Perhaps you should try some spelling variations:
toc sach » thuoc sach, nuoc sach, toc san
doc sach » nuoc sach, dac sac, bo sach
hanh tai » thanh tai, hang tai, han tai
hoc sach » hoc sinh, hoc cac, hoc anh
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
hieu va » lieu va, hieu qua
cao tuc » dao tuc, cao duc, cao suc
va hanh » van hanh, va thanh, va danh
tai cua » thai cua, tai cuc, tri cua
va cao » va cac, va co, va dao
tuc va » thuc va, truc va, tuc xa
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((toc sach) OR (hoc sach))) or (doc sach)) ky tang xa hoi. hieu va cao tuc va hanh tai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((toc sach) OR (hoc sach))) OR (doc sach)) ky tang xa hoi. hieu va cao tuc va hanh tai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((toc sach) OR (hoc sach))) or (doc sach)) ky tang xa hoi. hieu va cao tuc va hanh tai cua te".
• Adding a wildcard symbol may retrieve word variants: ((((toc sach) OR (hoc sach))) or (doc sach)) ky tang xa hoi. hieu va cao tuc va hanh tai cua te*.