Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
doi cua » dai cua, hoi cua
va dinh » van dinh, va kinh, va tinh
cau loc » hau loc, cau hoc, cau luc
hieu va » lieu va, hieu qua
hieu ve » hieu van
nang xa » nang x, lang xa, nang ma
loc va » hoc va, luc va
di cua » dai cua, de cua, do cua

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 ky nang xa hoi. ((hieu ve) or (hieu va)) cau loc va dinh ((di cua) OR (doi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang xa hoi. ((hieu ve) OR (hieu va)) cau loc va dinh ((di cua) OR (doi cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang xa hoi. ((hieu ve) or (hieu va)) cau loc va dinh ((di cua) OR (doi cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang xa hoi. ((hieu ve) or (hieu va)) cau loc va dinh ((di cua) OR (doi cua)) tre*.