Perhaps you should try some spelling variations:
thuc dan » thuc hanh, hoc dan, thuc vat
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
ky tang » ky nang, ky dang, kho tang
tang ma » mang may, tang van
van cam » van nam, van lam, van cau
sach ky » sac ky, sach y, sach ty
cua tu » cua tuc, cua su, cua te
luc va » duc va, tuc va, loc va
ma hoi » mai hoi, xa hoi, ma hoa
cua cu » cua chu, cua cau, cua su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky tang ma hoi. hieu van cam ((luc va) or (thuc dan)) thanh thieu ((cua tu) OR (cua cu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky tang ma hoi. hieu van cam ((luc va) OR (thuc dan)) thanh thieu ((cua tu) OR (cua cu))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky tang ma hoi. hieu van cam ((luc va) or (thuc dan)) thanh thieu ((cua tu) OR (cua cu))*".