全文获取类型
收费全文 | 333篇 |
免费 | 6篇 |
国内免费 | 8篇 |
专业分类
林业 | 3篇 |
农学 | 6篇 |
241篇 | |
综合类 | 69篇 |
农作物 | 1篇 |
水产渔业 | 3篇 |
畜牧兽医 | 12篇 |
园艺 | 7篇 |
植物保护 | 5篇 |
出版年
2024年 | 1篇 |
2023年 | 3篇 |
2022年 | 5篇 |
2021年 | 6篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 7篇 |
2015年 | 14篇 |
2014年 | 19篇 |
2013年 | 17篇 |
2012年 | 16篇 |
2011年 | 16篇 |
2010年 | 24篇 |
2009年 | 23篇 |
2008年 | 18篇 |
2007年 | 26篇 |
2006年 | 15篇 |
2005年 | 21篇 |
2004年 | 9篇 |
2003年 | 16篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 9篇 |
1997年 | 2篇 |
1996年 | 6篇 |
1995年 | 1篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 7篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有347条查询结果,搜索用时 31 毫秒
51.
In view of the ubiquitous co-existence of methamidophos, acetochlor and copper (Cu) in agricultural soils, ecological detoxification of methamidophos in phaiozem by earthworms was examined using the detoxic incubation experiments with illumination. It was validated that the earthworm Eisenia fetida is a useful soil animal in the process of methamidophos detoxification as the assistance of soil microbes and enzymes. Due to the action of earthworms, the half life of methamidophos with concentration of 15 mg/kg in phaiozem could decrease from 5.61 days to 5.08 days. Dynamics of methamidophos detoxification by earthworms could conform to the logistic model. Under the condition of multiple pollution combined with acetochlor (20 mg/kg) and Cu (300 mg/kg), ecological detoxification of methamidophos by earthworms became complicated. Acetochlor played a promoting role in the biodegradation of methamidophos to some extent, while it was basically inhibited by Cu. 相似文献
52.
Fabien Thomas Jean-Pierre Rossi Thibaud Decaëns Michel Grimaldi Patrick Lavelle Paulo Fernando da Silva Martins Evelyne Garnier-Zarli 《European Journal of Soil Biology》2008,44(5-6):545
Soil ecosystem engineers produce biogenic structures (casts, mounds, galleries) that strongly affect soil processes. A comparative analysis of the physical characteristics of the casts produced by the earthworm Andiodrilus pachoensis was carried out in four pastures sowed with Brachiaria brizantha and four primary forests on the deforestation front of the Amazonian forest. In both systems, we recorded surface cast density and spatial patterns as well as surface cast physical properties. Cast and vegetation distributions were mapped within plots of sizes ranging from 25 to 50 m2, and cast production was monitored during 2 months. Cast spatial distribution varied greatly among plots and across spatial scales ranging from regular at small spatial scales (0–20 cm) to clumped for larger distance ranges (>80 cm). Cast density was not significantly correlated with grass tuft density and their production was independent from the presence of grass tufts in pastures or litter quantity in forests. Although bulk soil properties (pH, C content, structural stability, etc) differed between pastures and forests, cast physical properties did not differ significantly among the studied ecosystem. 相似文献
53.
J. J. Jiménez A. G. Moreno T. Decaëns P. Lavelle M. J. Fisher R. J. Thomas 《Biology and Fertility of Soils》1998,28(1):101-110
The structure and seasonal changes of earthworm communities were evaluated in a natural savanna and in a improved grass-legume
pasture in a Colombian oxisol over a period of 18 months. One plot of 90×90 m was isolated in each of the systems and each
month five samples of 1 m2×0.5 m and ten of 20×20×20 cm were randomly selected from a stratified block design. Species richness was similar in the two
evaluated plots (seven species), whereas diversity measured by the index, H (Shannon and Weaver 1949) was clearly different, i.e. H=2.89 in natural savanna and H=1.29 in pasture. This is explained by differences in earthworm community structure. The average annual density in the savanna
was 49.8, ranging from 10.8 to 135.8 individuals (ind) m–2, and biomass was 3.3 g m–2 (hand-sorting method), ranging from 0.9 to 11.5 g m–2. In the man-made pasture, density was 80.1 ind m–2 on average, ranging from 24 to 215.8 ind m–2 and biomass was more than tenfold higher, ranging from 29.2 to 110.4 g m–2. This was especially due to the presence of a large glossoscolecid anecic species, Martiodrilus carimaguensis Jiménez and Moreno, which has been greatly favoured by conversion of savanna to pasture. Endogeic species were dominant in
the natural savanna whereas the anecic species accounted for 88% of total earthworm biomass in the pasture. Total earthworm
density and biomass were significantly different in the two systems studied (t-test). The results indicate a clearly positive response of earthworm communities to improved pastures, a type of land use
that is being increasingly adopted in moist neotropical savannas.
Received: 20 October 1997 相似文献
54.
Lumbricus terrestris L. distribution within an experimental humus mosaic in a mountain spruce forest
An experiment was designed at a mountain site to study the distribution of adult Lumbricus terrestris in relation to a small-scale mosaic of humus forms representative of different stages of a spruce forest ecosystem. Good
agreement was found between distribution in the mosaic and that in the field. ANOVA tests demonstrated the strong influence
of humus form on earthworm abundance when comparing a vermimull (high earthworm burrowing activity) taken from a spruce regeneration
site (61.8 individuals m–2) with a leptomoder (no earthworm burrowing activity) taken from a 60-year-old spruce stand (6.2 individuals m–2). Other humus forms were intermediate (mean density 34.6 individuals m–2). The same pattern was found with individual biomass, but with lower significance. Main differences observed in the experimental
design were attributed to the immediate carrying density of the humus forms. A distinction was made between humus profiles
built up with or without spruce cover. In the latter case (regeneration site and bilberry heath), the immediate carrying capacity
indicated by the experimental approach overestimated the field density by a factor of 4. Under spruce this overestimate was
even higher (approximately 10 times too high in an adult spruce stand (160 years old) and 30 times too high under moss cover).
The increase in density due to experimental conditions was not determined for leptomoder humus accumulated under the actively
growing spruce stand (60 years old) since the earthworm density was near zero in both cases. Relationships between humus form
and earthworm populations are discussed.
Received: 9 June 1997 相似文献
55.
蚯蚓及其在环境保护上的应用 I.蚯蚓及其在自然生态系统中的作用 总被引:3,自引:0,他引:3
邱江平 《上海交通大学学报(农业科学版)》1999,(3)
蚯蚓是土壤中的主要动物类群,在陆地生态系统中具有重要的功能。蚯蚓促进植物残枝落叶的降解,有机物质的分解和矿化这一复杂的过程,并具有混合土壤、改善土壤结构、提高土壤透气、排水和深层持水能力的作用。它们的这些作用与其生物量和三种生态类型( 表层种、内层种和深层种) 密切相关。 相似文献
56.
以鲜活饵料双齿围沙蚕(Perinereis aibuhitensis)、赤子爱胜蚓(Eisenia foetida)和人工配合饵料投喂凡纳滨对虾(Litopenaeus vannamei),并测定各种饵料对其生长和免疫指标的影响。结果表明,沙蚕和蚯蚓单独投喂或与人工配合饵料配合投喂都可显著提高凡纳滨对虾的生长速率,但用沙蚕单独投喂的对虾成活率较低。蚯蚓与人工配合饵料配合投喂可显著提高对虾血清中抗菌活力、溶菌活力、酚氧化酶活力和血细胞数量;蚯蚓单独投喂可显著提高血清中抗菌活力、酚氧化酶活力和血细胞数量,对血清中溶菌活力作用不明显。沙蚕与人工配合饵料配合投喂可显著提高对虾血清中抗菌和溶菌活力.但对血清中酚氧化酶活力和血细胞数量变化作用不明显;单独投喂沙蚕对所测各项免疫指标影响均不显著。研究结果证实:利用蚯蚓和沙蚕可显著提高对虾的生长速率,但蚯蚓的饵料效果优于沙蚕。[中国水产科学,2006,13(4):561—565] 相似文献
57.
Bing XIA Dan HUANG Mao YE Hao QIU Hongfeng CHEN Keqiang ZHAO Rongliang QIU Rongrong YING 《土壤圈》2023,(6):927-937
The biosurfactants rhamnolipids and the “soil ecosystem engineers” earthworms are often used to remediate contaminated soils. However, the effects of rhamnolipids on earthworm intestinal flora and microbial community in soil containing earthworms are not clearly understood. In our study, a 21-d microcosm experiment was carried out to reveal the effects of rhamnolipids on microbial abundance, composition, and metabolism, as well as contaminant degradation capacity. Both rhamnolipids and earthworm... 相似文献
58.
Summary The axial forces generated by the earthworm Aporrectodea rosea were measured by directing the earthworm to tunnel into soil discs mounted on an electronic balance connected to a datalogger. The area over which the force acted was estimated from the size of the hole created by the tunnelling. The maximum force recorded by an individual worm was 0.760 N and the mean maximum value was 0.465 N. The maximum pressures recorded was 116.5 kPa, while the mean maximum pressure was 72.8 kPa. These axial pressures are approximately one-tenth of the maximum axial pressure recorded for plant roots. The statistical distribution of activity as the worms tunnelled through the soil discs was analysed. Pressures recorded were well in excess of physiologically measured pressures and the generation of forces within muscles to achieve these pressures was calculated by some assumptions. It was estimated that there is a maximum tension in the circular muscles of 0.15 N per segment of the worm. 相似文献
59.
60.