Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nha thuoc, cay thuoc
thuat san » thuat toan, thuat song, thuat lanh
hieu van » hieu va, thien van, lieu va
thanh vi » hanh vi, thanh va, thanh ve
va thanh » gia thanh, ban thanh, va tinh
tu sach » thu sach, su sach, te sach
lang xa » lang ha, dang xay, lang van
ky lang » ky nang, ky dang, ky tang
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: ((tu sach) or (thuat san)) ky lang xa hoi. hieu van ((nam thuoc) OR (nam thu)) va thanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuat san)) ky lang xa hoi. hieu van ((nam thuoc) OR (nam thu)) va thanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thuat san)) ky lang xa hoi. hieu van ((nam thuoc) OR (nam thu)) va thanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuat san)) ky lang xa hoi. hieu van ((nam thuoc) OR (nam thu)) va thanh vi cua tre*.