Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
truc va » thuc va, thuc vat, trung va
hieu ve » hieu va, hieu van
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
luc va » duc va, tuc va, loc va
vi cau » va cau, ve cau, di cau
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 y ((nang xa) or (lang xa)) hoi. hieu ve cam ((luc va) or (truc va)) hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang xa) OR (lang xa)) hoi. hieu ve cam ((luc va) OR (truc va)) hanh vi cau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang xa) or (lang xa)) hoi. hieu ve cam ((luc va) or (truc va)) hanh vi cau tren*.