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81.
Assessing allelic richness in a set of populations requires that variations of sample size be taken into account. One way of doing this is to estimate the number of alleles expected in samples of specified size, using the rarefaction method applied in ecology. An alternative method, based on extrapolation, consists of adding to the number of alleles actually seen in a population the expected number of alleles missing, given the number of genes examined in the population and the allelic frequencies observed over the whole set of populations. Heterogeneity of allelic richness across populations and across loci can also be tested in this framework by numerical re-sampling. Both methods provide a measure of “private” allelic richness, a useful criterion in genetic diversity preservation, by allowing evaluation of the uniqueness of each population in terms of allele numbers. The two methods are compared on isozyme loci in the argan tree of Morocco and on microsatellite genotypes in the European pig. In both species, allelic richness and gene diversity behave quasi-independently over the populations compared and a higher differentiation is observed in allelic richness compared to gene diversity. In general, the rarefaction technique is sensitive to the sample size of reference and may lack sensitivity to rare alleles when the sample size of reference is small. Extrapolation may thus be recommended especially when the sample sizes of the populations are either low on average or highly unbalanced among populations. 相似文献
82.
Jean-Louis Doucet Yao Lambert Kouadio David Monticelli Philippe Lejeune 《Forest Ecology and Management》2009,258(11):2407-2415
Studies of regeneration in African rain forests suggest that without silvicultural treatments, natural succession in logging gaps may not result in the establishment of timber species. In this paper we present the results of an experimental enrichment planting with moabi (Baillonella toxisperma Pierre), a valuable and important timber species harvested in Central Africa. Although forest gaps are generally considered as favourable for the regeneration of this species, a survey conducted in a forest concession in south-eastern Cameroon provided an estimate of only 12.7 seedlings ha−1, suggesting that the species was, in fact, poorly represented in logging gaps within the study area. To further investigate the dynamics of the moabi in logging gaps, 795 seeds were sown in 15 logging gaps and 410 nursery-raised seedlings were planted in 15 other gaps. A biannual monitoring program over a 30-month period showed a lower survival rate for seedlings from sowing (75.9%) compared to that of nursery-raised seedlings (95.3%). Planted seedlings reached an average of 229.3 cm tall whereas seedlings from sowing were 167.5 cm tall, with the observed difference roughly corresponding to the average height of the nursery-raised seedlings at the time they were introduced to the logging gaps. After 30 months, the diameters of planted seedlings (16.8 mm) were also greater than those of the directly sown individuals (12.5 mm). Forest gap characteristics significantly influenced the growth of the plants. Factors accounting for the differences were total solar radiation, the soil content of coarse sand, the topographic position of the gap, the vegetation cover and the density of Macaranga spp. Whilst total solar radiation had a positive influence on growth, the remaining factors had impacted growth negatively. A streamlined technique was tested by planting 7 seedlings in 250 gaps. Without additional site maintenance, 29.3% of the moabi seedlings emerged naturally from the competing vegetation after 24 months. With biannual maintenance some 89.4% of seedlings became successfully established. Clearance operations had no significant influence on the height of plants whilst plant diameter was greater in cleared gaps. The total cost of the enrichment technique was 5.5 EUR per gap without maintenance and 7.5 EUR per gap with a single maintenance measure. Whilst long-term monitoring is needed, this study suggests a high survival rate of moabi introduced in logging gaps, and a growth rate 10 times higher than previously reported under canopy cover. These findings, combined with the low costs of the enrichment technique, support the use of silvicultural measures in logging gaps to restore the forest. 相似文献
83.
Lisa Shindo Christelle Belingard Jean-Louis Edouard Mélanie Saulnier 《Annals of Forest Science》2017,74(4):67
? Key message This paper presents ring width data of silver fir trees (Abies alba Mill.) from buildings and living trees from 1214 to 2009 in southeastern France. A 796-year chronology spanning the period 1214–2009 has been built. Data can be used for dating projects, paleoecology studies, and climate reconstructions. Dataset access is at https://hal.archives-ouvertes.fr/hal-01528324 . Associated metadata is available at https://metadata-afs.nancy.inra.fr/geonetwork/srv/fre/catalog.search#/metadata/a74b4869-318c-458c-a5fe-f9ff44a5082c 相似文献
84.
Between-breed genetic diversity is classically considered as a major criterion to be taken into account when setting priorities for conservation of domestic animal breeds. However, it has been argued that methods based on the between-breed component of genetic diversity may not be optimal because they ignore the within-breed component of variation. The paper considers the most common methods used to evaluate those two components when genetic diversity is evaluated on the basis of genetic markers, and proposes to define an aggregate diversity combining linearly the two components. This implies defining for each breed (or population) its contributions to the between-breed and to the within-breed diversity. When defining an aggregate diversity, one can weight these contributions by FST and 1−FST, respectively, since the fixation index FST of Wright represents the proportion of the total genetic variation which is due to differences in allelic frequencies between populations. Such an approach is valid when the objective is genetic improvement by selection within a so-called “meta-population”. However, in a more general context of animal breeding, when heterosis and complementarities between breeds have to be considered, as well as adaptation to specific environments, more weight should be given to the between-breed variation. The proper weight to apply may require solutions adapted to each particular situation. In a long-term conservation perspective, priorities should also take into account the degree of endangerment of each breed. By combining diversity contributions and probability of extinction, a cryopreservation potential (or priority) may be estimated for each breed. The problem is illustrated on a sample of 11 European pig breeds typed for 18 microsatellite loci. 相似文献
85.
Chetboul V Sampedrano CC Gouni V Nicolle AP Pouchelon JL Tissier R 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2006,20(4):885-893
BACKGROUND: Strain (St) and strain rate (SR) imaging are new ultrasound modalities based on tissue Doppler imaging (TDI) that allow quantitative assessment of segmental myocardial contraction or stretching and rate of deformation, respectively. HYPOTHESIS: Regional peak systolic St and SR could allow repeatable and reproducible assessment of systolic function of the right (RVW) and left (LVFW) myocardial walls in dogs. ANIMALS: Six healthy Beagle dogs were used to determine the repeatability and reproducibility of regional peak systolic St and SR in the RVW and LVFW (Study 1). These variables were also assessed in 30 healthy dogs of several breeds (Study 2). METHODS: Longitudinal peak systolic St and SR were recorded in 2 segments (basal and apical) of the RVW and LVFW. Radial peak systolic St and SR of the LVFW were also assessed. RESULTS: All within- and most (7/10) between-day coefficients of variation were <15%. Absolute values of the longitudinal deformation indices were significantly higher (P < .001) in the RVW (St = -39.5 +/- 5.5% and SR = -5.2 +/- 0.8 s(-1) at the base; St = -36.3 +/- 4.3% and SR = -4.7 +/- 1.1 s(-1) at the apex) than in the LVFW. Absolute values were also higher for the radial (St = 62.9 +/- 10.4% and SR = 5.8 +/- 1.1 s(-1), P < .001) than for the longitudinal LFVW motions. CONCLUSIONS AND CLINICAL IMPORTANCE: St and SR imaging is a repeatable and reproducible method for assessing systolic myocardial function. The combination of these indices with conventional echocardiographic variables may be useful for screening canine myocardial diseases. 相似文献
86.
The chemical composition of East European (Republic of Moldova, Ukraine, and Romania) oaks was investigated profoundly for the first time in the present study and compared with American and French counterparts. Taking into account the high natural variability of oak extractives contents, the wide-ranging sampling was performed for all oak origins: 276 French oaks, 102 East European oaks of both species (Quercus robur L. and Quercus petraea Liebl.), and 56 American oaks (Quercus alba). These oaks were compared with great attention paid to the extractives, which are most important for sensorial impact in wine or spirit maturation, such as ellagitannins and principal odorant substances (aromatic aldehydes, lactones and phenols). The substances in question were studied by application of HPLC and GC-MS techniques. The pattern of all studied extractive contents allowed adequate separation of oak samples according to their geographical origin or botanical species. The highest separation rate was for American and French oaks, whereas East European samples could be partially misclassified in two sets mentioned above. The most important variables for species discrimination were whiskey lactone related variables and ellagitannins, whereas the most important features for distinguishing the origin were eugenol, 2-phenylethanol, vanillin, and syringaldehyde. These substances allowed the distinction of French and East European woods of the same species. With regard to chemical composition, East European wood held the intermediary place between American and French oaks according to their ellagitannin and whiskey lactone levels; nevertheless, it was characterized by specific high values of eugenol, aromatic aldehydes, and 2-phenylethanol. 相似文献
87.
Savary G Guichard E Doublier JL Cayot N Moreau C 《Journal of agricultural and food chemistry》2006,54(3):665-671
Diffusion-ordered spectroscopy (DOSY)-pulsed field gradient (PGF) nuclear magnetic resonance (NMR) spectroscopy was used to measure self-diffusion coefficients of aroma molecules in model fruit preparations. The impact of the sucrose content on aroma diffusion was specifically investigated, and the relationship with viscosity, water activity, and dry matter parameters was evidenced. DOSY-PGF NMR spectroscopy was found to be a relevant and accurate technique to follow self-diffusion of aroma compounds at low concentrations in a complex food matrix and to obtain information on diffusion of the sucrose and of the water molecules. We showed that aroma self-diffusion was strongly decreased in fruit preparation because of the high sucrose content, which induces the formation of a network through hydrogen bonds with water. Self-diffusion coefficients were determined for aroma molecules of different natures, and values are related to the physicochemical properties of the molecule. 相似文献
88.
Julie Sardos Sara Muller Marie-France Duval Jean-Louis Noyer Vincent Lebot 《Agriculture and Human Values》2016,33(3):721-736
In Vanuatu (Oceania), small-scale farmers’ subsistence still largely relies on the sustainable use and maintenance of a wide-ranging biodiversity out of which root and tuber crops provide the bulk of daily subsistence. In neighboring countries, foreign influence since the first European contacts, further associated changes and the introduction of new crop species have induced a loss of cultivated diversity. This paper presents a baseline study of the diversity of root and tuber crops in ten communities throughout Vanuatu. In a context where the smallholders’ agrosystems are increasingly considered as key components for the global conservation of crop genetic resources, this study provides clues to better understand the effective roles of biodiversity in traditional agrosystems. It also provides insights on the rationale behind the constitution of agricultural portfolios and discusses how the cultivated diversity allows communities to cope with changes and pressures. The paper also shows that recently introduced crops neither seem to have compromised agricultural diversity nor drastically changed the agrosystems in Vanuatu. On the contrary, such crops are used by farmers to strengthen the resilience of their agrosystems. A discussion then presents the idea of continuity through change and novelty as a critical factor for resilience. The paper concludes by discussing the role of indigenous agriculture and culture in ensuring food security and in development strategies in a larger context. 相似文献
89.
François Serres Jean-Louis Pouchelon Laure Poujol Hervé P. Lefebvre Cathy Trumel Thomas Daste Carolina Carlos Sampedrano Vassiliki Gouni Renaud Tissier Gerhard Hawa Valérie Chetboul 《Journal of Veterinary Cardiology》2009,11(2):103-121
Objectives
Although mitral valve disease (MVD) is the most common canine heart disease, readily available prognostic markers of the disease are still lacking. The aim of this study was to evaluate the comparative ability of N-terminal pro-B-type natriuretic peptide plasma concentration (NT-proBNP) and various echocardiographic variables to predict outcome in dogs with MVD.Animals, materials and methods
Seventy-four dogs with ISACHC classes 2 and 3 MVD (Groups A and B, respectively) were prospectively recruited. NT-proBNP and several echo-Doppler variables at inclusion were compared as predictors of outcome at 6 months in 54/74 dogs.Results
NT-proBNP was significantly higher in Group B than in Group A (P < 0.0001), and was the only tested variable significantly different between survivor and non-survivor dogs in both groups (P < 0.05). In the whole canine population, a threshold of 1500 pmol/L could discriminate survivor from non-survivor dogs with a sensitivity and specificity of 80% and 73%, respectively. When combining ISACHC class with NT-proBNP levels, a cut-off of 1265 pmol/L was predictive of survival in Group A, whereas the cut-off was 2700 pmol/L for Group B.Conclusions
NT-proBNP is correlated with MVD severity and could be used in combination with clinical status to predict cardiac outcome. 相似文献90.
Nicolle AP Chetboul V Tessier-Vetzel D Carlos Sampedrano C Aletti E Pouchelon JL 《The Canadian veterinary journal. La revue veterinaire canadienne》2006,47(8):792-795
A dog was presented with a history of dyspnea, coughing, and ascites. Angiostrongylosis and severe pulmonary arterial hypertension (PAH) were found, as well as a marked discordance between the electrical and mechanical events of the heart. Pulmonary arterial hypertension related to Angiostrongylus vasorum has rarely been reported. 相似文献