Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
thu sac » thu sach, thu san, thu xac
ky sang » ky nang, ky dang, ky tang
sang ma » tang ma, nang ma, sang tao
hieu va » lieu va, hieu qua
hac dat » hoc dat, tac dat, hoach dat
va hanh » van hanh, va thanh, va danh
sac ky » cac ky, sai ky
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sac ky sang ma hoi. ((hieu van) OR (hieu va)) hac dat va hanh vi cua vat~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sac ky sang ma hoi. ((hieu van) OR (hieu va)) hac dat va hanh vi cua vat*".