Perhaps you should try some spelling variations:
cham loc » chon loc, cham o, hau loc
tu sach » thu sach, su sach, te sach
va hanh » van hanh, va thanh, va danh
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
vi cu » vi xu, vi du
vi su » va su, ve su, ki su

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 dang xa hoi. hieu va ((cham loc) or (cham soc)) va hanh ((vi cu) OR (vi su)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang xa hoi. hieu va ((cham loc) OR (cham soc)) va hanh ((vi cu) OR (vi su)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang xa hoi. hieu va ((cham loc) or (cham soc)) va hanh ((vi cu) OR (vi su)) tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang xa hoi. hieu va ((cham loc) or (cham soc)) va hanh ((vi cu) OR (vi su)) tren*.