Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
nang mai » nang ma, nang tai, lang mai
nam thuc » nam thuoc, am thuc, nam thu
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
va nam » van nam, ha nam, va nay
cua tu » cua tuc, cua su, cua cu

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 (thuoc sach)) ky nang mai hoi. hieu va nam thuc van hanh vi ((cua te) OR (cua tu))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuoc sach)) ky nang mai hoi. hieu va nam thuc van hanh vi ((cua te) OR (cua tu)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thuoc sach)) ky nang mai hoi. hieu va nam thuc van hanh vi ((cua te) OR (cua tu))".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thuoc sach)) ky nang mai hoi. hieu va nam thuc van hanh vi ((cua te) OR (cua tu))*.