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101.
Etienne Baras Grace V. Montalvan Naranjos Dustin V. Silva del Aguila Fred Chu Koo Rémi Dugué Carlos Chavez Fabrice Duponchelle Jean‐François Renno C. Carmen Garcia‐Dávila Jesus Nuñez 《Aquaculture Research》2012,43(12):1764-1776
Food intake (FI) and gut evacuation (Rg) were measured in larvae of Pseudoplatystoma punctifer (4.5–18.4 mm SL) fed Artemia nauplii, taking advantage of the translucence of their abdominal region to achieve this in a non‐destructive way, using digital photographs and mathematical reconstruction of gut volume content (ellipsoidal and cylindrical models for stomach and intestine respectively). The inaccuracy of the method, with reference to counts of nauplii following fish dissection, was low (2.9 ± 1.5%) and independent of fish size (P = 0.6153). Pigmentation hampered measurement in fish >18–19 mm SL. Anaesthesia was needed in fish >9.5 mm SL, thereby preventing the measurement of Rg in individual fish. The FI increased rapidly during the ontogeny, passing from <7% M at 0.6 mg, to 14% M at 1 mg and 21% M at 15–40 mg, and then decreased slightly in larger fish. At 28.5°C, Rg (% M h?1) was modelled as Rg = ?8.22 + 12.11 log FI + 6.30 log M – 12.67 (log M)2 (R2 = 0.904, d.f. = 27, with FI in% M and M in mg). Extrapolations of Rg over 24 h gave estimates of daily food rations that fit well with those measured in cannibalistic P. punctifer. 相似文献
102.
Detection of genetically isolated entities within the Mediterranean species of Bemisia tabaci: new insights into the systematics of this worldwide pest
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103.
Modeste Lambert Sameza Marie Ampere Bedine Boat Séverin Tchameni Nguemezi Lile Christere Nguemnang Mabou Pierre Michel Jazet Dongmo Fabrice Fekam Boyom Chantal Menut 《European journal of plant pathology / European Foundation for Plant Pathology》2014,140(2):243-250
This study was carried out to determine the antimicrobial activity of essential oil derived from leaves of eucalyptus (Eucalyptus globulus) against Phytophthora colocasiae, the causal agent of taro leaf blight (TLB). Essential oil was obtained by Clevenger-type water distillation. The major compounds in this essential oil were identified using gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC/MS). Antimicrobial activity of the essential oil was tested in vitro against mycelial growth, sporangia and zoospores germination of P. colocasiae. Additionally, in situ tests were conducted on detached healthy taro leaves discs and evaluating necrosis symptoms of TLB were assessed. Results of the chemical composition of the essential oil analysis showed that, 1.8-cineole (26.4 %), α-pinene (14.1 %) and p-cymene (10.2 %) are the most abundant compounds. In addition, four components could be identified in noticeable amounts (18.1 % in the total): regulator G1/G2 and its derivatives as well as flavesone, a regulator G3 derivative. G is a generic term for a family of 2,3-dioxabicyclo[4,4,0] decane system growth regulators. Here, G-regulators and derivatives are described for the first time in E. globulus. Antimicrobial activity of the essential oil was recorded with total inhibition of mycelia growth and sporangia germination at 0.625 mg/ml, while the complete inhibition of zoospores germination was recorded at 0.156 mg/ml. In situ results showed that essential oil completely inhibited the appearance of disease symptoms, necrosis development and sporulation at 3.5 mg/ml. These results demonstrated that, the essential oil of Eucalyptus globulus has high ability to inhibit the development of P. colocasiae, and might be used for controlling TLB. 相似文献
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107.
Gilles Bezançon Jean-Louis Pham Monique Deu Yves Vigouroux Fabrice Sagnard Cédric Mariac Issoufou Kapran Aïssata Mamadou Bruno Gérard Jupiter Ndjeunga Jacques Chantereau 《Genetic Resources and Crop Evolution》2009,56(2):223-236
Changes in the diversity of landraces in centres of diversity of cultivated plants need to be assessed in order to monitor
and conserve agrobioversity—a key-element of sustainable agriculture. This notably applies in tropical areas where factors
such as increased populations, climate change and shifts in cropping systems are hypothesized to cause varietal erosion. To
assess varietal erosion of staple crops in a country subjected to various anthropogenic and natural environmental changes,
we carried out a study based on a comparison of the diversity of pearl millet and sorghum varieties collected in 79 villages
spanning the entire cereal-growing zone of Niger over a 26 year period (1976–2003). For these two crops, the number, name
and type of varieties according to important traits for farmers were considered at different spatial scales (country, region,
village) at the two collection dates. The results confirmed the high diversity of millet and sorghum varieties in Niger. No
erosion of varietal diversity was noted on a national scale during the period covered. Some changes were observed but were
limited to the geographical distribution of certain varieties. This highlights that farmers’ management can preserve the diversity
of millet and sorghum varieties in Niger despite recurrent and severe drought periods and major social changes. It also indicates
that rainfed cereal cropping systems in Niger should remain to be based on millet and sorghum, while reinforcing farmers’
seed systems. 相似文献
108.
Thibaud Decaëns Pierre Margerie Michael Aubert Mickaël Hedde Fabrice Bureau 《Applied soil ecology》2008,39(3):321-335
This paper addresses the factors that constrain the assembly of earthworm communities in temperate land use systems. An occurrence matrix containing 44 localities and 20 species was build from data sets of different studies carried out in Haute Normandie (France). The whole data set included species lists from the three main landscape units and from a range of land use types from unmanaged forests and grasslands to intensive pastures and annual crops. We used species pool, multivariate (correspondence analysis) and null model analyse to explore how species occurring in a given community are sorted from the regional species pool. Special attention was paid to identifying non-randomness in co-occurrence and morpho-ecological patterns and to describing community patterns in response to habitat constraints. Twenty species of Lumbricidae were identified in the total species pool. We found no significant effect of landscape units on species richness and density, while land use type had a significant impact on both variables, with the lowest values in crops and forests, and the highest values in grasslands. Correspondence analysis highlighted how broad land use types, soil gradients and land use intensity influence patterns of community composition and ecological coherence. Non-random patterns in guild proportion were found in a few situations, with differences between grasslands and forests. This shows that environmental filters select species at specific scales according to particular ecological traits, resulting in a convergence of these traits between species of a given community. Local species richness never exceeded nine species and species co-occurrence was significantly lower than expected by chance and much lower than described in the literature for other taxa. Although no significant patterns of limiting similarity were observed at the scale of our study, we conclude that earthworm communities are also highly structured by competition. Our study thus agrees with the idea that both habitat and competitive constraints operate simultaneously to determine how community assembly takes place. 相似文献
109.
Jean-Philippe Lejeune DVM Fabrice Audigie DVM PhD Nicole Schneider DVM Dominique Duvivier DVM PhD Jackie Tapprest DVM Jean-Marie Denoix DVM PhD Didier Serteyn DVM PhD 《Journal of Equine Veterinary Science》2006,26(3):102-112
The anatomic variations and the degenerative changes in the collateral cartilages and middle and distal phalanges in 6 Ardenner colts were characterized by radiography, scintigraphy, and magnetic resonance imaging (MRI). The radiographic changes were assessed between the ages of 16.5 and 25 months. An anatomic variation of the middle and distal phalanges was demonstrated in some of the colts. MRI examination of the 6 colts revealed an association between the deep digital flexor tendon cross-sectional area and body weight as well as foot circumference. Also, a thin collateral sesamoidean (suspensory navicular) ligament was observed subjectively. The presence of an extensive ossification of the collateral cartilages of the foot was found in these young horses. The ossification was characterized by the existence of 2 separate ossification centers, which had a tendency to unite. The radiographic interphalangeal degenerative lesions seen appear as bone remodeling of the dorsal edges of the middle and distal phalanx, on the insertion sites of collateral ligaments of the distal interphalangeal joint, the digital extensor tendon, and the distal interphalangeal joint capsule. 相似文献
110.