Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
dau luc » dau luan, dau nuoc, dau luot
cau luc » cau truc, cau phuc
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
vi cua » vai cua, di cua
de cua » le cua, te cua, dieu cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y nang ma hoi. hieu qua ((dau luc) OR (cau luc)) van hanh ((vi cua) or (de cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ma hoi. hieu qua ((dau luc) OR (cau luc)) van hanh ((vi cua) OR (de cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ma hoi. hieu qua ((dau luc) OR (cau luc)) van hanh ((vi cua) or (de cua)) tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ma hoi. hieu qua ((dau luc) OR (cau luc)) van hanh ((vi cua) or (de cua)) tre*.