unobtainable
adj. 难获得的；不能得到的
例句
Tickets seem unobtainable to the ordinary mortal.
票对于普通大众来说似乎是得不到的。
《柯林斯英汉双解大词典》
Fish was unobtainable in certain sections of Tokyo.
在东京的某些地方无法买到鱼。
From the Middle East the Chinese acquired a blue pigment—a purified form of cobalt oxide unobtainable at that time in China—that contained only a low level of manganese.
中国人从中东获得了一种蓝色颜料，这是一种当时在中国很难得到的纯净的氧化钴，这种颜料只含有少量的锰。
