Perhaps you should try some spelling variations:
viet tech » viet sach
hieu viet » sieu viet, hieu viec, lieu viet
tech nuoc » dich nuoc, sach nuoc
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
va dauh » va danh, va doanh
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
va dau » va dao
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ky nang ma hoi. hieu viet tech nuoc ((va dauh) or (va dau)) di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang ma hoi. hieu viet tech nuoc ((va dauh) OR (va dau)) di cua tre.
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang ma hoi. hieu viet tech nuoc ((va dauh) or (va dau)) di cua tre*.