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101.
Peeter Nõges Wouter Van de Bund Ana Cristina Cardoso Anna-Stiina Heiskanen 《Hydrobiologia》2007,584(1):373-379
In most cases the negative impacts of climate change to aquatic ecosystems cannot be mitigated by measures in the river basin
management. Ignoring climate change by the Water Framework Directive may have strong implications for the typology and quality
assessment systems used for water bodies. As a result of climate change, water bodies, especially those located near the type
boundaries may change their type. Compared to typology characteristics, water quality parameters are even more labile and
may be easily affected by climate change. The paper exemplifies that the anticipated deterioration of water quality within
the time frame relevant for WFD implementation may be large enough to endanger the fulfillment of the set water quality objectives.
The review of the river basin characterization every six years, as required by the WFD, might also include re-evaluation of
reference conditions according to the changes observed at pristine reference sites. As a consequence, the restoration targets
(i.e., the good ecological status) would also need to be evaluated periodically. 相似文献
102.
The loss of biotic integrity in ecosystems due to human pressure has been receiving much attention from the scientific community.
The primary aim of this study is to understand how the increasing human pressure on natural forests in the Azorean archipelago
(North Atlantic) is affecting their epigean arthropod communities and which biological parameters it affects most. An expert
team did fieldwork covering most of the natural forests (mainly inside nature reserves) of the archipelago using standardized
pitfall trapping. To build a multimetric index we tested a number of taxonomic and ecological parameters that can potentially
be influenced by disturbance. Sixteen of these were found to be significantly influenced by disturbance in forests. We retained
seven metrics due to both, desirable scalability properties and relatively low correlation between them. These included the
percentages of endemic and predator species richness and also predator abundance, which are inversely related to disturbance;
and the percentages of native and saprophagous species richness and introduced and herbivore abundance, which are positively
related to disturbance. All seven metrics were combined in an Index of Biotic Integrity (IBI) value. We then proceeded to
understand which potential disturbance factors are influencing the biotic integrity of communities and how such influence
is felt. Five disturbance factors were found to influence the IBI, although in different ways: the size and fragmentation
of reserves, the distance of sites to the reserve borders, the invasion by alien plants and the density of human paths at
the sites. Given that only percentages of taxonomical or ecological characteristics were chosen as metrics, we tested and
found the scalability of the IBI to be possible, allowing the comparison of sites with different collecting effort or even
the comparison of reserves with different areas and numbers of collecting sites in each. Finally, we propose a novel graphical
representation for multimetric indices like the IBI, one which allows retaining much of the information that is usually lost
in multimetric indices. 相似文献
103.
siRNA delivery by a transferrin-associated lipid-based vector: a non-viral strategy to mediate gene silencing 总被引:1,自引:0,他引:1
Cardoso AL Simões S de Almeida LP Pelisek J Culmsee C Wagner E Pedroso de Lima MC 《The journal of gene medicine》2007,9(3):170-183
BACKGROUND: RNA interference provides a powerful technology for specific gene silencing. Therapeutic applications of small interfering RNA (siRNA) however require efficient vehicles for stable complexation, protection, and extra- and intracellular delivery of these nucleic acids. Here, we evaluated the potential of transferrin (Tf)-associated liposomes for siRNA complexation and gene silencing. METHODS: Cationic liposomes composed of DOTAP : Cholesterol associated with or without transferrin (Tf) were complexed with siRNA at different lipid/siRNA charge ratios. Complexation and protection of siRNA from enzymatic degradation was assessed with the PicoGreen intercalation assay and gel electrophoresis. Cellular internalization of these siRNA Tf-lipoplexes was detected by confocal microscopy. Luciferase assay, immunoblot and fluorescence-activated cell sorting (FACS) analysis were used to evaluate reporter gene silencing in Huh-7 hepatocarcinoma and U-373 glioma cells. c-Jun knockdown in HT-22 cells was evaluated by quantitative real-time polymerase chain reaction (RT-PCR). Cytotoxicity of the siRNA complexes was assessed by Alamar blue, lactate dehydrogenase and MTT assays. RESULTS: Complexation of siRNA with the cationic liposomes in the presence of Tf results in the formation of stable particles and prevents serum-mediated degradation. Confocal microscopy showed fast cellular internalization of the Tf-lipoplexes via endocytosis. In the GFP glioma cells Tf-lipoplexes showed enhanced gene silencing at minimum toxicity in comparison to Tf-free lipoplexes. Targeting luciferase in the hepatocarcinoma cell line resulted in more than 70% reduction of luciferase activity, while in HT-22 cells 50% knockdown of endogenous c-Jun resulted in a significant protection from glutamate-mediated toxicity. CONCLUSIONS: Cationic liposomes associated with Tf form stable siRNA lipoplexes with reduced toxicity and enhanced specific gene knockdown activity compared to conventional lipoplexes. Thus, such formulations may constitute efficient delivery systems for therapeutic siRNA applications. 相似文献
104.
Ocarino NM Marubayashi U Cardoso TG Guimaraes CV Silva AE Torres RC Serakides R 《Journal of musculoskeletal & neuronal interactions》2007,7(1):84-93
The effect of physical activity in the treatment of osteopenia induced by ovariectomy was studied in 34 two-month-old Wistar female rats. Animals were divided into three groups in which two were formed by ovariectomized (OVX) animals and the other one had sham-operated animals. Group 1, active OVX'd rats; group 2, sedentary OVX'd rats and group 3, sham-operated ones (control). After three months of daily physical activity in a motor-driven treadmill all rats were sacrificed. In order to perform a histomorphometric analysis, long bones, vertebrae, and nasal bone were selected at necropsy. Ovariectomized rats which exercised showed an increased trabecular bone volume, cortical thickness in the long bones and vertebrae and also an increased nasal bone thickness. Physical activity also increased the connection of osteocytes. It was concluded that physical activity in osteopenia treatment increases and restores the mass of bones directly and indirectly submitted to physical impact. 相似文献
105.
André M. Almeida Luís A. Cardoso Dulce M. Santos José M. Torné Pedro S. Fevereiro 《In vitro cellular & developmental biology. Plant》2007,43(3):167-177
Trehalose, a nonreducing disaccharide of glucose, is one of the most effective osmoprotectants. Several strategies leading
to its accumulation have been envisaged in both model and crop plants using genes of bacterial, yeast and, more recently,
plant origin. Significant levels of trehalose accumulation have been shown to cause abiotic stress tolerance in transgenic
plants. In this review, we describe the most biologically relevant features of trehalose: chemical and biological properties;
occurrence and metabolism in organisms with special reference to plants; protective role in stabilizing molecules; physiological
role in plants with special reference to carbohydrate metabolism. The emphasis of this review, however, will be on manipulation
of trehalose metabolism to improve abiotic stress tolerance in plants. 相似文献
106.
Scalon Cunha LC Andrade e Silva ML Cardoso Furtado NA Vinhólis AH Gomes Martins CH da Silva Filho AA Cunha WR 《Zeitschrift für Naturforschung. C, Journal of biosciences》2007,62(9-10):668-672
Triterpene acids (ursolic, oleanoic, gypsogenic, and sumaresinolic acids) isolated from Miconia species, along with a mixture of ursolic and oleanolic acids and a mixture of maslinic and 2-a-hydroxyursolic acids, as well as ursolic acid derivatives were evaluated against the following microorganisms: Streptococcus mutans, Streptococcus mitis, Streptococcus sanguinis, Streptococcus salivarius, Streptococcus sobrinus, and Enterococcus faecalis, which are potentially responsible for the formation of dental caries in humans. The microdilution method was used for the determination of the minimum inhibitory concentration (MIC) during the evaluation of the antibacterial activity. All the isolated compounds, mixtures, and semi-synthetic derivatives displayed activity against all the tested bacteria, showing that they are promising antiplaque and anticaries agents. Ursolic and oleanolic acids displayed the most intense antibacterial effect, with MIC values ranging from 30 microg/mL to 80 microg/mL. The MIC values of ursolic acid derivatives, as well as those obtained for the mixture of ursolic and oleanolic acids showed that these compounds do not have higher antibacterial activity when compared with the activity observed with either ursolic acid or oleanolic acid alone. With regard to the structure-activity relationship of triterpene acids and derivatives, it is suggested that both hydroxy and carboxy groups present in the triterpenes are important for their antibacterial activity against oral pathogens. 相似文献
107.
Sébastien JD Giroux Celmar Alves-Leiva Yann Lécluse Patrick Martin Olivier Albagli Isabelle Godin 《BMC developmental biology》2007,7(1):79
Background
Hematopoietic development in vertebrate embryos results from the sequential contribution of two pools of precursors independently generated. While intra-embryonic precursors harbour the features of hematopoietic stem cells (HSC), precursors formed earlier in the yolk sac (YS) display limited differentiation and self-renewal potentials. The mechanisms leading to the generation of the precursors in both sites are still largely unknown, as are the molecular basis underlying their different potential. A possible approach to assess the role of candidate genes is to transfer or modulate their expression/activity in both sites. We thus designed and compared transduction protocols to target either native extra-embryonic precursors, or hematopoietic precursors. 相似文献108.
109.
Cardoso MB Putaux JL Nishiyama Y Helbert W Hÿtch M Silveira NP Chanzy H 《Biomacromolecules》2007,8(4):1319-1326
Lamellar square single crystals of V-amylose were obtained by adding alpha-naphthol to metastable dilute aqueous solutions of synthetic amylose chains with an average degree of polymerization of 100. The morphology and structure of the crystals were studied using low-dose transmission electron microscopy including high-resolution imaging, as well as electron and X-ray diffraction. The crystals are crystallized in a tetragonal P4(1)2(1)2 or P4(3)2(1)2 space group with unit cell parameters, calculated from X-ray diffraction data, a = b = 2.2844 nm (+/-0.0005) and c = 0.7806 nm (+/-0.001), implying the presence of two amylose chains per unit cell. High-resolution lattice images of the crystals confirmed that the amylose chains were crystallized as 8-fold helices corresponding to the repeat of four maltosyl units. 相似文献
110.
Mariana Cardoso Helena Silva Carla Patinha Natlia Costa Susana Nunes ngela Cunha 《The Annals of applied biology》2022,180(1):99-108
The halophyte species Salicornia ramosissima has long been consumed as food and is currently regarded as a high-value gourmet item. However, given that these plants grow in estuarine areas, often impacted by pollution, and are prone to the accumulation of ions, the risks associated with food borne pathogens or toxic metals has to be carefully considered. The objective of this work was to gather evidence that S. ramossissima harvested locally in an estuarine system (Ria de Aveiro, Portugal) can be safely consumed as a healthy and catering-amenable food. Fresh shoots, taken as green vegetables, and dried powdered shoots (green salt) intended as seasoning, were analysed for total aerobic bacteria, total coliforms, Escherichia coli, Bacillus cereus and fungi (yeasts and moulds). The nutritional profile and the concentration of macro and micro elements, including potential toxic elements, was also established. Fresh shoots and green salt were incorporated in catering meals (soup and a meat dish) and subjected to sensory analyses. The microbiological quality of fresh shoots and green salt was compliant with the guidelines for salad greens and herbs and spices, respectively. The nutritional and elemental profile revealed that fresh shoots have a high content in fibre and NaCl. From the concentration of Na determined in green salt, a daily dose of 7 g was estimated as corresponding to the recommended daily dietary intake Na. None of the other elements was present in concentrations that could exceed the dietary intake limits. In the sensory tests, fresh shoots were well accepted as salad greens but green salt, used as seasoning, was considered as insufficient in terms of saltiness and does not completely substitute cooking salt. The results confirm the nutritional and sensory value of S. ramossisima and represent a promising prospect for the incorporation of locally harvested or crop cultivated plants in catering meals. 相似文献