Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
van phan » van phong, van thanh, luan phan
sach ty » sach y, sach tu, sach thu
tu sach » thu sach, su sach, te sach
hieu vu » hieu va, hieu ve, hieu su
nang ho » nang hoc, nang co, tang ho
ty nang » ky nang, ty xang, ty hang
ho hoi » hoc hoi, hoa hoi, hoi hoi

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 ty nang ho hoi. hieu vu ((cau truc) or (pham thuc)) van phan ((lap va) OR (tap va)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ho hoi. hieu vu ((cau truc) OR (pham thuc)) van phan ((lap va) OR (tap va)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang ho hoi. hieu vu ((cau truc) or (pham thuc)) van phan ((lap va) OR (tap va)) triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ho hoi. hieu vu ((cau truc) or (pham thuc)) van phan ((lap va) OR (tap va)) triet*.