Perhaps you should try some spelling variations:
trinh vat » trinh van, trinh luat, sinh vat
trinh ve » trinh he, trinh va, trinh vi
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
cac duc » cac du, cao duc, cac dac
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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 ky nang ma hoi. hieu va cac duc va ((trinh ve) or (trinh vat)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ma hoi. hieu va cac duc va ((trinh ve) OR (trinh vat)) cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ma hoi. hieu va cac duc va ((trinh ve) or (trinh vat)) cua tre*.