Perhaps you should try some spelling variations:
lang van » dang van, tang van, hoang van
thu sach » thuat sach, thuoc sach, thu hoach
cham hoc » cham soc, chat hoc, cham hoi
va hanh » van hanh, va thanh, va danh
vu cham » va cham, vu kham, tu cham
hieu vu » hieu va, hieu ve, hieu su
tu sach » su sach, te sach, tu cach
lang ha » long ha
cu tren » tu tren, dua tren
vi cu » vi su, vi xu, vi du

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) or (thu sach)) y ((lang ha) or (lang van)) hoi. hieu vu cham hoc va hanh vi cu tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) y ((lang ha) OR (lang van)) hoi. hieu vu cham hoc va hanh vi cu tren.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) y ((lang ha) or (lang van)) hoi. hieu vu cham hoc va hanh vi cu tren*.