Perhaps you should try some spelling variations:
te sach » toc sach
hieu va » lieu va, hieu qua
va cam » va cham, va cac, va cao
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
de cua » le cua, dieu cua
te cua » tue cua, le cua
luc va » duc va, tuc va, loc va
x hoi » xa hoi, o hoi, x ho

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 v nang x hoi. hieu va cam ((luc va) or (thuc vat)) thanh ((de cua) OR (te cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach v nang x hoi. hieu va cam ((luc va) OR (thuc vat)) thanh ((de cua) OR (te cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach v nang x hoi. hieu va cam ((luc va) or (thuc vat)) thanh ((de cua) OR (te cua)) tre".
• Adding a wildcard symbol may retrieve word variants: te sach v nang x hoi. hieu va cam ((luc va) or (thuc vat)) thanh ((de cua) OR (te cua)) tre*.