全文获取类型
收费全文 | 137篇 |
免费 | 7篇 |
专业分类
林业 | 8篇 |
农学 | 4篇 |
46篇 | |
综合类 | 15篇 |
农作物 | 8篇 |
水产渔业 | 9篇 |
畜牧兽医 | 35篇 |
园艺 | 2篇 |
植物保护 | 17篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 4篇 |
2019年 | 5篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 4篇 |
2012年 | 8篇 |
2011年 | 10篇 |
2010年 | 6篇 |
2009年 | 6篇 |
2008年 | 11篇 |
2007年 | 6篇 |
2006年 | 5篇 |
2005年 | 9篇 |
2004年 | 8篇 |
2003年 | 13篇 |
2002年 | 4篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有144条查询结果,搜索用时 31 毫秒
51.
A habitat model for brown bear conservation and land use planning in the central Apennines 总被引:2,自引:0,他引:2
We investigated the brown bear habitat suitability in an 8000 km2 study area encompassing Abruzzo, Latium, and Molise regions in central-southern Italy. Based on long-term field surveys and published records, we classified bear habitat as occupied or unoccupied in 92 out of 320 sample squares (5 × 5 km). For each sample square 36 habitat variables were measured from topographic maps and Corine land-cover III level digital maps. The influence of habitat features on bear presence was investigated by multivariate and one-way analyses of variance and by logistic regression analysis. The logistic model correctly classified 95.5% of sample squares of bear presence and 93.8% of those where bears were absent. Average altitude, deciduous woodlands and ecotone length, showed a positive relationship with bear presence, whereas vineyard-olive groves and shrublands were negatively correlated with bear presence. No specific land management guidelines or strategies exist for bear conservation in central Italy, based on knowledge of habitat-population relationships. The landscape scale habitat model we developed could be useful to predict bear occurrence, to identify critical areas for a brown bear conservation strategy, and to enhance the arrangement of the protected areas network for the conservation of this species. 相似文献
52.
53.
Carlos Egberto Rodrigues Júnior Sandro Natal Daniel Diego Galetti Martins Diogo Teruo Hashimoto Fausto Foresti Fabio Porto‐Foresti 《水产资源保护:海洋与淡水生态系统》2020,30(6):1251-1254
- Billfish are oceanic pelagic species that are often caught by tuna fleets and are of great interest for sport fishing. Two species of billfish have specific legislation prohibiting their marketing and export in Brazil.
- DNA barcoding is a universal system of molecular identification based on a sequence of mitochondrial DNA cytochrome oxidase subunit I (COI), which serves as a diagnostic genomic marker in each species.
- The barcode DNA technique was used to identify billfish marketed in the second largest fishing warehouse in Latin America, the CEAGESP (Companhia de Entrepostos e Armazéns Gerais de São Paulo), located in São Paulo, Brazil. Seventy‐nine samples of billfish were collected during three inspection visits carried out by Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis.
- After DNA sequencing, 70 samples (88.60%) were identified to the species level; 21 (30.00%) were identified as Xiphias gladius, 43 (61.42%) as Istiophorus platypterus and six (8.57%) as Kajikia albida. The sale of this latter species is prohibited in Brazil and it is considered Vulnerable on the list of endangered species of the IUCN and in the official list of species of endangered Fauna – Fish and Aquatic Invertebrates.
- Molecular analyses proved to be very efficient at uncovering irregularities in the identification of the white marlin (K. albida), which was traded illegally in CEAGESP, demonstrating the ineffectiveness of the current monitoring techniques used and emphasizing the need for the adoption of better public policies for the conservation of the species.
54.
Parisi A Lanzilotta SG Addante N Normanno G Di Modugno G Dambrosio A Montagna CO 《Veterinary research communications》2007,31(1):113-123
Eleven cattle farms, 8 layer farms, 7 broiler farms and 30 broiler meat samples were investigated in south-eastern Italy throughout
2003 to evaluate the prevalence, the molecular type and antimicrobial resistance of thermophilic Campylobacters. A total of
398 samples were analysed. One Campylobacter isolate for each positive faecal swab and three isolates per positive broiler meat sample were selected for further analysis.
Multiplex PCR was performed for species-level identification and PCR-RFLP of the flagellin A gene for genotyping. Resistance
to 14 antimicrobials was studied in 188 Campylobacter isolates. Prevalence of campylobacters was high both on farms (100%) and in food samples (73%). On 4/11 cattle farms and
on 10/15 poultry farms more than one species was isolated. The presence of more than one genotype was found on 8/11 cattle
farms, on 10/15 poultry farms and in 8/22 Campylobacter-positive food samples. High rates of resistance to quinolone were observed: 9/31 (29%) C. jejuni bovine isolates, 4/22 (18%) C. jejuni poultry isolates, and 14/26 (54%) C. coli poultry isolates. Resistance to sulphamethoxazole-trimethoprim was also observed frequently: 18/26 (69%) of the avian C. coli strains, 25/31 (80%) of the C. jejuni strains isolated from poultry and 15/22 (68%) of those isolated from cattle were resistant. There was a significant difference
between the rate of resistance to macrolides of C. coli and C. jejuni isolated in poultry, which amounted to 23% and 3%, respectively. This study provided data on the prevalence and antimicrobial
resistance of thermophilic campylobacters in south-eastern Italy and confirmed that flaA-typing is an efficient tool to study the epidemiology of Campylobacter strains in short-term investigations. 相似文献
55.
Tuberoso CI Kowalczyk A Coroneo V Russo MT Dessì S Cabras P 《Journal of agricultural and food chemistry》2005,53(26):10148-10153
The chemical composition of the essential oil from flowering tops of Achillea ligustica All. was studied. Samples were collected in different localities of Sardinia (Italy) and hydrodistilled both with Clevenger-type and with simultaneous distillation-extraction apparatus. The yields ranged between 0.88 +/- 0.06 and 0.43 +/- 0.02% (vol/dry wt). The essential oils were analyzed by GC-MS, and a total of 96 components were detected. From a qualitative point of view, irrelevant differences between samples were observed. Strong chemical variability depending on the origin of the samples was observed. The major compounds found were santolina alcohol (6.7-21.8%, for the first time detected in A. ligustica), borneol (3.4-20.8%), sabinol (2.1-15.5%), trans-sabinyl acetate (0.9-17.6%), alpha-thujone (0.4-25.8%), and, among sesquiterpenes, viridiflorol (0.7-3.6%). No significant differences were detected between essential oils extracted by hydrodistillation and simultaneous distillation-extraction with CH2Cl2 and n-hexane. Antioxidant activity as DPPH radical scavenging activity was expressed in TEAC and ranged between 0.40 and 0.88 mmol/L. The antimicrobial and antifungal activities were investigated on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Penicillium commune, Fusarium oxysporum, Rizoctonia solani, and Aspergillus flavus, showing low activity. 相似文献
56.
Sandro Froehner Karina Scurupa Machado Luiz Fernando Dombroski Anderson Correa Nunes Regina Tiemy Kishi Tobias Bleninger Juan Sanez 《Water, air, and soil pollution》2012,223(7):3965-3973
Hydrophobic organic compounds are common in the environment, especially in water bodies like rivers and lakes. Generally, due to their physico-chemical characteristics, mainly to hydrophobicity, these compounds are adsorbed by suspended material or other compartments which provide compatibility. Thus, compounds such as polycyclic aromatic hydrocarbons (PAHs) are rapidly adsorbed onto suspended material or even naturally occurring biofilms in water bodies. Biofilms can be defined as complex structures with cells and aggregates of cells. The extracellular polymers present empty spaces that can be filled by water. The biofilm is a sessile microbial community with several kinds of organisms such as bacteria, protozoa, fungi, algae, and extracellular polymeric substances, which may be found on almost any surface exposed to water. Here, biofilms were used to monitor the presence of PAHs in the Barigui River in Curitiba, Brazil. For the measurements and collection of representative microcoenoses, a biofilm sampling device was designed consisting of six glass plates installed in an open polyvinyl chloride pipe of 30?cm diameter and 60?cm length. The sampling device was exposed in the Barigui River for 2?weeks campaigns. The formed biofilm was treated and chemical analysis was performed for PAHs determination. The results showed that biofilms can trap most of the PAHs, especially those with high K ow values (octanol?Cwater partition coefficient). Four campaigns were conducted. The total PAHs concentration ranged from 11,204.34?±?560.12 to 45,846.90?±?2,290.45?ng/g. According to the isomers ratio, the main source of PAHs in the first and second campaign was of pyrolytic origin, in other words, the PAHs were by-products from burning of light-refined oil products (gasoline and diesel oil). Meanwhile, the other campaigns revealed that the main source is of petrogenic origin. However, the possibility of both sources is not discarded considering the scenario studied and the records of sediments samples. Most of the investigations carried out focused on the loading of river sediments and suspended solids, but the biofilms might detect the amount that could be taken up by benthic organisms, for instance. 相似文献
57.
Uwe Schindler Lothar Mueller Milton da Veiga Yuming Zhang Sandro Schlindwein Chunsheng Hu 《植物养料与土壤学杂志》2012,175(4):527-534
Knowledge of the soil hydraulic functions is required for various hydrological studies and for the simulation of water and solute fluxes in unsaturated soils. Sand/kaolin boxes are frequently used to determine these properties in the low‐tension range. For higher tensions the pressure plate extractor is mainly applied. The extended evaporation method allows a more efficient determination of the water‐retention curve in an adequate range. Besides this method enables to quantify simultaneously the unsaturated hydraulic‐conductivity function. The objective of this study was to compare the water‐retention curves obtained from the standard methods (STM) with those determined with the extended evaporation method (EEM). A set of 90 natural soil samples of different texture and origin was analyzed, and the agreement between the methods was statistically evaluated. The average water‐content deviation (AWCD) of all samples was 1.83 vol.%, and the root mean square error (RMSE) 2.08 vol.%. The deviation of soil water‐storage capacity in the pore‐size classes 0–6, 6–30, 30–500, 500–1500 kPa varied between minimum –0.17 and 0.25 vol.% and maximum –2.89 and 2.36 vol.%, and confirmed the good comparability among the adopted methods. Systematic deviations between the methods were not found. 相似文献
58.
Natural infection with two genotypes of Cryptosporidium in red squirrels (Sciurus vulgaris) in Italy
We investigated the genotypes of Cryptosporidium infecting red squirrels (Sciurus vulgaris L.) in two areas of the Western Alps in Italy. Examination of 141 faecal samples from 70 red squirrels revealed oocysts of Cryptosporidium in 17 animals (24.3%). Based on 18S rRNA gene sequencing, two genotypes of Cryptosporidium species were found: 15 squirrels were positive for the Cryptosporidium ferret genotype and 2 for the Cryptosporidium chipmunk genotype I. The occurrence and intensity of Cryptosporidium infection did not differ between the study areas or sex. More than 85% of the positive animals were adults; however no difference was found between Cryptosporidium infection in the juvenile and adult age groups. Oocysts of the Cryptosporidium ferret genotype measured 5.5 +/- 0.3 x 5.2 +/- 0.2 microm (shape index 1.06) and the Cryptosporidium chipmunk genotype I 5.8 +/- 0.3 x 5.4 +/- 0.3 microm (shape index 1.07). Neonatal and adult CD1 and BABL/c mice inoculated with 1 x 10(3) fresh oocysts of both genotypes did not produce detectable infection. 相似文献
59.
Giorgio Marchesini Lorenzo Serva Maria Chinello Matteo Gazziero Sandro Tenti Massimo Mirisola Elisabetta Garbin Barbara Contiero Daniel Grandis Igino Andrighetto 《Grass and Forage Science》2019,74(3):415-426
The aim of this study was to assess the effects of earliness (according to FAO class), maturity stage at harvest and environmental conditions on the ensilability of maize hybrids described by their fermentation products and by a fermentation quality index (FQI). Maize hybrids belonging to early (n = 14) and late (n = 15) FAO classes were grown in low, medium and high potential yield areas and harvested at an early (EH), medium (MH) and late maturity stage (LH), that is, at 1/3, 2/3 and 5 d after the 2/3 milk line stage, respectively, according to a split‐plot design. Upon harvest, each sample (n = 522) was analysed for dry matter (DM) and water‐soluble carbohydrates (WSC) before being ensiled in vacuum‐packed bags (n = 1,044). After 60 days of conservation, samples were analysed for DM and fermentation products. In the pre‐ensiling phase, DM was higher in early hybrids (p = .001), low yield areas (p < .001) and at LH maturity (p < .001), whereas WSC contents were higher in early hybrids (p < .001), medium yield areas (p < .001) and at EH maturity (p < .001). With regard to silages, early hybrids had a higher FQI (p < .001), which was highest in areas with a high yield potential (p < .01) and at EH maturity (p < .01). Late hybrids proved to be better suited for low yield areas compared with early hybrids (p < .01) and had a higher FQI at EH and MH than at LH maturity (p < .01). 相似文献
60.
Sánez Juan Froehner Sandro Hansel Fabrício Parron Lucilia Knapik Heloise Fernandes Cristóvão Rizzi Juliane 《Journal of Soils and Sediments》2017,17(3):861-872
Journal of Soils and Sediments - Fecal sterols (FSs) and bile acids (BAs) are biomarkers that can be used to track sewage pollution. These biomarkers offer an alternative to microbiological... 相似文献