Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
nang hoa » nang hoat, hang hoa, nang hoc
vat hanh » vat thanh, van hanh, va hanh
su triet » su viet, su tien, ve triet
tu sach » thu sach, su sach, te sach
hoa doi » hoa dai, hoc doi, xoa doi
hieu va » lieu va, hieu qua
thu vat » thuc vat, thu va, thuat vat
hanh va » hang va, hanh vi
va nam » van nam, ha nam, va nay

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) or (toc sach)) ky nang hoa doi. hieu va nam thu vat hanh va su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (toc sach)) ky nang hoa doi. hieu va nam thu vat hanh va su triet.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (toc sach)) ky nang hoa doi. hieu va nam thu vat hanh va su triet*.