Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
cua viet » ca viet, hoa viet, cua vat
mai khoa » tai khoa, may khoa, dai khoa
va thanh » gia thanh, ban thanh, va tinh
viec bao » viec ban, viec lam, viec va
lang mai » lang dai, lang hai, lang man
tu lang » cu lang, tu lanh, xu lang
bao tuc » bao thuc, dao tuc, bao luc
va hanh » van hanh, va danh, ban hanh
te sach » toc sach
vai cua » dai cua, hai cua, lai cua
tu sach » thu sach, su sach, tu cach

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (te sach)) tu lang mai khoa. hieu viec bao tuc ((va hanh) OR (va thanh)) vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) tu lang mai khoa. hieu viec bao tuc ((va hanh) OR (va thanh)) vai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (te sach)) tu lang mai khoa. hieu viec bao tuc ((va hanh) OR (va thanh)) vai cua viet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) tu lang mai khoa. hieu viec bao tuc ((va hanh) OR (va thanh)) vai cua viet*.