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11.
基于NOAA/SWPC公布的太阳活动数据,我们选取第24太阳活动峰年附近的12个连续月份(2011年7月至2012年6月)和第23太阳活动周谷年附近的12个连续月份(2005年7月至2006年6月),统计了这两段时间中太阳黑子群和耀斑的活动规律,并根据时间、黑子群分布纬度、寿命和磁场类型等对峰年和谷年进行了详细分析和比较,主要结论如下所述.(1)黑子群数随时间的变化在峰年和谷年均比较随机,峰年期间黑子数比谷年增多1.5倍左右.耀斑爆发与黑子群活动具有良好的相关性,但峰年期间存在某个月份耀斑数很少的现象,而谷年期间存在某个月份耀斑数集中增多的现象.(2)无论峰年还是谷年,δ类型黑子群的耀斑产率(耀斑总数与黑子群总数之比)最大,但β型黑子群产生的耀斑爆发最多.耀斑产率与磁场类型有密切关系,但与其所处太阳活动周中的阶段无关.(3)黑子群和耀斑的纬度分布的南北不对称性,以X级耀斑最为显著.峰年较谷年的耀斑数增加主要集中在C级和M级.(4)耀斑产率同黑子群寿命具有良好的相关性,但黑子群的数目同它们的寿命之间没有明显的规律.  相似文献   
12.
Dozens of human cases infected with H7N9 subtype avian influenza virus (AIV) have been confirmed in China since March, 2013. Distribution data of sexes, ages, professions and regions of the cases were analyzed in this report. The results showed that the elderly cases, especially the male elderly, were significantly more than expected, which is different from human cases of H5N1 avian influenza and human cases of the pandemic H1N1 influenza. The outbreak was rated as a Grade Ⅲ (severe) outbreak, and it would evolve into a Grade IV (very severe) outbreak soon, using a method reported previously. The H7N9 AIV will probably circulate in humans, birds and pigs for years. Moreover, with the driving force of natural selection, the virus will probably evolve into highly pathogenic AIV in birds, and into a deadly pandemic influenza virus in humans. Therefore, the H7N9 outbreak has been assumed severe, and it is likely to become very or extremely severe in the future, highlighting the emergent need of forceful scientific measures to eliminate any infected animal flocks. We also described two possible mild scenarios of the future evolution of the outbreak.  相似文献   
13.
In wheat, plant height is an important agronomic trait, and a number of quantitative trait loci (QTLs) controlling plant height have been located. In this study, using the conditional and unconditional QTL mapping methods, combined with data from five different growth stages over two years of field trials, the developmental behavior for plant height in wheat was dissected. Nine unconditional QTLs and 8 conditional QTLs were identified, of which 6 were detected by both methods. None of the 11 QTLs was detected at all of the 5 investigated developmental stages, but 7 QTLs were detected at certain stages in both years. Further analysis identified 9 unconditional QTLs at different stages, which could explain the phenotypic variation from 4.81% to 17.35%. It was noteworthy that one major QTL designated QHt-4B-2, which was located on chromosome 4B, was detected on May 18 and 25 in both years, and its genetic contributions to plant height ranged from 13.42% to 16.13%. Moreover, of the 8 conditional QTLs identified, six were detected in both years, in the order of QHt-3BQHt-4B-1QHt-4B-2QHt-4DQHt-5A and QHt-2B expressed at the same developmental stage. The results indicate that QTL expression during plant height development is selective and in a temporal order.  相似文献   
14.
This letter reports a chemiluminescene immunoassay method combined with immunomagnetic separation to rapidly detect Cyfra 21-1, in which bio-functionlized magnetic nanocomposites were used as mobile substrate for capturing and isolating the cyfra 21-1 proteins. After the captured Cyfra 21-1 further reacted with horseradish peroxidase-conjugated anti-Cyfra 21-1 antibody to form a sandwich immunocomplex, the chemiluminescence would be produced as a result of addition of the chemiluminescent substrate. A home-made optical biosensor was designed to detect the chemiluminescence instead of other large instruments. There is a good linear response between the chemiluminescence intensity and the concentration of Cyfra 21-1 in the range from 0.2 to 50 ng/mL. The whole detection process including incubation, washing and detection could be performed within 45 min. The proposed method offers a simple, noninvasive and reliable tool for detecting non-small cell lung cancer and has potential application for clinical testing.  相似文献   
15.
从U (2 ) L ×U (2 ) R 手征孤立子模型出发 ,通过(πωf1 )模型考察了轴矢量介子 f1 (1 2 82 )对于孤立子转动惯量和重子多重态质量劈裂的影响。通过 f1 对转动惯量贡献的计算发现 :1 .f1 对于转动惯量具有一定的减小作用 ,但是量级很小 ,这表明以往忽略 f1 的研究是近似合理 ,f1 介子的引入可以略微增大质量劈裂 ;2 .在合理选取ω与重子流耦合常数的情况下 ,得到的静态质量与实验比较符合。这是首次对 f1 介子在手征孤立子模型中的效应进行定量估算。  相似文献   
16.
通过同位素稀释质谱法(IDMS)及电感耦合等离子体质谱(ICP-MS)外标法,研究了不同微波消解酸体系对聚氯乙烯重金属含量测量结果的影响。实验结果表明,单一的硝酸及过氧化氢体系不能将PVC样品完全消解,消解之后样品底部有大量残渣剩余,ICP-MS外标法与IDMS方法数据有较大偏差;采用IDMS方法对样品以及消解后残渣进行分析,发现PVC中元素已经与稀释剂发生了同位素交换并趋于平衡,证明了IDMS方法的可靠性;采用硝酸、盐酸及过氧化氢的混合酸体系实现了样品的完全消解,对其消解后的溶液采用ICP-MS外标法进行元素检测,结果与IDMS方法一致;同时,延长消解时间对样品的消解也有一定的促进作用。  相似文献   
17.
采用硅酸钾溶液作为成膜物,以硅溶胶和烷氧基硅烷为主要原料,制备出片状无机富锌涂料。结果表明,含40%(质量分数)锌的片状无机富锌涂料的耐盐雾时间超过3000h。该富锌涂料通过了720h划痕实验,阴极保护性能非常好。该涂料与环氧云铁中间漆复合后,在3.5%NaCl溶液中浸泡15?d的涂层阻抗值仍然处于10.9Ω/cm2以上,并且lg|Z|~lgf曲线的斜率一直保持-1左右。  相似文献   
18.
研究求解一类对称双正型的线性互补问题的EAOR迭代算法.证明了由此算法产生的迭代序列的聚点是线性互补问题的解.并且,当互补问题中的矩阵为对称双正加阵或严格对称双正阵时,算法产生的迭代序列存在子序列收敛到互补问题的解.而当矩阵为非退化对称双正加阵时,该序列收敛.  相似文献   
19.
用冶炼法合成LaNi5+TiFe0.5Mn0.1复合贮氢合金,研究了LaNi5+TiF0.5,Mn0.1合金的贮氢性能。研究结果表明:由于TiFe.9Mn0.1合金的加入,可有效地降低LaNi5的平台压力;当TiFe0.5Mn0.1的质量分数为15%左右时,放氢曲线中出现两个平台;TiFe0.9Mn0.1的质量分数趋于25%时,它的平台压力又逐渐升高,贮氢量逐渐增大,温度升高则第二个平台消失,贮氢量降低。该合金适用于低温贮氢。  相似文献   
20.
使用扫描电子显微镜、原子力显微镜和X射线衍射研究了多孔硅薄膜的微结构.SEM图像显示:多孔硅膜表面的微结构比较均匀;沿纵向方向薄膜内部空腔呈流线型分布;孔和孔之间的间距为10~20 nm.AFM形貌表明:其表面在1×1μm范围内的均方根粗糙度为4.75 nm.XRD结果说明:多孔硅薄膜晶体晶格常数随深度增加而变大,多孔硅薄膜孔壁上Si?H键的比例将减少.  相似文献   
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