Perhaps you should try some spelling variations:
duoc lam » duoc pham, duoc ly, duoc li
hieu van » hieu va, thien van, lieu va
nang ma » tang ma, sang ma, nang cao
sach ly » sach y, sach lo, sach hay
sach ty » sach y, sach tu, sach thu
hanh va » hang va, hanh vi
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
va cua » va chua, via cua, ca cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc ((sach ly) OR (sach ty)) nang ma hoi. hieu van nam ((duoc ma) or (duoc lam)) hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc ((sach ly) OR (sach ty)) nang ma hoi. hieu van nam ((duoc ma) OR (duoc lam)) hanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc ((sach ly) OR (sach ty)) nang ma hoi. hieu van nam ((duoc ma) or (duoc lam)) hanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc ((sach ly) OR (sach ty)) nang ma hoi. hieu van nam ((duoc ma) or (duoc lam)) hanh va cua tre*.