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191.
Angeles Adn Pedro Del Estal Flor Budia Manuel Gonzlez Elisa Viuela 《Pest management science》1996,48(3):261-268
Laboratory studies were conducted to determine the effect of the naturally derived compound spinosad on Ceratitis capitata Wied. (Diptera, Tephritidae). The organophosphate fenthion was used as a standard. Direct dose-dependent mortality and reduced fecundity were observed in oral treatment of adults with spinosad. The LC90 values 14 h and seven days after treatment were 19·50 and 0·49 mg litre−1 respectively. Fenthion was less active (the LC50 eight days after treatment was 1·17 mg litre−1) and did not affect the fecundity of the fly. Adults were also very susceptible to spinosad and fenthion via residual contact. For spinosad, 100% mortality was recorded 48 h after treatment for a dose of 10 mg litre−1. Spinosad was more effective than fenthion in suppressing larval development when neonate larvae were reared on treated diet supplemented with a range of concentrations from 0·02 to 0·83 mg kg−1 diet. Last-instar larvae were much less susceptible to spinosad or fenthion when exposed via dipping or when they pupated in treated medium and both products had similar performance. A lack of ovicidal activity was observed in direct egg-treatments with spinosad but significant reductions from 1 mg litre−1 onwards were recorded for fenthion. 相似文献
192.
A production season of turbot larvae Scophthalmus maximus (Linnaeus, 1758) reared on copepods in a Danish (56°N) semi‐intensive outdoor system
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Per M Jepsen Hans H Jakobsen Thomas A Rayner Elisa Blanda Aliona Novac Kirsten Engell‐Sørensen Benni W Hansen 《Aquaculture Research》2017,48(9):4958-4974
Turbot were reared from yolk sack larvae to juvenile in an outdoor semi‐intensive system. Three production cycles were monitored from May to September. A pelagic food chain was established with phytoplankton, copepods and turbot larvae. Abiotic and biotic parameters of lower trophic levels together with turbot larval survival, development, prey electivity and growth were monitored. A decreasing larval survival from 18.4% in May to 13.6% in July and just 7.0% in September was observed. The overall phytoplankton and copepod abundance decreased during the productive season. The turbot larval growth showed significant differences between larvae below (isometric) and above (allometric) 7 mm. Larval fish gut content showed no differences with available prey between production cycles. Therefore, it appears that the available prey concentration is governing their growth in this outdoor system. First‐feeding turbot larvae exhibited active selection for nauplii whereas developed larvae switched to copepodites and adult copepods. Although developing turbot larva exhibited active selection towards copepod size classes, there was no evidence of selective feeding on either of the two dominant copepod species. The turbot larvae's prey ingestion was modelled together with the standing stock of copepod biomass. The model results indicated that the estimated need for daily ingestion exceeded the standing stock of copepods. Hence, the initially established food web was unable to sustain the added turbot larvae with starvation as a consequence. We therefore suggest several solutions to circumvent starvation in the semi‐intensive system. 相似文献
193.
Villalba-Villalba Ana Gloria Pacheco-Aguilar Ramón Ramirez-Suarez Juan Carlos Valenzuela-Soto Elisa Miriam Castillo-Yáñez Francisco Javier Márquez-Ríos Enrique 《Fisheries Science》2011,77(4):697-705
Vermiculated sailfin catfish (Pterygoplichthys disjunctivus, Weber, 1991), a member of the Loricariidae family and an invasive species of several inland waters around the world, possess
an enormous digestive tract representing about 10% of fish weight. Thus, the aim of this study was to partially characterize
proteases from their digestive tracts. Azocasein digestion of the crude extract of intestine at different pH values and temperatures
revealed the presence of alkaline proteases with optimum activities at pH 9.0 and 50°C. Incubation assays of the crude extract
with inhibitors such as phenyl methyl sulfonyl fluoride, N-α-p-tosyl-l-lysine chloromethyl ketone, N-tosyl-phenyalanine chloromethyl ketone, benzamidine, pepstatin A and ethylenediamine tetra-acetic acid showed that trypsin
and chymotrypsin are the main alkaline proteinases present. Zymography showed that the crude extract of Pterygoplichthys
disjunctivus viscera contained proteases with molecular masses ranging from 21.5 to 116 kDa. Trypsin and chymotrypsin were inhibited by
the following ions in decreasing order: Hg2+, Fe2+, Cu2+, Li+, Mg2+, K+, while Mn2+, and Ca2+ had no effect. Activities decreased continuously as the NaCl concentration increased from 0 to 30%. These results constitute
important background information for future studies and for the potential biotechnological use of the crude digestive extract
from this invasive species. 相似文献
194.
Juan Estrella‐Martínez Bernd R. Schne Ruth H. Thurstan Elisa Capuzzo James D. Scourse Paul G. Butler 《Fish and Fisheries》2019,20(3):537-551
Understanding the recruitment variability of the Atlantic herring North Sea stock remains a key objective of stock assessment and management. Although many efforts have been undertaken linking climatic and stock dynamic factors to herring recruitment, no major attempt has been made to estimate recruitment levels before the 20th century. Here, we present a novel annually resolved, absolutely dated herring recruitment reconstruction, derived from stable carbon isotope geochemistry (δ13C), from ocean quahog shells from the Fladen Ground (northern North Sea). Our age model is based on a growth increment chronology obtained from fourteen shells. Ten of these were micromilled at annual resolution for δ13C analysis. Our results indicate that the anthropogenically driven relative depletion of 13C, the oceanic Suess effect (oSE), became evident in the northern North Sea in the 1850s. We calculated a regression line between the oSE‐detrended δ13C results (δ13C?) and diatom abundance in the North Sea, the regression being mediated by the effect of phytoplankton on the δ13C of the ambient dissolved inorganic carbon. We used this regression to build an equation mediated by a nutritional link to reconstruct herring recruitment using δ13C?. The reconstruction suggests that there were five extended episodes of low‐recruitment levels before the 20th century. These results are supported by measured recruitment estimates and historical fish catch and export documentation. This work demonstrates that molluscan sclerochronological records can contribute to the investigation of ecological baselines and ecosystem functioning impacted by anthropogenic activity with implications for conservation and stock management. 相似文献
195.
Crops are negatively affected by abiotic and biotic stresses, however, plant‐microbe cooperation allows prompt buffering of these environmental changes. Microorganisms exhibit an extensive metabolic capability to assist plants in reducing these burdens. Interestingly, beneficial microbes may also trigger, at the host side, a sequence of events from signal perception to metabolic responses leading to stress tolerance or protection against biotic threats. Although plants are well known for their vast chemical diversity, plant‐microbial interactions often stimulate the production of a rich and different repertoire of metabolites in plants. The targeted microbial‐plant interactions reprogramming plant metabolism represent potential means to foster various pest managements. However, the molecular mechanisms of microbial modulation of plant metabolic plasticity are still poorly understood. Here, we review an increasing amount of reports providing evidence for alterations to plant metabolism caused by beneficial microbial colonization. In addition, we highlight the vital importance of these metabolic reprograms for plants under stress erratic conditions. © 2019 Society of Chemical Industry 相似文献
196.
Gregorio Egea Elisa Pagán Alain Baille Rafael Domingo Pedro A. Nortes Alejandro Pérez-Pastor 《Irrigation Science》2009,27(6):431-441
The suitability of trunk diameter reference baselines for irrigation scheduling of mature drip-irrigated almond trees [Prunus dulcis (Mill). D.A. Webb cv Marta] was assessed in a 3-year experiment conducted on well-watered trees in south-eastern Spain. Continuous
measurements of trunk daily growth rate (DGR) and maximum daily trunk shrinkage (MDS) were carried out throughout the growing
season (April–November). Day-to-day variations in MDS and DGR were related with meteorological variables. DGR was found to
be weakly correlated to all the meteorological variables, while MDS showed significant relationships with most of them. The
mean air vapour pressure deficit during the period 10.00–15.00 h solar time (VPDmx) was the environmental variable that best correlated with MDS. The relationships obtained were similar for all the phenological
phases, except postharvest, when MDS showed a tendency towards lower values for a given atmospheric evaporative demand. The
increase in trunk diameter over the 3 years also appeared to affect the relationships to some extent. As a practical procedure,
it is proposed determining the baseline periodically (every 1 or 2 years) during the early stages (II–III) of the almond phenological
cycle, for use as reference MDS for the subsequent growth stages, because over longer periods several factors affecting the
stability of the baseline, in particular trunk diameter growth, might introduce changes in the baseline. 相似文献
197.
The purpose of this study was to evaluate the effect of a skip-a-day feeding regime on the growth of one-year-old sturgeon, Acipenser stellatus. Sturgeons possess a spiral valve intestine, which slows down the passage of food to longer than 24 hours, providing a scientific justification for the experiment. The experiment had a duration of 12 weeks and consisted of two treatments groups with four replicates each. One group of sturgeons (n = 120) was offered feed every day, on a continuous basis, at 2% of their body weight daily; while a second group of sturgeons (n = 120) were fed every other day, also at 2% of their body weight daily. The sturgeons had an average initial body weight of 178 ± 32 g and measured 44.6 ± 2.9 cm in total length. At the end of the experimental period, all sturgeons were alive, in good health, and no statistically significant differences (P > 0.05) on growth performance indices were detected between sturgeons fed every day and every other day. The average weights and lengths of sturgeons at the end of the trial were 406 ± 96 g and 55.4 ± 4.4 cm. The results of this study suggest that yearling sturgeon may be fed every other day rather than daily. A skip-a-day feeding regime can result in feed savings for a commercial operation, help protect the natural resources such as those for making fish meal, and lessen the impact of excess nutrients in natural bodies of water. 相似文献
198.
Benni Winding Hansen Elisa Blanda Guillaume Drillet Jacob Kring Højgaard Mohamed-Sofiane Mahjoub Thomas Allan Rayner 《Aquaculture International》2016,24(4):949-964
It is well established in Denmark to rear calanoid copepods in outdoor tanks for use as live feed during turbot (Scophthalmus maximus) larval production. However, the copepod assemblages, composed of a mixture of all development stages and therefore body sizes, vary over time and do not always match the larval needs. When turbot larvae reach metamorphosis and are transferred indoor for weaning, the outdoor tank sediments may reveal vast amounts of copepod eggs undergoing dormancy. Here, we report a copepod species succession firstly among Centropages hamatus and then Acartia spp. both with resting eggs as part of their life cycles as a result of two different nutrients treatments and a control. We found a tendency to a higher egg production and indeed more eggs in the sediment of nutrient amended tanks. In fact close to 5 million eggs per square meter, making up to 400 million eggs per tank was found in the sediment after one production. Instead of discarding the sediment between production batches, we propose to collect it and generate an egg bank. These eggs can be stored for months to a year, however, according to the results, a large loss rate occurred, which could be potentially decreased by the optimization of storage conditions. Those procedures will enable hatchery managers to apply newly hatched copepod nauplii exactly when the turbot larvae start feeding which would potentially solve the, often occurring, mismatch between the time of start-feeding turbot larvae and actual available prey field. 相似文献
199.
Smagghe G Pineda S Carton B Del Estal P Budia F Viñuela E 《Pest management science》2003,59(11):1203-1209
Methoxyfenozide (RH-2485) was found to be 7.5-fold less toxic in terms of LD50 values against last-instar larvae of a greenhouse-selected strain of the beet armyworm Spodoptera exigua (Hübner) that was collected in July 2001 in an experimental greenhouse for resistance at Murcia in southern Spain, in comparison with a laboratory susceptible strain. To date, the compound is the newest member of this new group of moulting hormone accelerating IGRs to reach the marketplace against Lepidoptera. To understand this different potency in the greenhouse-selected S exigua, oxidative metabolism and acetylcholinesterase activities were measured in last-instar larvae and adults. In addition, we determined, by the use of 14C-labelled methoxyfenozide, the pattern of absorption in body tissues and excretion via faeces in last-instar larvae of the greenhouse-selected strain and compared the results with those from the laboratory susceptible strain. It was striking that the rate of excretion was about twice as high in the greenhouse-selected strain, resulting in a more rapid clearance of insecticide amounts from the insect body. Data are discussed in relation to mechanisms of lower toxicities for this new group of IGRs. 相似文献
200.
Pfeiffer Tobias von Galen Astrid Zink Petra Hübner Sebastian Linkies Ada Felgentreu Dieter Drechsel Jannika Birr Tim Röder Olaf Kotte Mathias Dietel Kristin Junge Helmut Schwarz Elisa Koch Eckhard 《植物病害和植物保护杂志》2021,128(5):1227-1241
Journal of Plant Diseases and Protection - Plant-based screening experiments were conducted with the aim of identifying biocontrol bacteria and fungi for seed treatment of maize. Candidate... 相似文献