Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
van hanh » van thanh, ban hanh, van anh
tu sach » su sach, te sach, tu cach
hieu ve » hieu va, hieu van
y nang » ky nang, ly nang, v nang
nang o » nang co, nang ho, nang ro
ve bac » ve bao, ve cac, ve ban
bo van » vo van, so van, do van
o hoi » co hoi, o hoc, o hai
vi su » ve su, ki su, oi su

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) OR (thu sach)) y nang o hoi. hieu ve bac bo van hanh ((vi su) or (va su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) y nang o hoi. hieu ve bac bo van hanh ((vi su) OR (va su)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) y nang o hoi. hieu ve bac bo van hanh ((vi su) or (va su)) triet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) y nang o hoi. hieu ve bac bo van hanh ((vi su) or (va su)) triet*.