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141.
Multi-electrode 3D resistivity imaging of alfalfa root zone 总被引:2,自引:0,他引:2
Mariana Amato Giovanni Bitella Roberta Rossi Jos A. Gmez Stella Lovelli Joo J. Ferreira Gomes 《European Journal of Agronomy》2009,31(4):213-222
Information on the amount and spatial distribution of plant roots is increasingly needed for understanding and managing crop behaviour. Soil electrical resistivity (ρ) tomography has been proposed as a non-destructive method for root biomass quantification and mapping in trees but evidence is needed on the applicability of the technique at low root density and in herbaceous plants.We produced high-resolution 3D DC soil resistivity tomograms in containers with bare soil (B), and alfalfa (Medicago sativa L.) (A1) on a silt loam soil, and alfalfa on a loam (A2). Root biomass (RMD), root length density (RLD), soil electrical conductivity (EC) and water content (θ) were measured destructively.The pattern of soil resistivity matched the spatial distribution of θ in bare soil and of RMD in rooted soil. Univariate linear relations were found between ρ and θ in bare soil and between ρ, RLD and RMD in rooted soil. Across all data RMD and soil texture (P < 0.01) explained a high proportion of variability in soil resistivity.This allows to conclude that soil resistivity is quantitatively related to root biomass in herbaceous plants even at low root density (biomass < 0.001 Mg m−3), providing a basis for the development of resistivity-founded methods for the non-destructive spatial detection of root mass in situ, but the response in ρ is of the same order of magnitude as the effects of grain size and water content. Therefore in field studies reciprocal masking of low-density roots and other soil features is possible, and the effect of variation in other soil properties should be explicitly addressed. 相似文献
142.
Nednaldo Dantas-Santos Jailma Almeida-Lima Arthur Anthunes Jacome Vidal Dayanne Lopes Gomes Ruth Medeiros Oliveira Silvia Santos Pedrosa Paula Pereira Francisco Miguel Gama Hugo Alexandre Oliveira Rocha 《Marine drugs》2012,10(9):2002-2022
Sulfated fucans comprise families of polydisperse natural polysaccharides based on sulfated L-fucose. Our aim was to investigate whether fucan nanogel induces cell-specific responses. To that end, a non toxic fucan extracted from Spatoglossum schröederi was chemically modified by grafting hexadecylamine to the polymer hydrophilic backbone. The resulting modified material (SNFuc) formed nanosized particles. The degree of substitution with hydrophobic chains was close to 100%, as estimated by elemental analysis. SNFfuc in aqueous media had a mean diameter of 123 nm and zeta potential of −38.3 ± 0.74 mV, as measured by dynamic light scattering. Nanoparticles conserved their size for up to 70 days. SNFuc cytotoxicity was determined using the MTT assay after culturing different cell lines for 24 h. Tumor-cell (HepG2, 786, H-S5) proliferation was inhibited by 2.0%–43.7% at nanogel concentrations of 0.05–0.5 mg/mL and rabbit aorta endothelial cells (RAEC) non-tumor cell line proliferation displayed inhibition of 8.0%–22.0%. On the other hand, nanogel improved Chinese hamster ovary (CHO) and monocyte macrophage cell (RAW) non-tumor cell line proliferation in the same concentration range. The antiproliferative effect against tumor cells was also confirmed using the BrdU test. Flow cytometric analysis revealed that the fucan nanogel inhibited 786 cell proliferation through caspase and caspase-independent mechanisms. In addition, SNFuc blocks 786 cell passages in the S and G2-M phases of the cell cycle. 相似文献
143.
Path analysis for selection of drought tolerant sugarcane genotypes through physiological components
Paulo Pedro da Silva Lailton SoaresJoão Gomes da Costa Luciana da Silva VianaJúlio César Farias de Andrade Eduardo Rebelo GonçalvesJoão Messias dos Santos Geraldo Veríssimo de Souza BarbosaVelber Xavier Nascimento Adriana Reis TodaroAlessandro Riffel Maria Fatima Grossi-de-SaMárcio Henrique Pereira Barbosa Antônio Euzébio Goulart Sant’AnaCícero Eduardo Ramalho Neto 《Industrial Crops and Products》2012,37(1):11-19
Water deficit is among the main environmental factors limiting agricultural productivity of sugarcane in Northeast Brazil by affecting virtually every aspect of plant growth, with consequent reduction of the agro-industrial productivity of this crop. This study aimed to use path analysis to evaluate the physiological components of sugarcane under two water conditions, with photosynthesis as the basic variable, in order to obtain subsidies that can help the genetic breeding of this crop by selection of superior clones with drought tolerance. The experiment was carried out in a greenhouse with a completely randomized experimental design, 4 × 2 factorial arrangements (four sugarcane genotypes × two soil moisture regimes: control, with 80-100% available water and stressed, with 0-20% water available) and with four replications. Each plot consisted of one pot with 12 kg of substrate containing one plant. Treatments were maintained at a humidity close to field capacity with daily replacement of the evapotranspired water with a water supply for 66 days of cultivation for treatments under stress. Evaluations were conducted on the fourth day after severe water stress at 70 days of cultivation. Data from nine physiological variables were considered, with six of these being used in the model after exclusion of those that were contributing to multicollinearity. Variables used in path analysis were enough to explain the variation found in photosynthesis under both water conditions. Stomatal conductance, transpiration and the SPAD index should be considered as a priority in breeding programs for sugarcane aiming to get more productive and tolerant genotypes to water stress, and selection indexes should be used with due consideration of these variables to promote gains in photosynthesis. 相似文献
144.
Vanessa Dias Capriles Eveline Lopes Almeida Reinaldo Eduardo Ferreira Jos Alfredo Gomes Arêas Caroline Joy Steel Yoon Kil Chang 《Cereal Chemistry》2008,85(5):614-618
The sum of wheat flour and corn starch was replaced by 10, 20, or 30% whole amaranth flour in both conventional (C) and reduced fat (RF) pound cakes, and the effects on physical and sensory properties of the cakes were investigated. RF presented 33% fat reduction. The increasing amaranth levels darkened crust and crumb of cakes, which decreased color acceptability. Fresh amaranth‐containing cakes had similar texture characteristics to the controls, evaluated both instrumentally and sensorially. Sensory evaluation revealed that replacement by 30% amaranth flour decreased C cakes overall acceptability scores, due to its lower specific volume and darker color. Amaranth flour levels had no significant effect on overall acceptability of RF cakes. Hence, the sum of wheat flour and corn starch could be successfully replaced by up to 20% amaranth flour in C and up to 30% in RF pound cakes without negatively affecting sensory quality in fresh cakes. Moisture losses for all the cakes were similar, ≈1% per day during storage. After six days of storage, both C and RF amaranth‐containing cakes had higher hardness and chewiness values than control cakes. Further experiments involving sensory evaluation during storage are necessary to determine the exact limit of amaranth flour replacement. 相似文献
145.
João Chambel Ricardo Costa Mónica Gomes Susana Mendes Teresa Baptista Rui Pedrosa 《Aquaculture International》2014,22(6):1743-1751
The aim of this study was to evaluate the effect of hydrogen peroxide, iodine solution (PVP) and methylene blue on eggs disinfection of three ornamental fish species, Danio rerio, Pterophyllum scalare and Gymnocorymbus ternetzi. The main idea was to create conditions to enhance the hatching rates. Eggs of each species were exposed to different concentrations of hydrogen peroxide (5, 10, 15 and 25 mg/L), PVP (0.25, 0.5, 0.75 and 1 mg/L) and methylene blue (0.5 1, 2 and 3 mg/L). The optimal doses ranged between species and chemicals: for G. ternetzi, the concentrations that high enhanced the hatching rate were 1 mg/L for the PVP treatment, 25 mg/L for the hydrogen peroxide treatment and 3 mg/L for methylene blue treatment; for P. scalare, the best results were achieved with 25 mg/L for hydrogen peroxide treatment and 3 mg/L for methylene blue treatment. By contrast, for all the different chemical did not increased the D. rerio hatching rate. Results showed that hydrogen peroxide and methylene blue are the most versatile, effective and safe to use in these species. On the other hand, PVP can be used but with many precautions due to very low safety margin. Results clearly show that the optimal concentration of chemicals for eggs disinfection is fish species dependent and it is completely wrong to extrapolate concentrations between different chemicals and fish species. Our study suggests that P. scalare can be used as a model in study of effectiveness of new chemicals with potential to disinfect water and increase hatching rates. 相似文献
146.
Márcio Fléquisson Alves Miranda Maria Betânia Galvão dos Santos Freire Brivaldo Gomes Almeida Fernando José Freire Luiz Guilherme Medeiros Pessoa 《Archives of Agronomy and Soil Science》2018,64(9):1207-1221
This study aimed to evaluate the use of phytoremediation and soil conditioners in the recovery of physical attributes of a saline-sodic Fluvic Neossol in Brazil Northeast. The applied treatments were: Atriplex nummularia L., as phytoremediation plant, due to its ability to extract salts from the soil; organic conditioners, such as bovine and sheep manure; gypsum and polymer, as chemical conditioners. Samples with preserved structure were collected at the time of the experiment installation and 18 months after in the layers 0–10 cm and 10–30 cm. The analyzed attributes were: water dispersed clay, dispersion index, bulk density, penetration resistance, soil porosity, and saturated hydraulic conductivity. The use of sheep manure, gypsum and polymer promoted an increase in saturated hydraulic conductivity in the 0–10 cm layer from 4.51 to 16.37 cm day?1, 11.26 to 23.95 cm day?1 and 7.24 to 22.77 cm day?1, respectively. Gypsum increased the macroporosity in the superficial layer by 42.6%. Atriplex and polymer were more efficient at reducing soil penetration resistance. The polymer was more efficient at improving the physical properties. However, it is necessary to consider phytoremediation with Atriplex as a more sustainable alternative that can still be used as complementary fodder in animal feed. 相似文献
147.
Effect of increasing monensin sodium levels in diets with virginiamycin on the finishing of Nellore cattle 下载免费PDF全文
João Marcos B. Benatti João Alexandrino Alves Neto Ivanna M. de Oliveira Flávio D. de Resende Gustavo R. Siqueira 《Animal Science Journal》2017,88(11):1709-1714
This study evaluated the effect of increasing levels of monensin sodium (MON) in diets with virginiamycin (VM) on the finishing of feedlot cattle. Two hundred and eighty intact male Nellore cattle (348 ± 32 kg body weight, 22 months) received one of the following five diets: control diet (without additives); diet containing VM (25 mg per kg dry matter) combined with 0 (MON0), 10 (MON10), 20 (MON20) or 30 (MON30) mg MON per kg dry matter. During adaptation (28 days), the MON0 diet increased dietary net energy for maintenance and gain compared to the control diet (P = 0.04). The combination of additives linearly reduced dry matter intake, body weight and average daily gain (P < 0.01). Considering the total study period (110 days), there was a trend of greater net energy intake for maintenance (P = 0.09) and hot carcass weight (P = 0.06) for animals fed MON0 compared to the control diet. The combination of additives linearly reduced dry matter intake (P = 0.04) and linearly increased gain : feed and dietary net energy for maintenance and gain (P < 0.01). The combination of VM with MON at a dose of 30 mg/kg dry matter is recommended for Nellore feedlot cattle because it improves the efficiency of energy utilization. 相似文献
148.
Biofilms of Candida spp. from the ocular conjunctiva of horses with reduced azole susceptibility: a complicating factor for the treatment of keratomycosis? 下载免费PDF全文
Raimunda Sâmia Nogueira Brilhante Paula Vago Bittencourt Débora de Souza Collares Castelo‐Branco Glaucia Morgana de Melo Guedes Jonathas Sales de Oliveira Lucas Pereira Alencar Rossana de Aguiar Cordeiro Mariana Pinheiro Evilázio Fernandes Nogueira‐Filho Waldemiro de Aquino Pereira‐Neto José Júlio Costa Sidrim Marcos Fábio Gadelha Rocha 《Veterinary ophthalmology》2017,20(6):539-546
149.
Comparison of two species‐specific oscillometric blood pressure monitors with direct blood pressure measurement in anesthetized cats 下载免费PDF全文
150.
Net mineral requirements for growth of Saanen goat kids in early life are similar among genders 下载免费PDF全文
A. N. Mendonça C. J. Härter S. F. Souza D. Oliveira O. Boaventura Neto B. Biagioli K. T. Resende I. A. M. A. Teixeira 《Journal of animal physiology and animal nutrition》2017,101(1):113-120
The current mineral requirements for growing goat kids are based on sheep and cattle studies without differentiating between the stages of development or gender. The aims of this study were to determine the net requirements for growth of Ca, P, Mg, Na and K of Saanen goat kids during the initial stages of growth and to analyse the effect of gender on the net requirements for growth of these macrominerals. Eighteen female, 19 intact male and 10 castrated male Saanen goat kids were studied. The kids were selected applying a completely randomized design and slaughtered when their body weight (BW) reached approximately 5, 10 and 15 kg to determine the mineral requirements for growth at these stages. The net mineral requirements for growth were similar among genders. The goat kids had slightly increased net requirements of Ca, P and Mg for growth with increasing BW from 5 to 15 kg. The net requirements for growth of Ca, P, Mg, Na and K ranged from 9.61 to 9.67 g/kg of BW gain, 7.14 to 7.56 g/kg of BW gain, 0.34 to 0.37 g/kg of BW gain, 1.26 to 1.13 g/kg of BW gain, 1.88 to 1.82 g/kg of BW gain as the animals grew from 5 to 15 kg respectively. In conclusion, when formulating diets for Saanen goat kids in early growth stage mineral levels do not need to adjusted based on gender. 相似文献