Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
toc sach » hoc sach, doc sach, thuoc sach
vat hanh » vat thanh, van hanh, va hanh
vu sach » vu bach, su sach, vu khach
nang xa » lang xa, nang ma, mang xa
cua tre » cua te, cuu tre, cua triet
hieu v » hieu va, hieu ve, hieu 2
v pham » vi pham, d pham
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: ((vu sach) or (toc sach)) ky ((nang xa) OR (nang x)) hoi. hieu v pham thuc vat hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (toc sach)) ky ((nang xa) OR (nang x)) hoi. hieu v pham thuc vat hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((vu sach) or (toc sach)) ky ((nang xa) OR (nang x)) hoi. hieu v pham thuc vat hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((vu sach) or (toc sach)) ky ((nang xa) OR (nang x)) hoi. hieu v pham thuc vat hanh vi cua tre*.