Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
dau thuc » dan thuc, dai thuc, dam thuc
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
va dau » va dao
v nang » va nang, vu nang, van nang
cua tu » cua tuc, cua su, cua cu

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 (hoc sach)) v nang xa hoi. hieu va dau thuc va hanh vi ((cua te) OR (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) v nang xa hoi. hieu va dau thuc va hanh vi ((cua te) OR (cua tu)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) or (hoc sach)) v nang xa hoi. hieu va dau thuc va hanh vi ((cua te) OR (cua tu))".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) v nang xa hoi. hieu va dau thuc va hanh vi ((cua te) OR (cua tu))*.