Perhaps you should try some spelling variations:
toc sach » hoc sach, thuoc sach, nuoc sach
doc sach » hoc sach, nuoc sach, dac sac
danh tai » doanh tai, dinh tai, hanh tai
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cam tuc » cam xuc, cam tu, nam thuc
xa danh » va danh, dia danh, nam danh
va cam » va cham, va cac, va cao
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) or (doc sach)) ky nang xa hoi. hieu va cam tuc xa danh tai ((cua tu) OR (cua su))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (doc sach)) ky nang xa hoi. hieu va cam tuc xa danh tai ((cua tu) OR (cua su)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (doc sach)) ky nang xa hoi. hieu va cam tuc xa danh tai ((cua tu) OR (cua su))".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (doc sach)) ky nang xa hoi. hieu va cam tuc xa danh tai ((cua tu) OR (cua su))*.