Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
van cau » van dau, van hau, van chat
sach ty » sach y, sach tu, sach thu
van cac » van hac, van bac, dan cac
ty nang » ky nang, ty xang, ty hang
nang o » nang co, nang ho, nang ro
bo van » vo van, so van, do van
vi cua » vai cua
di cua » dai cua, doi cua, de cua
o hai » co hai, so hai, o lai

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