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
121.
The analysis of shellfish extracts for the determination of paralytic shellfish poisoning (PSP) toxins by liquid chromatography with fluorescence detection repeatedly showed the presence of a compound suspected to interfere with gonyautoxin 4. The first aim of this study was to confirm by liquid chromatography coupled to tandem mass spectrometry that this compound was not gonyautoxin 4. The second part of this work was to improve a nonvolumetric C(18) solid-phase extraction (SPE) procedure to evaluate the removal of the interference associated with the recovery of PSP toxins. The cleanup procedure was modified into a volumetric SPE procedure and proved to efficiently and totally remove the interference while recovering from 78 to 85% of the PSP toxins available as commercial standards (saxitoxin, neosaxitoxin, gonyautoxins 1-4) and considered as major PSP toxins in human intoxication, with 85% recovery for gonyautoxin 4. The efficiency of this cleanup procedure was checked on shellfish extracts containing this interference and originating from France and Turkey. 相似文献
122.
Habitat remnants on urban green-space areas (i.e. parks, gardens and golf courses) sometimes provide refuge to urban-avoiding wildlife, leading some to suggest these areas may play a role in wildlife conservation if they are appropriately designed and managed. The high densities observed on some green-space areas may however be attributed to external influences. Localised efforts to enhance the habitat value of urban green-space areas may therefore have little more than a cosmetic effect. This study investigated environmental factors influencing bird, reptile, mammal and amphibian diversity on Australian golf courses to assess the efficacy of small-scale conservation efforts. Abundance and species richness did not simply reflect local habitat qualities but were instead, partly determined by the nature of the surrounding landscape (i.e. the area of adjacent built land, native vegetation and the number of connecting streams). Vertebrate abundance and species richness were however, also associated with on-site habitat characteristics, increasing with the area of native vegetation (all vertebrates), foliage height diversity and native grass cover (birds), tree density, native grass cover and the number of hollows (mammals), woody debris, patch width and canopy cover (reptiles), waterbody heterogeneity and aquatic vegetation complexity (frogs). Localised conservation efforts on small land types can benefit urban-avoiding wildlife. Urban green-space areas can provide refuge to urban-avoiding vertebrates provided combined efforts are made at patch (management), local (design) and landscape (planning) scales. 相似文献
123.
Liger-Belair G Prost E Parmentier M Jeandet P Nuzillard JM 《Journal of agricultural and food chemistry》2003,51(26):7560-7563
In this paper, the NMR technique was used, for the first time, to accurately determine the diffusion coefficient D of CO(2)-dissolved molecules in various carbonated beverages, including champagne and sparkling wines. This parameter plays an important role concerning the bubble growth during its rise through the liquid (see ref 3). The diffusion coefficient of CO(2)-dissolved molecules D was compared with that deduced from the well-known Stokes-Einstein equation and found to significantly deviate from the general trend expected from Stokes-Einstein theory, i.e, D(SE) proportional, variant 1/eta, where D(SE) is the Stokes-Einstein diffusion coefficient and eta the viscosity of the liquid medium. 相似文献
124.
The effects of management practices on energy, water and carbon exchanges were investigated in a young pine plantation in south-west France. In 2009-10, carbon dioxide (CO(2)), H(2)O and heat fluxes were monitored using the eddy covariance and sap flow techniques in a control plot (C) with a developed gorse layer, and an adjacent plot that was mechanically weeded and thinned (W). Despite large differences in the total leaf area index and canopy structure, the annual net radiation absorbed was only 4% lower in plot W. We showed that higher albedo in this plot was offset by lower emitted long-wave radiation. Annual evapotranspiration (ET) from plot W was 15% lower, due to lower rainfall interception and transpiration by the tree canopy, partly counterbalanced by the larger evaporation from both soil and regrowing weedy vegetation. The drainage belowground from plot W was larger by 113 mm annually. The seasonal variability of ET was driven by the dynamics of the soil and weed layers, which was more severely affected by drought in plot C. Conversely, the temporal changes in pine transpiration and stem diameter growth were synchronous between sites despite higher soil water content in the weeded plot. At the annual scale, both plots were carbon sinks, but thinning and weeding reduced the carbon uptake by 73%: annual carbon uptake was 243 and 65 g C m(-2) on plots C and W, respectively. Summer drought dramatically impacted the net ecosystem exchange: plot C became a carbon source as the gross primary production (GPP) severely decreased. However, plot W remained a carbon sink during drought, as a result of decreases in both GPP and ecosystem respiration (R(E)). In winter, both plots were carbon sources, plots C and W emitting 67.5 and 32.4 g C m(-2), respectively. Overall, this study highlighted the significant contribution of the gorse layer to mass and energy exchange in young pine plantations. 相似文献
125.
Shiming Liu Danny J. Llewellyn Warwick N. Stiller John Jacobs Jean-Marc Lacape Greg A. Constable 《Euphytica》2011,178(3):309-320
Exploiting genetic variation through inter-specific breeding has improved cotton yield, fibre properties and adaptability.
The objectives of this study were to examine heritability and predicted selection response of yield components and fibre properties
in a recombinant inbred line (RIL) population from an inter-specific cross between Gossypium hirsutum (Gh) variety Guazuncho 2, and G. barbadense (Gb) line VH8-4602. A population of 93 and 82 RILs was tested in two seasons, with two parents and local controls, Sicot
75 (Gh) and Sipima 280 (Gb) in field experiments. Seed cotton samples hand harvested before and after defoliation were used
to measure lint percent, boll weight, 100 seed weight and the lint to measure fibre length, uniformity, short fibre index
(SFI), elongation, strength, micronaire, maturity ratio (MR), percent of maturity (PM) and fineness. There was large phenotypic
variation for individual traits and transgressive segregation occurred in lint percent, lint weight/seed, fibre no./seed,
uniformity, SFI, elongation, MR and PM. Narrow sense heritabilities were moderate for yield components (34.3–41.2%) and for
key fibre properties, length, strength, micronaire and fineness (38.3–42.1%), which led to a predicted selection response
of 6.7–24.0% for yield components and 3.9–10.9% for key fibre properties under a selection intensity of 10%. Favourable associations
were found between key fibre properties, but an adverse association between lint percent and each of these fibre properties.
Only five RILs were identified with desirable combinations. The results demonstrated the value of exploiting inter-specific
variation to develop cotton germplasm and how breeding strategies can be improved. 相似文献
126.
Andries K Verhasselt P Guillemont J Göhlmann HW Neefs JM Winkler H Van Gestel J Timmerman P Zhu M Lee E Williams P de Chaffoy D Huitric E Hoffner S Cambau E Truffot-Pernot C Lounis N Jarlier V 《Science (New York, N.Y.)》2005,307(5707):223-227
The incidence of tuberculosis has been increasing substantially on a worldwide basis over the past decade, but no tuberculosis-specific drugs have been discovered in 40 years. We identified a diarylquinoline, R207910, that potently inhibits both drug-sensitive and drug-resistant Mycobacterium tuberculosis in vitro (minimum inhibitory concentration 0.06 mug/ml). In mice, R207910 exceeded the bactericidal activities of isoniazid and rifampin by at least 1 log unit. Substitution of drugs included in the World Health Organization's first-line tuberculosis treatment regimen (rifampin, isoniazid, and pyrazinamide) with R207910 accelerated bactericidal activity, leading to complete culture conversion after 2 months of treatment in some combinations. A single dose of R207910 inhibited mycobacterial growth for 1 week. Plasma levels associated with efficacy in mice were well tolerated in healthy human volunteers. Mutants selected in vitro suggest that the drug targets the proton pump of adenosine triphosphate (ATP) synthase. 相似文献
127.
Janke C Rogowski K Wloga D Regnard C Kajava AV Strub JM Temurak N van Dijk J Boucher D van Dorsselaer A Suryavanshi S Gaertig J Eddé B 《Science (New York, N.Y.)》2005,308(5729):1758-1762
Polyglutamylation of tubulin has been implicated in several functions of microtubules, but the identification of the responsible enzyme(s) has been challenging. We found that the neuronal tubulin polyglutamylase is a protein complex containing a tubulin tyrosine ligase-like (TTLL) protein, TTLL1. TTLL1 is a member of a large family of proteins with a TTL homology domain, whose members could catalyze ligations of diverse amino acids to tubulins or other substrates. In the model protist Tetrahymena thermophila, two conserved types of polyglutamylases were characterized that differ in substrate preference and subcellular localization. 相似文献
128.
Gancel AL Grimplet J Sauvage FX Ollitrault P Brillouet JM 《Journal of agricultural and food chemistry》2006,54(17):6212-6218
Fusion of citrus diploid parental protoplasts generates allotetraploid hybrids which do not retain their parental traits with regard to leaf aroma compound biosynthesis. The aim of this study was thus to examine hybrid leaf proteomes in comparison with their parents. Leaf soluble proteins from two citrus allotetraploid hybrids (mandarin + lime and mandarin + kumquat) and their diploid parents (mandarin, lime, and kumquat) were submitted to 2-D gel electrophoresis. Leaf proteome maps of the tetraploid hybrids were compared with those of their parents on the basis of the presence/absence of spots and of their spot relative volumes. The two allotetraploid hybrid maps were found closer to that of their mandarin parent than to those of their nonmandarin parents in terms of the presence/absence of spots as well as at a quantitative level. This approach has to be related to the already observed dominance of mandarin in allotetraploids with regard to volatile compound biosynthesis in leaves. 相似文献
129.
Bolduc MP Bazinet L Lessard J Chapuzet JM Vuillemard JC 《Journal of agricultural and food chemistry》2006,54(13):4651-4657
Several modifications that occur in milk during its processing and storage are driven by different oxidation-reduction reactions. In this study, a smooth electrolytic process was used to modify the redox state of the active species of milk thereby creating a mean to control these reactions. Five electroreduction treatments (2, 4, 6, 8, and 10 V) were applied to pasteurized skim milk. Parameters such as redox potential, dissolved oxygen, pH, conductivity, and current intensity were monitored during the course of each treatment. The proposed technology allows modulation of the redox potential of milk. Significant decreases of redox potential (441-707 mV) and of dissolved oxygen (3.3-8.3 mg L(-1)) were obtained. However, the results suggest that only a short-term modulation is created and that natural "milk equilibrium" is reestablished after 4-5 days of storage depending on the voltage difference applied during the electrochemical treatment. 相似文献