Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang mai » nang ma, nang tai, lang mai
mai khoi » mai khoa, tai khoa, cac khoi
hanh tai » thanh tai, han tai, hinh tai
hang tai » hang va, dung tai
tu sach » thu sach, su sach, te sach
cac duc » cac du, cao duc, cac dac
duc ban » duc tan, duc van, dua ban
buu tre » cuu tre

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) or (toc sach)) ky nang mai khoi. lieu va cac duc ban ((hanh tai) or (hang tai)) buu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (toc sach)) ky nang mai khoi. lieu va cac duc ban ((hanh tai) OR (hang tai)) buu tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) ky nang mai khoi. lieu va cac duc ban ((hanh tai) or (hang tai)) buu tre*.