Perhaps you should try some spelling variations:
cham duc » pham duc, pham duy, phan duc
hanh lam » thanh lap, hanh kem, hanh va
su sach » so sach, vu sach
ky tang » ky nang, ky dang, kho tang
hieu vu » hieu va, hieu ve, hieu su
va hanh » van hanh, va thanh, va danh
chu tre » cho tre, chu tri, cuu tre
y tang » 6 tang, 7 tang, 5 tang

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 ((y tang) OR (ky tang)) ma hoa. hieu vu ((cham duc) or (cham soc)) va hanh lam chu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y tang) OR (ky tang)) ma hoa. hieu vu ((cham duc) OR (cham soc)) va hanh lam chu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((y tang) OR (ky tang)) ma hoa. hieu vu ((cham duc) or (cham soc)) va hanh lam chu tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((y tang) OR (ky tang)) ma hoa. hieu vu ((cham duc) or (cham soc)) va hanh lam chu tre*.