Perhaps you should try some spelling variations:
nang tai » hang tai, tang tai, sang tai
dan hanh » dang hanh, dan khanh, dan thanh
thuc dan » thuc hanh, hoc dan, thuc vat
so sach » so sanh, bo sach, co sach
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
sach v » sach va, sach y, sach 2
va cua » va chua, via cua, ma cua
ca cua » co cua
ve am » va am

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 v ((nang ma) or (nang tai)) hoi. hieu ve am thuc dan hanh ((va cua) OR (ca cua)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach v ((nang ma) OR (nang tai)) hoi. hieu ve am thuc dan hanh ((va cua) OR (ca cua)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach v ((nang ma) or (nang tai)) hoi. hieu ve am thuc dan hanh ((va cua) OR (ca cua)) viet".
• Adding a wildcard symbol may retrieve word variants: so sach v ((nang ma) or (nang tai)) hoi. hieu ve am thuc dan hanh ((va cua) OR (ca cua)) viet*.