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81.
Molecular dynamics of synthetic leucine-serine ion channels in a phospholipid membrane 总被引:2,自引:0,他引:2 下载免费PDF全文
Molecular dynamics calculations were carried out on models of two synthetic leucine-serine ion channels: a tetrameric bundle with sequence (LSLLLSL)(3)NH(2) and a hexameric bundle with sequence (LSSLLSL)(3)NH(2). Each protein bundle is inserted in a palmitoyloleoylphosphatidylcholine bilayer membrane and solvated by simple point charge water molecules inside the pore and at both mouths. Both systems appear to be stable in the absence of an electric field during the 4 ns of molecular dynamics simulation. The water motion in the narrow pore of the four-helix bundle is highly restricted and may provide suitable conditions for proton transfer via a water wire mechanism. In the wider hexameric pore, the water diffuses much more slowly than in bulk but is still mobile. This, along with the dimensions of the pore, supports the observation that this peptide is selective for monovalent cations. Reasonable agreement of predicted conductances with experimentally determined values lends support to the validity of the simulations. 相似文献
82.
Fluorosis is a metabolic disease that is endemic in nearly 25 countries with India being one of the most affected. It primarily affects the bone and the teeth. Moringa oleifera (MO) leaves are known to reduce the effect of fluorosis on various tissues. Therefore, it is of interest to document the effect of Moringa oleifera leaves on the hematological profile of fluorosis affected rats. Twenty four Sprague Dawley rats were housed two per cage in a room with 12 hours light and 12 hours dark cycle. The rats were allowed to adjust to the laboratory environment for about one to two weeks before the beginning of the study. This study reveals that MO leaves is effective in reducing the plasma fluoride content. It also helps in improving the Hb % and RBC count in fluorosis affected rats. Data shows that Moringa olifera leaves powder is effective in reducing the plasma fluoride content. It also helps in improving the Hemoglobin percentage & Red Blood Cell count in fluorosis affected rats. 相似文献
83.
Nazeh M. Al-Abd Zurainee Mohamed Nor Marzida Mansor MS Hasan Mustafa Kassim 《The Korean journal of parasitology》2016,54(3):273-280
We evaluated the activity of methanolic extracts of Melaleuca cajuputi flowers against the filarial worm Brugia pahangi and its bacterial endosymbiont Wolbachia. Anti-Wolbachia activity was measured in worms and in Aedes albopictus Aa23 cells by PCR, electron microscopy, and other biological assays. In particular, microfilarial release, worm motility, and viability were determined. M. cajuputi flower extracts were found to significantly reduce Wolbachia endosymbionts in Aa23 cells, Wolbachia surface protein, and microfilarial release, as well as the viability and motility of adult worms. Anti-Wolbachia activity was further confirmed by observation of degraded and phagocytized Wolbachia in worms treated with the flower extracts. The data provided in vitro and in vivo evidence that M. cajuputi flower extracts inhibit Wolbachia, an activity that may be exploited as an alternative strategy to treat human lymphatic filariasis. 相似文献
84.
Lake Ichkeul in northern Tunisia is a Ramsar site, a MAB Biosphere Reserve and a UNESCO World Heritage Site. The system is one of the most important coastal wetlands in North Africa, especially as an over-wintering area for migratory birds, particularly Palaearctic waterfowl. The present study was aimed at diagnosing the status of fish species in Lake Ichkeul and documenting their annual and seasonal occurrence within the system. Fish samples were collected monthly at 22 sites from March 2011 to April 2012 using a variety of gears, including a dragnet, gillnet, trammelnet, frynet and beach-seine. Temperature and salinity measurements were taken at each site, while fishes were obtained from only 11 sites, representing mainly lacustrine stations. A total of 18 fish species belonging to 14 genera and 12 families were identified, with Mugilidae dominating with four species, followed by Syngnathidae with three species. This study represents a relative recovery in terms of fish species richness, since only 13 species were recorded here between 2003 and 2007. However, the numbers of fish caught, especially of the commercial taxa, seem to have declined in recent years, and the number of species currently present is much lower than that of several decades ago. Increasing human pressures, particularly reductions in catchment freshwater inputs, a breakdown in ecosystem connectivity, pollution and over-fishing appear to be the principal causes for the decline in fish abundance and diversity. 相似文献
85.
Yan Chao Cui Yu Sheng Qiu Qiong Wu Gang Bu Amira Peli Seoh Wei Teh Kok Pian Ang Narcisse MS Joseph Avin Ee-Hwan Koh Aisha Farhana Badr Alzahrani Mohammed Safwan Ali Khan Antony V Samrot Pooi Ling Mok Suresh Kumar Subbiah 《Experimental biology and medicine (Maywood, N.J.)》2021,246(10):1177
Osteoblasts play an important role in bone regeneration and repair. The hypoxia condition in bone occurs when bone undergoes fracture, and this will trigger a series of biochemical and mechanical changes to enable bone repair. Hence, it is interesting to observe the metabolites and metabolism changes when osteoblasts are exposed to hypoxic condition. This study has looked into the response of human osteoblast hFOB 1.19 under normoxic and hypoxic conditions by observing the cell growth and utilization of metabolites via Phenotype MicroArrays™ under these two different oxygen concentrations. The cell growth of hFOB 1.19 under hypoxic condition showed better growth compared to hFOB 1.19 under normal condition. In this study, osteoblast used glycolysis as the main pathway to produce energy as hFOB 1.19 in both hypoxic and normoxic conditions showed cell growth in well containing dextrin, glycogen, maltotriose, D-maltose, D-glucose-6-phospate, D-glucose, D-mannose, D-Turanose, D-fructose-6-phosphate, D-galactose, uridine, adenosine, inosine and α-keto-glutaric acid. In hypoxia, the cells have utilized additional metabolites such as α-D-glucose-1-phosphate and D-fructose, indicating possible activation of glycogen synthesis and glycogenolysis to metabolize α-D-glucose-1-phosphate. Meanwhile, during normoxia, D-L-α-glycerol phosphate was used, and this implies that the osteoblast may use glycerol-3-phosphate shuttle and oxidative phosphorylation to metabolize glycerol-3-phosphate. 相似文献
86.
Ingunn MS Engebretsen Karen M Moland Jolly Nankunda Charles A Karamagi Thorkild Tylleskär James K Tumwine 《International breastfeeding journal》2010,5(1):1-11
Background
In resource-poor settings, HIV positive mothers are recommended to choose between 'Exclusive breastfeeding' (EBF) or 'Exclusive replacement feeding' (ERF). Acceptability, Feasibility, Affordability, Sustainability and Safety (AFASS) has been the World Health Organization (WHO)'s a priori criteria for ERF the last ten years. 'AFASS' has become a mere acronym among many workers in the field of prevention of mother-to-child transmission of HIV, PMTCT. Thereby, non-breastfeeding has been suggested irrespective of social norms. EBF for the first half of infancy is associated with huge health benefits for children in areas where infant mortality is high. But, even if EBF has been recommended for a decade, few mothers are practicing it. We set out to understand fathers' and mothers' infant feeding perceptions and the degree to which EBF and ERF were 'AFASS.'Methods
Eight focus groups with 81 informants provided information for inductive content analysis. Four groups were held by men among men and four groups by women among women in Mbale District, Eastern Uganda.Results
Two study questions emerged: How are the different feeding options understood and accepted? And, what are men's and women's responsibilities related to infant feeding? A mother's commitment to breastfeed and the husband's commitment to provide for the family came out strongly. Not breastfeeding a newborn was seen as dangerous and as unacceptable, except in cases of maternal illness. Men argued that not breastfeeding could entail sanctions by kin or in court. But, in general, both men and women regarded EBF as 'not enough' or even 'harmful.' Among men, not giving supplements to breast milk was associated with poverty and men's failure as providers. Women emphasised lack of time, exhaustion, poverty and hunger as factors for limited breast milk production. Although women had attended antenatal teaching they expressed a need to know more. Most men felt left out from health education.Conclusion
Breastfeeding was the expected way to feed the baby, but even with existing knowledge among mothers, EBF was generally perceived as impossible. ERF was overall negatively sanctioned. Greater culture-sensitivity in programs promoting safer infant feeding in general and in HIV-contexts in particular is urgently needed, and male involvement is imperative.Trial Registration
The study was part of formative studies for the ongoing study PROMISE EBF registered at http://clinicaltrials.gov (NCT00397150). 相似文献87.
CYP99A3: functional identification of a diterpene oxidase from the momilactone biosynthetic gene cluster in rice 总被引:1,自引:0,他引:1
Rice (Oryza sativa) produces momilactone diterpenoids as both phytoalexins and allelochemicals. Strikingly, the rice genome contains a biosynthetic gene cluster for momilactone production, located on rice chromosome 4, which contains two cytochrome P450 (CYP) mono-oxygenases, CYP99A2 and CYP99A3, with undefined roles; although it has been previously shown that RNA interference double knock-down of this pair of closely related CYPs reduced momilactone accumulation. Here we attempted biochemical characterization of CYP99A2 and CYP99A3, which was ultimately achieved by complete gene recoding, enabling functional recombinant expression in bacteria. With these synthetic gene constructs it was possible to demonstrate that while CYP99A2 does not exhibit significant activity with diterpene substrates, CYP99A3 catalyzes consecutive oxidations of the C19 methyl group of the momilactone precursor syn-pimara-7,15-diene to form, sequentially, syn-pimaradien-19-ol, syn-pimaradien-19-al, and syn-pimaradien-19-oic acid. These are presumably intermediates in momilactone biosynthesis, as a C19 carboxylic acid moiety is required for formation of the core 19,6-γ-lactone ring structure. We further were able to detect syn-pimaradien-19-oic acid in rice plants, which indicates physiological relevance for the observed activity of CYP99A3. In addition, we found that CYP99A3 also oxidized syn-stemod-13(17)-ene at C19 to produce, sequentially, syn-stemoden-19-ol, syn-stemoden-19-al, and syn-stemoden-19-oic acid, albeit with lower catalytic efficiency than with syn-pimaradiene. Although the CYP99A3 syn-stemodene-derived products were not detected in planta, these results nevertheless provide a hint at the currently unknown metabolic fate of this diterpene in rice. Regardless of any wider role, our results strongly indicate that CYP99A3 acts as a multifunctional diterpene oxidase in momilactone biosynthesis. 相似文献
88.
The core domain of retrotransposon integrase in Hordeum: predicted structure and evolution 总被引:1,自引:0,他引:1
Suoniemi A; Tanskanen J; Pentikainen O; Johnson MS; Schulman AH 《Molecular biology and evolution》1998,15(9):1135-1144
Propagation of long terminal repeat (LTR)-bearing retrotransposons and
retroviruses requires integrase (IN, EC 2.7.7.-), encoded by the
retroelements themselves, which mediates the insertion of cDNA copies back
into the genome. An active retrotransposon family, BARE-1, comprises
approximately 7% of the barley (Hordeum vulgare subsp. vulgare) genome. We
have generated models for the secondary and tertiary structure of BARE-1 IN
and demonstrate their similarity to structures for human immunodeficiency
virus 1 and avian sarcoma virus INs. The IN core domains were compared for
80 clones from 28 Hordeum accessions representative of the diversity of the
genus. Based on the structural model, variations in the predicted, aligned
translations from these clones would have minimal structural and functional
effects on the encoded enzymes. This indicates that Hordeum retrotransposon
IN has been under purifying selection to maintain a structure typical of
retroviral INs. These represent the first such analyses for plant INs.
相似文献
89.
Monophyly of the order Rodentia inferred from mitochondrial DNA sequences of the genes for 12S rRNA, 16S rRNA, and tRNA-valine 总被引:1,自引:2,他引:1
A recent analysis of amino acid sequence data (Graur et al.) suggested that
the mammalian order Rodentia is polyphyletic, in contrast to most
morphological data, which support rodent monophyly. At issue is whether the
hystricognath rodents, such as the guinea pig, represent an independent
evolutionary lineage within mammals, separate from the sciurognath rodents.
To resolve this problem, we sequenced a region (2,645 bp) of the
mitochondrial genome of the guinea pig containing the complete 12S
ribosomal RNA, 16S ribosomal RNA, and transfer RNA(VAL) genes for
comparison with the available sciurognath and other mammalian sequences.
Several methods of analysis and statistical tests of the data all show
strong support for rodent monophyly (91%-98% bootstrap probability, or BP).
Calibration with the mammalian fossil record suggests a Cretaceous date
(107 mya) for the divergence of sciurognaths and hystricognaths. An older
date (38 mya) for the controversial Mus- Rattus divergence also is
supported by these data. Our neighbor-joining analyses of all available
sequence data (25 genes) confirm that some individual genes support rodent
polyphyly but that tandem analysis of all data does not. We propose that
the conflicting results are due to several compounding factors. The unique
biochemical properties of some hystricognath metabolic proteins, largely
responsible for generating this controversy, may have a single explanation:
a cascade effect resulting from inactivation of the zinc-binding abilities
of insulin. After excluding six genes possibly affected by insulin
inactivation, analyses of all available sequence data (7,117 nucleotide
sites, 3,099 amino acid sites) resulted in strong support for rodent
monophyly (94% BP for DNA sequences, 90% for protein sequences), which
lends support to the insulin-cascade hypothesis.
相似文献
90.
Sohrab?P?Shah Yong?Huang Tao?Xu Macaire?MS?Yuen John?Ling BF?Francis?OuelletteEmail author 《BMC bioinformatics》2005,6(1):34