Perhaps you should try some spelling variations:
hanh gian » thanh gian, thanh giang, manh giang
sanh ky » hanh ky, sang ky, nganh ky
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
hieu va » lieu va, hieu qua
ma hoi » mai hoi, xa hoi, ma hoa
do va » do van, so va
bo va » bao va, so va, co va

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

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