Perhaps you should try some spelling variations:
thien van » thi van
dua tren » dung tren
cau thuc » cau truc, cuu thuc, can thuc
hai dua » hai cua, dai dua, hai qua
dan hai » doan hai, dang hai, dan khai
thuc va » thuc vat, thuc dan, thuc day
van cau » van dau, van hau, van chat
su sach » vu sach
nang ma » tang ma, sang ma, mang may
so sach » so sanh, bo sach, co sach
va dan » ca dan, va dao, va dau

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