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51.
The present work compared inbred (CBA/Ca) and outbred (Swiss white) strains of mice for their capacity to cope with a Neospora caninum infection and to consistently produce tissue cysts. In each experiment Swiss white and CBA/Ca mice were given three different doses of NC-1 tachyzoites. Lymphoproliferative and humoral responses as well as cytokine production were evaluated eight weeks after infection (PI) whereas tissue cyst production and histopathology were assessed 4, 6 and 10 weeks PI in immunosuppressed mice. Tissue cysts were observed 10 weeks after infection only in CBA/Ca mice receiving the two highest inoculum doses. Furthermore this strain showed the highest specific lymphoproliferative response. A mixed cytokine response with elevated IFN-gamma and fairly low IL-4 and IL-10 secretion was recorded. In both strains, no lesions were observed in the tissues of infected mice. This study indicates that CBA/Ca female mice infected with 5 x 10(6) NC-1 tachyzoites represent a useful model for the study of specific maternal immune responses in pregnant animals. 相似文献
52.
The agricultural sector is often considered to be the largest water consumer and the policy aimed at saving irrigation water exists across Europe. The flip-side of such policy, however, is the disappearance of traditional irrigation canals since farmers are encouraged to turn to drip irrigation and overhead irrigation gradually. Given this, we would like to argue that traditional irrigation canals need to be reexamined. Such canals are not only built aquatic infrastructure, they are also the product of a culture and social relationship with water in the Mediterranean region. Canals form a complex system which is driven by environmental, economic and social factors. Our sociological and environmental research in Provence (and around the Durance basin more specifically) points up how the very dense territorial network of gravity-fed canals is useful in water management, as well as in other shared uses over the long-term. The findings underscore the positive environmental role played by these historical and anthropogenic constructions. They contribute to refilling the aquifer and also act as a valuable environmental good and service (e.g., run-off regulation, biodiversity, landscape, recreation, etc.). Further, several local actors have underscored their role as part of an intangible cultural heritage and as important for the area's economic and social development. Such canals play a central role in sustainable development since beyond their productive role in agriculture, they play a social role (new uses) and an ecological role (as reservoirs for biodiversity and ecological corridors). 相似文献
53.
Éric Niqueux Jean-Paul Picault Michel Amelot Chantal Allée Josiane Lamandé Carole Guillemoto Isabelle Pierre Pascale Massin Guillaume Blot François-Xavier Briand Nicolas Rose Véronique Jestin 《Veterinary microbiology》2014
EU annual serosurveillance programs show that domestic duck flocks have the highest seroprevalence of H5 antibodies, demonstrating the circulation of notifiable avian influenza virus (AIV) according to OIE, likely low pathogenic (LP). Therefore, transmission characteristics of LPAIV within these flocks can help to understand virus circulation and possible risk of propagation. This study aimed at estimating transmission parameters of four H5 LPAIV (three field strains from French poultry and decoy ducks, and one clonal reverse-genetics strain derived from one of the former), using a SIR model to analyze data from experimental infections in SPF Muscovy ducks. The design was set up to accommodate rearing on wood shavings with a low density of 1.6 ducks/m2: 10 inoculated ducks were housed together with 15 contact-exposed ducks. Infection was monitored by RNA detection on oropharyngeal and cloacal swabs using real-time RT-PCR with a cutoff corresponding to 2–7 EID50. Depending on the strain, the basic reproduction number (R0) varied from 5.5 to 42.7, confirming LPAIV could easily be transmitted to susceptible Muscovy ducks. The lowest R0 estimate was obtained for a H5N3 field strain, due to lower values of transmission rate and duration of infectious period, whereas reverse-genetics derived H5N1 strain had the highest R0. Frequency and intensity of clinical signs were also variable between strains, but apparently not associated with longer infectious periods. Further comparisons of quantitative transmission parameters may help to identify relevant viral genetic markers for early detection of potentially more virulent strains during surveillance of LPAIV. 相似文献
54.
Hendy EJ Gagan MK Alibert CA McCulloch MT Lough JM Isdale PJ 《Science (New York, N.Y.)》2002,295(5559):1511-1514
A 420-year history of strontium/calcium, uranium/calcium, and oxygen isotope ratios in eight coral cores from the Great Barrier Reef, Australia, indicates that sea surface temperature and salinity were higher in the 18th century than in the 20th century. An abrupt freshening after 1870 occurred simultaneously throughout the southwestern Pacific, coinciding with cooling tropical temperatures. Higher salinities between 1565 and 1870 are best explained by a combination of advection and wind-induced evaporation resulting from a strong latitudinal temperature gradient and intensified circulation. The global Little Ice Age glacial expansion may have been driven, in part, by greater poleward transport of water vapor from the tropical Pacific. 相似文献
55.
Zach Bohannan Raghavendra Sumanth Pudupakam Jamin Koo Harrison Horwitz Josephine Tsang Amanda Polley Enyang James Han Elmer Fernandez Stanley Park Deanna Swartzfager Nicholas Seah Xi Qi Chantal Tu Wendi Velando Rankin Douglas H. Thamm Hye‐Ryeon Lee Sungwon Lim 《Veterinary and comparative oncology》2021,19(1):160-171
We report a precision medicine platform that evaluates the probability of chemotherapy drug efficacy for canine lymphoma by combining ex vivo chemosensitivity and immunophenotyping assays with computational modelling. We isolated live cancer cells from fresh fine needle aspirates of affected lymph nodes and collected post‐treatment clinical responses in 261 canine lymphoma patients scheduled to receive at least 1 of 5 common chemotherapy agents (doxorubicin, vincristine, cyclophosphamide, lomustine and rabacfosadine). We used flow cytometry analysis for immunophenotyping and ex vivo chemosensitivity testing. For each drug, 70% of treated patients were randomly selected to train a random forest model to predict the probability of positive Veterinary Cooperative Oncology Group (VCOG) clinical response based on input variables including antigen expression profiles and treatment sensitivity readouts for each patient's cancer cells. The remaining 30% of patients were used to test model performance. Most models showed a test set ROC‐AUC > 0.65, and all models had overall ROC‐AUC > 0.95. Predicted response scores significantly distinguished (P < .001) positive responses from negative responses in B‐cell and T‐cell disease and newly diagnosed and relapsed patients. Patient groups with predicted response scores >50% showed a statistically significant reduction (log‐rank P < .05) in time to complete response when compared to the groups with scores <50%. The computational models developed in this study enabled the conversion of ex vivo cell‐based chemosensitivity assay results into a predicted probability of in vivo therapeutic efficacy, which may help improve treatment outcomes of individual canine lymphoma patients by providing predictive estimates of positive treatment response. 相似文献
56.
Ly-Nguyen B Van Loey AM Smout C Verlent I Duvetter T Hendrickx ME 《Journal of agricultural and food chemistry》2004,52(26):8144-8150
A proteinaceous pectin methylesterase inhibitor (PMEI) was isolated from kiwi fruit (Actinidia chinensiscv. Hayward) and purified by affinity chromatography on a cyanogen bromide (CNBr) Sepharose 4B-orange PME column. The optimal pH of banana PME activity was 7.0, whereas that for carrot and strawberry PME activity was 9.0. The optimal pH for the binding between kiwi fruit PMEI and these PMEs was 7.0. The kiwi fruit PMEI has a different affinity for PME depending on the plant source. The inhibition kinetics of kiwi fruit PMEI to banana and strawberry PME followed a noncompetitive type, whereas that to carrot PME followed a competitive type. The kiwi fruit PMEI was mixed with banana, carrot, and strawberry PME to obtain PMEI-PME complexes, which were then subjected to thermal (40-80 degrees C, atmospheric pressure) or high-pressure (10 degrees C, 100-600 MPa) treatment. Experimental data showed that the PMEI-PME complexes were easily dissociated by both thermal and high-pressure treatments. 相似文献
57.
Bergeron C Gafner S Batcha LL Angerhofer CK 《Journal of agricultural and food chemistry》2002,50(14):3967-3970
Recent work has shown that enzymatic degradation and oxidation of cichoric acid and other caffeic derivatives occurs in Echinacea preparations. However, very little is known as to the means of stabilizing these phytopreparations. To stabilize the glycerin extract of Echinacea purpurea, we have evaluated the effects of 3 natural antioxidants (citric acid, malic acid, and hibiscus extract) on the stability of the major caffeic acid derivatives (caftaric acid, caffeic acid, cichoric acid, and 2-O-feruloyl-tartaric acid). Chlorogenic acid, which normally occurs in an ethanol extract of E. purpurea, was not present in the glycerin extract. The caffeic acid derivatives, with the exception of 2-O-feruloyl-tartaric acid, were subject to degradation in the control sample. 2-O-Feruloyl-tartaric acid was stable during the whole testing period. All antioxidant treatments greatly improved the stability of caffeic acid derivatives. Stability was dependent upon the concentration of antioxidant added. 相似文献
58.
Denitrification and nitrous oxide to nitrous oxide plus dinitrogen ratios in the soil profile under three tillage systems 总被引:1,自引:0,他引:1
Abdirashid?A.?ElmiEmail author Chandra?Madramootoo Chantal?Hamel Aiguo?Liu 《Biology and Fertility of Soils》2003,38(6):340-348
There is a growing interest in the adoption of conservation tillage systems [no-till (NT) and reduced tillage (RT)] as alternatives to conventional tillage (CT) systems. A 2-year study was conducted to investigate possible environmental consequences of three tillage systems on a 2.4-ha field located at Macdonald Research Farm, McGill University, Montreal. The soil was a sandy loam (0.5 m depth) underlain by a clay layer. Treatments consisted of a factorial combination of CT, RT, and NT with the presence or absence of crop residue. Soil NO3--N concentrations tended to be lower in RT than NT and CT tillage treatments. Denitrification and N2O emissions were similar among tillage systems. Contrary to the popular assumption that denitrification is limited to the uppermost soil layer (0–0.15 m), large rates of N2O production were measured in the subsurface (0.15–0.45 m) soil, suggesting that a significant portion of produced N2O may be missed if only soil surface gas flux measurements are made. The N2O mole fraction (N2O:N2O+N2) was higher in the drier season of 1999 under CT than in 2000, with the ratio occasionally exceeding 1.0 in some soil layers. Dissolved organic C concentrations remained high in all soil depths sampled, but were not affected by tillage system. 相似文献
59.
Marine Fish Larvae Feeding: Formulated Diets or Live Prey? 总被引:7,自引:0,他引:7
Jeannine People Le Ruyet Jean Claude Alexandre Laurence Thébaud Chantal Mugnier 《Journal of the World Aquaculture Society》1993,24(2):211-224
In the rearing of larval marine fish, any diet that reduces dependance on live prey production is of technical and economic interest. Weaning juveniles with a completely developed digestive tract to a conventional diet, (i.e., "late weaning") can be successful in any marine fish species. For example, weaning one-month-old sea bass (20 mg) to the study's reference diet, Sevbar, resulted in over 85% survival (40% from hatching) and 1.25 g fish at day 90 (at 19 C)
In contrast, "early weaning" of larvae to special microdiets during the first month is still difficult. The best way to reduce live prey utilization in sea bass is to wean larvae at about 3–4 mg in size (day 20). If weaning could be accomplished 15 days earlier, Artemia savings could be as high as 80%. However, this introduces risks relative to growth retardation (30% weight loss) and lower juvenile quality, including greater size variability and skeletal abnormalities. Similar results have been obtained with commercial microparticles (Fry Feed Kyowa) and experimental microbound diets (MBD) made from raw materials (alginate MBD) or preferably from freeze-dried protein sources (zein MBD).
Total replacement of live prey is still impossible in marine fish. Sea bass larvae fed formulated diets exclusively from first feeding (0.3 mg larval wet weight), or even from their second week of life onwards, exhibited low survival and poor growth. Better results can be obtained when formulated diets are used in combination with live prey from first feeding, although the optimal ratio of live prey to formulated diet is still to be specified. 相似文献
In contrast, "early weaning" of larvae to special microdiets during the first month is still difficult. The best way to reduce live prey utilization in sea bass is to wean larvae at about 3–4 mg in size (day 20). If weaning could be accomplished 15 days earlier, Artemia savings could be as high as 80%. However, this introduces risks relative to growth retardation (30% weight loss) and lower juvenile quality, including greater size variability and skeletal abnormalities. Similar results have been obtained with commercial microparticles (Fry Feed Kyowa) and experimental microbound diets (MBD) made from raw materials (alginate MBD) or preferably from freeze-dried protein sources (zein MBD).
Total replacement of live prey is still impossible in marine fish. Sea bass larvae fed formulated diets exclusively from first feeding (0.3 mg larval wet weight), or even from their second week of life onwards, exhibited low survival and poor growth. Better results can be obtained when formulated diets are used in combination with live prey from first feeding, although the optimal ratio of live prey to formulated diet is still to be specified. 相似文献
60.
Cuny Damien Van Haluwyn Chantal Shirali Pirouz Zerimech Fharid Jérôme Laurence Haguenoer Jean Marie 《Water, air, and soil pollution》2004,152(1-4):55-69
The purpose of this research is to present toxic effects of some heavy metals (cadmium, lead and zinc) on lichen physiology. In the North of France, those metals are concentrated for example in industrial polluted soils near metallurgic plants and waste dumps. Our investigations were conducted on Diploschistes muscorum (Scop.) R. Sant, a terricolous lichen growing on previously quoted soils as well as on non-contaminated ones. Different stress parameters were investigated as potassium leakage – which is related to the loss of membrane integrity – and oxidative stress through following parameters: malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD). It seems, therefore, that heavy metals induce oxidative stress in this lichen, in which we found membrane damage and enhancement of SOD activity and GSH concentrations. With regard to very high concentrations of Cd, Pb and Zn, a resistance involving antioxidant mechanisms limits the expected damage. Those mechanisms involve GSH, SOD as well as secondary metabolites, which have this resistance property. This study is a first step of investigation to use – in the future– physiological parameters as tool for environment assessment. 相似文献