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101.
Kap‐Hoon Han Yoon‐Hee Chun Bárbara De Castro Pimentel Figueiredo Frederico Marianetti Soriani Marcela Savoldi Agostinho Almeida Fernando Rodrigues Charlie Timothy Cairns Elaine Bignell Jaqueline Moisés Tobal Maria Helena S. Goldman Jong‐Hwan Kim Yong‐Sun Bahn Gustavo Henrique Goldman Márcia Eliana Da Silva Ferreira 《Molecular microbiology》2010,75(6):1372-1388
Carbon dioxide (CO2) and its hydration product bicarbonate (HCO3‐) are essential molecules in various physiological processes of all living organisms. The reversible interconversion between CO2 and HCO3‐ is in equilibrium. This reaction is slow without catalyst, but can be rapidly facilitated by Zn2+‐metalloenzymes named carbonic anhydrases (CAs). To gain an insight into the function of multiple clades of fungal CA, we chose to investigate the filamentous fungi Aspergillus fumigatus and A. nidulans. We identified four and two CAs in A. fumigatus and A. nidulans, respectively, named cafA‐D and canA‐B. The cafA and cafB genes are constitutively, strongly expressed whereas cafC and cafD genes are weakly expressed but CO2‐inducible. Heterologous expression of the A. fumigatus cafB, and A. nidulans canA and canB genes completely rescued the high CO2‐requiring phenotype of a Saccharomyces cerevisiaeΔnce103 mutant. Only the ΔcafAΔcafB and ΔcanB deletion mutants were unable to grow at 0.033% CO2, of which growth defects can be restored by high CO2. Defects in the CAs can affect Aspergilli conidiation. Furthermore, A. fumigatusΔcafA, ΔcafB, ΔcafC, ΔcafD and ΔcafAΔcafB mutant strains are fully virulent in a low‐dose murine infection. 相似文献
102.
Tobias Manigold Andrés Mori Rebecca Graumann Elena Llop Valeska Simon Marcela Ferrés Francisca Valdivieso Constanza Castillo Brian Hjelle Pablo Vial 《PLoS pathogens》2010,6(2)
In man, infection with South American Andes virus (ANDV) causes hantavirus cardiopulmonary syndrome (HCPS). HCPS due to ANDV is endemic in Southern Chile and much of Argentina and increasing numbers of cases are reported all over South America. A case-fatality rate of about 36% together with the absence of successful antiviral therapies urge the development of a vaccine. Although T-cell responses were shown to be critically involved in immunity to hantaviruses in mouse models, no data are available on the magnitude, specificity and longevity of ANDV-specific memory T-cell responses in patients. Using sets of overlapping peptides in IFN-γ ELISPOT assays, we herein show in 78 Chilean convalescent patients that Gn-derived epitopes were immunodominant as compared to those from the N- and Gc-proteins. Furthermore, while the relative contribution of the N-specific response significantly declined over time, Gn-specific responses remained readily detectable ex vivo up to 13 years after the acute infection. Tetramer analysis further showed that up to 16.8% of all circulating CD3+CD8+ T cells were specific for the single HLA-B*3501-restricted epitope Gn465–473 years after the acute infection. Remarkably, Gn465–473–specific cells readily secreted IFN-γ, granzyme B and TNF-α but not IL-2 upon stimulation and showed a ‘revertant’ CD45RA+CD27−CD28−CCR7−CD127− effector memory phenotype, thereby resembling a phenotype seen in other latent virus infections. Most intriguingly, titers of neutralizing antibodies increased over time in 10/17 individuals months to years after the acute infection and independently of whether they were residents of endemic areas or not. Thus, our data suggest intrinsic, latent antigenic stimulation of Gn-specific T-cells. However, it remains a major task for future studies to proof this hypothesis by determination of viral antigen in convalescent patients. Furthermore, it remains to be seen whether Gn-specific T cells are critical for viral control and protective immunity. If so, Gn-derived immunodominant epitopes could be of high value for future ANDV vaccines. 相似文献
103.
Influence of Cross-linked Waxy Maize Starch on the Aggregation Behavior of Casein Micelles During Acid-induced Gelation 总被引:1,自引:0,他引:1
The influence of cross-linked waxy maize starch on the aggregation behavior of casein micelles was investigated using a combination
of physico-chemical techniques. Milk was homogenized at two different temperatures (55 and 65 °C) and then heated at 95 °C
for 5 min in a pilot scale system. The possible interactions between modified starch and milk proteins during lactic acid
fermentation were evaluated. While 1% starch did not show differences in the whey protein complexes formed during heating
compared to milk with no starch (as measured by size exclusion chromatography), a higher (2.5%) concentration of starch clearly
showed an increased amount of heat-induced whey protein aggregates. The gelation pH also increased significantly with 2.5%
starch compared to that of the control samples. The storage modulus (G′) increased with increasing levels of starch, and confocal
microscopy confirmed that the microstructure of the casein gels was altered by the presence of modified starch. Milk-starch
mixtures preheated and homogenized at 55 or 65 °C exhibited similar physico-chemical behavior during acidification. The results
suggested a lack of interaction between starch granules and casein micelles during acidification, and scanning electron microscopy
images collected with a self-assembled monolayer technique also confirmed that starch granules were not attached to milk caseins
but only embedded in the protein gel matrix. 相似文献
104.
Marcela Kovářová Kristýna Bartůňková Tomáš Frantík Helena Koblihová Kateřina Prchalová Miroslav Vosátka 《BMC plant biology》2010,10(1):19
Background
Japanese knotweed, Reynoutria japonica, is known for its high growth rate, even on adverse substrates, and for containing organic substances that are beneficial to human health. Its hybrid, Reynoutria × bohemica, was described in the Czech Republic in 1983 and has been widespread ever since. We examined whether Reynoutria × bohemica as a medicinal plant providing stilbenes and emodin, can be cultivated in spoil bank substrates and hence in the coalmine spoil banks changed into arable fields. We designed a pot experiment and a field experiment to assess the effects of various factors on the growth efficiency of Reynoutria × bohemica on clayish substrates and on the production of stilbenes and emodin in this plant. 相似文献105.
Katarina J?rlestedt Catherine I. Rousset Maryam Faiz Ulrika Wilhelmsson Anders St?hlberg Hana Sourkova Marcela Pekna Carina Mallard Henrik Hagberg Milos Pekny 《PloS one》2010,5(4)
Background
Astroglial cells are activated following injury and up-regulate the expression of the intermediate filament proteins glial fibrillary acidic protein (GFAP) and vimentin. Adult mice lacking the intermediate filament proteins GFAP and vimentin (GFAP−/−Vim−/−) show attenuated reactive gliosis, reduced glial scar formation and improved regeneration of neuronal synapses after neurotrauma. GFAP−/−Vim−/− mice exhibit larger brain infarcts after middle cerebral artery occlusion suggesting protective role of reactive gliosis after adult focal brain ischemia. However, the role of astrocyte activation and reactive gliosis in the injured developing brain is unknown.Methodology/Principal Findings
We subjected GFAP−/−Vim−/− and wild-type mice to unilateral hypoxia-ischemia (HI) at postnatal day 9 (P9). Bromodeoxyuridine (BrdU; 25 mg/kg) was injected intraperitoneally twice daily from P9 to P12. On P12 and P31, the animals were perfused intracardially. Immunohistochemistry with MAP-2, BrdU, NeuN, and S100 antibodies was performed on coronal sections. We found no difference in the hemisphere or infarct volume between GFAP−/−Vim−/− and wild-type mice at P12 and P31, i.e. 3 and 22 days after HI. At P31, the number of NeuN+ neurons in the ischemic and contralateral hemisphere was comparable between GFAP−/−Vim−/− and wild-type mice. In wild-type mice, the number of S100+ astrocytes was lower in the ipsilateral compared to contralateral hemisphere (65.0±50.1 vs. 85.6±34.0, p<0.05). In the GFAP−/−Vim−/− mice, the number of S100+ astrocytes did not differ between the ischemic and contralateral hemisphere at P31. At P31, GFAP−/−Vim−/− mice showed an increase in NeuN+BrdU+ (surviving newly born) neurons in the ischemic cortex compared to wild-type mice (6.7±7.7; n = 29 versus 2.9±3.6; n = 28, respectively, p<0.05), but a comparable number of S100+BrdU+ (surviving newly born) astrocytes.Conclusions/Significance
Our results suggest that attenuation of reactive gliosis in the developing brain does not affect the hemisphere or infarct volume after HI, but increases the number of surviving newborn neurons. 相似文献106.
Lu Barbalho de Macêdo Marcela dos Santos Magalhes Lucas Castanhola Dias Khelven Klay de Azevedo Lemos Ryshely Sonaly de Moura Borges Mrcia Viviane Alves Saraiva Moacir Franco de Oliveira Antnio Chaves de Assis Neto Carlos Eduardo Bezerra de Moura 《Animal Reproduction》2022,19(3)
Sex steroid hormones are critical in gonadal differentiation in turtles. The gonads are not the only organs responsible for producing these hormones during this phase. Mesonephros play an important role in steroidogenesis. The present study aimed to investigate the presence of steroidogenic cells in mesonephros of Podocnemis expansa during gonadal differentiation and to evaluate their morphology and ultrastructure. Ten embryos of P. expansa were collected from 5 nests on day 36 of incubation, during spawning period on an artificial beach. Embryos were extracted from eggs by slicing the shell and euthanized. They were dissected under a stereoscopic microscope to collect the gonad-mesonephro complex, in which were fixed and subsequently processed for light microscopy, immunohistochemistry and transmission electron microscopy analysis. During histological analysis was observed mesonephros has typical morphological structure. Immunohistochemistry showed immunoreaction to aromatase in cells of intertubular space. Confirming these findings, it was possible to observe a type of intertubular cell in several regions of mesonephro, being more predominant in region close to blood vessels, distal and proximal tubules. In ultrastructural analysis these cells were characterized by having a clear, large, and rounded nucleus with evident nucleolus and cytoplasm rich in electron-dense droplets. This study demonstrated for the first time the presence of cells with morphological, immunohistochemical and ultrastructural characteristics similar to steroid-producing cells in P. expansa mesonephrons, suggesting that this organ may contribute to gonadal differentiation in this species. 相似文献
107.
108.
Lysionek A Zubillaga M Salgueiro J Caro R Ettlin E Boccio J 《Biological trace element research》2001,84(1-3):123-128
The bioavailability of iron from a new commercial source containing ferric gluconate stabilized with glycine sold under the
trade name Bioferrico™ was studied in this work by means of the prophylactic-preventive test in rats. NaFeEDTA was also studied
by the same methodology for comparative purposes and ferrous sulfate was used as the reference standard. The test was conducted
for 4 wk with male weaned rats, which were randomized into four groups of at least eight animals each. A control group received
a basal diet of low-iron content, whereas the other groups received the same diet with iron added at a dose of 20 mg/kg as
FeSO4·7H2O, NaFeEDTA, and Bioferrico, respectively. Individual hemoglobin concentrations (HbC) and weights were determined at the beginning
and at the end of the study and food intake was daily registered. The iron bioavailability (BioFe) of each source was calculated
as the ratio between the amount of iron incorporated into hemoglobin during the treatment (HbFe) and the total iron intake
per animal (ToFeIn). A relative biological value (RBV) was obtained for each iron source under study as the ratio between
the BioFe of the tested compound and that of the reference standard. The RBVs were 98% and 86% for Bioferrico and NaFeEDTA,
respectively. Bioferrico showed a high bioavailability and behaved inertly in relation to the sensorial properties of the
fortified food when it was added to flour. These qualities emphasize Bioferrico as a promising source for iron fortification. 相似文献
109.
110.
Subversion of the cytoskeleton by intracellular bacteria: lessons from Listeria,Salmonella and Vibrio 下载免费PDF全文
Entry into host cells and intracellular persistence by invasive bacteria are tightly coupled to the ability of the bacterium to disrupt the eukaryotic cytoskeletal machinery. Herein we review the main strategies used by three intracellular pathogens to harness key modulators of the cytoskeleton. Two of these bacteria, namely Listeria monocytogenes and Salmonella enterica serovar Typhimurium, exhibit quite distinct intracellular lifestyles and therefore provide a comprehensive panel for the understanding of the intricate bacteria–cytoskeleton interplay during infections. The emerging intracellular pathogen Vibrio parahaemolyticus is depicted as a developing model for the uncovering of novel mechanisms used to hijack the cytoskeleton. 相似文献