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101.
102.
While riparian vegetation can play a major role in protecting land, water and natural habitat in catchments, there are high
costs associated with tree planting and establishment and in diverting land from cropping. The distribution of costs and benefits
of riparian revegetation creates conflicts in the objectives of various stakeholder groups, and elicitation of importance
weights of objectives and determination of rankings of a number of policy options by these stakeholder groups becomes critical
in decision-making. The analytic hierarchy process (AHP) is a multicriteria analysis technique that provides an appropriate
tool to accommodate the conflicting views of various stakeholder groups. The AHP allows the users to assess the relative importance
of multiple criteria (or multiple alternatives against a given criterion) in an intuitive manner. This paper presents an application
of AHP to obtain preference weights of environmental, social and economic objectives which have been used in ranking riparian
revegetation policy options in a small catchment (watershed) in north Queensland, Australia. The preference weights towards
environmental, economic and social objectives have been obtained for the various stakeholder groups (landholders, representatives
of local sugar mill staff, environmentalists, recreational fishers and the local community). The AHP technique has proved
useful in eliciting objectives and ranking policy options as well as in checking for consistency of the statements of stakeholder
groups. Implementation of this approach requires a complex data elicitation process. 相似文献
103.
Paul Joseph Dimitri Bakirtzis Audrey Vieille 《Wood material science & engineering》2015,10(1):130-144
AbstractSaving lives and properties are of primary importance in fire disasters. Unfortunately, current fire detectors are not fast enough to allow the detection of many fires, especially, at the smouldering stages. Some preliminary studies on laevoglucosan (LG), as an important product from cellulose degradation, have shown interesting properties and could be detected by devices classified as “electronic noses” (e-noses). In the present work, the mechanisms of pyrolysis of some ligno-cellulosic materials were investigated using thermo-gravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy and by a tube furnace with a view to determining the major degradation products from wood, white paper and cardboard samples. Additionally, an odour sensor, made of tin oxide semiconductor thin film, was employed to evaluate its sensitivity in detecting LG. It was found that LG can be readily found among the thermal degradation products of cellulosic materials in question, and that the metal oxide sensor employed was sufficiently sensitive in detecting its presence. Therefore, the work opens up the potential of using such a sensor as an “e-nose” for the early detection of fires stemming from forest product fire loads in storage places and in other enclosures. 相似文献
104.
Martina M. Backes 《Agroforestry Systems》2001,50(2):119-132
In order to precisely assess the role of agroforestry for the conservation of (agro-)biological diversity there is a need
to adjust sampling methods used in plant sociology. This study is on the contribution of agroforestry land use to the in-situ conservation of indigenous trees within a typical East-African smallholder farming system in Western Kenya. A modified approach
to measuring species richness and abundance is presented. The selection of tree-rich structures was done according to management
patterns rather than considering syntaxonomic classifications from the vegetation science point of view. This approach, which
is better suited to the strongly human-influenced vegetation of agroecosystems, employs between-management unit diversity
measures to help evaluate abundance and constancy of species in particular management units.
The predominant off-farm vegetation patterns are riverine forests, rocky hillsides, hedgerows, wooded grassland relicts, woodlands or colline forest
relicts and tree groves whereas the noticeable tree-rich on-farm management units are homegardens, homesteads, life fences, coffee- and banana-groves and annual cropping fields. 98% out
of all indigenous tree species known from Bungoma, occur in off-farm lands. 53% of the indigenous tree species occur in tree rich on-farm management units while 47% of the indigenous trees are dependent on the maintenance of off-farm lands. Hedgerows embody the most promising secondary vegetation structure that shows ample potential to accommodate a wide
range of indigenous perennial species outside the natural vegetation formations. The pattern of distribution of various vegetation
structures, and the mixture with diverse tree-based on-farm plots are interesting features in regard to floristic and eco-diversity on a landscape level. In this respect, three areas
that show different population densities and distinct agro-historical conditions were compared. In regions of particular high
population density the degree of association of various functional land use forms and woodland structures – each characterised
by its own floristic make-up – is comparatively high. In contrast, in regions with less population but that were settled at
a later date, one encounters fewer stands of woody plants with lower numbers of species.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
105.
R. Lal 《Agroforestry Systems》1989,8(2):97-111
Field runoff plots, 70 x 10 m each, were established on a tropical Alifisol in southwestern Nigeria to monitor water runoff,
soil erosion and nutrient loss in water runoff. The non-agroforestry control treatment (A) was established at two levels:
plow-till and no-till systems of seedbed preparation. There were two agroforestry systems based on contour hedgerows of (B)
Leucaena leucocephala and (C) Gliricidia sepium established at 4-m and 2-m spacings. Field plots were established in 1982 and hydrological measurements were made for uniform
maize-cowpea rotation for 12 consecutive growing seasons from 1982 through 1987.
Once established hedgerows of Leucaena at 2-m spacing were extremely effective in reducing water runoff and controlling erosion. Runoff, erosion and nutrient losses
were generally more from maize grown in the first season than from cowpea grown in the second. Mean seasonal erosion from
maize was 4.3, 0.10, 0.57, 0.10, 0.64 and 0.60 t/ha for plow-till, no-till, Leucaena-4m, Leucaena-2m, Gliricidia-2m treatments, respectively. Mean runoff in the first season from treatments listed in the order above was 17.0, 1.3, 4.9,
3.3, 4.3, and 2.4 percent of the rainfall received. There were high losses of Ca and K in water runoff from the plow-till
treatment. In contrast to runoff and erosion, losses of bases in water runoff from agroforestry treatments were relatively
high, high concentration of bases in runoff was probably due to nutrient recycling by the deep-rooted perennials. 相似文献
106.
107.
3种白腐菌木质素降解酶的比较 总被引:1,自引:0,他引:1
对3种白腐菌——黄孢原毛平革菌、变色栓菌和木质层孔菌在恒温振荡培养条件下产漆酶、锰过氧化物酶的情况进行比较研究,同时还对此3种菌在培养过程中还原糖的变化作了研究.结果表明:3种白腐菌中变色栓菌产漆酶相对最高,其漆酶酶活最高达到136.5 U/L,产酶最高时间为第8天;而木质层孔菌产锰过氧化物酶相对最高,其最高酶活达到880.2 U/L,产酶最高时间为第8天;同时在培养过程中还原糖含量随培养时间的延长而逐渐降低. 相似文献
108.
祁连山主要植被下土壤对降雨分配的研究 总被引:3,自引:0,他引:3
以祁连山主要植被类型下的土壤为研究对象,对其物理性质、渗透率、渗流速度及其地表径流进行研究,结果表明:土壤的物理性质决定着土壤对降雨的分配情况,有林地将降雨全部分配成入渗水,而牧坡草地根据降雨强度和持续时间不同将降雨按不同的比例分配成入渗水和地表径流水2部分,不同植被的土壤蓄水量也各不相同。林地土壤100cm土层蓄水量为320.2~509.7mm,比牧坡草地高5.4%~60.47%,灌丛云杉和高山灌丛土壤蓄水量最高;轻度放牧的草地土壤蓄水量比强度放牧的高33.48%。 相似文献
109.
110.
杉木人工林地力衰退研究概述 总被引:6,自引:0,他引:6
介绍了我国杉木人工林地力衰退的现状,从森林土壤条件、杉木人工林的营养循环特点和人为经营措施等方面分析了导致杉木人工林地力衰退的原因,提出营建人工复层林、林地施肥、适当延长轮伐期,加强植被管理和进行定位观测等措施防止地力衰退。 相似文献