Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
tinh lai » tinh lao, tinh hai, minh lai
su triet » su viet, su tien, ve triet
so sach » so sanh, bo sach, co sach
nang ma » tang ma, sang ma, nang cao
van cac » van hac, van cau, van bac
cac day » cac dan, cac dai, cac cay
va tinh » may tinh

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y ((nang x) or (nang ma)) hoi. hieu van cac day va tinh lai su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((nang x) OR (nang ma)) hoi. hieu van cac day va tinh lai su triet.
• Adding a wildcard symbol may retrieve word variants: so sach y ((nang x) or (nang ma)) hoi. hieu van cac day va tinh lai su triet*.