Perhaps you should try some spelling variations:
quoc su » quoc suu, duoc su, quoc so
benh de » benh ve, benh he, menh de
luoc su » duoc sua
te sach » toc sach
va cham » va chat, va tham
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
y lang » o lang, tay lang, yen lang
_ lang » o lang, _ land
de cua » le cua, te cua, dieu 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 ((y lang) or (_ lang)) xa hoi. hieu va cham ((quoc su) OR (luoc su)) benh de cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ((y lang) OR (_ lang)) xa hoi. hieu va cham ((quoc su) OR (luoc su)) benh de cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ((y lang) or (_ lang)) xa hoi. hieu va cham ((quoc su) OR (luoc su)) benh de cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ((y lang) or (_ lang)) xa hoi. hieu va cham ((quoc su) OR (luoc su)) benh de cua tre*.