Perhaps you should try some spelling variations:
toc sach » doc sach, thuoc sach, nuoc sach
cau tren » cu tren, dau tren, ca tren
hoc sach » hoc sinh, hoc cac, hoc anh
ky dang » ky nang, ky danh
dang xa » dang xay, lang xa, dang ha
va ngay » tan ngay
thuc va » thuc vat, thuc dan, thuc day
dan vai » dan va, dan tai, dan vat
vai cau » va cau, van cau, vai cac
va dan » ca dan, va dao, va dau
va nay » va cay

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (hoc sach)) ky dang xa hoi. hieu ((va nay) or (va ngay)) thuc va dan vai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) ky dang xa hoi. hieu ((va nay) OR (va ngay)) thuc va dan vai cau tren.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (hoc sach)) ky dang xa hoi. hieu ((va nay) or (va ngay)) thuc va dan vai cau tren*.