Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
trinh ve » trinh he, trinh va, trinh vi
va trinh » van trinh, va tinh, lap trinh
vien dai » hien dai
nien dai » nhien dai, hien dai, bien dai
nang ma » tang ma, sang ma, nang cao
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
ve cua » le cua, de cua, te cua

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) or (su sach)) ky nang ma hoi. thieu ((nien dai) OR (vien dai)) duc va trinh ve cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (su sach)) ky nang ma hoi. thieu ((nien dai) OR (vien dai)) duc va trinh ve cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (su sach)) ky nang ma hoi. thieu ((nien dai) OR (vien dai)) duc va trinh ve cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (su sach)) ky nang ma hoi. thieu ((nien dai) OR (vien dai)) duc va trinh ve cua tre*.