Perhaps you should try some spelling variations:
thanh vai » thanh hai, thanh van, thanh tai
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
vai cua » dai cua, hai cua, lai cua
cac dac » cac dan, cac dai, cac bac
cac duc » cac du, cao duc, cac nuoc
su sach » so sach
cao hoi » cau hoi, co hoi, cao hoc
tu nang » tru nang, tu nong, tu nano
vu sach » vu bach, vu khach

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) or (vu sach)) tu nang cao hoi. hieu van ((cac duc) OR (cac dac)) va thanh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) tu nang cao hoi. hieu van ((cac duc) OR (cac dac)) va thanh vai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu sach)) tu nang cao hoi. hieu van ((cac duc) OR (cac dac)) va thanh vai cua viet".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) tu nang cao hoi. hieu van ((cac duc) OR (cac dac)) va thanh vai cua viet*.