全文获取类型
收费全文 | 135篇 |
免费 | 8篇 |
专业分类
林业 | 14篇 |
农学 | 6篇 |
51篇 | |
综合类 | 10篇 |
农作物 | 15篇 |
水产渔业 | 4篇 |
畜牧兽医 | 16篇 |
园艺 | 1篇 |
植物保护 | 26篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2021年 | 10篇 |
2020年 | 3篇 |
2019年 | 6篇 |
2018年 | 11篇 |
2017年 | 7篇 |
2016年 | 7篇 |
2015年 | 5篇 |
2014年 | 3篇 |
2013年 | 8篇 |
2012年 | 15篇 |
2011年 | 8篇 |
2010年 | 6篇 |
2009年 | 5篇 |
2008年 | 7篇 |
2007年 | 5篇 |
2006年 | 7篇 |
2005年 | 5篇 |
2004年 | 6篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有143条查询结果,搜索用时 140 毫秒
1.
2.
N. A. Savelyeva E. E. Belova N. E. Pervova A. A. Kolontsov 《Moscow University Soil Science Bulletin》2013,68(4):192-194
The effect of lead and cadmium ions on the fluctuating asymmetry of the side leaflets’ central veins of the common bean (Phaseolus vulgaris L.) was estimated. The impact of heavy metals on the parameter with the lead or cadmium content in the ground in the concentration of 650 mg/kg or 10 mg/kg respectively was not revealed. 相似文献
3.
Emamectin is a macrocyclic lactone insecticide with low toxicity to non-target organisms and the environment, and is considered an important component in pest-management programmes for controlling field crop pests. It is a powerful compound for controlling the cotton bollworm Helicoverpa armigera (Hübner). A spray concentration of 25 mg AI litre-1 in a cotton field resulted in over 90% suppression of H armigera larvae up to day 28 after treatment, while similar mortality of the Egyptian cotton leafworm Spodoptera littoralis Boisduval, under the same conditions, was maintained for 3 days only. Emamectin is a potent compound for controlling the western flower thrips Frankliniella occidentalis (Pergande) under both laboratory and field conditions and its activity on adults was over 10-fold greater than that of abamectin. Spray concentrations of 10 and 50 mg AI litre-1 in Ageratum houstonianum Mill flowers resulted in total suppression of adults up to day 11 and of larvae up to day 20 after treatment. Under standard laboratory conditions, emamectin exhibits a considerable activity on the whitefly Bemisia tabaci (Gennadius) and the leafminer Liriomyza huidobrensis (Blanchard). Further studies are required to evaluate its potential activity on the latter pests under field conditions. 相似文献
4.
5.
6.
Pyriproxyfen is a biorational insecticide that acts as a juvenile hormone (JH) analogue and disrupts insect development with an unknown molecular mode of action. Pyriproxyfen is one of the major insecticides used to control the whitefly Bemisia tabaci (Gennadius) and comply with integrated pest management (IPM) programmes, resulting in minimal effects on the environment, humans and beneficial organisms. During the last few years, resistance to pyriproxyfen has been observed in several locations in Israel, sometimes reaching a thousandfold or more. No information exists about the molecular basis underlying this resistance that may lead to understanding the mode of action of pyriproxyfen and developing molecular markers for rapid monitoring of resistance outbreaks. In this communication, a cDNA microarray from B. tabaci was used to monitor changes in gene expression in a resistant B. tabaci population. Based on statistical analysis, 111 expressed sequence tags (ESTs) were identified that were differentially upregulated in the resistant strain after pyriproxyfen treatment. Many of the upregulated ESTs observed in the present study belong to families usually associated with resistance and xenobiotic detoxification such as mitochondrial genes, P450s and oxidative stress, genes associated with protein, lipid and carbohydrate metabolism and others related to JH-associated processes in insects such as oocyte and egg development. 相似文献
7.
Gediminas Brazaitis Kęstutis Pėtelis Remigijus Žalkauskas Olgirda Belova Darius Danusevičius Vitas Marozas Gintarė Narauskaitė 《European Journal of Forest Research》2014,133(5):857-869
We analyse the relationships between the main Cervidae [moose (Alces alces), red deer (Cervus elaphus) and roe deer (Capreolus capreolus)] species and a complex of environmental factors in an extensive fragmented landscape of Central Lithuania. The highest determining positive influence on moose density was the proportions of wet forest sites. In forest complexes with fewer proportions of wet sites, the most important factor was the total forest area. The proportion of shrub cover, upland and dense undergrowth area, and road density also has significant effect on moose density. The total area of forest complexes has the highest determining positive influence on red deer density. The highest density of red deer was calculated in large forest complexes (>2,745 ha) with a <17.6 % proportion of pine and <36.5 % of deciduous forests. Other significant factors were core area, road density and urbanization level. Forest edge density has the highest influence on the roe deer populations. The highest density of roe deer was recorded on forest areas with >51 m ha?1 of edges in wet forest (>25.4 %) dominating areas. The proportion of deciduous, coniferous mixed and pine forest, also shrub and density of edges also had significant effect. 相似文献
8.
Zavarzina A. G. Demin V. V. Belova O. V. Leontievsky A. A. Lisov A. V. 《Eurasian Soil Science》2022,55(7):911-925
Eurasian Soil Science - Humic substances (HS) are heterogeneous and polydisperse compounds formed in soils, sediments and waters during the decay and transformation of organic residues (the process... 相似文献
9.
N. A. Saveljeva E. E. Belova D. A. Korotchenkov O. S. Mishina A. A. Kolontsov 《Russian Agricultural Sciences》2014,40(4):242-243
The treatment of buckwheat with biostimulants Floravit E and Atonic Plus in dilutions 10?2–10?3 and 3 × 10?2, accordingly, had no effect on the stability and development of plants, as one can judge by the fluctuating asymmetry of metrical and meristic traits. Treatment with Atonic Plus led to a reduction of fluctuating asymmetry when control plants had a high value of asymmetry. Floravit E in the dilution 10?1 caused an increase of fluctuating asymmetry of half leaf width. The same effect was observed when growing buck-wheat in a lead-contaminated soil. 相似文献
10.
The semiconducting properties of a wide range of minerals are often ignored in the study of their interfacial geochemical behavior. We show that surface-specific charge density accumulation reactions combined with bulk charge carrier diffusivity create conditions under which interfacial electron transfer reactions at one surface couple with those at another via current flow through the crystal bulk. Specifically, we observed that a chemically induced surface potential gradient across hematite (alpha-Fe2O3) crystals is sufficiently high and the bulk electrical resistivity sufficiently low that dissolution of edge surfaces is linked to simultaneous growth of the crystallographically distinct (001) basal plane. The apparent importance of bulk crystal conduction is likely to be generalizable to a host of naturally abundant semiconducting minerals playing varied key roles in soils, sediments, and the atmosphere. 相似文献