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Ohne Zusammenfassung 相似文献
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This study was conducted to examine whether the applications of N-inputs (compost and fertilizer) having different N isotopic compositions (δ15N) produce isotopically different inorganic-N and to investigate the effect of soil moisture regimes on the temporal variations in the δ15N of inorganic-N in soils. To do so, the temporal variations in the concentrations and the δ15N of NH4+ and NO3− in soils treated with two levels (0 and 150 mg N kg−1) of ammonium sulfate (δ15N=−2.3‰) and compost (+13.9‰) during a 10-week incubation were compared by changing soil moisture regime after 6 weeks either from saturated to unsaturated conditions or vice versa. Another incubation study using 15N-labeled ammonium sulfate (3.05 15N atom%) was conducted to estimate the rates of nitrification and denitrification with a numerical model FLUAZ. The δ15N values of NH4+ and NO3− were greatly affected by the availability of substrate for each of the nitrification and denitrification processes and the soil moisture status that affects the relative predominance between the two processes. Under saturated conditions for 6 weeks, the δ15N of NH4+ in soils treated with fertilizer progressively increased from +2.9‰ at 0.5 week to +18.9‰ at 6 weeks due to nitrification. During the same period, NO3− concentrations were consistently low and the corresponding δ15N increased from +16.3 to +39.2‰ through denitrification. Under subsequent water-unsaturated conditions, the NO3− concentrations increased through nitrification, which resulted in the decrease in the δ15N of NO3−. In soils, which were unsaturated for the first 6-weeks incubation, the δ15N of NH4+ increased sharply at 0.5 week due to fast nitrification. On the other hand, the δ15N of NO3− showed the lowest value at 0.5 week due to incomplete nitrification, but after a subsequence increase, they remained stable while nitrification and denitrification were negligible between 1 and 6 weeks. Changing to saturated conditions after the initial 6-weeks incubation, however, increased the δ15N of NO3− progressively with a concurrent decrease in NO3− concentration through denitrification. The differences in δ15N of NO−3 between compost and fertilizer treatments were consistent throughout the incubation period. The δ15N of NO3− increased with the addition of compost (range: +13.0 to +35.4‰), but decreased with the addition of fertilizer (−10.8 to +11.4‰), thus resulting in intermediate values in soils receiving both fertilizer and compost (−3.5 to +20.3‰). Therefore, such differences in δ15N of NO3− observed in this study suggest a possibility that the δ15N of upland-grown plants receiving compost would be higher than those treated with fertilizer because NO3− is the most abundant N for plant uptake in upland soils. 相似文献
3.
Hyeshin Hwang Younghye Ro Hyunkyoung Lee Jihyeon Kim Kyunghyun Lee Eun-Jin Choi You-Chan Bae ByungJae So Dohoon Kwon Ho Kim Inhyung Lee 《Journal of veterinary science (Suw?n-si, Korea)》2022,23(5)
BackgroundSince 2013, the number of requests for diagnosis for horses based on neurological symptoms has increased rapidly in South Korea. The affected horses have commonly exhibited symptoms of acute seasonal hindlimb ataxia. A previous study from 2015–2016 identified Setaria digitata as the causative agent.ObjectivesThis study is an epidemiological investigation to find out risk factors related to the rapid increase in hindlimb ataxia of horses due to aberrant parasites in South Korea.MethodsAn epidemiological investigation was conducted on 155 cohabiting horses in 41 horse ranches where the disease occurred. The surrounding environment was investigated at the disease-causing horse ranches (n = 41) and 20, randomly selected, non-infected ranches.ResultsHindlimb ataxia was confirmed in nine cohabiting horses; this was presumed to be caused by ectopic parasitism. Environments that mosquitoes inhabit, such as paddy fields within 2 km and less than 0.5 km from a river, had the greatest association with disease occurrence.ConclusionsMost horse ranches in South Korea are situated in favorable environments for mosquitoes. Moreover, the number of mosquitoes in the country has increased since 2013 due to climate change. Additional research is required; however, these data show that it is necessary to establish guidelines for the use of anthelmintic agents based on local factors in South Korea and disinfection of the environment to prevent disease outbreaks. 相似文献
4.
Hemoglobin G Taegu, an electrophoretically slow hemoglobin with a structural anomaly believed to be in the beta-T-3 section of the beta chain, was the only variant found among 6700 normal Koreans. Four subjects, 0.06 percent, had the G-hemoglobin variant in addition to normal hemoglobin A. Hemoglobin E, known in numerous groups from Southeast Asia and the variant most frequently seen in Chinese subjects, was not found among the Koreans we tested. 相似文献
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Anna Ro?en 《Soil biology & biochemistry》2006,38(1):180-182
The study was conducted on Dendrobaena octaedra—a small epigeic earthworm species common in different forest types. In the laboratory the P (parent animals collected in forest) and F1 generations were cultured separately in containers filled with 50 g artificial soil. The containers were kept at 15±0.5 °C, 80% humidity and constant artificial light of low intensity. Every month during the 47 months of culture, the animals and cocoons were removed from the soil by washing on a sieve, weighed, and replaced into new soil. Individuals of the F1 generation did not reproduce continuously. Cocoon production was seasonal, despite culture in constant conditions throughout the whole experiment. Reproduction was highest in spring and summer, and dropped in the winter months. Seasonality characterized the fraction of animals reproducing as well as the number of cocoons produced. The observed seasonal changes in the cocoon production of the F1 generation cultured in constant conditions suggest that internal regulation of reproduction may exist in the earthworm D. octaedra. External factors like temperature, moisture, photoperiod or food supply, which could be responsible for seasonality of reproduction were missing. 相似文献
7.
Seok-In Yun Hee-Myong Ro Woo-Jung Choi Gwang-Hyun Han 《Journal of Soils and Sediments》2011,11(7):1253-1261
Purpose
Although nitrification plays a key role in the fate of soil nitrogen (N) under global warming, little information is available for the nitrifiers’ response to changing temperatures. Nitrogen isotope fractionation associated with nitrification can be a proxy of nitrifiers’ sensitivity to changing temperature. We hypothesized that the temperature-induced balance between the transport of substrate NH4+ into the microbial cell (supply) and the intracellular NH4+ oxidation (consumption) governs the intracellular NH4+ concentration and then affects nitrification rates and associated isotope fractionations. This study was conducted to understand the microbial response of NH4+ oxidation to changing temperatures by examining the effect of changing temperature on nitrification rate and apparent isotope fractionation. 相似文献8.
9.
Lunder Mojca Roškar Irena Hošek Jan Štrukelj Borut 《Plant foods for human nutrition (Dordrecht, Netherlands)》2019,74(1):47-53
Plant Foods for Human Nutrition - The diet rich in fruits and vegetables reduces the risk of metabolic syndrome, including diabetes development by various mechanisms of action, mainly due to the... 相似文献
10.
Binod Prasad Luitel Na-Young Ro Ho-Cheol Ko Jung-Sook Sung Ju-Hee Rhee On-Sook Hur 《Journal of Crop Science and Biotechnology》2018,21(5):499-506
A total of 47 core collections of pepper (Capsicum chinense Jacq.) conserved in National Agrobiodiversity Center (NAC) were studied under field condition at Jeonju over two consecutive years (2015 and 2016). All accessions were characterized for their 14 qualitative and 16 quantitative characters. Results revealed that both qualitative and quantitative characters exhibited wide variation among the studied germplasm. Distribution of fruit characters (fruit length, width, and fruit wall thickness) among the accessions was positively skewed. Of the 47 accessions evaluated, 38.3% accessions had conical shaped fruits and mature fruit color was predominantly red (51.1%), orange (21.3%) and yellow (14.9%). Principal component analyses revealed that (i) 56.64% of the qualitative (fruit shape, color and fruit surface) variation and (ii) 89.42% of the quantitative (plant width, height and fruit maturity days) variation were explained by the first two components. Clustering revealed two groups and dendrogram revealed morphological variation among accessions. The phenotypic diversity exists in this core collections provide valuable information to improve agronomic traits in pepper breeding program. 相似文献