Perhaps you should try some spelling variations:
va thieu » va thiet, va hieu, va tieu
van chat » cao chat
nang mai » nang ma, nang tai, lang mai
mai hoi » mai khoi, dai hoi, lai hoi
ve chat » va chat
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
tu sach » thu sach, su sach, te sach
xac va » tac va, ac va, bac va
luc va » duc va, tuc va, loc va
vi va » vi van, vai va, vu va

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 ty nang mai hoi. hieu ((ve chat) OR (van chat)) ((xac va) or (luc va)) hanh vi va thieu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang mai hoi. hieu ((ve chat) OR (van chat)) ((xac va) OR (luc va)) hanh vi va thieu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang mai hoi. hieu ((ve chat) OR (van chat)) ((xac va) or (luc va)) hanh vi va thieu".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang mai hoi. hieu ((ve chat) OR (van chat)) ((xac va) or (luc va)) hanh vi va thieu*.