Perhaps you should try some spelling variations:
thanh tai » thanh hai, thanh toan, doanh tai
va thanh » gia thanh, ban thanh, va tinh
nang dai » nang dau, lang dai, nang cai
nang tai » hang tai, tang tai, sang tai
hieu van » hieu va, thien van, lieu va
tai cuu » tai cuc, tai buu, tai cua
truc va » thuc va, thuc vat, trung va
van cau » van dau, van hau, van chat
cuu tre » cua tre, cau tren, cau treo
sach ky » sach y, sach ty, sach kem
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ky) or (sac ky)) ((nang dai) OR (nang tai)) hoi. hieu van cau truc va thanh tai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sac ky)) ((nang dai) OR (nang tai)) hoi. hieu van cau truc va thanh tai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sac ky)) ((nang dai) OR (nang tai)) hoi. hieu van cau truc va thanh tai cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sac ky)) ((nang dai) OR (nang tai)) hoi. hieu van cau truc va thanh tai cuu tre*.