Perhaps you should try some spelling variations:
hang tai » hang va, dung tai
hanh tai » thanh tai, han tai, hinh tai
hieu van » hieu va, thien van, lieu va
su sach » so sach, vu sach
sach ty » sach y, sach tu, sach thu
cua tre » cua te, cuu tre, cua triet
ty nang » ky nang, ty xang, ty hang
nang ma » tang ma, sang ma, nang cao
xa duc » xuan duc
ha duc » ho duc, ha dac, hoa duoc
ma hoi » mai hoi, xa hoi, ma hoa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ma hoi. hieu van ((ha duc) OR (xa duc)) van ((hanh tai) OR (hang tai)) cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang ma hoi. hieu van ((ha duc) or (xa duc)) van ((hanh tai) OR (hang tai)) cua tre~".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ma hoi. hieu van ((ha duc) or (xa duc)) van ((hanh tai) OR (hang tai)) cua tre*.