Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
thanh ha » thanh hoa, thanh hai, nhanh ha
cau tren » dau tren, ca tren, cau treo
hieu va » lieu va, hieu qua
xuc gia » duc gia, luc gia, tuc gia
cu tren » tu tren, dua tren
y nang » ky nang, ly nang, v nang
va cam » va cham, va cac, va cao
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: doc sach y nang x hoi. hieu va cam ((xuc gia) or (quoc gia)) thanh ha ((cau tren) OR (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach y nang x hoi. hieu va cam ((xuc gia) OR (quoc gia)) thanh ha ((cau tren) OR (cu tren))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach y nang x hoi. hieu va cam ((xuc gia) or (quoc gia)) thanh ha ((cau tren) OR (cu tren))*".