Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
hieu ve » hieu va, hieu van
lua tre » cua tre, luy tre, dua tren
y nang » ky nang, ly nang, v nang
ve cac » va cac, vien cac
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
vi lua » vi luu
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) y nang x hoi. hieu ve cac nuoc va dan vi lua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y nang x hoi. hieu ve cac nuoc va dan vi lua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) y nang x hoi. hieu ve cac nuoc va dan vi lua tre*.