Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dieu cua » dieu tra
huu phuc » huu thuc, huu phach, huu duc
nang xa » nang x, lang xa, nang ma
tang ma » mang may, tang van
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
phuc va » phuc vu, thuc va, chuc va
va hanh » van hanh, va thanh, va danh
de cua » le cua, te cua
ve huu » le huu, vu huu, va huu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky ((nang xa) or (tang ma)) hoi. hieu ve huu phuc va hanh ((de cua) OR (dieu cua)) tu~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((nang xa) OR (tang ma)) hoi. hieu ve huu phuc va hanh ((de cua) OR (dieu cua)) tu*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky ((nang xa) or (tang ma)) hoi. hieu ve huu phuc va hanh ((de cua) OR (dieu cua)) tu*".