Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang tai » hang tai, tang tai, sang tai
hanh mai » hanh ma, hanh mau, hanh may
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
tai hoi » tai khoi, dai hoi, tai hai
hieu va » lieu va, hieu qua
va cham » va chat, va tham
luc va » tuc va, loc va
thiet » thieu

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 ty nang tai hoi. hieu va cham ((luc va) or (duc va)) hanh mai va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang tai hoi. hieu va cham ((luc va) OR (duc va)) hanh mai va thiet.
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang tai hoi. hieu va cham ((luc va) or (duc va)) hanh mai va thiet*.