Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
doc sach » hoc sach, toc sach, nuoc sach
su sach » vu sach
ve pham » vi pham, v pham, ve phan
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
nang ma » tang ma, sang ma, nang cao
so sach » so sanh, bo sach, co sach
vi cua » vai cua, di cua
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((su sach) OR (so sach))) or (doc sach)) ky nang ma hoi. hieu ve pham thuc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((su sach) OR (so sach))) OR (doc sach)) ky nang ma hoi. hieu ve pham thuc van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((su sach) OR (so sach))) or (doc sach)) ky nang ma hoi. hieu ve pham thuc van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((((su sach) OR (so sach))) or (doc sach)) ky nang ma hoi. hieu ve pham thuc van hanh vi cua tre*.