Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu ve » hieu va, hieu van
duc van » duc va, duc tan, duc manh
xuc van » luc van, xuc ban, thuc van
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
ma hoi » mai hoi, xa hoi, ma hoa
ve cac » va cac, vien cac
vi cua » vai cua, di cua
cua cu » cua chu, cua cau, cua su

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