Perhaps you should try some spelling variations:
cham doc » cham soc, chat doc, chau doc
cau tren » cu tren, dau tren, ca tren
nang xa » lang xa, mang xa, ang xa
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
va cham » va chat, va tham
va hanh » van hanh, va thanh, va danh
hanh va » hang va, hanh vi
tu van » tu va
doc va » duoc va, hoc va, duc va
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: tu van ky ((((nang xa) or (nang ma))) or (nang x)) hoi. hieu va cham doc va hanh va cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu van ky ((((nang xa) OR (nang ma))) OR (nang x)) hoi. hieu va cham doc va hanh va cau tren.
• Adding a wildcard symbol may retrieve word variants: tu van ky ((((nang xa) or (nang ma))) or (nang x)) hoi. hieu va cham doc va hanh va cau tren*.