Perhaps you should try some spelling variations:
hieu hien » bieu hien, dieu hien, chieu chien
hien bach » vien bach, thien hach, hien hanh
dung doi » huong doi, dung tai, dung co
duoc va » nuoc va, duc va, duoc ma
doi cua » dai cua, hoi cua
su sach » so sach, vu sach
tuoc va » thuoc va, nuoc va, tuc va
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
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 ty nang ma hoi. hieu hien bach ((tuoc va) or (duoc va)) dung doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ma hoi. hieu hien bach ((tuoc va) OR (duoc va)) dung doi cua tre.
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ma hoi. hieu hien bach ((tuoc va) or (duoc va)) dung doi cua tre*.