Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
nam duoc » nam thuoc, da duoc, dat duoc
ma hanh » da hanh, na hanh, ban hanh
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
va cua » va chua, via cua, ca cua
x hoi » xa hoi, o hoi, x ho

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 y nang x hoi. hieu van nam duoc ((ma hanh) OR (va hanh)) va cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y nang x hoi. hieu van nam duoc ((ma hanh) OR (va hanh)) va cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach y nang x hoi. hieu van nam duoc ((ma hanh) OR (va hanh)) va cua tre*.