Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
va trien » va truyen, va thiet, va tuyen
ky lang » ky nang, ky dang, ky tang
lang xa » lang ha, dang xay, lang van
qua cam » qua cham, qua cac, qua ca
xuc van » duc van, luc van, vuc van
hanh ve » hanh vi, hanh va

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) or (toc sach)) ky lang xa hoi. hieu qua cam xuc van ((hanh ve) OR (hanh kem)) va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky lang xa hoi. hieu qua cam xuc van ((hanh ve) OR (hanh kem)) va trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (toc sach)) ky lang xa hoi. hieu qua cam xuc van ((hanh ve) OR (hanh kem)) va trien".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) ky lang xa hoi. hieu qua cam xuc van ((hanh ve) OR (hanh kem)) va trien*.