全文获取类型
收费全文 | 128篇 |
免费 | 1篇 |
专业分类
林业 | 30篇 |
农学 | 4篇 |
基础科学 | 1篇 |
46篇 | |
综合类 | 14篇 |
农作物 | 2篇 |
水产渔业 | 7篇 |
畜牧兽医 | 11篇 |
园艺 | 3篇 |
植物保护 | 11篇 |
出版年
2024年 | 1篇 |
2018年 | 1篇 |
2016年 | 1篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 8篇 |
2011年 | 13篇 |
2010年 | 7篇 |
2009年 | 4篇 |
2008年 | 10篇 |
2007年 | 5篇 |
2006年 | 8篇 |
2005年 | 15篇 |
2004年 | 12篇 |
2003年 | 11篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1993年 | 3篇 |
1985年 | 3篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有129条查询结果,搜索用时 15 毫秒
21.
22.
François Charles Jennifer Coston-Guarini Jean-Marc Guarini François Lantoine 《Journal of Wood Science》2018,64(4):427-435
Experiments were done to investigate in situ colonization of pine wood blocks by marine wood borers at the mouth of a small mountain river in the foothills of the Eastern Pyrenees. Standardized blocks were recovered after remaining underwater for increasingly long durations, until the available resource was exhausted by the shipworms assemblage that developed. Computer-aided tomography (CT) was used for visualizing and quantifying biogenic structures into the wooden blocks. The biodiversity survey of the wood pieces colonized indicated that up to three species of shipworms shared the resource at the same time. The specific wood consumption rate of Nototeredo norvagica was estimated 185 mm3 ind?1 day?1. The quantification of voids created by shipworm crowding indicated that total tunnelling represents, on average, 60% of the initial volume of a wood block, revising upward earlier estimates of wood destruction by 28%. CT analysis provides the quantitative measurements necessary to parameterize individual-based growth models linking wood consumption with the species diversity of shipworm assemblages. 相似文献
23.
Annamaria Leccese Sylvie Bureau Maryse Reich M. G. C. Catherine Renard Jean-Marc Audergon Carmelo Mennone Susanna Bartolini Raffaella Viti 《Plant foods for human nutrition (Dordrecht, Netherlands)》2010,65(2):112-120
We have investigated the effect of cultivation systems and fruit post-harvest management on the antioxidant properties of
apricot fruits. Trees of five cultivars ‘Tyrinthos’, ‘Cafona’, ‘Bella d’Italia’, ‘Vitillo’ and ‘Pellecchiella’ were cultivated
under integrated and organic systems. Fruits were collected at full maturity stage and analyzed either immediately or after
storage at 4±0.5 °C and 85% of relative humidity for seven and 14 days. The main pomological traits (weight, colour, flesh
firmness, total soluble sugars, titratable acidity) and antioxidant properties were analyzed. The total antioxidant capacity
(TAC by TEAC method), total phenols content (TP by Folin-Ciocalteu method) and carotenoid content by HPLC-DAD were monitored.
Cultivar characterization by principal component analysis (PCA) indicated a large variability on pomological and antioxidant
properties of apricot fruits. ‘Bella d’Italia’ showed better TAC and TP values compared to the other cultivars. ANOVA interactions
between cultivar and cultivation system (organic/integrated) were found for the antioxidant properties. These interactions
may help to select a set of genotypes with better performances under organic system, which in our study might be indicated
in ‘Cafona’ and ‘Bella d’Italia’. 相似文献
24.
Silversides DW Benoit JM Collard F Gilson C 《The Canadian veterinary journal. La revue veterinaire canadienne》2011,52(6):670-672
A female French bulldog was presented with an enlarged clitoris. Abdominal surgery revealed a normal uterus and gonads resembling testes. Histologically, the gonads contained seminiferous tubules. The karyotype was XX, and the SRY gene was not detected. A diagnosis of XX male, SRY negative disorder of sexual development was made. 相似文献
25.
Four Turkish provenances and five Lebanese provenances of Cedrus libani A. Rich. and one Cypriot provenance of C. brevifolia Henry were compared during the third year of growth in a controlled-climate greenhouse after exposure to a well-watered or moderate-drought treatment. Effects of treatment on CO(2) assimilation (A), stomatal conductance (g(s)), (13)C isotope composition (delta(13)C), growth and biomass were assessed. Hydraulic conductivity and shoot vulnerability to cavitation were measured in well-watered plants only. The Lebanese provenances of C. libani had the highest growth rates, but were the most sensitive to drought. The Turkish provenances of C. libani showed moderate growth rates and moderate drought sensitivity. Cedrus brevifolia had the lowest growth rate and was least sensitive to drought. For each provenance, mean biomass values were positively correlated with delta(13)C and intrinsic water-use efficiency (A/g(s)), and negatively correlated with g(s). Drought reduced growth and favored carbon storage in roots, increasing the ratio of root biomass to aboveground biomass. The drought treatment increased delta(13)C and A/g(s). Specific hydraulic conductivity (K(s)) was similar for the provenance groups, whereas leaf-specific conductivity (K(l)) was lower in the Lebanese provenances than in the other provenances. Within each provenance group, provenances with the highest K(l) were most susceptible to xylem cavitation, but were also the most productive. Growth and drought adaptation were linked with precipitation in each provenance's native range. 相似文献
26.
27.
Isolates of a soil Pseudoimonas, as well as other soil bacteria, showed a different sensitivity towards NO?2 when grown under aerobic or anaerobic conditions. The tolerance to NO?2 was increased in the presence of O2: for instance, a concentration of of NO?2-N proved to be toxic to a Pseudomonas sp. under anaerobic conditions, whereas over were needed aerobically to suppress its growth completely. The addition of NO?3 as an electron acceptor for anaerobic respiration did not overcome the inhibitive effect of NO?3. The pH range, at which NO?2 was utilized anaerobically, was narrowed with increasing NO?2 concentration (pH 6.8–8.8 at of NO?2-N and 7.4–8.5 and of NO?2-N).Tolerance to nitrite varied considerably among the bacteria tested. Each species was able to overcome the inhibitory effect of NO?2 up to a certain concentration, while the length of the lag phase was related to NO?2 concentration. 相似文献
28.
Enzyme-catalyzed copolymerization of phenols with one to five chlorines (4-chlorophenol; 2,4- and 2,6-dichlorophenol; 4-bromo-2-chlorophenol; 2,3,6- and 2,4,5-trichlorophenol; 2,3,5,6-tetrachlorophenol; and pentachlorophenol) and syringic acid was studied with an extracellular laccase of the fungus Rhizoctonia praticola. This reaction is of interest since it presents a model for explaining the incorporation of anthropogenic compounds into humic substances. When the laccase was incubated together with the halogenated phenols and syringic acid, two types of hybrid products were found: (1) phenols covalently bound to an orthoquinone product of syringic acid resulting in the formation of quinonoid oligomers, and (2) phenols covalently bound to decarboxylated products of syringic acid resulting in the formation of phenolic oligomers. Mass spectra of hybrid oligomers gave typical chlorine isotopic patterns which coincided with their respective chlorophenol monomer. It was concluded that all hybrid products contained only one halogenated phenol molecule and that no dehalogenation took place. 相似文献
29.
Inferring the effects of landscape structure on roe deer (Capreolus capreolus) movements using a step selection function 总被引:1,自引:0,他引:1
Aurélie Coulon Nicolas Morellet Michel Goulard Bruno Cargnelutti Jean-Marc Angibault A. J. Mark Hewison 《Landscape Ecology》2008,23(5):603-614
In this study, we sought to understand how landscape structure affects roe deer movements within their home-range in a heterogeneous
and fragmented agricultural system of south-western France. We analysed the movements of 20 roe deer fitted with GPS collars
which recorded their locations every 2–6 h over several months (mean = 9 months). Based on empirical observations and previous
studies of roe deer habitat use, we hypothesised that roe deer should avoid buildings and roads, move preferentially along
valley bottoms and through the more wooded areas of the landscape. To test these hypotheses we paired each observed movement
step with 10 random ones. Using conditional logistic regression, we modelled a step selection function, which represents the
probability of selecting a given step as a function of these landscape variables. The selected model indicated that movements
were influenced by all the tested landscape features, but not always in the predicted direction: our results suggested that
roe deer tend to avoid buildings, roads, valley bottoms and possibly the more wooded areas (although the latter result should
be interpreted with caution, as it may be influenced by a bias in the rate of GPS fix acquisition in woods). The distances
to buildings and to roads were the most influential variables in the model, suggesting that the avoidance of potential sources
of disturbance may be a key factor in determining ranging behaviour of roe deer in human dominated landscapes. 相似文献
30.
Marron N Villar M Dreyer E Delay D Boudouresque E Petit JM Delmotte FM Guehl JM Brignolas F 《Tree physiology》2005,25(4):425-435
To test if some leaf parameters are predictors of productivity in a range of Populus deltoides (Bartr.) Marsh. x P. nigra L. clones, we assessed leaf traits and productivity in 2-month-old rooted cuttings from 31 clones growing in 4-l pots in a greenhouse, under conditions of controlled temperature and optimal irrigation. We evaluated four groups of variables describing (1) productivity (total biomass), (2) leaf growth (total leaf number increment and total leaf area increment rate), (3) leaf structure (specific leaf area and nitrogen and carbon contents) and (4) carbon isotope discrimination (delta), which is negatively correlated with time-integrated water-use efficiency. High-yielding clones did not necessarily display high leaf growth rates, but they displayed a larger total leaf area, lower specific leaf area and lower leaf nitrogen concentration than clones with low productivity. Total leaf area was mainly controlled by maximal individual leaf area and total leaf area increment rate (r = 0.51 and 0.56, respectively). Carbon isotope discrimination did not correlate with total biomass, but it was associated with total number of leaves and total leaf area increment rate (r = 0.39 and 0.45, respectively). Therefore, leaf area and specific leaf area were better indicators of productivity than leaf growth traits. The observed independence of delta from biomass production provides opportunities for selecting poplar clones combining high productivity and high water-use efficiency. 相似文献