全文获取类型
收费全文 | 279篇 |
免费 | 23篇 |
专业分类
林业 | 41篇 |
农学 | 3篇 |
基础科学 | 3篇 |
60篇 | |
综合类 | 17篇 |
农作物 | 10篇 |
水产渔业 | 42篇 |
畜牧兽医 | 108篇 |
园艺 | 9篇 |
植物保护 | 9篇 |
出版年
2023年 | 5篇 |
2022年 | 1篇 |
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 6篇 |
2018年 | 7篇 |
2017年 | 9篇 |
2016年 | 14篇 |
2015年 | 14篇 |
2014年 | 11篇 |
2013年 | 16篇 |
2012年 | 23篇 |
2011年 | 25篇 |
2010年 | 9篇 |
2009年 | 22篇 |
2008年 | 18篇 |
2007年 | 15篇 |
2006年 | 10篇 |
2005年 | 11篇 |
2004年 | 6篇 |
2003年 | 10篇 |
2002年 | 1篇 |
2001年 | 2篇 |
1999年 | 6篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 2篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1932年 | 4篇 |
1931年 | 1篇 |
1930年 | 1篇 |
1928年 | 1篇 |
1925年 | 1篇 |
排序方式: 共有302条查询结果,搜索用时 31 毫秒
101.
Nguyen Thi Ngoc Anh Mathieu Wille Nguyen Van Hoa Patrick Sorgeloos 《Journal Of Applied Aquaculture》2013,25(3):256-270
Supplementation of microalgae and Artemia nauplii with practical formulated feeds containing fresh or dried Artemia biomass for larval rearing of black tiger shrimp, Penaeus monodon, was assessed. Five feeding treatments were carried out in a recirculating seawater system with fifteen 30-L fiberglass tanks. Shrimp nauplii were stocked at a density of 150 L?1 for 23 days. In the control treatment, live feed was supplemented with commercial formulated feed (Inve Aquaculture NV, Belgium). In two other treatments, live feed was supplemented with a pelleted feed based on either fresh or dried Artemia. In the remaining two treatments live feed was supplemented with a combination of 50% commercial feed and 50% fresh or dried Artemia feeds. Overall, performance of PL in the combination treatments (commercial feed and Artemia diets) were equal to or better than those fed commercial feed alone as seen by the better growth rate and higher resistance to formalin stress. The results indicate that feed containing fresh or dried Artemia biomass can partially supplement live feeds for larval rearing of P. monodon. 相似文献
102.
Using summed individual species models and state-of-the-art modelling techniques to identify threatened plant species hotspots 总被引:1,自引:0,他引:1
Miia Parviainen Mathieu Marmion Miska Luoto Wilfried Thuiller Risto K. Heikkinen 《Biological conservation》2009,142(11):2501-2509
Reliable identification of hotspot areas with high numbers of threatened plant species has a central role in conservation planning. We investigated the potentiality of identifying the distribution, richness and hotspots of threatened plant species at a 25 ha resolution using eight state-of-the-art modelling techniques (GLM, GAM, MARS, ANN, CTA, GBM, MDA and RF) in a taiga landscape in north-eastern Finland. First, the individual species models developed based on occurrence records of 28 species in the 1677 grid squares and derived from different statistical techniques were extrapolated to the whole study area of 41 750 km2. Second, the projected presence/absence maps were then combined to create species richness maps, and the top 5% of grid cells ranked by species richness were classified as hotspots. Finally, we created an overall summary map by combining the individual hotspot maps from all eight modelling techniques and identified areas where the individual hotspots maps overlapped most. There were distinguishing differences in projections of the geographic patterns of species richness and hotspots between the modelling techniques. Most of the modelling techniques predicted several hotspot locations sporadically around the study area. However, the overall summary map showed the highest predictive performance based on Kappa statistics, indicating that the locations where the hotspot maps from the eight models coincided most harboured highest observed species richness. Moreover, the summary map filtered out the patchy structures of individual hotspot maps. The results show that the choice of modelling technique may affect the accuracy and prediction of hotspot patterns. Such differences may hamper the development of useful biodiversity model applications for conservation planning, and thus it is beneficial if the conservation decision-making can be based on sets of alternative maps and overlaying of predictions from multiple models. 相似文献
103.
Kam-Rigne Laossi Diana Cristina Noguera Jérôme Mathieu Sébastien Barot 《Soil biology & biochemistry》2009,41(8):1668-1673
Competition between plants for essential resources determines the distribution of biomasses between species as well as the composition of plant communities through effects on species reproductive potentials. Soil organisms influence plant competitive ability and access to resources; thus they should modify plant community composition. The effects of an endogeic (Aporrectodea caliginosa) and an anecic (Lumbricus terrestris) earthworm species on the competition between grass (Poa annua), two forbs (Veronica persica and Cerastium glomeratum) and legume (Trifolium dubium) were investigated in a greenhouse experiment. We established two types of plant communities: monocultures and polycultures of the four species. L. terrestris increased the biomass of P. annua and V. persica (in monocultures as well as in polycultures). However, the presence of L. terrestris allowed the grass to produce the highest biomass in polycultures suggesting that this earthworm species promoted the growth of P. annua against the other plant species. In monocultures as well as in polycultures, the presence of L. terrestris to increased the number of seeds of T. dubium and the total seed mass of V. persica. These results suggest that L. terrestris enhanced the short term competitive ability of P. annua by promoting its growth. The increased number of seeds of T. dubium in the presence of L. terrestris suggests that this earthworm species could enhance the long-term competitive ability of this legume and may increase its number of individuals after several generations. 相似文献
104.
Mathieu M Motte S Ray L Pensis A Jespers P Brimioulle S Laroute V Naeije R Mc Entee K 《American journal of veterinary research》2006,67(7):1236-1243
OBJECTIVE: To investigate the effects of preventive angiotensin converting enzyme inhibitor treatment with ramipril in dogs with progressively severe experimentally induced heart failure. ANIMALS: 20 dogs. PROCEDURES: Dogs were randomly allocated to receive no treatment (control) or ramipril (0.125 mg/kg, PO, daily) for 7 weeks. Physical examination, repetitive catheterization of the right side of the heart, and echocardiography were performed before the study (day 0) and weekly for 7 weeks. Renal plasma flow (RPF) as determined by para-aminohippuric acid clearance and glomerular filtration rate (GFR) as determined by creatinine and iohexol clearances were measured on day 0 and at weeks 4 and 7. RESULTS: Overpacing induced a progressive increase in right atrial pressure (RAP) and pulmonary artery pressure, occluded (PAPO), with a decrease in systemic arterial pressure. There were progressive alterations of echocardiographic indices of diastolic and systolic ventricular function. The RPF and GFR decreased before cardiac output decreased, and filtration fraction increased. The logarithm of the urinary sodium-to-potassium concentration ratio (log(10)[Na(+)/K(+)]) decreased. Significant effects of ramipril included a delay in clinical signs of heart failure, a late decrease in RAP and PAPO, and increases in the sodium excretion fraction and log(10)(Na(+)/K(+)). There was a satisfactory agreement between the creatinine and iohexol clearance measurements. Conclusions AND CLINICAL RELEVANCE: Results suggest that, in this rapid-evolving, dilated cardiomyopathy, activation of the renin-angiotensin system contributes to the pathophysiology of heart failure late in the disease and essentially by an activation of renal salt and water retention. 相似文献
105.
Samer Alasaad Joerns Fickel Luca Rossi Mathieu Sarasa Buenaventura Ben?-tez-Camacho José E Granados Ramón C Soriguer 《Acta veterinaria Scandinavica》2012,54(1):56
Background
Hybridization between closely related wild and domestic species is of great concern because it can alter the evolutionary integrity of the affected populations. The high allelic variability of Major Histocompatibility Complex (MHC) loci usually excludes them from being used in studies to detect hybridization events. However, if a) the parental species don’t share alleles, and b) one of the parental species possesses an exceptionally low number of alleles (to facilitate analysis), then even MHC loci have the potential to detect hybrids.Results
By genotyping the exon2 of the MHC class II DRB1 locus, we were able to detect hybridization between domestic goats (Capra hircus) and free-ranging Iberian ibex (Capra pyrenaica hispanica) by molecular means.Conclusions
This is the first documentation of a Capra pyrenaica × Capra hircus hybridization, which presented us the opportunity to test the applicability of MHC loci as new, simple, cost-effective, and time-saving approach to detect hybridization between wild species and their domesticated relatives, thus adding value to MHC genes role in animal conservation and management. 相似文献106.
Geneviève Lejeune Chhun-Huor Ung Mathieu Fortin Xiao Jing Guo Marie-Claude Lambert Jean-Claude Ruel 《European Journal of Forest Research》2009,128(5):505-513
We simplified Kozak’s taper model by setting the inflection point at 1.3 m (dbh) without losing accuracy and precision. The
simplification was required to facilitate the estimation of the covariance parameters when using a mixed-effects method. This
method was necessary to take into account the correlation among multiple diameter measurements on an individual stem. The
simple stem taper model was fitted to an extended data set collected across the province of Quebec, Canada. Comparison of
the predicted stem taper and the derived stem volume with those obtained using existing models showed a comparable predictive
power for the simple model. Including a prediction of the tree random effects based on supplementary diameter measurements
of the bole improves the predictive ability of the model around the extra diameter observation. This model offers welcome
simplicity as a means of predicting tree taper at coarse resolution for planning tree harvesting. 相似文献
107.
Mathieu Fortin Steve Bédard Josianne DeBlois Sébastien Meunier 《Annals of Forest Science》2008,65(2):205-205
This study proposes a generalized linear mixed model to predict individual tree mortality in northern hardwood stands under uneven-aged management. The model is based on a complementary log-log (CLL) link function, and was calibrated using permanent-plot data. Tree vigor, stem product, diameter at breast height and stand basal area were tested as explanatory variables. A plot and an interval random effect were specified to account for spatial correlations. When compared with the traditional logit link function, the CLL facilitates the inclusion of the time factor. In this case study, there was an important variability of mortality predictions between the plots and the intervals for a given plot. The interval random effect is thought to be associated with catastrophic mortality. Since both tree vigor and stem product proved to be significant mortality predictors, we recommend that these variables be evaluated to increase the accuracy of mortality models. 相似文献
108.
Véronique Chable Mathieu Conseil Estelle Serpolay François Le Lagadec 《Euphytica》2008,164(2):521-529
Plant breeding for organic agriculture (OA) was stimulated when it came under the European Organic Agriculture Regulation
(2092/91) in 2004. In Brittany, the need for specific varieties for organic farming arose early for the Brassica species because of the unsuitability of most of the modern varieties to the principles of OA. Moreover, the private sector
of plant breeding finds it economically difficult to satisfy the demands of OA. The aim of the present study is to provide
varieties and seed for organic farmers for two vegetable Brassica crops, and to show how genetic resources can contribute to this purpose in the framework of a Participatory Plant Breeding
(PPB) programme. The emergence of PPB in Brittany is the result of several concomitant and favourable circumstances: the will
of the professionals (represented by IBB, Inter Bio Bretagne), their organization (an experimental station, the PAIS, Plateforme
Agrobiologique d’IBB à Suscinio), the research initiative in INRA and the availability of genetic resources. From genetic
resource observations, our experience showed several breeding situations: reviving a traditional activity (Roscoff cauliflower
and local cabbages), extending tradition (autumn cauliflower), diversifying production by new introductions (coloured cauliflowers),
and creating new forms of population varieties (broccoli and coloured cauliflowers). Farmers have taken charge of population
breeding by mass selection and the PAIS, with INRA scientific support, has taken up innovative selection and the improvement
of varieties completing the farmers’ initiatives. The PAIS remained the central point for information and for providing the
seed for trials. Seed production will be managed in a collective way. Until now, the exchange of seed remained an experimental
dimension of PPB. French seed legislation represents a limitation on the development of seed exchange by PPB. 相似文献
109.
V. Brault C. Lévy-Leduc A. Mathieu A. Jullien 《Journal of Agricultural, Biological & Environmental Statistics》2018,23(3):374-389
In this paper, we address the change-point estimation issue in multivariate observations which consist in functions having piecewise constant first derivatives corrupted by some additional noise. We propose to solve this problem by rewriting it as a variable selection issue in a sparse multivariate linear model. Moreover, the methodology that we propose takes into account the dependence that may exist within the multivariate observations. Then, the performance of our approach is assessed through some numerical experiments and compared to other alternative and classical methods. Finally, we apply our methodology to experimental data in order to study the vegetative development of oilseed rape. The evolution of the number of leaves of oilseed rape can be modeled as a function having piecewise constant first derivatives corrupted by some additional noise where the change-points correspond to key times in the plant phenology. Our novel estimation method increases the accuracy of the change-point estimation in comparison with classical approaches. Moreover, we show that the parameters of the covariance matrix depend on the level of competition between plants. Supplementary materials accompanying this paper appear online. 相似文献