Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
cua viet » ca viet, hoa viet, cua vat
van hanh » van thanh, ban hanh, van anh
sach ty » sach y, sach tu, sach thu
hanh di » hanh vi, hanh de, hang di
luc van » luoc van, luu van, duc van
cam luc » cam xuc, cau luc
so sach » so sanh, bo sach, co sach
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
sang ma » tang ma, nang ma, sang tao
va cam » va cham, va cac, va cao

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ty ((sang ma) or (lang xa)) hoi. hieu va cam luc van hanh di ((cua viet) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty ((sang ma) OR (lang xa)) hoi. hieu va cam luc van hanh di ((cua viet) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: so sach ty ((sang ma) or (lang xa)) hoi. hieu va cam luc van hanh di ((cua viet) or (cau tren))*.