全文获取类型
收费全文 | 288篇 |
免费 | 14篇 |
专业分类
林业 | 29篇 |
农学 | 7篇 |
62篇 | |
综合类 | 8篇 |
农作物 | 19篇 |
水产渔业 | 31篇 |
畜牧兽医 | 83篇 |
园艺 | 3篇 |
植物保护 | 60篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 17篇 |
2020年 | 9篇 |
2019年 | 11篇 |
2018年 | 12篇 |
2017年 | 12篇 |
2016年 | 16篇 |
2015年 | 8篇 |
2014年 | 6篇 |
2013年 | 16篇 |
2012年 | 19篇 |
2011年 | 19篇 |
2010年 | 17篇 |
2009年 | 16篇 |
2008年 | 24篇 |
2007年 | 19篇 |
2006年 | 15篇 |
2005年 | 10篇 |
2004年 | 12篇 |
2003年 | 3篇 |
2002年 | 9篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1975年 | 1篇 |
1971年 | 2篇 |
1970年 | 4篇 |
1969年 | 2篇 |
1964年 | 1篇 |
排序方式: 共有302条查询结果,搜索用时 0 毫秒
51.
Liliam Cristina Angelo Antonio Salvio Mangrich Karen Mary Mantovani Sailer Santos dos Santos 《Journal of Soils and Sediments》2014,14(2):353-359
Purpose
Charcoal is utilized in Brazil for the metallurgical industry. Small size pieces, called charcoal fines, are rejected and sometimes are used to produce energy by burning. This charcoal can be used as soil conditioner to improve retention of metal ions in soil. However, changing the charcoal's surface chemistry via oxidation may increase retention of metal ions.Materials and methods
Two kinds of oxidants were employed, nitric acid and selenium dioxide/hydrogen peroxide. Vanadyl ion (VO2+) and copper ion (Cu2+) were utilized as probe to study the metal ion complexation by the partially oxidized charcoal obtained. FTIR and EPR spectroscopy were used to characterize the materials.Results and discussion
Oxidation with nitric acid increased nitrogen content, while oxidation with SeO2/H2O2 elevated carbon content of treated charcoals. Organic free radicals (OFRs) with the unpaired electron in p orbitals of aromatic structures were confirmed by the EPR g-factors that ranged from 2.0038 to 2.0031. The oxidation with selenium dioxide/hydrogen peroxide formed charcoal with largest quantity of OFR. Loading charcoal with VO2+ and Cu2+ resulted in formation of complexes were oxygen acted as coordination atom. The formed complexes were of axial symmetry. The configurations around the Cu2+ ions were: CUNCu2+ complex (more stable square planar symmetry) and CFNCu2+ complex (less stable distorted tetrahedral configuration). Both complexes had oxygen as coordinating atoms. CFNVO2+ and CFSeVO2+ complexes presented complexation sites of axial symmetry, C4v, with oxygen as coordinating atoms.Conclusions
The oxidative treatment of charcoal with SeO2/H2O2 is more appropriate to produce soil organic conditioner for complexation of metal ions. 相似文献52.
John G. Howieson Robert J. Harrison Ron J. Yates Belinda Hackney Angelo Loi Brad J. Nutt 《Grass and Forage Science》2021,76(1):82-92
The patterns and extent of hard seed breakdown of dormant seeds and pods following burial in the soil in February (summer) varied for up to 19 accessions of 12 species of annual forage legumes. The experiments, at six sites across southern Australia, were designed to identify legumes whose patterns of hard seed breakdown would suit them to agronomic evaluation in a summer sowing research program. For a subset of accessions, sufficient hard seed breakdown was demonstrated between February and April to allow a high proportion of seed to germinate in late autumn—a desirable pattern for summer sowing. Although there was a large G x E interaction, some cultivars of Ornithopus sativus Brot., O. compressus L. and Trifolium spumosum L. had a pattern that was reproducible at all sites. The experiments also identified accessions of Biserrula pelecinus L. and T. glanduliferum Boiss., which had the desirable pattern in regions of south‐eastern Australia, but not Western Australia. A pragmatic approach for selection of forage legume accessions in situ for evaluation within a summer sowing program was demonstrated. 相似文献
53.
54.
Federico Tinivella Lucia M. Hirata Mikael A. Celan Sandra A. I. Wright Tahsein Amein Annegret Schmitt Eckhard Koch Jan M. van der Wolf Steven P. C. Groot Dietrich Stephan Angelo Garibaldi Maria Lodovica Gullino 《European journal of plant pathology / European Foundation for Plant Pathology》2009,123(2):139-151
Greenhouse trials were carried out in order to test the efficacy of different seed treatments as alternatives to chemicals
against Colletotrichum lindemuthianum cause of anthracnose on bean and Ascochyta spp. cause of Ascochyta blights on pea, respectively. Resistance inducers, commercially formulated microorganisms, non-formulated
selected strains of different microorganisms (fungi, bacteria and yeasts) and plant extracts were applied as dry or liquid
seed treatments on naturally infested seeds. Seedling emergence and disease incidence and/or severity were recorded. Almost
all seed treatments turned out to be ineffective in controlling the Ascochyta infections, which is in line with the literature
stating that these pathogens are difficult to control. The only alternative treatments that gave some control of Ascochyta spp. were thyme oil and a strain of Clonostachys rosea. The resistance inducers tested successfully controlled infections of bean by C. lindemuthianum. Among the formulated microorganisms, Bacillus subtilis-based formulations provided the best protection from anthracnose. Some strains of Pseudomonas putida, a disease-suppressive, saprophytic strain of Fusarium oxysporum and the mustard powder-based product Tillecur also proved to be effective against bean anthracnose. However, among the resistance
inducers as well as among the other groups, certain agents caused a significant reduction of plant emergence. Different alternative
seed treatments can therefore be used for the control of C. lindemuthianum on bean, while on pea only thyme oil and a strain of Clonostachys rosea showed some effectiveness against Ascochyta spp. 相似文献
55.
Menezes IA Marques MS Santos TC Dias KS Silva AB Mello IC Lisboa AC Alves PB Cavalcanti SC Marçal RM Antoniolli AR 《Fitoterapia》2007,78(3):192-195
The essential oil of the Hyptis fruticosa leaves was analyzed by GC/MS and evaluated for antinociceptive property as well as acute toxicity in mice. The essential oil, at doses of 100, 200, and 400 mg/kg (s.c.), produced significant inhibition of acetic acid-induced writhing, but did not manifest a significant effect in hot-plate test. There was no acute toxicity at doses up to 5 g/kg. Bicyclogermacrene, 1,8-cineole, alpha-pinene, and beta-caryophyllene were the major compounds detected in the essential oil. 相似文献
56.
57.
Quirico Migheli Elena Briatore Angelo Garibaldi 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(1):49-57
The RAPD fingerprinting procedure was used in combination with pathogenicity assays on differential cultivars to characterize a representative collection of 72 Fusarium spp. isolates of different geographic origin collected from diseased carnation. In F. oxysporum f. sp. dianthi, isolates were grouped according to the physiologic race: group 1 included isolates of race 4; group 2 was formed by isolates of race 2 and single representatives of races 5 and 6; group 3 included isolates of races 1 and 8. No correlation was found between RAPD data and geographic origin of the isolates tested: representatives of race 2 isolated in Italy, Israel and Japan had the same amplification profile. Three isolates which showed a low level of pathogenicity on all carnation cultivars tested shared an identical amplification pattern and are probably saprophytic F. oxysporum. Finally, two F. redolens isolates from Japan and seven non-pathogenic isolates of F. proliferatum collected from diseased carnation in Italy, Israel and The Netherlands were clearly distinguishable according to their RAPD fingerprint. The results are discussed in relation to previous studies on the genetic diversity of F. oxysporum f. sp. dianthi and to the development of forma specialis- and pathotype-specific diagnostic tools. 相似文献
58.
59.
Sueli A. Taniwaki Angelo J. Magro Ana Claudia Gorino José P. Oliveira-Filho Marcos R.M. Fontes Alexandre S. Borges João P. Araujo Jr. 《Veterinary microbiology》2013
Papillomaviruses (PVs) infect a wide range of animal species and show great genetic diversity. To date, excluding equine sarcoids, only three species of PVs were identified associated with lesions in horses: Equus caballus papillomavirus 1 (EcPV1-cutaneous), EcPV2 (genital) and EcPV3 (aural plaques). In this study, we identified a novel equine PV from aural plaques, which we designated EcPV4. Cutaneous samples from horses with lesions that were microscopically diagnosed as aural plaques were subjected to DNA extraction, amplification and sequencing. Rolling circle amplification and inverse PCR with specific primers confirmed the presence of an approximately 8 kb circular genome. The full-length EcPV4 L1 major capsid protein sequence has 1488 nucleotides (495 amino acids). EcPV4 had a sequence identity of only 53.3%, 60.2% and 51.7% when compared with the published sequences for EcPV1, EcPV2 and EcPV3, respectively. A Bayesian phylogenetic analysis indicated that EcPV4 clusters with EcPV2, but not with EcPV1 and EcPV3. Using the current PV classification system that is based on the nucleotide sequence of L1, we could not define the genus of the newly identified virus. Therefore, a structural analysis of the L1 protein was carried out to aid in this classification because EcPV4 cause lesion similar to the lesion caused by EcPV3. A comparison of the superficial loops demonstrated a distinct amino acid conservation pattern between EcPV4/EcPV2 and EcPV4/EcPV3. These results demonstrate the presence of a new equine PV species and that structural studies could be useful in the classification of PVs. 相似文献
60.
Rossano Bolpagni Sara Magrini Andrea Coppi Angelo Troìa Janne Alahuhta Marit Mjelde Mattia M. Azzella 《水产资源保护:海洋与淡水生态系统》2021,31(10):2690-2696
- Isoëtes sabatina is the rarest aquatic quillwort in Europe. Although recently found (2013) in Lake Bracciano (central Italy), the species is just one step away from extinction with an estimated population not exceeding 400 individuals and a spatial range of a few hundred square metres.
- Lake Bracciano is a deep, oligo-mesotrophic Mediterranean volcanic lake that has been subjected to human activities. From January to October 2017, the lake experienced a dramatic water level decrease (up to −1.50 m), which significantly affected the littoral zone and the habitat of I. sabatina.
- To improve the chances of survival of I. sabatina, the first eco-taxonomic investigation on this species was carried out to describe its genetic distinctness, physical and chemical requirements and companion species.
- The phylogenetic position of I. sabatina was investigated by applying standard DNA barcoding methods. Simultaneously, during summer 2019, the physical and chemical features of water and sediments of the I. sabatina population and five small Alpine lakes colonized by Isoëtes echinospora – a supposed close relative – were characterized. These data were then compared with the available data on the trophic requirements of the target obligate aquatic Isoëtes, together with Isoëtes lacustris and Isoëtes malinverniana.
- The present survey confirmed the taxonomic and ecological distinctness of I. sabatina – providing the first evidence of genetic differentiation from I. echinospora. Isoëtes sabatina grows in waters with temperature, conductivity and total alkalinity up to 30°C, 561 μS cm−1 and 3.45 meq L−1, respectively.
- The edaphic requirements of I. sabatina confirm its outstanding conservation value, and this study offers a basic understanding of how to prevent its extinction. Now, all possible actions must be taken immediately to save this species.