Perhaps you should try some spelling variations:
thien van » thi van
cau thuc » cau truc, cuu thuc, can thuc
dua tren » dung tren
so sanh » do sanh
ly nang » ky nang, ly hang, ly vang
nang ma » tang ma, sang ma, nang cao
so sach » bo sach, co sach, hoc sach
van cau » van dau, van hau, van chat
thuc ca » thuc cua, thuc can, thuc cao
dan hai » doan hai, dang hai, dan khai
hai dua » hai cua, dai dua, hai qua
su sach » vu sach
ma hoi » mai hoi, xa hoi, ma hoa
ca dan » cac dan, ca dao

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) or (((so sach) OR (so sanh)))) ly nang ma hoi. thien van cau thuc ca dan hai dua tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (((so sach) OR (so sanh)))) ly nang ma hoi. thien van cau thuc ca dan hai dua tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (((so sach) OR (so sanh)))) ly nang ma hoi. thien van cau thuc ca dan hai dua tren*".