Perhaps you should try some spelling variations:
tham thuc » tam thuc, thai thuc, thach thuc
pham thuc » phap thuc, pham chuc, pham thu
nham thuc » nhan thuc, nam thuc, nham thu
hieu van » hieu va, thien van, lieu va
cau tren » cu tren, dau tren, ca tren
nang ma » tang ma, sang ma, nang cao
va hanh » van hanh, va thanh, va danh
tu bai » tu ban, tu bat, te bai
bai ky » ban ky, sai ky, bac ky
ma hoi » mai hoi, xa hoi, ma hoa
vi cau » va cau, ve cau, di cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu bai ky nang ma hoi. hieu van ((tham thuc) or (((pham thuc) or (nham thuc)))) va hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu bai ky nang ma hoi. hieu van ((tham thuc) OR (((pham thuc) OR (nham thuc)))) va hanh vi cau tren.
• Adding a wildcard symbol may retrieve word variants: tu bai ky nang ma hoi. hieu van ((tham thuc) or (((pham thuc) or (nham thuc)))) va hanh vi cau tren*.