Perhaps you should try some spelling variations:
hanh tinh » hanh trinh, nhanh tinh, thanh tinh
hieu van » thien van, lieu va, hieu ve
tinh cuu » trinh cuu, dinh cuu, tinh cua
so sach » so sanh, bo sach, co sach
ky lang » ky dang, ky tang, tay lang
hieu va » lieu va, hieu qua
cau duc » cao duc, cau luc, chu duc
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ((ky lang) or (ky nang)) xa hoi. ((hieu van) OR (hieu va)) cau duc va hanh tinh cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((ky lang) OR (ky nang)) xa hoi. ((hieu van) OR (hieu va)) cau duc va hanh tinh cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((ky lang) or (ky nang)) xa hoi. ((hieu van) OR (hieu va)) cau duc va hanh tinh cuu tre".
• Adding a wildcard symbol may retrieve word variants: so sach ((ky lang) or (ky nang)) xa hoi. ((hieu van) OR (hieu va)) cau duc va hanh tinh cuu tre*.