Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
luc nhan » luc nhat, cu nhan, tue nhan
thi hang » thi hanh, thi nang, thi hong
luc phan » duc phan, luan phan, thuc phan
dang va » dang van, dang vat, hang va
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
ty nang » ky nang, ty xang, ty hang
va cau » van cau, va cac, va dau
ve cam » ve cham, ve cac, va cam

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