Perhaps you should try some spelling variations:
cuu ngan » cuu nhan, cuu nan, cuu ngon
cua ngan » cua ban, vu ngan, cua dan
dau tren » dau tien, dat tren, dau tieng
tu sach » thu sach, su sach, te sach
ty nang » ky nang, ty xang, ly nang
ty hang » ly hang, ty xang, thi hang
hieu ve » hieu va, hieu van
ve cham » va cham, ve chat, vu cham
va dau » va dao

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) or (ty hang)) xa hoi. hieu ve cham ((cuu ngan) OR (cua ngan)) hang va dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ty hang)) xa hoi. hieu ve cham ((cuu ngan) OR (cua ngan)) hang va dau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) or (ty hang)) xa hoi. hieu ve cham ((cuu ngan) OR (cua ngan)) hang va dau tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty nang) or (ty hang)) xa hoi. hieu ve cham ((cuu ngan) OR (cua ngan)) hang va dau tren*.