Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
cau tren » cu tren, dau tren, ca tren
cao hoi » cau hoi, co hoi, cao hoc
nam luu » nam suu, tam luu, nam luat
luu van » cuu van, luan van, luu hanh
y nang » ky nang, ly nang, v nang
vi cau » va cau, ve cau, di cau

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)) y nang cao hoi. hieu van nam luu van hanh vi cau tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) y nang cao hoi. hieu van nam luu van hanh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) y nang cao hoi. hieu van nam luu van hanh vi cau tren*.