全文获取类型
收费全文 | 867篇 |
免费 | 79篇 |
专业分类
林业 | 63篇 |
农学 | 34篇 |
基础科学 | 7篇 |
143篇 | |
综合类 | 43篇 |
农作物 | 56篇 |
水产渔业 | 81篇 |
畜牧兽医 | 442篇 |
园艺 | 7篇 |
植物保护 | 70篇 |
出版年
2023年 | 15篇 |
2022年 | 23篇 |
2021年 | 34篇 |
2020年 | 41篇 |
2019年 | 41篇 |
2018年 | 49篇 |
2017年 | 40篇 |
2016年 | 37篇 |
2015年 | 36篇 |
2014年 | 44篇 |
2013年 | 60篇 |
2012年 | 50篇 |
2011年 | 57篇 |
2010年 | 38篇 |
2009年 | 42篇 |
2008年 | 34篇 |
2007年 | 35篇 |
2006年 | 31篇 |
2005年 | 23篇 |
2004年 | 14篇 |
2003年 | 25篇 |
2002年 | 24篇 |
2001年 | 13篇 |
2000年 | 14篇 |
1999年 | 19篇 |
1998年 | 18篇 |
1997年 | 11篇 |
1996年 | 11篇 |
1995年 | 3篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 7篇 |
1991年 | 6篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1984年 | 1篇 |
1983年 | 5篇 |
1982年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1967年 | 1篇 |
1963年 | 1篇 |
1954年 | 1篇 |
排序方式: 共有946条查询结果,搜索用时 0 毫秒
41.
José Antonio Lucas García Augustín Probanza Beatriz Ramos Francisco J. Gutiérrez Mañero 《植物养料与土壤学杂志》2001,164(1):1-7
The metabolic capacities of rhizosphere bacteria can depend on intraspecific genetic variability at strain level. We sampled bacteria from the rhizosphere of three populations of four different Lupinus species at two growth stages (flowering: GS1 and fruiting: GS2). Isolates were identified to the genus level by classical biochemical tests. The most abundant genera found were Bacillus, Aureobacterium, Cellulomonas, Pseudomonas, and Arthrobacter. Genetic divergence of rhizobacteria was tested by PCR-RAPDs. The genetic distances were low, with mean values of 37 % for Bacillus, 25 % for Aureobacterium, 46 % for Cellulomonas, 16 % for Pseudomonas, and 23 % for Arthrobacter. Aureobacterium, the most abundant genus, predominated in the rhizosphere of all populations and at both growth stages (GS1 and GS2) of L. angustifolius. The Aureobacterium strains consisted of 11 groups with 90 % similarity indexes. The cluster analysis of these groups shows that strains isolated from different lupin species and sampling times have extraordinary low diversity indexes, or are even identical. This fact, together with the low genetic distance detected in the rhizosphere, reveals a clear specificity in the plant-bacteria interaction. This specificity could be related with several aspects of plant physiology. 相似文献
42.
43.
Lima Talma Jordana Costa Roberto Germano de Medeiros Geovergue Rodrigues de Medeiros Ariosvaldo Nunes Ribeiro Neila Lidiany de Oliveira Juliana Silva Guerra Ricardo Romão de Carvalho Francisco Fernando Ramos 《Tropical animal health and production》2019,51(2):363-368
Tropical Animal Health and Production - The objective of this study was to evaluate the ruminal parameters (pH, N-NH3, and microbial protein) and morphometry of the rumen and intestine of sheep fed... 相似文献
44.
Morphofunctional description of mucous cells in the gills of the Arapaimidae Arapaima gigas (Cuvier) during its development 下载免费PDF全文
C. A. Ramos O. T. F. da Costa W. L. P. Duncan M. N. Fernandes 《Anatomia, histologia, embryologia》2018,47(4):330-337
The gill structure of the Amazonian fish Arapaima gigas (Cuvier 1829) shows ontogenetic changes during development, particularly due the transition from the aquatic to the obligatory air breathing mode of respiration. However, three main cell types can be found in the gills: mitochondrial rich cells, pavement cells and mucous cells (MCs). The MCs are involved in the secretory pathway. The functions of the secreted molecules include mechanical protection of epithelia, protection against parasites and bacterial infection, and role on ion regulation. In this study, we analysed mucous cell location and mucous cell type, based on pH, during the development of A. gigas. Using samples obtained from the environment, gills were collected and fixed in buffered solution. Histological techniques for the identification of MCs were performed Alcian Blue (AB) and periodic acid‐Schiff (PAS). The results showed the presence of PAS+ and AB+ cells in the whole filament in all examined fish. In animals less than 50 g, few MCs were present, and no differences were observed in AB+ and PAS+ cells. In animals weighing close to 500 g, more PAS+ cells than AB+ cells were observed, and in animals that weighed more than 1,000 g, more AB+ cells than PAS+ cells were observed. These observations may be a result of the ontogenetic changes in the gill epithelia, which can change the osmorespiratory compromise in ion regulation functions as well the glycosaminoglycans secreted by PAS cells, which in large animals can play a role in the protection against parasites and bacterial infection. 相似文献
45.
Alana Batista dos Santos Mara Lúcia Albuquerque Pereira Herymá Giovane de Oliveira Silva Gleidson Giordano Pinto de Carvalho Taiala Cristina de Jesus Pereira Leandro Sampaio Oliveira Ribeiro José Augusto Gomes Azevêdo Maria das Graças Conceição Parada Costa Silva Larisse Borges Sousa Leandro Borges Sousa Daiane de Oliveira Alencar 《Tropical animal health and production》2016,48(3):509-515
46.
Clinical,histopathological and immunohistochemical characterization of a novel equine ocular disorder: heterochromic iridocyclitis with secondary keratitis in adult horses 下载免费PDF全文
47.
48.
Sofia Knapic Isabel Pinto Seppä Arto Usenius Helena Pereira 《European Journal of Forest Research》2011,130(5):745-751
Recent research is underway to study cork oak (Quercus suber L.) wood potential for production of wood components. A total of 35 stems of young and mature cork oaks were sampled, live sawn into flitches, scanned using VTT’s WoodCIM®, and the measured data computed by VTT’s PuuPilot software, allowing stem 3D reconstruction. Sawing simulations were run for 0.5 m and 1 m logs and the whole stem. Sawn products were (1) planks, (2) parquet, (3) lamparquet, and (4) external component of multilayer planks. Cork oak stems showed a moderate to small taper (mean 24 mm/m). Curviness varied between straight to significantly crooked stems (mean value 40 mm) Batch yields for the tested products ranged 25–43% and 37–50% for 0.5 m logs of young and mature trees, respectively; for 1 m logs, batch yields ranged 19–41% and 25–54%. When using the whole stem, batch yields were lower, ranging 11–38% and 15–50%. Higher yields were obtained for all log lengths and samples for production of lamparquet, parquet, and multilayer component. 相似文献
49.
Two ethanolic propolis extracts (EPE) with and without the caffeic acid phenethyl ester (CAPE), CAPE and galangin (major components of propolis) were investigated for anti-inflammatory activity in rats using carrageenin foot oedema, carrageenin pleurisy and adjuvant arthritis. In our experiments, EPE with CAPE and CAPE alone significantly inhibited carrageenin oedema, carrageenin pleurisy and adjuvant arthritis. In contrast EPE without CAPE and galangin did not exhibit anti-inflammatory effects in acute and chronic inflammation. These results suggest that the anti-inflammatory activity of propolis is due to CAPE. 相似文献
50.
Species of Botryosphaeriaceae are associated with canker and dieback of Eucalyptus spp. worldwide, but little is known about their effect on the host physiology. The aim of this study was to evaluate the impact of Botryosphaeriaceae isolates from nine species in three genera (Botryosphaeria, Diplodia and Neofusicoccum), previously isolated from eucalypts, on three different Eucalyptus hosts (seedlings of E. nitens, cuttings of E. globulusand of E. globulus× E. cypellocarpa). An approach combining standard pathogenicity trials with evaluation of plant morpho‐physiological parameters was used. The size of the lesions produced revealed differences in fungal aggressiveness and host susceptibility. Isolates of Neofusicoccum kwambonambienseand Diplodia corticolawere the most aggressive, while Botryosphaeria dothidea and Diplodia seriataisolates were the least aggressive. In general, hybrid E. globulus× E. cypellocarpa plants developed smaller lesions, followed by E. nitens and E. globulus. Eucalyptus nitensplants showed minimal modifications on the morpho‐physiological profile when infected, although more severe symptoms and mortality were observed. This is probably due to a more variable genetic background of the plants. However, in general, no direct association between putative fungal aggressiveness and plant physiological disorders could be found. Results suggested that under optimal growth conditions plants manage to cope with pathogen attack and maintain their physiological performance. 相似文献