Perhaps you should try some spelling variations:
thieu nien » thien nhien
hieu vien » hieu hien, hieu viec, hieu tieng
thu sach » thuat sach, thuoc sach, thu hoach
lang tai » lang thai, hang tai, tang tai
tai cua » thai cua, tai cuc, tri cua
va lang » va nang, hoa lang
dai tuc » dai thuc, dai truc, dao tuc
nang ma » tang ma, sang ma, nang cao
tu sach » su sach, te sach, tu cach
tuc va » thuc va, truc va, tuc xa
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (tu sach)) ky nang ma hoa. ((hieu vien) OR (thieu nien)) dai tuc va lang tai cua tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) ky nang ma hoa. ((hieu vien) OR (thieu nien)) dai tuc va lang tai cua tu.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (tu sach)) ky nang ma hoa. ((hieu vien) OR (thieu nien)) dai tuc va lang tai cua tu".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) ky nang ma hoa. ((hieu vien) OR (thieu nien)) dai tuc va lang tai cua tu*.