Perhaps you should try some spelling variations:
cham truc » cau truc, nham thuc, pham thuc
van hanh » van thanh, ban hanh, van anh
truc van » truc va, thuc van, truc ban
thu sach » tu sach, thuat sach, thuoc sach
hieu va » lieu va, hieu qua
va cham » va chat, va tham
sang ma » tang ma, nang ma, sang tao
de su » den su, ve su, da su
de tu » do tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y ((sang ma) or (mang may)) hoi. hieu va cham truc van hanh ((de su) or (de tu)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y ((sang ma) OR (mang may)) hoi. hieu va cham truc van hanh ((de su) OR (de tu)) triet.
• Adding a wildcard symbol may retrieve word variants: thu sach y ((sang ma) or (mang may)) hoi. hieu va cham truc van hanh ((de su) or (de tu)) triet*.