Perhaps you should try some spelling variations:
dang matu » dang mau, dang vat, dong mau
tham thuc » nham thuc, pham thuc, tam thuc
su triet » su viet, su tien, ve triet
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
dang mat » dang vat, dang mau, dung mat
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
su sach » so sach, vu sach
hanh ki » hanh vi, hanh ky, hanh kien
tu sach » thu sach, te sach, tu cach
ki su » ky 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) or (su sach)) vu ((dang mat) or (dang matu)) hoi. hieu va tham thuc van hanh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) vu ((dang mat) OR (dang matu)) hoi. hieu va tham thuc van hanh ki su triet.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) vu ((dang mat) or (dang matu)) hoi. hieu va tham thuc van hanh ki su triet*.