以下色谱分离方法中,按照流动相中溶质分子与固定相相互作用的机理不同表述正确的是( )①吸附色谱;②分配色谱;③离子交换色谱;④凝胶色谱;⑤柱色谱;⑥纸色谱;⑦超临界流体色谱;⑧正相色谱;⑨反相色谱。
A. ⑧⑨
B. ⑤⑥⑦
C. ①②⑤⑥
D. ①②③④
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传统吸附剂中,无机吸附剂是( )
A. 活性炭
B. 氧化铝
C. 纤维素
D. 淀粉
Apical ramification is more common in()
A. the maxillary incisors
B. the canines
C. the mandibular incisors
D. the molars
E. None of the above is correct.
The permanent teeth that erupt first in the mouth and do not replace any deciduous teeth are()
A. the central incisors
B. the lateral incisors
C. the canines
D. the first premolars
E. the first molars
The elevations of the crown includes()
A. the deformed lingual fossa
B. the inclined planes
C. the developmental groove
D. the ridges
E. the fissure
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