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41.
亚马逊热带雨林毁林遥感监测是目前最先进遥感体系。通过探讨亚马逊热带雨林的遥感监测及保护发展基本做法,以期为中国森林资源监测与保护提供借鉴和启示。  相似文献   
42.
  1. Frugivorous fish provide often conflicting ecosystem services of seed dispersal and food provisioning in tropical rivers. Fishing may reduce the size and abundance of frugivorous fish, thus affecting their potential as seed dispersers, which could affect the conservation of these fish and of floodplain forests.
  2. The goal of this study was to assess the influence of co-managed protected areas in the form of extractive reserves (RESEX) and small-scale fisheries on frugivorous fish in the Tapajós and Negro rivers, in the Brazilian Amazon. The study examined whether: (i) frugivorous fish are important for fisheries and selectively caught; and (ii) frugivorous fish abundance, size and fisheries catch per unit of effort are higher inside the RESEX than outside.
  3. The analyses included fisheries-dependent data (3,753 fish landings) and independent data (12,730 sampled fish) collected in 16 fishing communities (eight for each river). In both rivers, frugivorous fish are among the 10 species caught the most and frugivorous biomass was proportionately higher in landings than in samplings, indicating fisheries selectivity towards these fishes.
  4. In both rivers, catches of frugivorous fish were higher outside the RESEX than inside. Catch per unit effort and the proportion of frugivores in the catch were higher outside the RESEX in the Tapajós River but did not vary between sites inside and outside the RESEX in the Negro River. Frugivorous fish were larger inside the RESEX in the Negro, but smaller inside the RESEX in the Tapajós.
  5. The results indicated that the ecosystem services of seed dispersal and food source provided by frugivorous fish are not in conflict in the tropical rivers studied. Therefore, these clearwater and blackwater rivers in the Brazilian Amazon show a balance between fisheries and conservation of frugivorous fish, which play an essential role in the functioning of tropical floodplain forest ecosystems.
  相似文献   
43.
Fishes and aquaticenvironments are often overlooked in conservation and sustainabledevelopment projects in Amazonia, yet the diversity of fishes(> 3 000 species) and the socio-economic value of thefisheries and the aquatic habitats have a great importance forthe region. Fishes are not only the principal source of proteinfor local people (> 70 kg/capita), many are also traded asornamental fishes in a worldwide market. The middle Rio Negrobasin is the major fishing grounds for live ornamental aquariumfish. Nearly 20 million live fishes are exported from the regionannually, generating more than US$ 2 000 000 annually forthe local economy. The trade in ornamental fish now contributesover 60% of the income revenue in the municipality. The goal ofProject Piaba is to promote an economically viable fishery forlocal fishers, and an ecologically sustainable resource for agreen aquarium industry. To arrive at these goals first requiresan understanding of the ecosystems and sociocultural systems ofconcern. The Project Piaba team has made baseline studies on thediversity of fishes and habitats, and socio-economic processes ofthe ornamental fishery. Five principal project goals are:(1) To collect baseline data on the ecosystem, socio-economy and diversity of fishes, to analyze the impact of the ornamental fish trade on social and natural environments.(2) To diagnose diseases, to introduce fish care techniques, to improve the survival and quality of fishes and turtles, and eventually to establish quarantine protocols at each level of the trade.(3) To provide environmental education and socio-cultural history to local fishers, distributors and public, and to promote career development in aquarium science and conservation.(4) To create community based fishery management strategies which would include managed harvest levels, stock enhancement of fishes and turtles and the development of aquaculture.(5) To assist in the revision of policies by regulatory agencies in order to protect vulnerable species and enhance the economic viability of the region  相似文献   
44.
美国的亚马逊公司发布了第一款电子图书阅览器Kindle后引发了全球用户的关注。以"网上书店"著称的当当网如推出电子图书阅览器,其市场前景能否超越Kindle,分别从地域性、时效性、功能资源、价格和版权5个方面分析了当当网与亚马逊的优劣和差异。  相似文献   
45.
The cultivation of rubber trees in the humid tropical Amazon region is only possible with the use of crown grafts with species of Hevea sp. that are resistant to South American leaf blight – (SALB) [Microcyclus ulei (P. Henn.) v. Arx.]. However, it has been observed that plants with grafted crowns are not efficient in remobilizing magnesium from the crown to the latex. The experimental design was a randomized block, with three replicates. Five crown clones were studied (CPAA C 01, CPAA C 06, CPAA C 18, CPAA C 45, and CBA 2) with two magnesium (Mg) levels [source: magnesium sulfate(MgSO4): low-Mg (150 g plant?1 of MgSO4 × 7H2O] and high-Mg (450 g plant?1 of MgSO4 × 7H2O). The panel clone used for tapping was CNS AM 7905 (Hevea brasiliensis). The results showed that the Mg levels influenced the crown clones differently in relation to yield, efficiency index and leaf and soil Mg concentration. Clone CPAA C 01 with a high-Mg produced over 2.0 t ha?1 of dry rubber. Clones CPAA C 01 and CPAA C 45 were the most efficient, while clone CPAA C 06 showed moderate efficiency and clones CPAA C 18 and CBA 2 were inefficient in using Mg. The Mg concentration in the latex was not influenced by the two Mg levels, with the only differences being between the crown clones.  相似文献   
46.
This study reports on the cross-species amplification of 23 microsatellite markers previously developed for Theobroma cacao L. (Sterculiaceae), source of chocolate in three economically important Amazonian species of Theobroma (T. grandiflorum, T. subincanum, T. sylvestre). Thirteen of the 23 microsatellite loci tested were polymorphic across the three species at 2–13 alleles per locus. The observed heterozygosity per locus varied from 0.18 to 0.84 and expected heterozygosity ranged from 0.28 to 0.87. The high level of transferability and genetic information content of these microsatellite loci indicate their usefulness for population genetic, mating system and breeding studies of these economically important Amazonian fruit trees.  相似文献   
47.
48.
Abstract

The effects of application of zinc fertilizer on dry matter yield, uptake and distribution of zinc and other nutrients by Amazon and Amelonado cocoa cultivars grown in a soil of low zinc content in the greenhouse were investigated.

There was a differential response to zinc fertilization by the two cocoa cultivars. Maximum dry matter yields of Amazon and Amelonado were attained with 10 ppm Zn and 50 ppm Zn, respectively. Under similar experimental conditions Amelonado seedlings expressed zinc deficiency symptoms whereas Amazon did not.

Zinc concentrations in the leaves, stem and roots of both cuitivars did not give a good index of the zinc status of the crops. This was because of the existence of the “Piper‐Steenbjerg”; effect in that nil zinc rates often gave higher leaf concentration of the zinc than next higher rate. In general, the relative content of zinc followed the pattern; leaves > roots > stem with the Amazon cultivar containing more zinc than the Amelonado.

The distribution of absorbed Cu in the leaves, stem and roots did not differ in both varieties. Whereas Fe uptake was mostly concentrated in the roots, Mn absorbed was largely concentrated in the leaves of both varieties and only Mn uptake in the leaves of Amazon consistently increased with Zn application.

The differences in the uptake and distribution of nutrients between the two cocoa cultivars was attributed to differences in their ability to extract nutrients from the soil and in their requirements for metabolic processes.  相似文献   
49.
Human rabies has re-emerged in Latin America due to bat associated transmission. We present data related to attacks by hematophagous bats in three riverine communities in the Rio Negro basin, Brazilian Amazon. A cross-sectional survey was carried out to obtain demographic and epidemiological data through interviews with 201 inhabitants. A total of 721 bat attacks with bites took place from 2004 to 2006, 238 (33%) reported by residents in Campinas do Rio Preto, 329 (46%) in águas Vivas and 154 (21%) in the community of Malalahá. Incidence density among surveyed inhabitants was 84 attacks/100 persons-years in Campinas do Rio Preto, 249 attacks/100 persons-years in águas Vivas and 81 attacks/100 persons-years in Malalahá. The proportion of surveyed inhabitants bled by bats at least once was 67% (63/94) in Campinas do Rio Preto, 96% (42/44) in águas Vivas and 62% (39/63) in Malalahá. Among subjects bled by bats, the average number of bites was 4.6 ± 4.2 standard deviations (SD) in Campinas do Rio Preto, 8 ± 6 SD in águas Vivas and 4.1 ± 3.9 SD in Malalahá. Regarding houses, 67% (26/39) had animals in the peridomestic environment (chickens and/or dogs) and all were vulnerable to bats due to gaps in the walls and/or in the windows and doors. In 13 dwellings, rudimentary protection against bats through the fixation of fishing nets and/or straw nets to the windows and other openings was observed. Among dwellers reporting attacks, 48% (68/144) received the full post-exposure anti-rabies vaccination protocol with five doses of diploid human cell vaccine, 28% (39/144) received an incomplete schedule (1-4 doses), and 26% (37/144) did not receive any dose. No cases of rabies were reported during the study; however, regular pre-exposure vaccination in the studied populations must be considered.  相似文献   
50.
Wood density is an important variable in estimates of biomass and carbon flux in tropical regions. However, the Amazon region lacks large-scale wood-density datasets that employ a sampling methodology adequate for use in estimates of biomass and carbon emissions. Normalization of the available datasets is needed to avoid bias in estimates that combine previous studies of wood density that used wood sampling at diverse positions in the bole or with various methods of density determination. This paper examines the question of whether regressions for radial variation and for variation in wood density along the bole, both developed in dense forest in central Amazonia (CA), are suitable for the open forests in southern Amazonia (SA) that are currently the target of most of Amazonia's deforestation activity. The wood density of the heartwood and density of full disks or slices (bark, sapwood and heartwood) in each tree were measured to assess the radial variation. For variation along the length of the bole, wood densities at breast height and at the top of the bole were used. Moisture content of the bole was measured in SA and compared with values reported by studies from CA in similar dense forest. Comparing regressions that predict full-disk density from heartwood density, the pattern of radial variation differs slightly and significantly between the two forest types (ANCOVA p = 0.006); the slopes have similar values but the intercepts differ. Variation along the bole in the two forest types does not differ significantly (p = 0.144), so the CA model for predicting mean bole density from the density of a slice at breast height gives an unbiased estimate of the mean bole density when applied to SA trees. In SA the mean moisture content of the bole was 0.416 (±0.068 S.D.; n = 223 trees). Moisture content of the bole had a strong inverse relationship with basic wood density (r = −0.77), which explains the lower moisture content in the trees in CA relative to SA. A much weaker inverse relationship was found between moisture content and green wood density (r = −0.292). The relationship between wood basic density and green (‘fresh’) density presented in this study provides an alternative means of obtaining basic wood density directly in the field when oven drying of samples is not possible.  相似文献   
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