首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   100篇
  免费   3篇
林业   5篇
农学   1篇
  10篇
综合类   6篇
农作物   7篇
水产渔业   8篇
畜牧兽医   59篇
植物保护   7篇
  2022年   8篇
  2021年   8篇
  2020年   1篇
  2019年   2篇
  2018年   2篇
  2017年   6篇
  2016年   2篇
  2015年   5篇
  2014年   1篇
  2013年   1篇
  2012年   6篇
  2011年   10篇
  2010年   5篇
  2009年   3篇
  2008年   4篇
  2007年   3篇
  2006年   3篇
  2005年   8篇
  2004年   2篇
  2003年   8篇
  2002年   7篇
  2001年   4篇
  2000年   4篇
排序方式: 共有103条查询结果,搜索用时 15 毫秒
81.
In this study, we investigated the effects of oral ingestion of Lactobacillus crispatus KT‐11 strain (KT‐11) on the immune response in an allergic rhinitis mouse model, ovalbumin (OVA)‐sensitized BALB/c mice. Sneezing activity in mice that were administered a KT‐11‐supplemented diet was significantly lower than that in mice administered a KT‐11‐free diet (control diet) at age 11 weeks. We found that serum OVA‐specific immunoglobulin E (IgE) levels and total number of interleukin (IL)‐4+CD4+ spleen cells in mice that were administered a KT‐11‐supplemented diet were significantly lower than in mice administered a control diet. The ratio of spleen interferon‐γ+CD4+/IL‐4+CD4+ cells was higher in the mice administered the KT‐11‐supplemented diet compared to that in mice administered the control or L. rhamnosus GG‐supplemented diet. In contrast, the number of CD11b+CD80+ and FcεRIα+CD117+ cells was significantly lower in mice administered the KT‐11‐supplemented diet. These results suggested that KT‐11 reduced OVA‐induced allergic symptoms in BALB/c mice via the adjustment of the T helper type 1/T helper type 2 balance, and a decrease in the number of antigen‐presenting cells and high affinity IgE receptor‐positive mast cells.  相似文献   
82.
We report the isolation and characterization of CjNdly, a homolog in Japanese cedar (Cryptomeria japonica D. Don) of the FLORICAULA/LEAFY (FLO/LFY) genes. We determined the entire nucleotide sequence of CjNdly, including short 5'- and 3'-untranslated regions. The deduced amino acid sequence was similar to those of the products of the FLO/LFY genes from other species. The nucleotide sequence showed the closest homology to that of the NEEDLY gene in Pinus radiata D. Don. Although no proline-rich region has been reported previously in homologous gene products from gymnosperms, we found such a region at the amino-terminal end of the deduced amino acid sequence encoded by CjNdly. We detected the expression of CjNdly in both reproductive and vegetative tissues and organs of C. japonica. Heterologous expression of CjNdly in transgenic tobacco plants induced precocious flowering of regenerating shoots on agar-solidified medium and flowers with an abnormal phenotype, namely, petal-like stamens. Our findings suggest that the CjNdly gene may have important roles in flower development in Japanese cedar, resembling those of its angiosperm homologs.  相似文献   
83.
For soil water and solute transport research, time domain reflectometry (TDR) has been commonly used since its introduction to soil research in 1980 by Topp and his colleagues. Although TDR seems to be very versatile for laboratory and field experiments, it requires modest user skills for accurate measurements and the instrument itself is still expensive. A new soil moisture and electrical conductivity (EC) sensor was recently developed at a reduced cost. The new sensor independently measures soil water content, and soil bulk electrical conductivity using frequency phase-shift techniques, and soil temperatures using a thermistor. We evaluated the new sensor for measurements of water content, and EC using three different sensors in variably saturated soils. There was little deviation among the units for water content measurement except at near saturation. Separate exponential curves provided good calibrations for all the soils used in the full range of water content between air-dry and saturation. In saline water up to 54 mS m?1, the mV output in the EC measurement mode was linearly related to solution EC. Although slopes were quite similar among the three sensors, the intercepts differed from the manufacturer’s calibration. The calibrations for volumetric water content and electrical conductivity provided by the manufacturer were not good enough for any use. The temperature effect on volumetric water content could be negligible or easily compensated with a simple formula. Little EC dependency of the sensor on volumetric water content was observed.  相似文献   
84.
Soil salinity is a major environmental stress causing significant loss of crop productivity. Barley (Hordeum vulgare L.) is one of the few field crops that can grow in salt-affected fields and varietal differences in productivity under salinity conditions were known. To clarify the trait most responsible for grain production under salt stress, barley cultivars that were salt tolerant (OUE812) or salt sensitive (OUC613) were grown from seedling to harvest stage in vermiculite containing various concentrations of NaCl. Dry weight of aboveground parts and grain weight decreased significantly with increasing NaCl concentration. The dry weight of the aboveground parts and grain weight decreased more significantly in OUC613 than in OUE812 for plants treated with 150 mM and 200 mM NaCl. A marked reduction in ripening percentage caused significantly decreased grain production in OUC613 as compared with OUE812. In plants treated with 200 mM NaCl, the photosynthetic rate decreased three weeks after starting the NaCl treatment, but a significant difference between cultivars in photosynthetic rate did not appear until seven weeks of NaCl treatment. OUE812 kept a higher photosynthetic rate during ripening than did OUC613 and dry matter production during the period from ripening to harvest was significantly larger in OUE812 than in OUC613. Keeping a higher photosynthetic rate might have contributed to higher grain production in OUE812. Higher ripening percentage and higher rate of photosynthesis during ripening might be target traits in breeding to improve the tolerance of barley to long-term salt stress.  相似文献   
85.
In the Japanese macaque, semen has been collected by electro-ejaculation (EE), using the higher voltage stimuli compared to other species including genus Macaca. Semen coagulates immediately after ejaculation, which makes difficult to produce high-quality semen for artificial insemination. Recently, semen collection using urethral catheterization (UC) has been reported in carnivore and this technique may allow semen collection without coagulation in a less invasive manner. Further, the temporal preservation temperature and cooling rate of semen during cryopreservation affect post thawing sperm quality. In this study, to improve semen quality and quantity, as well as the animal welfare, semen collection was performed by EE with high (5–15 V) or low (3–6 V) voltage, UC and a combination of the two (EE-UC). It has been suggested that a high voltage is necessary for semen collection, but 10 V stimulation was effective enough and 15 V is for additional sperm collection. Also, liquid semen was collected by EE-UC and this could increase the total number of sperm. Further, to improve the post thawing sperm motility, semen was kept at four temperatures (4, 15, 25 and 37°C) for 60 min, and processed with two cooling procedures (slow cooling before second dilution and fast cooling after second dilution). Holding semen at 25°C and fast cooling after the second dilution maintained progressive motile sperm rate. The present results will contribute to the improvement of semen collection and animal welfare of Japanese macaques.  相似文献   
86.
The agricultural fields were contaminated by the radionuclides 134Cs and 137Cs after the nuclear power plant accident in Fukushima. Prior to the accident, local farmers had successfully established sustainable agriculture in Iitate Village using natural farming practices and recycling. Since 2011, decontamination work such as stripping-off the top soil has been ongoing on agricultural land. Although decontamination is essential, it could cause an unfortunate decrease in soil fertility. Here, we examined the use of organic matter as a means to quickly recover the fertility of the agricultural top soil. We transplanted rice crops into three paddy plots: one received rice straw that had been harvested there last year, another received composted manure, and the third (control) received no additives after decontamination. We applied 40 kg/10a of basal fertilizer and 20 kg/10a of KCl each plot. The rates of Cs concentration in unhulled rice/rice straw were around 0.001. Tendency of plant heights increase and leaf chlorophyll content decrease were similar in the three treatment plots. However, the numbers of stems on 111 days after the transplant were 21, 15, and 19, unhulled rice yield were 513, 462, and 310 g/m2, in the rice straw, cattle manure compost, and control plots, respectively. Soil properties of three plots were similar. Radioactive Cs concentrations in the new rice from each treatment plots were lower than the maximum allowed level set by the Japanese government. These results revealed that treating soil with rice straw might have great potential to aid the recovery of a paddy field after stripping-off the top soil. Notably, this treatment significantly improved the yield of rice and supplied organic matter without additional labor.  相似文献   
87.
The aim of the present study was to evaluate the effects of continuous administration of linoleic acid or linolenic acid into the intra-uterine horn, ipsilateral to the corpus luteum, on the duration of the estrous cycle and plasma progesterone (P4) concentration. The effects of linoleic and linolenic acids on bovine uterine and luteal functions were also studied using a tissue culture system. Intra-uterine administration of linoleic or linolenic acid (5 mg/10 ml of each per day) in cows, between days 12 and 21, resulted in a prolonged estrous cycle compared to the average duration of the last one to three estrous cycles before administration in each group (P < 0.05). Moreover, plasma P4 concentration in cows treated with linoleic or linolenic acid was high between days 19 and 21 (linoleic acid), or on day 20 (linolenic acid), compared to that of the control cows (saline administration; P < 0.05 or lower). Both linoleic (500 µg/ml) and linolenic (5 and 500 µg/ml) acids stimulated prostaglandin (PG) E2 but inhibited PGF2α production by cultured endometrial tissue (P < 0.01), while P4 production by cultured luteal tissue was not affected. These findings suggest that both linoleic and linolenic acids support luteal P4 production by regulating endometrial PG production and, subsequently, prolonging the duration of the estrous cycle in cows.  相似文献   
88.
Large highly pathogenic avian influenza (HPAI) outbreaks caused by clade 2.3.4.4e H5N6 viruses occurred in Japan during the 2016–2017 winter. To date, several reports regarding these outbreaks have been published, however a comprehensive study including geographical and time course validations has not been performed. Herein, 58 Japanese HPAI virus (HPAIV) isolates from the 2016–2017 season were added for phylogenetic analyses and the antigenic relationships among the causal viruses were elucidated. The locations where HPAIVs were found in the early phase of the outbreaks were clustered into three regions. Genotypes C1, C5, and C6–8 HPAIVs were found in specific areas. Two strains had phylogenetically distinct hemagglutinin (HA) and non-structural (NS) genes from other previously identified strains, respectively. The estimated latest divergence date between the viral genotypes suggests that genetic reassortment occurred in bird populations before their winter migration to Japan. Antigenic differences in 2016–2017 HPAIVs were not observed, suggesting that antibody pressure in the birds did not contribute to the selection of HPAIV genotypes. In the late phase, the majority of HPAI cases in wild birds occurred south of the lake freezing line. At the end of the outbreak, HPAI re-occurred in East coast region, which may be due to the spring migration route of Anas bird species. These trends were similar to those observed in the 2010–2011 outbreaks, suggesting there is a typical pattern of seeding and dissemination of HPAIV in Japan.  相似文献   
89.
Fisheries Science - The brittle star Ophiura sarsii with a disc diameter (DD) of less than 9&nbsp;mm is an important prey item for flathead flounder Hippoglossoides dubius in Funka...  相似文献   
90.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号