Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
cau tren » cu tren, dau tren, ca tren
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
va cham » va chat, va tham
cham oc » cham soc, cham o, cham hoi
hanh va » hang va, hanh vi
oc van » hoc van, luoc van, quoc van
va cau » van cau, va cac, va dau

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 ((nang xa) or (nang ma)) hoi. lieu va cham oc van hanh va cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y ((nang xa) OR (nang ma)) hoi. lieu va cham oc van hanh va cau tren*.