您要查找的是不是：
- 素plain
- 像素pixel
- 肾上腺素adrenalin
- 护发素hair conditioner
- 这样的全才是很难得的。Such a universal genius is hard to come by.
- 霉素zymoid
- 老狐狸难得陷罗网。An old fox is not easily snared.
- 生物素biotin
- 这样的机会极其难得。Such a chance comes once in a blue moon.
- 素的etic
- 我难得有空。I am seldom at leisure.
- 精华素essence; quintessence
- 弹力素elastin
- 头孢菌素cephalosporin
- 核素nuclide
- 阿霉素adriamycin
- 番茄红素lycopene
- 凝集素agglutinin
- 白细胞介素interleukin
- 阿奇霉素azithromycin
