Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
toc sach » hoc sach, doc sach, thuoc sach
van cac » van hac, van cau, van bac
nang co » nang cao, nang doc, nang noi
ty nang » ky nang, ty xang, ty hang
co hai » co dai, co hoi, o hai
cac so » cac co, cac bo, cac ho
so van » su van, vo van
vi cua » vai cua
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ty nang co hai. hieu van cac so van hanh ((vi cua) OR (di cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ty nang co hai. hieu van cac so van hanh ((vi cua) OR (di cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ty nang co hai. hieu van cac so van hanh ((vi cua) OR (di cua)) tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ty nang co hai. hieu van cac so van hanh ((vi cua) OR (di cua)) tre*.