先导的

Pymetrazine is chosed as the lead compound, and 21 compounds were firstly designed and synthesized. These compounds were characterized by introducing phenyl derivatives with different functional groups to replace pyridine ring with the isosteric principle and the method of homogeneous synthesis and reasonable biologically designing in order to find new compounds with potential biological activity. These compounds were confirmed by IR, H NMR and MS spectra.

本文选取吡蚜酮为先导化合物，运用电子等排理念，综合类同合成、生物合理设计的方法，引入含有不同官能团的苯基衍生物替代吡蚜酮的结构中心吡啶环，设计合成了21个未见文献报道的化合物，寻找具有潜在生物活性的新三嗪酮类化合物，通过核磁共振氢谱、红外光谱、质谱等手段进行了结构表征，并验证正确。

So the study on chemical constituents towards Laurencia can enrich the knowledge of this genus and provide a new way for seeking the lead compounds of new medicine.

因此研究凹顶藻Laurencia的化学成分，可以丰富人们对该种属的认识，同时对寻找新的药物先导化合物提供重要的依据。

On terms that develop market economy and interests pluralistically today, to make at all levels government bodies and his staff member admit and take serving administrative idea inside really in terms of agreement is thought guide to advance administrative information opening.

在今天发展市场经济和利益多元化的条件下，使各级政府机关及其工作人员从契约的角度真正认同、内化服务行政的观念是推进行政信息公开的思想先导。

Firstly, corona inception voltage of the post insulator and surface leader inception voltage of the bushing versus relative humidity were investigated. The predischarge phenomena in connection with relative humidity were observed under AC voltage by photographing.

首先，对支柱绝缘子的电晕起始电压及套管表面先导起始电压与空气相对湿度的关系进行了研究；用静止照相的方法分别观察了支柱绝缘子和套管在不同相对湿度范围内的工频预放电现象。

Among them, pyrazole and its derivatives play an important part, exhibit better bioactivity and are becoming one kind of the most important leading structures in the fields of the organic synthesis.

在这些化合物中，吡唑类的化合物，尤其是吡唑类的芳环化合物被发现有着广泛的生物活性，因此成为了重要的药物研究先导结构，在很多有机合成及生物代谢过程中起着承上启下的中间体作用。

Hageman, Ph.D., group director for discovery pharmaceutics for Bristol-Myers Squibb Company in Princeton, New Jersey."There's a growing push to quickly identify unacceptable biopharmaceutical properties and toxicologic effects, using the most advanced technologies available, thus eliminating compounds with poor properties early."

Hageman博士说：&我们面临越来越大的压力去使用如今世界上最先进的技术尽快鉴定出不合适的生物药学特性以及毒性，从而尽早淘汰掉那些具有不良特性的先导化合物。&

To use phage display construction antibody library, trabant peptide library, protein mutant library and cDNA library, thus generally using this technology to screen single chain antibody, le...

利用噬菌体表面展示技术可以构建抗体库、随机肽库、蛋白质突变体库和cDNA文库，从而广泛用于单链抗体的筛选、先导化合物的筛选、疫苗的研制等，尤其是在单链抗体、模拟抗原表位的筛选及建立食品安全快速检测体系方面，具有广阔的应用前景。

In order to search for new types of highly active and low toxic pesticides, we considered alternaric acid as a lead compound and considered 5, 6-dihydro-2H-pyran2, 4-diones as a patent structure, designed and synthesized seven series of 5, 6-dihydro2H-pyran-2, 4-diones derivatives, tested their fungicidal, herbicidal and tobacco virucidal activities.

为了寻找高效低毒的农药品种，以交链孢酸为先导化合物，以5，6-二氢-6-烷基-2H-吡喃-2，4-二酮的结构为母体结构，设计并合成了七个系列的2，4-吡喃二酮化合物，用〓H NMR、〓C NMR、质谱和元素分析证明了其结构，并测试了部分化合物的杀菌、除草和抗烟叶病毒的活性。

In the past 30 years,every innovation of theory and practice would start from mind emancipating,which is the forerunner of reform and opening.

30年来，改革开放的每一个重大的实践活动和理论创新，都是由思想解放开始的，思想解放是改革开放实践的先导。

In order to realize the optimization of product combination effectively, it is important to correctly distinguish dominant product, forerunning product and line of dominant products. In this dissertation, we build a model to cognize the dominant product, forerunning product and line of dominant products on the base of statistic theory.

本文运用统计理论建立了企业主导产品、先导产品及产品链群的认定模型，帮助企业有效控制和优化产品结构；以产品所含特征要素与企业特征要素的相似性分析及逼近理想解的排序法为基础，采取定性分析与定量分析相结合的方式，建立了多属性产品组合决策模型。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。