obtain和attain 都含有"获得,达到"之意

obtain多指凭努力或恳求得到急需或很想得到的东西.

attain为正式用词,多用于庄重场合,主要指通过努力达到重要目的或得到珍贵的东西.

如：

Howard had failed to obtain a scholarship.霍华德没能得到奖学金.

The scientist attained great fame by a new discovery.

那科学家由于一次新发现而出了名.