Perhaps you should try some spelling variations:
thuoc thuan » phuoc thuan, thuoc tan, thuc huan
thuan hanh » thuan thanh, thuat thanh, thuc hanh
nam thuoc » nam thuc, nam thu, nha thuoc
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
hanh va » hang va, hanh vi
tu cach » tu cac
dang xa » dang xay, lang xa, dang va
vu sach » vu bach, su sach, vu khach
dang ha » dong ha, dung ha, lang ha
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 cach) or (vu sach)) ky ((dang xa) OR (dang ha)) hoi. hieu van nam thuoc thuan hanh va cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu cach) OR (vu sach)) ky ((dang xa) OR (dang ha)) hoi. hieu van nam thuoc thuan hanh va cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cach) or (vu sach)) ky ((dang xa) OR (dang ha)) hoi. hieu van nam thuoc thuan hanh va cua viet".
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (vu sach)) ky ((dang xa) OR (dang ha)) hoi. hieu van nam thuoc thuan hanh va cua viet*.