Perhaps you should try some spelling variations:
toc xach » tuoc xanh, hoc sach, doc sach
thuc dan » thuc hanh, hoc dan, thuc vat
toc sach » hoc sach, doc sach, thuoc sach
cong xa » cong xay, cong xua, cong ha
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc day
dan vai » dan va, dan tai, dan vat
vai cuu » vai cua
cuu tre » cua tre, cau tren, cau treo
va nam » van nam, ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc xach) OR (toc sach)) tai cong xa hoi. hieu va nam ((thuc va) or (thuc dan)) dan vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc xach) OR (toc sach)) tai cong xa hoi. hieu va nam ((thuc va) OR (thuc dan)) dan vai cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc xach) OR (toc sach)) tai cong xa hoi. hieu va nam ((thuc va) or (thuc dan)) dan vai cuu tre*".