Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tai cua » thai cua, tai cuc, tri cua
han tai » hang tai, nhan tai, van tai
truc va » thuc va, thuc vat, trung va
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
tang xa » trang xa, tang ma, lang xa
ky tang » ky nang, ky dang, kho tang
thu san » thuy san, thu ban, phu san
tuc va » thuc va, tuc xa, duc va
va cam » va cham, va cac, va cao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((toc sach) or (thu san)) ky tang xa hoi. hieu va cam ((tuc va) or (truc va)) han tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thu san)) ky tang xa hoi. hieu va cam ((tuc va) OR (truc va)) han tai cua tre.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (thu san)) ky tang xa hoi. hieu va cam ((tuc va) or (truc va)) han tai cua tre*.