brain slices. Using the selective SK2 antagonist Lei-Dab7 or SK2 antisense probes, we found that hippocampal SK2 channels are critical during two different time windows: 1) blockade of SK2 channels before the training impaired fear memory, whereas, 2) blockade of SK2 channels immediately after the training enhanced contextual fear memory. We provided the evidence that the post-training cleavage of the SK2 channels was responsible for the observed bidirectional effect of SK2 channel blockade on memory consolidation. Thus, Lei-Dab7-injection before training impaired the C-terminal cleavage of SK2 channels, while Lei-Dab7 given immediately after training facilitated the C-terminal cleavage. Application of the synthetic peptide comprising a leucine-zipper domain of the C-terminal fragment to Jurkat cells impaired SK2 channel-mediated currents, indicating that the endogenously cleaved fragment might exert its effects on memory formation by blocking SK2 channel-mediated currents. Our present findings suggest that SK2 channel proteins contribute to synaptic plasticity and memory not only as ion channels but also by additionally generating a SK2 C-terminal fragment, involved in both processes. The modulation of fear memory by down-regulating SK2 C-terminal cleavage might have applicability in the treatment of anxiety disorders in which fear conditioning is enhanced. 相似文献
179.
Differences in single-copy nuclear-DNA sequences among 13 species of
passerine birds were measured using DNA-DNA hybridization. A matrix of
pairwise dissimilarity values (delta mode distances) was constructed from
analysis of fitted thermal dissociation curves. A least-squares method of
phylogenetic estimation was used to construct two topologies from the
distance matrix, one constraining branch lengths of sister taxa to be equal
and the other permitting such lengths to vary. These topologies were
identical in the pattern of branching of taxa, and the difference in their
sums of squares was not statistically significant, suggesting that rates of
DNA evolution in sister groups of nine- primaried oscines are equal. A
nonparametric test for nonrandom variation in distances of sister groups to
outgroup taxa revealed no statistically significant deviation from random
variation that would be expected as a result of measurement error. However,
the level of measurement error was such that rates of DNA evolution in
sister taxa could vary by as much as 10% without being detected with the
statistical methods used here.
相似文献
180.
脑电信号数据压缩及棘波识别的小波神经网络方法 总被引:1,自引:0,他引:1
本文在对小波神经网络及其算法研究的基础上,提出了一种对脑电信号压缩表达和痫样脑电棘波识别的新方法。实验结果显示,小波网络在大量压缩数据的同时,能够较好的恢复原有信号,另外,在脑电信号的时频谱等高线图上,得到了易于自动识别的棘波和棘慢复合波特征,说明此方法在电生理信号处理和时频分析方面有着光明的应用前景。 相似文献