Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
thuc day » thuc dan, thuc vat
va triet » va thiet, ve triet, cua triet
tinh vai » tinh va, tinh hai, tinh bai
te sach » toc sach
thuc va » thuc vat, thuc dan
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
y nang » ky nang, ly nang, v nang
va nam » van nam, ha nam, va nay
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach y nang ma hoi. hieu va nam ((thuc va) OR (thuc day)) tinh vai ((va triet) or (va trien))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y nang ma hoi. hieu va nam ((thuc va) OR (thuc day)) tinh vai ((va triet) OR (va trien)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y nang ma hoi. hieu va nam ((thuc va) OR (thuc day)) tinh vai ((va triet) or (va trien))".
• Adding a wildcard symbol may retrieve word variants: te sach y nang ma hoi. hieu va nam ((thuc va) OR (thuc day)) tinh vai ((va triet) or (va trien))*.