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81.
Induction of angiogenesis is a potential treatment for chronic ischemia. Low molecular weight fucoidan (LMWF), the sulfated polysaccharide from brown seaweeds, has been shown to promote revascularization in a rat limb ischemia, increasing angiogenesis in vivo. We investigated the potential role of two heparan sulfate (HS) metabolism enzymes, exostosin-2 (EXT2) and heparanase (HPSE), and of two HS-membrane proteoglycans, syndecan-1 and -4 (SDC-1 and SDC-4), in LMWF induced angiogenesis. Our results showed that LMWF increases human vascular endothelial cell (HUVEC) migration and angiogenesis in vitro. We report that the expression and activity of the HS-degrading HPSE was increased after LMWF treatment. The phenotypic tests of LMWF-treated and EXT2- or HPSE-siRNA-transfected cells indicated that EXT2 or HPSE expression significantly affect the proangiogenic potential of LMWF. In addition, LMWF increased SDC-1, but decreased SDC-4 expressions. The effect of LMWF depends on SDC-4 expression. Silencing EXT2 or HPSE leads to an increased expression of SDC-4, providing the evidence that EXT2 and HPSE regulate the SDC-4 expression. Altogether, these data indicate that EXT2, HPSE, and SDC-4 are involved in the proangiogenic effects of LMWF, suggesting that the HS metabolism changes linked to LMWF-induced angiogenesis offer the opportunity for new therapeutic strategies of ischemic diseases.  相似文献   
82.
Cancer and infectious diseases continue to be a major public health problem, and new drugs are necessary. As marine organisms are well known to provide a wide range of original compounds, the aim of this study was to investigate the bioactivity of the main constituents of the cosmopolitan red alga, Sphaerococcus coronopifolius. The structure of several bromoditerpenes was determined by extensive spectroscopic analysis and comparison with literature data. Five molecules were isolated and characterized which include a new brominated diterpene belonging to the rare dactylomelane family and named sphaerodactylomelol (1), along with four already known sphaerane bromoditerpenes (2–5). Antitumor activity was assessed by cytotoxicity and anti-proliferative assays on an in vitro model of human hepatocellular carcinoma (HepG-2 cells). Antimicrobial activity was evaluated against four pathogenic microorganisms: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans. Compound 4 exhibited the highest antimicrobial activity against S. aureus (IC50 6.35 µM) and compound 5 the highest anti-proliferative activity on HepG-2 cells (IC50 42.9 µM). The new diterpene, sphaerodactylomelol (1), induced inhibition of cell proliferation (IC50 280 µM) and cytotoxicity (IC50 720 µM) on HepG-2 cells and showed antimicrobial activity against S. aureus (IC50 96.3 µM).  相似文献   
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During the last decades, the European loess belt has been confronted with a significant increase in environmental problems due to erosion on agricultural land. Spatially distributed runoff and erosion models operating at the catchment scale are therefore needed to evaluate the impact of potential mitigation measures. Expert-based models offer an alternative solution to process-based and empirical models, but their decision rules are only valid for the local conditions for which they have been derived. The STREAM model, which was developed in Normandy (France), has been applied in two Belgian catchments having a similar soil texture, as well as in a catchment of southern France differing by soil, land use and climate characteristics. The performance of hydrological models can be assessed for instance by calculating the Nash–Sutcliffe efficiency criterion (ENS). When applied to Belgium, the model results are satisfactory to good after an adaptation of the decision rules (0.90 < ENS < 0.93 for runoff predictions and 0.85 < ENS < 0.89 for erosion predictions). Given the important environmental differences between Normandy and southern France, the model rules were also adapted for application in the latter environment. Unfortunately, the quality of runoff predictions was insufficient to simulate erosion in southern France. In conclusion, STREAM is a reliable model providing satisfactory runoff and erosion predictions in the regions where hortonian overland flow dominates. Nevertheless, an adaptation of decision rules based on local multi-scale (plot, field, catchment) data is needed, before running the model. STREAM can then serve as a decision support tool to design for instance flood control measures.  相似文献   
85.
Scrapie is a fatal, neurodegenerative disease of sheep and goats. It is also the earliest known member in the family of diseases classified as transmissible spongiform encephalopathies (TSE) or prion diseases, which includes Creutzfeldt-Jakob disease in humans, bovine spongiform encephalopathy (BSE), and chronic wasting disease in cervids. The recent revelation of naturally occurring BSE in a goat has brought the issue of TSE in goats to the attention of the public. In contrast to scrapie, BSE presents a proven risk to humans. The risk of goat BSE, however, is difficult to evaluate, as our knowledge of TSE in goats is limited. Natural caprine scrapie has been discovered throughout Europe, with reported cases generally being greatest in countries with the highest goat populations. As with sheep scrapie, susceptibility and incubation period duration of goat scrapie are most likely controlled by the prion protein (PrP) gene (PRNP). Like the PRNP of sheep, the caprine PRNP shows significantly greater variability than that of cattle and humans. Although PRNP variability in goats differs from that observed in sheep, the two species share several identical alleles. Moreover, while the ARR allele associated with enhancing resistance in sheep is not present in the goat PRNP, there is evidence for the existence of other PrP variants related to resistance. This review presents the current knowledge of the epidemiology of caprine scrapie within the major European goat populations, and compiles the current data on genetic variability of PRNP.  相似文献   
86.
The physicochemical properties of 8,8-methylmethine catechin-malvidin 3-O-glucoside isomers, commonly referred to as catechin-ethyl-malvidin 3-O-glucoside, have been studied in aqueous solutions and compared with those of the parent anthocyanin (malvidin 3-O-glucoside). The hydration and acidity constants (pKh and pKa) of the catechin-ethyl-malvidin 3-O-glucoside pigments and malvidin 3-O-glucoside were determined by UV-visible spectroscopic measurements. The ethyl-linked catechin-malvidin 3-O-glucoside pigments present higher stability toward hydration than the parent anthocyanin. The high resistance of these ethyl-linked pigments toward the hydration is related to the self-association that offers optimal protection from the nucleophilic attack of water. Moreover, the ethyl link may confer to the molecule enough flexibility to undergo intramolecular interaction, further protecting it from hydration and bisulfite discoloration. In the wine pH range (3.2-4.0), due to the low pKa and high pKh values, the ethyl-linked pigments are present as colored forms (flavylium cation and quinonoid bases).  相似文献   
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88.
ABSTRACT

Most marine aquaculture activities remain strongly dependent on coastal ecosystems. In the case of shellfish farming, this dependency is related mainly to water quality and to the various ecological interactions resulting from the dynamics of coastal food webs. Such ecological constraints have influenced the overall evolution of blue mussel farming in the Mont-Saint-Michel Bay, leading producers to negotiate collective arrangements regarding production capacity and techniques and to develop production strategies at the farm level. This article presents an analysis of the location choices of mussel farmers in the Mont-Saint-Michel Bay based on an empirical investigation conducted in 2002. A typology of farms with respect to their land structure is developed in which some farms choose to concentrate their activity in a single part of the bay while others distribute their activity more widely. Determinants of the location choices of each farm category, including distance to port, natural productivity differentials, and predation of mussel stocks, are analyzed. The role of the institutional arrangements allowing mussel farmers to develop these location strategies is also discussed.  相似文献   
89.
This paper conducts an analysis of the socioeconomic determinants of Vietnam's cross‐provincial variations in natural disaster vulnerability. The purpose is twofold: (i) to capture disaggregated vulnerability variations normally obscured by national statistics, thereby providing more nuanced insights into Vietnam's vulnerability to natural disasters; and (ii) to take advantage of the fact that the overall political system and key institutional structures to a large extent are constant across Vietnam's provinces, which makes the analysis a novel addition to the many disaster studies based on cross‐national variations. The paper's analysis indicates that much of Vietnam's cross‐provincial variations in natural disaster fatalities and economic costs can be explained by differences in key socioeconomic factors. High provincial rates of inequality, poverty and infant mortality, for instance, appear to drive up natural disaster fatalities. Local adaptation efforts should focus as much on these broader socioeconomic dimensions as they focus on the geophysical susceptibility to natural hazards of individual areas.  相似文献   
90.
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