Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
van hanh » van thanh, ban hanh, van anh
lang xa » lang ha, dang xay, lang van
dac van » cac van, dao van, dam van
cac dac » cac dan, cac dai, cac bac
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
sang ma » tang ma, nang ma, sang tao
tu sach » thu sach, su sach, te sach
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thuat sach) or (tu sach)) ky ((sang ma) or (lang xa)) hoi. hieu va cac dac van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuat sach) OR (tu sach)) ky ((sang ma) OR (lang xa)) hoi. hieu va cac dac van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((thuat sach) or (tu sach)) ky ((sang ma) or (lang xa)) hoi. hieu va cac dac van hanh vi cua tre*.