Perhaps you should try some spelling variations:
trinh viet » ninh viet, trinh vat
vien cac » vien bach, vien dai, gian cac
viet cua » viec cua, viet ca, viet qua
sach thu » sach thue, sach thieu, sach tham
va trinh » van trinh, va tinh, lap trinh
vien da » vien dai, hien dai
tang ma » mang may, tang van
sach ty » sach y, sach tu, xach tay
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
dac va » duc va, day va, dat va

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ty) or (sach thu)) tang ma hoi. hieu ((vien cac) OR (vien da)) dac va trinh viet cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach thu)) tang ma hoi. hieu ((vien cac) OR (vien da)) dac va trinh viet cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) or (sach thu)) tang ma hoi. hieu ((vien cac) OR (vien da)) dac va trinh viet cua tre*".