Perhaps you should try some spelling variations:
tham thuc » pham thuc, tam thuc, thai thuc
nham thuc » nhan thuc, nam thuc, nham thu
phap thuc » phap thu, phap hoc, phap tu
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
ky tang » ky nang, ky dang, kho tang
tang ma » mang may, tang van
sach ky » sac ky, sach y, sach ty
hanh ve » hanh vi, hanh va, hanh kem
ve cua » le cua, de cua, te cua
ma hoi » mai hoi, xa hoi, ma hoa
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 ky tang ma hoi. lieu va ((((tham thuc) OR (nham thuc))) or (phap thuc)) va hanh ve cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky tang ma hoi. lieu va ((((tham thuc) OR (nham thuc))) OR (phap thuc)) va hanh ve cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky tang ma hoi. lieu va ((((tham thuc) OR (nham thuc))) or (phap thuc)) va hanh ve cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ky tang ma hoi. lieu va ((((tham thuc) OR (nham thuc))) or (phap thuc)) va hanh ve cua te*.