Perhaps you should try some spelling variations:
cau tren » dau tren, ca tren, cau treo
hanh vai » hanh vi, hanh va, hanh tai
tu sach » thu sach, su sach, te sach
va hanh » van hanh, va thanh, va danh
cam tuc » cam xuc, cam tu, nam thuc
hieu ve » hieu va, hieu van
nang ma » tang ma, sang ma, nang cao
cu tren » tu tren, dua tren
ve cam » ve cham, ve cac, va cam
tuc va » thuc va, truc va, tuc xa

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 ma) or (nang x)) hoi. hieu ve cam tuc va hanh vai ((cau tren) OR (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang ma) OR (nang x)) hoi. hieu ve cam tuc va hanh vai ((cau tren) OR (cu tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang ma) or (nang x)) hoi. hieu ve cam tuc va hanh vai ((cau tren) OR (cu tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang ma) or (nang x)) hoi. hieu ve cam tuc va hanh vai ((cau tren) OR (cu tren))*.