Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
va triet » va thiet, va trien, ve triet
van hanh » van thanh, ban hanh, van anh
nhan duc » nhan duoc, nhan luc, phan duc
duc van » duc va, duc tan, duc manh
va nhan » van nhan, ca nhan, va phan
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
lang ha » long ha
nang xa » nang x, lang xa, nang ma
su tien » su kien, su hien, tu tieng

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