您要查找的是不是：
- 甾择环A stereoselective ring A
- 苯并卟啉衍生物单酸环A photosensitizer
- 环A的子集S叫作A的子环。 A subset S of a ring A is a subring of A.
- 环 loop
- 本组化合物的HOMO、LUMO主要分布在母环A环和B环的C 3位到N 6位这一区域以及O 2 1位上 ; The component of HOMO and LUMO mainly distributed from C-3 to N-6 and O-21 on the ring A,B;
- 甾 steroid nucleus
- 择日 choose an auspicious day
- 环比 link relative ratio
- 不仅A而且 not merely A but also B
- 圆环 traffic circle
- 与其说A不如说 not so much A as B
- 环的 annular
- A股 A-share
- 环氧 epoxy
- 把A误以为 take A for B
- 环氧乙烷 epoxy ethane
- 环己 hexanaphthene
- 苋甾酮A amarasterone A
- 外环 outer ring
- 环保护 ring protection
