Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
thu sach » tu sach, thuat sach, thuoc sach
cham tuc » nham thuc, tham thuc, cham soc
ty nang » ky nang, ty xang, ty hang
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
sach ty » sach y, sach tu, sach thu
xa hanh » xa thanh, xa khanh, va hanh
vai va » mai va, dai va, lai va
hai va » hai van, thai va, hoi va
thiet » thieu

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 ty nang cao hoi. hieu ve ((cham tuc) OR (pham thuc)) xa hanh ((vai va) or (hai va)) thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang cao hoi. hieu ve ((cham tuc) OR (pham thuc)) xa hanh ((vai va) OR (hai va)) thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty nang cao hoi. hieu ve ((cham tuc) OR (pham thuc)) xa hanh ((vai va) or (hai va)) thiet".
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang cao hoi. hieu ve ((cham tuc) OR (pham thuc)) xa hanh ((vai va) or (hai va)) thiet*.