全文获取类型
| 收费全文 | 119篇 |
| 免费 | 8篇 |
专业分类
| 林业 | 8篇 |
| 农学 | 4篇 |
| 基础科学 | 1篇 |
| 35篇 | |
| 综合类 | 10篇 |
| 农作物 | 6篇 |
| 水产渔业 | 10篇 |
| 畜牧兽医 | 34篇 |
| 园艺 | 3篇 |
| 植物保护 | 16篇 |
出版年
| 2024年 | 2篇 |
| 2022年 | 1篇 |
| 2021年 | 8篇 |
| 2020年 | 6篇 |
| 2019年 | 5篇 |
| 2018年 | 7篇 |
| 2017年 | 3篇 |
| 2016年 | 7篇 |
| 2015年 | 6篇 |
| 2014年 | 5篇 |
| 2013年 | 6篇 |
| 2012年 | 11篇 |
| 2011年 | 6篇 |
| 2010年 | 2篇 |
| 2009年 | 4篇 |
| 2008年 | 10篇 |
| 2007年 | 5篇 |
| 2006年 | 7篇 |
| 2005年 | 3篇 |
| 2004年 | 8篇 |
| 2003年 | 3篇 |
| 2002年 | 7篇 |
| 2001年 | 1篇 |
| 2000年 | 1篇 |
| 1993年 | 1篇 |
| 1985年 | 1篇 |
| 1982年 | 1篇 |
排序方式： 共有127条查询结果，搜索用时 31 毫秒
71.
Munn DH Sharma MD Lee JR Jhaver KG Johnson TS Keskin DB Marshall B Chandler P Antonia SJ Burgess R Slingluff CL Mellor AL 《Science (New York, N.Y.)》2002,297(5588):1867-1870
Antigen-presenting cells (APCs) can induce tolerance or immunity. We describe a subset of human APCs that express indoleamine 2,3-dioxygenase (IDO) and inhibit T cell proliferation in vitro. IDO-positive APCs constituted a discrete subset identified by coexpression of the cell-surface markers CD123 and CCR6. In the dendritic cell (DC) lineage, IDO-mediated suppressor activity was present in fully mature as well as immature CD123+ DCs. IDO+ DCs could also be readily detected in vivo, which suggests that these cells may represent a regulatory subset of APCs in humans. 相似文献
72.
Antonello Santini Antonia Šrobárová Ján Pavlovkin Milada Čiamporová Alberto Ritieni 《European journal of plant pathology / European Foundation for Plant Pathology》2008,120(4):363-371
The possible role of the fusariotoxin, fusaproliferin in plant pathology was investigated with respect to cell membrane potential.
Electron microscopy was used to study both the early effect of fusaproliferin on the host’s plasma membrane and ultrastructure
responses in the cells of maize leaves. The seedlings of resistant (Lucia) and susceptible (Pavla) to the fusaproliferin maize
cultivars were grown in the presence of fusaproliferin at different concentrations, namely 5 and 35 μg ml−1, respectively, and electrophysiological measurements were compared with those obtained using two different toxic compounds,
namely fusicoccin and 3-3(3,4 dichlorophenyl)-1,1-dimethylurea (DCMU). It was observed that only the higher concentration of fusaproliferin induced the onset of visible symptoms on the
leaves. Comparing the effect of fusaproliferin to that of fusicoccin and DCMU at the higher toxin concentration, it was observed
that functional differences in membrane potential induced severe damage to the mesophyll and outer chloroplast membrane; the
extent of changes in electrophysiology and ultrastructure disturbances depended on the toxin concentration and was greater
in the susceptible cv. Pavla. Results indicated that fusaproliferin could be involved in Fusarium pathogenesis either as a virulence factor or by enhancing the activity of other toxins that might be concomitantly present
in infected plants. 相似文献
73.
74.
75.
Victoria Martínez-Blay Jesica Pérez-Rodríguez Alejandro Tena Antonia Soto 《Journal of pest science》2018,91(2):625-637
Delottococcus aberiae De Lotto (Hemiptera: Pseudococcidae) is a new invasive citrus pest in Spain. It causes severe fruit distortions and, as a new invasive mealybug, there is a lack of information about its biology. This research aims to examine the seasonal trend of D. aberiae in citrus, using several sampling methods, as a first step to develop an integrated pest management program. Ten citrus orchards from Eastern Spain were periodically sampled during three years using absolute (plant material) and relative (corrugated cardboard band traps and sticky traps) sampling methods. The three sampling methods showed that D. aberiae completes multiple generations per year, two of them being clearly defined and resulting in high populations. D. aberiae peaked between May and June, damaging the developing fruit. Corrugated cardboard band traps were able to detect prepupa and pupa male instars and gravid females, providing a quantitative measurement of D. aberiae density at its first population peak. The use of corrugated cardboard band traps is recommended to monitor population levels and sticky traps to determine male flight periods, representing simple sampling techniques to monitor D. aberiae. These results will improve the sampling protocols and allow for the development of an integrated pest management program. 相似文献
76.
Koutsidis G De la Fuente A Dimitriou C Kakoulli A Wedzicha BL Mottram DS 《Journal of agricultural and food chemistry》2008,56(15):6105-6112
The effect of different sugars and glyoxal on the formation of acrylamide in low-moisture starch-based model systems was studied, and kinetic data were obtained. Glucose was more effective than fructose, tagatose, or maltose in acrylamide formation, whereas the importance of glyoxal as a key sugar fragmentation intermediate was confirmed. Glyoxal formation was greater in model systems containing asparagine and glucose rather than fructose. A solid phase microextraction GC-MS method was employed to determine quantitatively the formation of pyrazines in model reaction systems. Substituted pyrazine formation was more evident in model systems containing fructose; however, the unsubstituted homologue, which was the only pyrazine identified in the headspace of glyoxal-asparagine systems, was formed at higher yields when aldoses were used as the reducing sugar. Highly significant correlations were obtained for the relationship between pyrazine and acrylamide formation. The importance of the tautomerization of the asparagine-carbonyl decarboxylated Schiff base in the relative yields of pyrazines and acrylamide is discussed. 相似文献
77.
ABSTRACT Coevolution of the angular leaf spot pathogen, Phaeoisariopsis griseola, with its common bean host has been demonstrated, and P. griseola isolates have been divided into Andean and Mesoamerican groups that correspond to defined bean gene pools. Recent characterization of P. griseola isolates from Africa has identified a group of isolates classified as Andean using random amplified polymorphic DNA (RAPD), but which are able to infect some Mesoamerican differential varieties. These isolates, designated Afro-Andean, have been identified only in Africa. Random amplified microsatellites, RAPD, and restriction digestion of amplified ribosomal intergenic spacer region were used to elucidate the relationships among the Afro-Andean, Andean, and Mesoamerican groups of P. griseola. Cluster and multiple correspondence analysis of molecular data separated isolates into Andean and Meso-american groups, and the Afro-Andean isolates clustered with Andean isolates. Analysis of molecular variance ascribed 2.8% of the total genetic variation to differences between Afro-Andean and Andean isolates from Africa. Gene diversity analysis revealed no genetic differentiation (G(ST) = 0.004) between Afro-Andean and Andean isolates from Africa. However, significant levels of genetic differentiation (G(ST) = 0.39) were observed between Afro-Andean or Andean isolates from Africa and Andean isolates from Latin America, revealing significant geographical differentiation within the Andean lineage. Results from this study showed that Afro-Andean isolates do not constitute a new P. griseola group and do not represent long-term evolution of the pathogen genome, but rather are likely the consequents of point mutations in genes for virulence. This finding has significant implications in the deployment of resistant bean genotypes. 相似文献
78.
Antonia Srobarova Antonio Moretti Rosalia Ferracane Alberto Ritieni Antonio Logrieco 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(4):299-306
The occurrence of Fusarium species of Liseola section and related toxins was investigated for two years (1996 and 1998) on maize ear rot samples collected in the most important areas for maize growing in Slovakia. The species most frequently isolated was F. verticillioides, followed by F. proliferatum in 1996 and F. subglutinans in 1998. Most of the strains belonged to mating populations A, D, and E of the teleomorph Gibberella fujikuroi. Fusarium graminearum was also frequently recovered in both the years of investigations. Toxin analysis of maize ears showed that most of the samples (21 out of 22) were contaminated with at least one toxin. In particular, the concentration of fumonisin B1, and fumonisin 2 was up to 26.9 and 5.1gg-1, respectively in 1996, and up to 12.1 and 6.3gg-1, respectively in 1998. Beauvericin was detected only in one sample in 1996. Seven samples in 1996 were contaminated by fusaproliferin up to 8.2gg-1, but just traces of the toxin were found in one sample in 1998. All 29 strains of F. verticillioides, two of three strains of F. proliferatum and none of eight F. subglutinans strains isolated from samples produced fumonisin B1 in culture on whole maize kernels (0.1–5646 and 940–1200ugg-1, respectively). Two strains of F. subglutinans and two of F. proliferatum produced beauvericin (up to 65 and 70gg-1, respectively). Ten strains of F. verticillioides produced beauvericin: 9 strains produced a low amount (up to 3gg-1), while only one of them produced a high level of toxin (375gg-1). Fusaproliferin was produced by two F. proliferatum strains (220 and 370gg-1), by seven F. subglutinans (20–1335gg-1) and by three F. verticillioides (10–35gg-1). This is the first report on fusaproliferin production by F. verticillioides, although at low level. 相似文献
79.
- 1. Invasive species may have direct effects on native species, such as predation or competition, as well as indirect effects such as altering habitat or the behaviour of a native species. Indirect effects can be difficult to detect, but whole‐system removal of invasive species presents an excellent opportunity for revealing these more subtle effects.
- 2. American bullfrogs were introduced to California in the late 1800s and have been implicated in the declines of native ranid species. Invasive American bullfrogs were removed from a series of 12 ponds to test for changes in microhabitat use of federally threatened California red‐legged frogs, using a neighbouring field site with six ponds as a control.
- 3. There was a marked increase in the total number of adult California red‐legged frogs seen in all of the ponds after the first year of bullfrog removal, suggesting that these adults were in the ponds, but hiding when invaders were present. Ontogenetic partitioning of habitat in this species was documented, as well as a shift in that partitioning and increased hiding behaviour with adult bullfrog presence. California red‐legged frogs used willows significantly more as cover, and were found on bare shores half as often when adult bullfrogs were present.
- 4. These results support recent suggestions that behavioural responses of prey to predators can play a substantial role in total predator effects and suggest that careful management of invasive species may be necessary to accurately evaluate population sizes of this threatened amphibian species.