全文获取类型
收费全文 | 1142篇 |
免费 | 64篇 |
出版年
2024年 | 2篇 |
2023年 | 12篇 |
2022年 | 27篇 |
2021年 | 50篇 |
2020年 | 31篇 |
2019年 | 35篇 |
2018年 | 45篇 |
2017年 | 43篇 |
2016年 | 54篇 |
2015年 | 83篇 |
2014年 | 82篇 |
2013年 | 98篇 |
2012年 | 84篇 |
2011年 | 75篇 |
2010年 | 38篇 |
2009年 | 48篇 |
2008年 | 45篇 |
2007年 | 54篇 |
2006年 | 53篇 |
2005年 | 43篇 |
2004年 | 28篇 |
2003年 | 32篇 |
2002年 | 24篇 |
2001年 | 23篇 |
2000年 | 6篇 |
1999年 | 13篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 5篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1941年 | 1篇 |
1940年 | 1篇 |
1903年 | 1篇 |
排序方式: 共有1206条查询结果,搜索用时 281 毫秒
991.
Oliveira Samara Rodrigues Bonfim Damasceno Franco Álvaro Xavier Quaresma Marielle Pires de Carvalho Cecília Mendes Morais da Cunha Jácome Marques Fabrícia da Silva Pantoja Patrícia Mendonça Vanessa Azevedo da Silva Osterne Vinicius José Correia Jorge Luis Almeida Assreuy Ana Maria Sampaio de Souza Marcellus Henrique Loiola Pontes do Nascimento Kyria Santiago Cavada Benildo Sousa Criddle David Neil Soares Pedro Marcos Gomes 《Glycoconjugate journal》2022,39(5):599-608
Glycoconjugate Journal - Lectins isolated from Canavalia ensiformis (ConA) and Canavalia brasiliensis (ConBr) are promising molecules to prevent cell death. Acute pancreatitis, characterized by... 相似文献
992.
Nadini Oliveira Martins Renata Torres de Souza Esteban Mauricio Cordero Danielle Cortez Maldonado Cristian Cortez Marjorie Mendes Marini Eden Ramalho Ferreira Ethel Bayer-Santos Igor Correia de Almeida Nobuko Yoshida José Franco da Silveira 《PLoS neglected tropical diseases》2015,9(11)
Background
The surface coat of Trypanosoma cruzi is predominantly composed of glycosylphosphatidylinositol-anchored proteins, which have been extensively characterized. However, very little is known about less abundant surface proteins and their role in host-parasite interactions.Methodology/ Principal Findings
Here, we described a novel family of T. cruzi surface membrane proteins (TcSMP), which are conserved among different T. cruzi lineages and have orthologs in other Trypanosoma species. TcSMP genes are densely clustered within the genome, suggesting that they could have originated by tandem gene duplication. Several lines of evidence indicate that TcSMP is a membrane-spanning protein located at the cellular surface and is released into the extracellular milieu. TcSMP exhibited the key elements typical of surface proteins (N-terminal signal peptide or signal anchor) and a C-terminal hydrophobic sequence predicted to be a trans-membrane domain. Immunofluorescence of live parasites showed that anti-TcSMP antibodies clearly labeled the surface of all T. cruzi developmental forms. TcSMP peptides previously found in a membrane-enriched fraction were identified by proteomic analysis in membrane vesicles as well as in soluble forms in the T. cruzi secretome. TcSMP proteins were also located intracellularly likely associated with membrane-bound structures. We demonstrated that TcSMP proteins were capable of inhibiting metacyclic trypomastigote entry into host cells. TcSMP bound to mammalian cells and triggered Ca2+ signaling and lysosome exocytosis, events that are required for parasitophorous vacuole biogenesis. The effects of TcSMP were of lower magnitude compared to gp82, the major adhesion protein of metacyclic trypomastigotes, suggesting that TcSMP may play an auxiliary role in host cell invasion.Conclusion/Significance
We hypothesized that the productive interaction of T. cruzi with host cells that effectively results in internalization may depend on diverse adhesion molecules. In the metacyclic forms, the signaling induced by TcSMP may be additive to that triggered by the major surface molecule gp82, further increasing the host cell responses required for infection. 相似文献993.
José Maria Rodrigues da Luz Sirlaine Albino Paes Karla Veloso Gon?alves Ribeiro Igor Rodrigues Mendes Maria Catarina Megumi Kasuya 《PloS one》2015,10(6)
We studied the biodegradation of green polyethylene (GP) by Pleurotus ostreatus. The GP was developed from renewable raw materials to help to reduce the emissions of greenhouse gases. However, little information regarding the biodegradation of GP discarded in the environment is available. P. ostreatus is a lignocellulolytic fungus that has been used in bioremediation processes for agroindustrial residues, pollutants, and recalcitrant compounds. Recently, we showed the potential of this fungus to degrade oxo-biodegradable polyethylene. GP plastic bags were exposed to sunlight for up to 120 days to induce the initial photodegradation of the polymers. After this period, no cracks, pits, or new functional groups in the structure of GP were observed. Fragments of these bags were used as the substrate for the growth of P. ostreatus. After 30 d of incubation, physical and chemical alterations in the structure of GP were observed. We conclude that the exposure of GP to sunlight and its subsequent incubation in the presence of P. ostreatus can decrease the half-life of GP and facilitate the mineralization of these polymers. 相似文献
994.
Late effects of sleep restriction: Potentiating weight gain and insulin resistance arising from a high‐fat diet in mice
下载免费PDF全文
![点击此处可从《Obesity (Silver Spring, Md.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
995.
Transparent Cuprous Oxide Photocathode Enabling a Stacked Tandem Cell for Unbiased Water Splitting
下载免费PDF全文
![点击此处可从《Liver Transplantation》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Paula Dias Marcel Schreier S. David Tilley Jingshan Luo João Azevedo Luísa Andrade Dongqin Bi Anders Hagfeldt Adélio Mendes Michael Grätzel Matthew T. Mayer 《Liver Transplantation》2015,5(24)
Photoelectrochemical water splitting represents an attractive method of capturing and storing the immense energy of sunlight in the form of hydrogen, a clean chemical fuel. Given the large energetic demand of water electrolysis, and the defined spectrum of photons available from incident sunlight, a two absorber tandem device is required to achieve high efficiencies. The two absorbers should be of different and complementary bandgaps, connected in series to achieve the necessary voltage, and arranged in an optical stack configuration to maximize the utilization of sunlight. This latter requirement demands a top device that is responsive to high‐energy photons but also transparent to lower‐energy photons, which pass through to illuminate the bottom absorber. Here, cuprous oxide (Cu2O) is employed as a top absorber component, and the factors influencing the balance between transparency and efficiency toward operation in a tandem configuration are studied. Photocathodes based on Cu2O electrodeposited onto conducting glass substrates treated with thin, discontinuous layers of gold achieve reasonable sub‐bandgap transmittance while retaining performances comparable to their opaque counterparts. This new high‐performance transparent photocathode is demonstrated in tandem with a hybrid perovskite photovoltaic cell, resulting in a full device capable of standalone sunlight‐driven water splitting. 相似文献
996.
Jarina Pena DaMata Bárbara Pinheiro Mendes Kátia Maciel-Lima Cristiane Alves Silva Menezes Walderez Ornelas Dutra Lirlandia Pires Sousa Maria Fátima Horta 《PloS one》2015,10(10)
Leishmania is an intracellular parasite in vertebrate hosts, including man. During infection, amastigotes replicate inside macrophages and are transmitted to healthy cells, leading to amplification of the infection. Although transfer of amastigotes from infected to healthy cells is a crucial step that may shape the outcome of the infection, it is not fully understood. Here we compare L. amazonensis and L. guyanensis infection in C57BL/6 and BALB/c mice and investigate the fate of macrophages when infected with these species of Leishmania in vitro. As previously shown, infection of mice results in distinct outcomes: L. amazonensis causes a chronic infection in both strains of mice (although milder in C57BL/6), whereas L. guyanensis does not cause them disease. In vitro, infection is persistent in L. amazonensis-infected macrophages whereas L. guyanensis growth is controlled by host cells from both strains of mice. We demonstrate that, in vitro, L. amazonensis induces apoptosis of both C57BL/6 and BALB/c macrophages, characterized by PS exposure, DNA cleavage into nucleosomal size fragments, and consequent hypodiploidy. None of these signs were seen in macrophages infected with L. guyanensis, which seem to die through necrosis, as indicated by increased PI-, but not Annexin V-, positive cells. L. amazonensis-induced macrophage apoptosis was associated to activation of caspases-3, -8 and -9 in both strains of mice. Considering these two species of Leishmania and strains of mice, macrophage apoptosis, induced at the initial moments of infection, correlates with chronic infection, regardless of its severity. We present evidence suggestive that macrophages phagocytize L. amazonensis-infected cells, which has not been verified so far. The ingestion of apoptotic infected macrophages by healthy macrophages could be a way of amastigote spreading, leading to the establishment of infection. 相似文献
997.
The oral health of seniors in Brazil: addressing the consequences of a historic lack of public health dentistry in an unequal society
下载免费PDF全文
![点击此处可从《Gerodontology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
998.
Suzete Rodrigues Gomes Fernanda Britto da Silva Inga L. Veitenheimer Mendes José Willibaldo Thomé Sandro L. Bonatto 《Zoologica scripta》2010,39(2):177-186
Gomes, S. R., Britto da Silva, F., Mendes, I. L. V., Thomé, J. W. & Bonatto, S. L. (2009). Molecular phylogeny of the South American land slug Phyllocaulis (Mollusca, Soleolifera, Veronicellidae). —Zoologica Scripta, 39, 177–186. Our main objectives were investigate the phylogenetic relationships between the species of the land slug Phyllocaulis and the monophyly of the genus based on mitochondrial (16S and COI) and nuclear (ITS2) DNA sequences from multiple individuals from each species. Evolutionary trees were constructed using Bayesian inference, maximum likelihood, maximum parsimony and neighbor‐joining methods. All species accepted in the current taxonomy based on penial characteristics and radular measurements were reciprocally monophyletic. Five species out of six formed a clade with the following highly supported relationship: Phyllocaulis gayi, Phyllocaulis soleiformis, Phyllocaulis renschi, Phyllocaulis variegatus, Phyllocaulis boraceiensis. The position of Vaginulus taunaisii changed according to the analysis, appearing as sister‐group of Phyllocaulis or as sister‐group of Phyllocaulis tuberculosus. Divergence times estimated from the 16S tree indicated that the extant species of Phyllocaulis shared a common ancestor around 1.3 Ma and that most species originated between 0.8 and 0.6 Ma. 相似文献
999.
Benedito Barraviera Rinaldo Poncio Mendes Paulo Câmara Marques Pereira Jussara Marcondes Machado Paulo Roberto Curi Domingos Alves Meira 《Mycopathologia》1988,104(2):87-91
Hemoglobin rates, hematocrit and glucose-6-phosphate dehydrogenase (G6PD) and glutathione reductase activities were measured in 38 patients with paracoccidioidomycosis treated with ketoconazole or sulfadoxin, and in 13 normal individuals.Ketoconazole-treated patients showed reduced G6PD and glutathione reductase activities. One of these patients was found to be G6PD-deficient and suffered a hemolytic episode during treatment, which, however, did not require interruption of therapy.The authors suggest that patients showing an erythrocyte enzyme defect should be monitored hematologically during treatment with ketoconazole. They also suggest that ketoconazole is an oxidant drug in addition to being a possible inhibitor of antioxidant erythrocyte enzymes. 相似文献
1000.
Milagros Medina Ricardo O. Louro Jean Gagnon Maria Luisa Peleato Joaquim Mendes Carlos Gómez-Moreno António V. Xavier M. Teixeira 《Journal of biological inorganic chemistry》1997,2(2):225-234
A soluble monoheme c–type cytochrome c
6 has been isolated from the cyanobacterium Anabaena PCC 7119. It is a basic protein, with a molecular mass of 9.7 kDa, which accepts electrons from Anabaena ferredoxin in the ferredoxin-NADP+reductase-dependent NADPH cytochrome c reductase activity assay. The turnover of the reaction has an optimum pH at 7.5. Flavodoxin can also replace ferredoxin in
this assay, but with only 20% efficiency. Plastocyanin from Anabaena PCC 7119, as well as the c
6 cytochromes from the green algae Chlorella fusca and Monoraphidium braunii are also shown to accept electrons from Anabaena ferredoxin. The reduction potential of cytochrome c
6 at pH 6.7 was determined to be 338 mV and is pH dependent, with pK
a
ox=8.4±0.1 and pK
a
red≈9.5. The ferric and ferrous cytochrome forms and their pH equilibria have been studied using visible, EPR and 1H-NMR spectroscopies. The amino acid sequence and the visible and NMR spectroscopic data indicate that the heme iron has a
methionine-histidine axial coordination in the pH range 5–11. However, the EPR data for the ferricytochrome are complex and
show that in this pH range five distinct forms are present. Between pH 5 and 9 the spectrum is dominated by two rhombic species,
with g–values at 2.94, 2.29, 1.43 and at 2.84, 2.34, 1.56, which interconvert with a pK
a of 8.4. The NMR data also show a main interconversion between two cytochrome forms at this pH, which coincides with that
determined from the pH dependence of the reduction potential. Both these forms were associated with a methionine-histidine
heme-iron coordination by correlation with the visible and NMR spectral data, although having crystal field parameters atypical
for this type of coordination. Anabaena cytochrome c
6 is one more example of a heme protein for which the widely used crystal field analysis of the EPR data (truth diagram) fails
to unequivocally determine the type of heme-iron ligation.
Received: 17 May 1996 / Accepted: 13 January 1997 相似文献