Perhaps you should try some spelling variations:
duc thanh » duc thang, duc tan, de thanh
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
duc hanh » duc anh, du hanh, duc manh
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
van cao » van dao, van bao, van hao
vi va » vi van, vai va, bi va
vu va » vu van, tu va, su va

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ty nang x ho. hieu van cao ((duc hanh) OR (duc thanh)) hanh ((vi va) or (vu va)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang x ho. hieu van cao ((duc hanh) OR (duc thanh)) hanh ((vi va) OR (vu va)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty nang x ho. hieu van cao ((duc hanh) OR (duc thanh)) hanh ((vi va) or (vu va)) triet".
• Adding a wildcard symbol may retrieve word variants: toc sach ty nang x ho. hieu van cao ((duc hanh) OR (duc thanh)) hanh ((vi va) or (vu va)) triet*.