Perhaps you should try some spelling variations:
toc sac » toc sach, toc san, hoc sach
truc va » thuc va, thuc vat, trung va
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
hieu va » lieu va, hieu qua
lai cua » hai cua, lai chau, thai cua
luc va » duc va, tuc va, loc va
sac ky » cac ky, sai ky
va cau » van cau, va cac, va dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sac ky dang xa hoi. hieu va cau ((luc va) or (truc va)) gianh ((lai cua) OR (dai cua)) te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sac ky dang xa hoi. hieu va cau ((luc va) OR (truc va)) gianh ((lai cua) OR (dai cua)) te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sac ky dang xa hoi. hieu va cau ((luc va) or (truc va)) gianh ((lai cua) OR (dai cua)) te".
• Adding a wildcard symbol may retrieve word variants: toc sac ky dang xa hoi. hieu va cau ((luc va) or (truc va)) gianh ((lai cua) OR (dai cua)) te*.