Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
thanh kim » thanh liem, thanh kinh, khanh kiem
thuc van » thuc vat, thuc dan, thuc va
hanh ky » hanh kem
hanh ki » hanh vi, hanh kien, hanh kem
tu sach » thu sach, su sach, te sach
sach vu » sach va, sach tu, sach uu
va tham » van tham, va cham, va thanh
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
vu nang » vuc nang, va nang, vu dang
su viet » so viet
ma hoi » mai hoi, xa hoi, ma hoa

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 vu nang ma hoi. hieu va tham thuc van ((((hanh ki) or (thanh kim))) or (hanh ky)) su viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach vu nang ma hoi. hieu va tham thuc van ((((hanh ki) OR (thanh kim))) OR (hanh ky)) su viet.
• Adding a wildcard symbol may retrieve word variants: tu sach vu nang ma hoi. hieu va tham thuc van ((((hanh ki) or (thanh kim))) or (hanh ky)) su viet*.