Perhaps you should try some spelling variations:
cau triet » cau trieu, su triet, cua triet
cau tren » cu tren, dau tren, ca tren
cam thuc » am thuc, nam thuc, cam thu
hanh hai » thanh hai, nhanh hai, hang hai
nang mai » nang ma, nang tai, lang mai
hieu van » hieu va, thien van, lieu va
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
su sach » vu sach
mai hoi » mai khoi, dai hoi, lai hoi
ly nang » ky nang, ly hang, ly vang
so sach » so sanh, bo sach, co sach
van cam » van nam, van lam, van cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (so sach)) ly nang mai hoi. hieu van cam thuc va hanh hai ((cau triet) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (so sach)) ly nang mai hoi. hieu van cam thuc va hanh hai ((cau triet) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) ly nang mai hoi. hieu van cam thuc va hanh hai ((cau triet) or (cau tren))*.