Perhaps you should try some spelling variations:
cham quoc » chuan quoc, han quoc, cham soc
toc sach » hoc sach, doc sach, thuoc sach
sau benh » san benh, phau benh, tai benh
quoc sau » quoc su, quoc suu, quoc sach
dang xay » dang van, van xay
benh vi » benh va, benh ve, benh li
va cham » va chat, va tham
hieu va » lieu va, hieu qua
lang xa » lang ha, lang van
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

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) OR (toc sach)) y ((lang xa) or (dang xay)) hoi. hieu va cham quoc sau benh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y ((lang xa) OR (dang xay)) hoi. hieu va cham quoc sau benh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) y ((lang xa) or (dang xay)) hoi. hieu va cham quoc sau benh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) y ((lang xa) or (dang xay)) hoi. hieu va cham quoc sau benh vi cua tre*.