Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang van » dang van, tang van, nong van
lang van » dang van, tang van, hoang van
phap duc » pham duc, phan duc, phap doc
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
va phap » va phat, ban phap
va hanh » van hanh, va thanh, va danh
de cua » le cua, dieu cua
te cua » tue cua, le cua

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 van) OR (lang van)) hoi. hieu va phap duc va hanh ((de cua) or (te cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((nang van) OR (lang van)) hoi. hieu va phap duc va hanh ((de cua) OR (te cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky ((nang van) OR (lang van)) hoi. hieu va phap duc va hanh ((de cua) or (te cua)) tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((nang van) OR (lang van)) hoi. hieu va phap duc va hanh ((de cua) or (te cua)) tre*.