Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang ma » tang ma, sang ma, nang cao
vu sach » vu bach, su sach, vu khach
van hac » van hoc, van ha, van hai
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
danh di » danh du, xanh di, danh dien
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
di cua » dai cua, doi cua, de cua

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 (vu sach)) ky nang ma hoi. hieu ((van ban) or (van hac)) thuc va danh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (vu sach)) ky nang ma hoi. hieu ((van ban) OR (van hac)) thuc va danh di cua tre.
• Adding a wildcard symbol may retrieve word variants: ((toc sach) or (vu sach)) ky nang ma hoi. hieu ((van ban) or (van hac)) thuc va danh di cua tre*.