Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
mien bac » vien bach, dien ban, gian bac
vien bac » vien bach, vien cac, tien bac
va thanh » gia thanh, ban thanh, va tinh
chi tre » choi tre, chi tro, chi tiet
thue va » thuc va, thuyet va, thuc vat
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
dang xa » dang xay, lang xa, dang ha
ky dang » ky nang, ky danh
cho tre » cho thue, khoe tre

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky dang xa hoi. hieu ((vien bac) OR (mien bac)) thue va thanh van ((chi tre) or (cho tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky dang xa hoi. hieu ((vien bac) OR (mien bac)) thue va thanh van ((chi tre) OR (cho tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky dang xa hoi. hieu ((vien bac) OR (mien bac)) thue va thanh van ((chi tre) or (cho tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky dang xa hoi. hieu ((vien bac) OR (mien bac)) thue va thanh van ((chi tre) or (cho tre))*.