Perhaps you should try some spelling variations:
cau tren » dau tren, ca tren, cau treo
thanh da » thanh dat, thanh dam, thanh dan
van cham » van chat, van tham, va cham
hieu van » hieu va, thien van, lieu va
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, mang may
soc gia » toc gia, hoc gia, so gia
cu tren » tu tren, dua tren
so sach » so sanh, bo sach, co sach

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 ty ((nang ma) or (nang cao)) hoi. hieu van cham soc gia thanh da ((cu tren) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ty ((nang ma) OR (nang cao)) hoi. hieu van cham soc gia thanh da ((cu tren) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: so sach ty ((nang ma) or (nang cao)) hoi. hieu van cham soc gia thanh da ((cu tren) or (cau tren))*.