全文获取类型
收费全文 | 177篇 |
免费 | 9篇 |
国内免费 | 3篇 |
专业分类
林业 | 8篇 |
农学 | 6篇 |
41篇 | |
综合类 | 12篇 |
农作物 | 38篇 |
水产渔业 | 4篇 |
畜牧兽医 | 62篇 |
园艺 | 1篇 |
植物保护 | 17篇 |
出版年
2022年 | 5篇 |
2021年 | 11篇 |
2020年 | 1篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 5篇 |
2016年 | 9篇 |
2015年 | 6篇 |
2014年 | 6篇 |
2013年 | 14篇 |
2012年 | 16篇 |
2011年 | 16篇 |
2010年 | 8篇 |
2009年 | 9篇 |
2008年 | 13篇 |
2007年 | 7篇 |
2006年 | 9篇 |
2005年 | 5篇 |
2004年 | 4篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 4篇 |
2000年 | 2篇 |
1999年 | 4篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1971年 | 2篇 |
1968年 | 1篇 |
1965年 | 2篇 |
1963年 | 2篇 |
排序方式: 共有189条查询结果,搜索用时 250 毫秒
171.
172.
In this study, we examined the protective effects of porphyra-334 against UVA-irradiated cellular damage and elucidated the underlying mechanisms. Porphyra-334 prevented UVA-induced cell death and exhibited scavenging activities against intracellular oxidative stress induced by UVA irradiation in skin fibroblasts. We found that porphyra-334 significantly reduced the secretion and expression of IL-6 and TNF-α, reduced nuclear expression of Nuclear factor-κB (NF-κB), and sustained NF-E2-related factor 2 (Nrf2) activation. Further mechanism research revealed that porphyra-334 promoted the Nrf2 signaling pathway in UVA-irradiated skin fibroblasts. Our results show that the antioxidant effect of porphyra-334 is due to the direct scavenging of oxidative stress and its inhibitory effects on NF-κB-dependent inflammatory genes, such as IL-6 and TNF-κ. Therefore, we hypothesize that boosting the Nrf2- NF-κB-dependent response to counteract environmental stress is a promising strategy for the prevention of UVA-related damage. 相似文献
173.
Haibo Zhang Chenggang Liang Kiyoshi Kawai Ken-ichi Takane Ryu Ohsugi 《Plant Production Science》2016,19(2):267-278
We report the effect of the introduction of a fungal glutamate dehydrogenase gene (gdhA) into forage rice (cv. Momiroman) by analyzing the transgenic rice plants in terms of growth, source function, and nitrogen contents. NADP (H)-dependent glutamate dehydrogenase activities in the gdhA-transgenic lines were markedly higher than those in non-transgenic control plants. Plant growth analysis at the seedling stage revealed that the leaf area and shoot and root dry weights of the high gdhA-expressors were higher than those of control plants under both high (high N) and low nitrogen (low N) conditions. These results suggested that the source ability was enhanced by the gdhA introduction. This was supported by the fact that the net photosynthesis rate at the heading stage was also higher in transgenic than in control leaves. Furthermore, under both high and low N conditions, the nitrogen contents in the shoots and roots, at seedling and grain-harvest stages, were significantly higher in high gdhA-expressors than in control plants, indicating that nitrogen uptake was higher in transgenic than in control plants. At the harvest stage, the high gdhA-expressors exhibited greater panicle and spikelet numbers per plant compared with control plants, resulting in higher grain weight, under the high N conditions. In addition, gdhA expression in forage rice significantly enhanced their tolerance to salt stress compared to control plants. The present study showed that the introduction of a fungal gdhA into forage rice could lead to higher source ability, better growth and higher grain weight by enhancing nitrogen uptake efficiency. 相似文献
174.
Jun-Sik Lim Eutteum Kim Pan-Dong Ryu Son-Il Pak 《Journal of veterinary science (Suw?n-si, Korea)》2021,22(5)
BackgroundAfrican swine fever (ASF) is a hemorrhagic fever occurring in wild boars (Sus scrofa) and domestic pigs. The epidemic situation of ASF in South Korean wild boars has increased the risk of ASF in domestic pig farms. Although basic reproduction number (R0) can be applied for control policies, it is challenging to estimate the R0 for ASF in wild boars due to surveillance bias, lack of wild boar population data, and the effect of ASF-positive wild boar carcass on disease dynamics.ObjectivesThis study was undertaken to estimate the R0 of ASF in wild boars in South Korea, and subsequently analyze the spatiotemporal heterogeneity.MethodsWe detected the local transmission clusters using the spatiotemporal clustering algorithm, which was modified to incorporate the effect of ASF-positive wild boar carcass. With the assumption of exponential growth, R0 was estimated for each cluster. The temporal change of the estimates and its association with the habitat suitability of wild boar were analyzed.ResultsTotally, 22 local transmission clusters were detected, showing seasonal patterns occurring in winter and spring. Mean value of R0 of each cluster was 1.54. The estimates showed a temporal increasing trend and positive association with habitat suitability of wild boar.ConclusionsThe disease dynamics among wild boars seems to have worsened over time. Thus, in areas with a high elevation and suitable for wild boars, practical methods need to be contrived to ratify the control policies for wild boars. 相似文献
175.
Bullerman LB Bianchini A Hanna MA Jackson LS Jablonski J Ryu D 《Journal of agricultural and food chemistry》2008,56(7):2400-2405
This study was designed to determine the efficacy of extrusion in reducing fumonisin B1 in corn flaking grits in the presence and absence of glucose. In addition, degradation products of fumonisin B1 during extrusion were identified and quantitated with a mass balance approach. Uncontaminated clean corn grits, grits spiked with 30 microg/g fumonisin B1, and grits fermented with Fusarium verticillioides M-2552 (40-50 microg/g fumonisin B1) were extruded in the presence and absence of glucose (10%, w/w) using a single-screw extruder. Extrusion decreased fumonisin B1 by 21-37%, whereas the same process with added glucose further decreased fumonisin B1 by 77-87%. LC-fluorescence and LC-MS showed that most fumonisin in the extruded samples without added glucose was the fumonisin B1 form, whereas the main degradation product in grits extruded with glucose was N-(deoxy- d-fructos-1-yl)fumonisin B1. The formation of hydrolyzed fumonisin B1 was not significant during extrusion. Results suggest that extrusion in the presence of glucose may reduce fumonisin B1 in corn grits significantly. 相似文献
176.
Multivariate analysis of nitrogen content for rice at the heading stage using reflectance of airborne hyperspectral remote sensing 总被引:4,自引:0,他引:4
Airborne hyperspectral remote sensing was adapted to establish a general-purpose model for quantifying nitrogen content of rice plants at the heading stage using three years of data. There was a difference in dry mass and nitrogen concentration due to the difference in the accumulated daily radiation (ADR) and effective cumulative temperature (ECT). Because of these environmental differences, there was also a significant difference in nitrogen content among the three years. In the multiple linear regression (MLR) analysis, the accuracy (coefficient of determination: R2, root mean square of error: RMSE and relative error: RE) of two-year models was better than that of single-year models as shown by R2 ≥ 0.693, RMSE ≤ 1.405 g m−2 and RE ≤ 9.136%. The accuracy of the three-year model was R2 = 0.893, RMSE = 1.092 g m−2 and RE = 8.550% with eight variables. When each model was verified using the other data, the range of RE for two-year models was similar or increased compared with that for single-year models. In the partial least square regression (PLSR) model for the validation, the accuracy of two-year models was also better than that of single-year models as R2 ≥ 0.699, RMSE ≤ 1.611 g m−2 and RE ≤ 13.36%. The accuracy of the three-year model was R2 = 0.837, RMSE = 1.401 g m−2 and RE = 11.23% with four latent variables. When each model was verified, the range of RE for two-year models was similar or decreased compared with that for single-year models. The similarities and differences of loading weights for each latent variable depending on hyperspectral reflectance might have affected the regression coefficients and the accuracy of each prediction model. The accuracy of the single-year MLR models was better than that of the single-year PLSR models. However, accuracy of the multi-year PLSR models was better than that of the multi-year MLR models. Therefore, PLSR model might be more suitable than MLR model to predict the nitrogen contents at the heading stage using the hyperspectral reflectance because PLSR models have more sensitive than MLR models for the inhomogeneous results. Although there were differences in the environmental variables (ADR and ECT), it is possible to establish a general-purpose prediction model for nitrogen content at the heading stage using airborne hyperspectral remote sensing. 相似文献
177.
Woong Yoon Min Young Lee Jung Min Ryu Yong Ju Moon Sang Hun Lee Jae Hong Park Seung Pil Yun Min Woo Jang Sung Su Park Ho Jae Han 《Journal of veterinary science (Suw?n-si, Korea)》2010,11(1):9-13
Multidetector row computed tomography (MDCT) provides anatomical information about the kidney and other internal organs. Presently, the suitability of 64-channel MDCT to assess the kidney of healthy micropigs was evaluated. Morphological evaluations of the kidney and the major renal vessels of six healthy micropigs were carried out using MDCT, recording kidney volume and the diameter and length of renal arteries and veins. The mean diameters and lengths of the renal artery were 0.44 ± 0.05 and 4.51 ± 0.55 cm on the right side and 0.46 ± 0.06 and 3.36 ± 0.27 cm on the left side, respectively. The mean diameters and lengths of the renal vein were 1.44 ± 0.52 and 4.22 ± 1.29 cm on the right side and 1.38 ± 0.17 and 5.15 ± 0.87 cm on the left side, respectively. The mean volume of the right kidney was 79.3 ± 14.5 mL and of the left kidney was 78.0 ± 13.9 mL. The data presented in this study suggest that the MDCT offers a noninvasive, rapid, and accurate method for the evaluation of the renal anatomy in living kidney donors. It also provides sufficient information about extra-renal anatomy important for donor surgery and determination of organ suitability. 相似文献
178.
LI Tian Ryu OHSUGI Tohru YAMAGISHI Haruto SASAKI 《水稻科学》2006,13(1):51-58
Photosynthetic product in rice plant is transported to grains mainly in the form of sucrose. Sucrose in the grains eventually becomes starch through a series of enzymatic reactions [1-2]. The starch weight accounts for 90% of the brown rice [3-4], so the course of the rice grain filling is the biochemical process in which starch is mainly formed, and the factor of light is indispensable at the course. Much research has been conducted to study the influence of the light on the grain starch synt… 相似文献
179.
LI Tian LIU Qi-hua Ryu OHSUGI Tohru YAMAGISHI Haruto SASAKI 《水稻科学》2006,13(3):205-210
Global warming is due to continuous increase in greenhouse effect caused by human productive activities. Much attention has been paid to the influence brought by the increase of temperature on crop growth. Many researches in China and other countries are … 相似文献
180.
灌浆结实期弱光对水稻籽粒蔗糖及其降解酶活性的影响 总被引:6,自引:2,他引:4
选用IR72(籼稻)和日本睛(粳稻),在开花后遮光处理,对弱光条件下籽粒蔗糖含量的动态变化和降解酶的活性进行了研究。结果表明:两品种籽粒的蔗糖含量减少,蔗糖分解加快,蔗糖合成酶(SS)活性下降,液泡型转化酶(VCI)和细胞壁结合型转化酶(WCI)活性提高。即在弱光条件下,转化酶活性的提高加快了蔗糖的分解。相关分析表明,蔗糖合成酶活性、细胞壁结合型转化酶活性与淀粉积累速率显著正相关。说明这两种酶在蔗糖的分解和淀粉的合成过程中起着十分重要的作用。 相似文献