Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
trinh di » trinh do, trinh dien, trinh dinh
cau phuc » cau truc, chau phu, huu phuc
hieu ve » hieu van
hieu va » lieu va, hieu qua
phuc va » phuc vu, thuc va, chuc va
tinh di » tinh doi, tinh da, tin di
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang

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 ma hoa. ((hieu ve) or (hieu va)) cau phuc va ((tinh di) OR (trinh di)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang ma hoa. ((hieu ve) OR (hieu va)) cau phuc va ((tinh di) OR (trinh di)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y nang ma hoa. ((hieu ve) or (hieu va)) cau phuc va ((tinh di) OR (trinh di)) cua tre".
• Adding a wildcard symbol may retrieve word variants: thu sach y nang ma hoa. ((hieu ve) or (hieu va)) cau phuc va ((tinh di) OR (trinh di)) cua tre*.