Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
cam truc » cau truc, nam truc, lam truoc
sang mai » sang ma, sang tai, lang mai
mai khoi » mai khoa, tai khoa, cac khoi
hieu va » lieu va, hieu qua
cu tren » tu tren, dua tren
sach ky » sac ky, sach ty, sach kem
hieu ve » hieu van
vi cu » vi su, vi xu, vi du

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 (sach y)) sang mai khoi. ((hieu ve) or (hieu va)) cam truc van hanh vi cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) sang mai khoi. ((hieu ve) OR (hieu va)) cam truc van hanh vi cu tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) OR (sach y)) sang mai khoi. ((hieu ve) or (hieu va)) cam truc van hanh vi cu tren*".