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

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 ma) or (nang x)) hoi. hieu ve ((cam tuc) or (am thuc)) van hanh vai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang ma) OR (nang x)) hoi. hieu ve ((cam tuc) OR (am thuc)) van hanh vai cau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang ma) or (nang x)) hoi. hieu ve ((cam tuc) or (am thuc)) van hanh vai cau tren*.