全文获取类型
收费全文 | 212篇 |
免费 | 11篇 |
专业分类
林业 | 8篇 |
农学 | 14篇 |
52篇 | |
综合类 | 17篇 |
农作物 | 20篇 |
水产渔业 | 17篇 |
畜牧兽医 | 69篇 |
园艺 | 4篇 |
植物保护 | 22篇 |
出版年
2023年 | 4篇 |
2022年 | 7篇 |
2021年 | 8篇 |
2020年 | 10篇 |
2019年 | 8篇 |
2018年 | 3篇 |
2017年 | 9篇 |
2016年 | 10篇 |
2015年 | 10篇 |
2014年 | 14篇 |
2013年 | 12篇 |
2012年 | 16篇 |
2011年 | 25篇 |
2010年 | 12篇 |
2009年 | 11篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 8篇 |
2005年 | 5篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 11篇 |
2001年 | 5篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1973年 | 1篇 |
1932年 | 1篇 |
排序方式: 共有223条查询结果,搜索用时 0 毫秒
91.
A comparative review of fisheries management experiences in the European Union and in other countries worldwide: Iceland,Australia, and New Zealand 下载免费PDF全文
Paul Marchal Jesper Levring Andersen Martin Aranda Mike Fitzpatrick Leyre Goti Olivier Guyader Gunnar Haraldsson Aaron Hatcher Troels Jacob Hegland Pascal Le Floc'h Claire Macher Loretta Malvarosa Christos D Maravelias Simon Mardle Arantza Murillas J Rasmus Nielsen Rosaria Sabatella Anthony D M Smith Kevin Stokes Thomas Thoegersen Clara Ulrich 《Fish and Fisheries》2016,17(3):803-824
This study compares the details and performance of fisheries management between the EU and a selection of other countries worldwide: Iceland, New Zealand, and Australia, which are considered in many respects to be among the most advanced in the world in fisheries management. Fisheries management in the EU, Iceland, Australia, and New Zealand has developed following different paths, despite being based on similar instruments and principles. Iceland, Australia, and New Zealand have been at the forefront of developing management practices such as stakeholder involvement, legally binding management targets (Australia, New Zealand), individual transferable quotas, and discard bans (Iceland, New Zealand). The EU has since the beginning of the 21st century taken significant steps to better involve stakeholders and establish quantitative targets through management plans, and a landing obligation is gradually being implemented from 2015 onward. The management of domestic fisheries resources in Australia, New Zealand, and Iceland has, overall, performed better than in the EU, in terms of conservation and economic efficiency. It should, however, be stressed that, compared to Australia, New Zealand, and Iceland, (i) initial over‐capacity was more of an issue in the EU when management measures became legally binding and also that (ii) EU has been progressive in developing common enforcement standards, on stocks shared by sovereign nations. The situation of EU fisheries has substantially improved over the period 2004–2013 in the northeast Atlantic, with fishery status getting close to that in the other jurisdictions, but the lack of recovery for Mediterranean fish stocks remains a concern. 相似文献
92.
Inés Martínez‐Pita Ismael Hachero‐Cruzado Clara Sánchez‐Lazo Oscar Moreno 《Aquaculture Research》2012,43(8):1134-1144
This paper describes the lipid composition of the commercial bivalve Donax trunculus and the differences originated when the animals were fed with two phytoplankton species (Tetraselmis suecica and Chaetoceros sp.) in a hatchery. We also analysed sex‐related differences in lipid classes and fatty acid profile. Total lipids were higher in females than in males. Triglycerides and phospholipids were the major lipid components, and the former dominated in females and the latter in males. The main fatty acids in both sexes were 16:0, 20:5n‐3 (eicosapentaenoic acid) and 22:6n‐3 (docosahexaenoic acid). Females showed higher percentages of saturated and monounsaturated fatty acids and lower levels of polyunsaturated fatty acids than males. Significant differences in total lipid, lipid classes and fatty acid profiles were also found due to diet. Docosahexaenoic acid decreased and total lipids, free fatty acids, arachidonic acid and EPA increased in both sexes. Despite these differences, the condition of the species was maintained and the broodstock even maturated. 相似文献
93.
Yolanda Torres‐Corral Clara Fernndez‐lvarez Ysabel Santos 《Journal of fish diseases》2019,42(10):1359-1368
This work describes a primer pair and a high‐throughput SYBR Green I‐based real‐time PCR protocol combined with melting curve analysis for identification and quantification of Vagococcus salmoninarum in bacterial cultures and infected fish tissues. The 16S rRNA gene was selected for the design of the primer pair (SalF and SalR). The sensitivity and specificity of this primer pair were compared with other previously designed for conventional PCR. Although both primer pairs showed 100% specificity using pure bacterial cultures or DNA extracted from bacteria or fish tissues, the primer pairs designed in this study showed the highest sensitivity with a detection limit of 0.034 × 100 amplicon copies per assay (equivalent to 2 × 10?11 ng/µl, Cq value of 30.49 ± 1.71). The developed qPCR protocol allowed the detection of V. salmoninarum in non‐lethal and lethal fish samples with detection levels of 0.17 × 100 gene copies in tissues artificially infected and 0.02 × 100 in tissues of fish experimentally infected with V. salmoninarum. The high sensitivity of the developed method suggests that it could be considered as a useful tool for diagnosis of vagococcosis and the detection of V. salmoninarum in asymptomatic or carrier fish. 相似文献
94.
Clara Medeira Virgínia Quartin Isabel Maia Inês Diniz Ma Céu Matos José Nobre Semedo Paula Scotti-Campos José C. Ramalho Isabel P. Pais Paula Ramos Elvira Melo António E. Leit?o Alfredo Cravador 《European journal of plant pathology / European Foundation for Plant Pathology》2012,134(1):145-159
The decline of cork oak (Quercus suber) stands in Iberian Peninsula is associated with infection by Phytophthora cinnamomi. Most Phytophthora species secrete elicitins, which can enhance defence reactions against some pathogens. Here cytological and physiological effects of the elicitins cryptogein and capsicein on cork oak root infection by P. cinnamomi were evaluated. The progression of the pathogen in root tissue and its effects on total fatty acid (TFA) composition of roots and leaves were analysed in seedlings. Net photosynthesis (P n ), stomatal conductance (g s ), chlorophyll a fluorescence measurements (quantum yield of linear electron transport ? e , photochemical quenching q P, non-photochemical quenching NPQ) and carotenoid determinations were carried out in well established (4?months) plants. In elicitin-treated roots, 2?days after inoculation, the pathogen which presented loss of viability and membrane degradation was mainly restricted to the intercellular spaces of the cortical parenchyma, and did not reach the vascular cylinder. Electron dense materials accumulated in the intercellular spaces of the cortex next to disorganized hyphae, suggested to be related with defence reactions. Cryptogein (or its interaction with P. cinnamomi) induced enhanced lipid synthesis in leaves, which may contribute to preserve membrane stability. P. cinnamomi decreased P n , g s , ? e , and q P, whereas elicitin-treated plants displayed values similar to controls. Overall, the results indicated a resistance response of cork oak against this oomycete, induced by the elicitins. 相似文献
95.
Mainar-Jaime RC Muñoz PM de Miguel MJ Grilló MJ Marín CM Moriyón I Blasco JM 《The Canadian veterinary journal. La revue veterinaire canadienne》2005,46(10):913-916
When brucellosis false positive serological reactions happen in cattle, the serial use of pairs of specificity-correlated serological tests (rose bengal, complement fixation, competitive ELISA) results in specificities lower than expected. In this situation, highly specific tests, such as the indirect ELISA used alone, may be more adequate than serial testing. 相似文献
96.
Alfaxalone for total intravenous anaesthesia in bitches undergoing elective caesarean section and its effects on puppies: a randomized clinical trial 下载免费PDF全文
97.
Diaz S Fonseca IP Rodrigues A Martins C Cartaxeiro C Silva MJ Brito TV Alexandre-Pires G Santos-Gomes GM 《Veterinary parasitology》2012,189(2-4):137-144
Canine leishmaniosis, caused by Leishmania infantum, is a systemic disease with variable clinical signs and a progressive evolution. This disease is characterized by impaired T cell-mediated immune response, which has been associated with disease chronicity and high mortality. Protective immunity against leishmaniosis is thought to be mediated by T cell and cytokine production. The T cell activation requires a primary signal delivered by the major histocompatibility complex (MHC) molecules present on the surface of antigen presenting cells, and a non-specific signal generated by co-stimulatory molecules. To characterize canine immune responses in the presence of L. infantum parasites or their antigens, in vitro cell cultures of canine macrophages and lymphocytes were established, and the macrophages presenting MHC class II molecules were evaluated as well as the expression of IL-12 and CD80-86 co-stimulatory molecules and nitric oxide production. The results showed for the first time the up-regulation of MHC class II molecules on the surface in canine peripheral blood monocyte-derived macrophages during L. infantum infection in the presence of lymphocytes. In addition, a lack of co-stimulatory expression and a reduced release of nitric oxide were observed, suggesting a loss of T cell function and consequently an inactivation of the macrophage oxidative burst which, in turn, favors the survival of Leishmania. These results constitute a new contribution for the understanding of the interactions between L. infantum and the canine immune system. 相似文献
98.
99.
Gagneux S Long CD Small PM Van T Schoolnik GK Bohannan BJ 《Science (New York, N.Y.)》2006,312(5782):1944-1946
Mathematical models predict that the future of the multidrug-resistant tuberculosis epidemic will depend on the fitness cost of drug resistance. We show that in laboratory-derived mutants of Mycobacterium tuberculosis, rifampin resistance is universally associated with a competitive fitness cost and that this cost is determined by the specific resistance mutation and strain genetic background. In contrast, we demonstrate that prolonged patient treatment can result in multidrug-resistant strains with no fitness defect and that strains with low- or no-cost resistance mutations are also the most frequent among clinical isolates. 相似文献
100.
Clara Sze KW Kshirsagar HH Venkatachalam M Sathe SK 《Journal of agricultural and food chemistry》2007,55(21):8745-8753
Soybean glycinin (11S) and beta-conglycinin (7S) were subjected to select chemical treatments at various concentrations and resulting changes in protein structures were investigated by circular dichroism (CD) and fluorescence spectrometry. Fluorescence quenching results indicated that urea >/=3 M caused significant unfolding of 11S, but not that of 7S. GuHCl was more effective than urea in denaturation of 11S. A two-step transition in 11S structure was observed with a possible existence of a folding intermediate at 2.5 M GuHCl. Sodium dodecyl sulfate (SDS) measurably altered secondary and tertiary structures of 11S and 7S below SDS critical micellar concentration (CMC), possibly due to formation of mixed peptide-SDS micelles. SDS treatment increased alpha-helical and unordered structures of both proteins at the expense of beta-sheet structure. NaCl and CaCl 2 caused a significant decrease in fluorescence intensity without shifting emission lambda max. Exposure of 7S and 11S to NaSCN respectively at >/=0.3 and >/=0.6 M NaSCN caused a significant increase in fluorescence intensity measured at the corresponding lambda max of the protein. beta-Mercaptoethanol (beta-ME), N-ethylmaleimide (NEM), and phytic acid caused variable red shifts, 2.5-4 nm, in the emission lambda max. 相似文献