Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
danh vai » danh sai, danh va, doanh van
vai cuu » vai cua
truc va » thuc va, trung va
van cam » van nam, van lam, van cau
sach ky » sac ky, sach y, sach ty
tang ma » mang may, tang van
cuu tre » cua tre, cau tren, cau treo
ma hoi » mai hoi, xa hoi, ma hoa
sai ky » sac ky

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 ky) or (sai ky)) tang ma hoi. hieu van cam ((truc va) OR (thuc vat)) danh vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sai ky)) tang ma hoi. hieu van cam ((truc va) OR (thuc vat)) danh vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sai ky)) tang ma hoi. hieu van cam ((truc va) OR (thuc vat)) danh vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sai ky)) tang ma hoi. hieu van cam ((truc va) OR (thuc vat)) danh vai cuu tre*.