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排序方式: 共有126条查询结果,搜索用时 15 毫秒
81.
本文提出检验总体分位数的基于排序集挑选抽样的符号检验,分析了不同挑选设计相对于均衡设计的Pitman渐近效率。具体给出不同分位数的最优设计,并且最优设计不依赖于总体分布。 相似文献
82.
Spectrum–effect relationship between HPLC fingerprints and antioxidant activity of Angelica sinensis
Qin Fan Ruijing Yang Feixia Yang Pengfei Xia Lei Zhao 《Biomedical chromatography : BMC》2020,34(2):e4707
Angelica sinensis is one of the most important traditional Chinese medicines and has antioxidant activities that greatly contribute to its pharmacological action. However, the compounds responsible for its antioxidant activity remain unknown. In this study, the fingerprints of 10 batches of A. sinensis collected from different locations in China were established with HPLC to identify the common peaks. The antioxidant activities of these 10 batches were evaluated with 2,2-diphenyl-1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, and ferric-reducing antioxidant power assays. The spectrum–effect relationship between HPLC fingerprints and antioxidant effect of A. sinensis was examined by the partial-least-square regression analysis and the variable importance in projection method. Results showed that the antioxidant effect of A. sinensis results from the synergistic effect of various compounds, and peaks X3 and X7–X18 were the main substances responsible for antioxidant efficacy. This study successfully identified the spectrum–effect relationship between HPLC fingerprints and the antioxidant effect of A. sinensis. This relationship can provide methods for establishing the quality standards for A. sinensis and developing new and effective products of A. sinensis based on its antioxidant ingredients. 相似文献
83.
84.
Research indicates that teacher efficacy influences student achievement and is situation specific. With the Next Generation Science Standards calling for the incorporation of engineering practices into K–12 classrooms, it is important to identify teachers’ engineering teaching efficacy. A study of K–5 teachers’ engineering self‐efficacy and engineering teaching efficacy revealed that that they have low engineering self‐efficacy and low teacher efficacy related to engineering pedagogical content knowledge. Additionally, significant differences existed in self‐efficacy levels based on gender, ethnicity, Title I school status, and grade level taught. 相似文献
85.
史璐瑜 《广东微量元素科学》2017,24(1)
目的 分析伴有盆腔黏连的妇科腹腔镜手术临床应用价值。方法 选择2015年3月至2016年3月珠海市妇幼保健院收治的伴有盆腔黏连妇科疾病患者96例,随机分为两组,各48例。对照组采用传统开腹手术,观察组应用腹腔镜手术。比较两组手术疗效及手术情况。结果观察组手术总有效率为95.8%,明显高于对照组的83.2%,差异有统计学意义(P0.05);观察组手术时间、出血量及住院时间分别为(76.7±9.4)min、(45.6±4.7)m L、(4.6±1.3)d,均明显少于对照组[(89.3±10.2)min、(98.4±11.6)m L、(10.3±2.4)d],差异有统计学意义(P0.05)。结论 伴有盆腔黏连的妇科腹腔镜手术应用价值显著,是一种安全可靠的盆腔黏连治疗手段,值得推广。 相似文献
86.
用反相高效液相色谱(RP-HPLC)法测定了马来酸噻吗洛尔眼用凝胶剂中噻吗洛尔的含量,并对制剂的药效进行了考察.色谱条件:Diamonsil C18色谱柱(4.6 mm×250 mm,5μm),流动相为甲醇-水-三乙胺(50∶50∶0.1,磷酸调节pH值到5.0),流动相流速1.0 mL.min-1,检测波长295 nm,柱温30℃.在上述色谱条件下,分别进行了线性、精密度、稳定性、回收率、样品含量测定等实验.结果表明,本检测方法简便、精确,适于马来酸噻吗洛尔眼用凝胶剂中噻吗洛尔含量的测定.该药物凝胶剂的药效优于滴眼液. 相似文献
87.
讨论有不服从发生时,临床试验数据EV模型中的参数估计和检验问题.在以前结果的基础上,文中给出模型中公共参数的一个改进估计,提出了一个药物治疗效果的检验方法.最后通过模拟研究考察上述估计和检验的效果。 相似文献
88.
Anti-DHBV (duck hepatitis B virus) activity was found in the aqueous extracts of Sophora flavescens Ait. in vivo. Liquid chromatography/electrospray ionization ion trap mass spectrometry was applied to characterize the components in duck serum after oral administration of S. flavescens extract. Oxymatrine (1), sophoranol (2), sophoridine (3) and matrine (4) were identified in the serum. Further research on the four compounds was evaluated for their antiviral activity against HBV (hepatitis B virus) in cell culture. The results suggested that oxymatrine, sophoranol and matrine were the efficacy substances for anti-HBV activity in aqueous extracts of S. flavescens Ait. 相似文献
89.
This paper considers sign test under ranked set sampling with unequal set sizes (RSSU), and proposes weighted sign tests associated with judgment ranks. The optimal weight vector is shown to be distribution-free, and RSSU is shown to be more efficient than ranked set sampling. 相似文献
90.
A central concept for understanding social dilemma behavior is the efficacy of an actor's cooperative behavior in terms of increasing group well-being. We report a decision and game theoretical analysis of efficacy in step-level public goods (SPGs). Previous research shows a positive relation between efficacy and contributions to SPGs and explains this relation by a purely motivational account. We show, however, that from a decision and game theory perspective an increasing relationship is not general, but only follows from very specific assumptions about players’ information and beliefs. We offer 3 examples of how the predicted efficacy–contribution relation depends on players’ information and beliefs. We discuss the implications of our results for the social psychology of efficacy in social dilemmas. 相似文献