Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
danh dai » danh dau, danh di, danh sai
va danh » va dinh, va dan, va hanh
cao duc » dao duc, cao suc, giao duc
cam duc » cam xuc, pham duc, nam duoc
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
sang xa » song xa, lang xa, sang ma
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 ((sang xa) or (tang ma)) hoi. hieu van ((cam duc) OR (cao duc)) va danh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sac ky ((sang xa) OR (tang ma)) hoi. hieu van ((cam duc) OR (cao duc)) va danh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((sang xa) or (tang ma)) hoi. hieu van ((cam duc) OR (cao duc)) va danh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((sang xa) or (tang ma)) hoi. hieu van ((cam duc) OR (cao duc)) va danh dai cua tre*.