Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
van hanh » van thanh, ban hanh, van anh
lang xa » lang ha, dang xay, lang van
duc van » duc va, duc tan, duc manh
cac duc » cac du, cao duc, cac dac
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
sang ma » tang ma, nang ma, sang tao
tu sach » su sach, te sach, tu cach
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: ((thu sach) or (tu sach)) ky ((sang ma) or (lang xa)) hoi. hieu va cac duc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) ky ((sang ma) OR (lang xa)) hoi. hieu va cac duc van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) ky ((sang ma) or (lang xa)) hoi. hieu va cac duc van hanh vi cua tre*.