Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
cua triet » cua viet, su triet, va triet
thu sach » tu sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
va doan » va doanh, van doan, va dan
doan vi » doan va, don vi, doan thi
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) OR (thuat sach)) ky nang x hoi. hieu van ((tac tu) or (cac du)) va doan vi cua triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuat sach)) ky nang x hoi. hieu van ((tac tu) OR (cac du)) va doan vi cua triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (thuat sach)) ky nang x hoi. hieu van ((tac tu) or (cac du)) va doan vi cua triet".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (thuat sach)) ky nang x hoi. hieu van ((tac tu) or (cac du)) va doan vi cua triet*.