Perhaps you should try some spelling variations:
tranh tren » trinh tren, tran tren, tranh trong
sach pham » sach tham, sach phat, sach phap
nang nghe » lang nghe, cong nghe, van nghe
bac nang » ban nang, bac giang, sach nang
toc canh » luoc canh, ngoc canh, luc canh
tren anh » tren lanh, tran anh, tien anh
anh khoa » doanh khoa, hang khoa
tu sach » thu sach, su sach, te sach
pham tu » phan tu, pham thi, pham tai
khoa he » hoa he, khoa hoc, khong he
tu bac » tu ban, tu cac, tu bat

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 pham tu bac nang nghe thong ) or ( toc canh tranh tren anh khoa he thong ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( tu sach pham tu bac nang nghe thong ) OR ( toc canh tranh tren anh khoa he thong )).
• Adding a wildcard symbol may retrieve word variants: (( tu sach pham tu bac nang nghe thong ) or ( toc canh tranh tren anh khoa he thong ))*.