Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thanh vi » hanh vi, thanh va, thanh ve
va thanh » gia thanh, ban thanh, va tinh
ca viet » va viet, hoa viet, san viet
truc va » thuc va, thuc vat, trung va
van cau » van dau, van hau, van chat
so sanh » do sanh
co viet » so viet, o viet, hoc viet
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
y nang » ky nang, ly nang, v nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sanh) or (cho sinh)) y nang ma hoi. hieu van cau truc va thanh vi ((ca viet) OR (co viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sanh) OR (cho sinh)) y nang ma hoi. hieu van cau truc va thanh vi ((ca viet) OR (co viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sanh) or (cho sinh)) y nang ma hoi. hieu van cau truc va thanh vi ((ca viet) OR (co viet))".
• Adding a wildcard symbol may retrieve word variants: ((so sanh) or (cho sinh)) y nang ma hoi. hieu van cau truc va thanh vi ((ca viet) OR (co viet))*.