Perhaps you should try some spelling variations:
thien van » thi van
tu sach » thu sach, su sach, te sach
cua tre » cua te, cua triet, dua tren
hang de » hoang de, hanh de, hang di
va hang » van hang, va nang, va lang
cam hoc » cao hoc, am hoc, cam hoa
van cam » van nam, van lam, van cau
ky dang » ky nang, ky danh
ky tang » ky nang, kho tang, ky trong
cuu 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: tu sach ((ky tang) or (ky dang)) ma hoa. thien van cam hoc va hang de ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky tang) OR (ky dang)) ma hoa. thien van cam hoc va hang de ((cua tre) OR (cuu tre))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky tang) or (ky dang)) ma hoa. thien van cam hoc va hang de ((cua tre) OR (cuu tre))*".