Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
cua tre » cua te, cua triet, dua tren
luc van » luoc van, luu van, duc van
cam luc » cam xuc, cau luc
cuu tre » cau tren, cau treo
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
tang xa » trang xa, tang ma, tang ha
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 ((tang xa) or (lang xa)) hoi. hieu ve cam luc van hanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((tang xa) OR (lang xa)) hoi. hieu ve cam luc van hanh vi ((cua tre) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: tu sach y ((tang xa) or (lang xa)) hoi. hieu ve cam luc van hanh vi ((cua tre) or (cuu tre))*.