Perhaps you should try some spelling variations:
phap thuc » phap thu, phap hoc, phap tu
tham thuc » nham thuc, pham thuc, tam thuc
sach kho » bach khoa, sach dao, sach nha
kho tang » cao tang
su sach » so sach, vu sach
hanh le » thanh le, hanh ve, hanh de
va hanh » van hanh, va thanh, va danh
mai hoi » mai khoi, dai hoi, lai hoi
ma hoi » xa hoi, ma hoa, me hoi
le cua » ly cua
cua te » cua tu

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 kho tang ((ma hoi) OR (mai hoi)). lieu va ((tham thuc) or (phap thuc)) va hanh le cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach kho tang ((ma hoi) OR (mai hoi)). lieu va ((tham thuc) OR (phap thuc)) va hanh le cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach kho tang ((ma hoi) OR (mai hoi)). lieu va ((tham thuc) or (phap thuc)) va hanh le cua te".
• Adding a wildcard symbol may retrieve word variants: su sach kho tang ((ma hoi) OR (mai hoi)). lieu va ((tham thuc) or (phap thuc)) va hanh le cua te*.