Perhaps you should try some spelling variations:
thien van » thi van
vat hanh » vat thanh, van hanh, va hanh
thu sach » tu sach, thuat sach, thuoc sach
mai hoi » mai khoi, dai hoi, lai hoi
sach ho » sach hoi, sach ha, sach lo
hieu va » lieu va, hieu qua
thu vat » thuc vat, thu va, thuat vat
ho nang » thi nang, kha nang, cao nang
hanh vu » hanh vi, hanh va, hanh tu
va viet » hoa viet, san viet, mai viet
ma hoi » xa hoi, ma hoa, me hoi
vu va » vu van, tu va, su va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ho nang ((ma hoi) or (mai hoi)). ((thien van) or (hieu va)) nam thu vat hanh vu va viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ho nang ((ma hoi) OR (mai hoi)). ((thien van) OR (hieu va)) nam thu vat hanh vu va viet.
• Adding a wildcard symbol may retrieve word variants: thu sach ho nang ((ma hoi) or (mai hoi)). ((thien van) or (hieu va)) nam thu vat hanh vu va viet*.