Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
hanh tai » thanh tai, hang tai, han tai
ky dang » ky danh
nam tuc » nam thuc, nam truc, nam tu
va hanh » van hanh, va thanh, va danh
tuc va » thuc va, truc va, tuc xa
cua tu » cua tuc, cua cu, cua te
cua su » qua su

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 dang) or (ky nang)) xa hoi. hieu van nam tuc va hanh tai ((cua tu) OR (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ky dang) OR (ky nang)) xa hoi. hieu van nam tuc va hanh tai ((cua tu) OR (cua su))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ((ky dang) or (ky nang)) xa hoi. hieu van nam tuc va hanh tai ((cua tu) OR (cua su))*".