Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
hanh vai » hanh vi, hanh tai, hanh van
cau tren » cu tren, ca tren, cau treo
dang mai » dang hai, dang mau, dang bai
hieu van » hieu va, thien van, lieu va
van cham » van chat, van tham, va cham
hanh va » hang va, hanh vi
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
mai hoi » mai khoi, dai hoi, lai hoi
ky dang » ky nang, ky danh
soc va » hoc va, loc va, doc va

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 mai hoi. hieu van cham soc va ((hanh vai) or (hanh va)) ((cau tren) or (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang mai hoi. hieu van cham soc va ((hanh vai) OR (hanh va)) ((cau tren) OR (dau tren)).
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang mai hoi. hieu van cham soc va ((hanh vai) or (hanh va)) ((cau tren) or (dau tren))*.