Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
lang van » dang van, tang van, hoang van
ban hanh » ban hang
nang duc » nang luc, nang doc, nang du
hieu cam » hieu cac, dieu cam, hieu ca
su triet » su viet, su tien, ve triet
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay
duc ban » duc tan, duc van, dua ban

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 ky ((lang xa) or (lang van)) hoi. hieu cam nang duc ban hanh vi ((va thiet) or (su triet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ky ((lang xa) OR (lang van)) hoi. hieu cam nang duc ban hanh vi ((va thiet) OR (su triet)).
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((lang xa) or (lang van)) hoi. hieu cam nang duc ban hanh vi ((va thiet) or (su triet))*.