Perhaps you should try some spelling variations:
vu khach » vu khanh, vu khac, vay khach
vu sach » vu bach, su sach
nang ma » tang ma, sang ma, nang cao
cam luc » cam xuc, cau luc
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
lang xa » lang ha, dang xay, lang van
ve cam » ve cham, ve cac, va cam
luc va » duc va, tuc va, loc va
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu sach) OR (vu khach)) lo ((lang xa) or (nang ma)) hoi. hieu ve cam luc va dan vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (vu khach)) lo ((lang xa) OR (nang ma)) hoi. hieu ve cam luc va dan vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) OR (vu khach)) lo ((lang xa) or (nang ma)) hoi. hieu ve cam luc va dan vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu sach) OR (vu khach)) lo ((lang xa) or (nang ma)) hoi. hieu ve cam luc va dan vi cua tre*.