Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
cau treo » cau theo, cau triet, cau trieu
gia hanh » gia thanh, giao hanh, gia anh
sach thu » sach thue, sach thieu, sach tham
cac duc » cac du, cao duc, cac dac
duc gia » quoc gia
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
ve cac » va cac, vien cac

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 ky) or (sach thu)) lang xa hoi. hieu ve cac duc gia hanh vi ((cau treo) OR (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach thu)) lang xa hoi. hieu ve cac duc gia hanh vi ((cau treo) OR (cau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach thu)) lang xa hoi. hieu ve cac duc gia hanh vi ((cau treo) OR (cau tren))".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach thu)) lang xa hoi. hieu ve cac duc gia hanh vi ((cau treo) OR (cau tren))*.