Perhaps you should try some spelling variations:
thien van » thi van
hanh dao » lanh dao, thanh dat, thanh dam
hanh dai » hanh tai, vanh dai, thanh dat
chat tuc » chat xuc, luat tuc, chat huu
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
dang ma » dang mau, dang mam, dang mat
ky dang » ky nang, ky danh
ma hoi » mai hoi, xa hoi, ma hoa
thiet » thieu

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 dang ma hoi. ((hieu ve) or (thien van)) chat tuc xa ((hanh dai) OR (hanh dao)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang ma hoi. ((hieu ve) OR (thien van)) chat tuc xa ((hanh dai) OR (hanh dao)) va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang ma hoi. ((hieu ve) or (thien van)) chat tuc xa ((hanh dai) OR (hanh dao)) va thiet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang ma hoi. ((hieu ve) or (thien van)) chat tuc xa ((hanh dai) OR (hanh dao)) va thiet*.