Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
tham thuc » nham thuc, tam thuc, thai thuc
hieu van » hieu va, thien van, lieu va
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
tu san » thu san, tu ban, tu can
vi cua » vai cua, di cua
tu sai » tu bai, tu cai, tu lai

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sai) OR (tu san)) ky nang ma hoi. hieu van ((tham thuc) or (pham thuc)) va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sai) OR (tu san)) ky nang ma hoi. hieu van ((tham thuc) OR (pham thuc)) va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sai) OR (tu san)) ky nang ma hoi. hieu van ((tham thuc) or (pham thuc)) va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sai) OR (tu san)) ky nang ma hoi. hieu van ((tham thuc) or (pham thuc)) va hanh vi cua tre*.