Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
cham truc » cau truc, nham thuc, nam truc
phan tap » phan lap, pha tap, phan tu
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
han tap » han tai, toan tap, nhan tai
hieu vu » hieu va, hieu ve, hieu su
nang co » nang cao, nang doc, nang noi
ty nang » ky nang, ty xang, ty hang
co hoi » co hoc, co loi
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: tu sach ty nang co hoi. hieu vu ((cham truc) or (pham thuc)) van ((phan tap) OR (han tap)) va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang co hoi. hieu vu ((cham truc) OR (pham thuc)) van ((phan tap) OR (han tap)) va thiet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang co hoi. hieu vu ((cham truc) or (pham thuc)) van ((phan tap) OR (han tap)) va thiet".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang co hoi. hieu vu ((cham truc) or (pham thuc)) van ((phan tap) OR (han tap)) va thiet*.