Perhaps you should try some spelling variations:
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
nay duc » ngay doc
duc lap » doc lap, duc lai, duc lam
voi hoa » voi hoat, voi khoa, boi hoa
sac ky » cac ky, sai ky
va nay » va ngay, va cay
vi hoa » vi hoc, va hoa, bi hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: su ((sac ky) or (sach y)) nang xa hoi. hieu va nay duc lap trinh ((vi hoa) OR (voi hoa)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sac ky) OR (sach y)) nang xa hoi. hieu va nay duc lap trinh ((vi hoa) OR (voi hoa)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sac ky) or (sach y)) nang xa hoi. hieu va nay duc lap trinh ((vi hoa) OR (voi hoa)) viet".
• Adding a wildcard symbol may retrieve word variants: su ((sac ky) or (sach y)) nang xa hoi. hieu va nay duc lap trinh ((vi hoa) OR (voi hoa)) viet*.