Perhaps you should try some spelling variations:
tai thuoc » tri thuoc, bai thuoc, tac thuoc
nang mai » nang ma, nang tai, lang mai
hang tai » hang va, dung tai
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
ve cac » va cac, vien cac
tuc va » thuc va, truc va, tuc xa
tren » trien, tran, tien

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ty nang mai hoi. hieu ve cac ((duc va) or (tuc va)) hang tai thuoc tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang mai hoi. hieu ve cac ((duc va) OR (tuc va)) hang tai thuoc tren.
• Adding a wildcard symbol may retrieve word variants: su sach ty nang mai hoi. hieu ve cac ((duc va) or (tuc va)) hang tai thuoc tren*.