Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
thuoc va » thuc va, thuoc ma, thuong va
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
sach thu » sach thue, sach thieu, sach tham
tu sach » thu sach, su sach, te sach
tinh va » tich va, trinh van, trinh vat
va tinh » may tinh
cua tre » cua te, cuu tre, cua triet
mang xa » lang xa, mang may, mang cua
va cua » va chua, via cua, ca 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 thu ((((mang xa) OR (dang xay))) or (nang x)) hoi. hieu van nam thuoc va tinh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thu ((((mang xa) OR (dang xay))) OR (nang x)) hoi. hieu van nam thuoc va tinh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thu ((((mang xa) OR (dang xay))) or (nang x)) hoi. hieu van nam thuoc va tinh va cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach thu ((((mang xa) OR (dang xay))) or (nang x)) hoi. hieu van nam thuoc va tinh va cua tre*.