Perhaps you should try some spelling variations:
nam thuoc » nam thuc, nam thu, nha thuoc
nang mai » nang ma, nang tai, nang cai
thai cua » than cua, tai cuc, tri cua
lang mai » lang dai, lang hai, lang man
lieu van » lieu va, hieu van, sieu van
va hanh » van hanh, va thanh, va danh
xa hanh » xa thanh, xa khanh, da hanh
cua tre » cua te, cuu tre, cua triet
sac ky » cac ky, sai ky
tu sac » tu sach, tu cac, tu san

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sac ky ((nang mai) or (lang mai)) hoi. lieu van nam thuoc ((xa hanh) OR (va hanh)) thai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((nang mai) OR (lang mai)) hoi. lieu van nam thuoc ((xa hanh) OR (va hanh)) thai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((nang mai) or (lang mai)) hoi. lieu van nam thuoc ((xa hanh) OR (va hanh)) thai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((nang mai) or (lang mai)) hoi. lieu van nam thuoc ((xa hanh) OR (va hanh)) thai cua tre*.