Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
doan van » doan va, hoang van, luan van
thuoc ma » hoc ma, duoc ma
cau tren » cu tren, dau tren, ca tren
lang xa » lang ha, dang xay, lang van
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach kem
sach ty » sach y, sach tu, sach thu
dan van » dang van, dao van, tan van
va nam » van nam, ha nam, va nay

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((sach ky) OR (sach ty)) lang xa hoi. hieu va nam thuoc ma ((dan van) OR (doan van)) cau tren~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc ((sach ky) or (sach ty)) lang xa hoi. hieu va nam thuoc ma ((dan van) OR (doan van)) cau tren~".
• Adding a wildcard symbol may retrieve word variants: doc ((sach ky) or (sach ty)) lang xa hoi. hieu va nam thuoc ma ((dan van) OR (doan van)) cau tren*.