Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hang tai » hang va, dung tai
sang tai » sang tao, tang tai, sang than
tai khoa » da khoa, noi khoa
luc van » luoc van, luu van, luc va
tai cuu » tai cuc, tai buu, tai cua
duc van » duc va, duc tan, duc manh
hieu ve » hieu va, hieu van
ky sang » ky nang, ky dang, ky tang
cuu tre » cua tre, cau tren, cau treo
ve cam » ve cham, ve cac, va cam

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) ky sang tai khoa. hieu ve cam ((luc van) or (duc van)) hang tai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) ky sang tai khoa. hieu ve cam ((luc van) OR (duc van)) hang tai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) ky sang tai khoa. hieu ve cam ((luc van) or (duc van)) hang tai cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) ky sang tai khoa. hieu ve cam ((luc van) or (duc van)) hang tai cuu tre*.