Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
ban hanh » ban hang
van hanh » van thanh, van anh, van ban
chat soc » cham soc, chat hoc, chat doc
va chat » van chat, va phat, cao chat
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
nang xa » lang xa, nang ma, mang xa
cuu tre » cua tre, cau tren, cau treo
vi cuu » vi luu, vinh cuu

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ty ((nang xa) or (nang x)) hoi. hieu va chat soc ((van hanh) or (ban hanh)) vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty ((nang xa) OR (nang x)) hoi. hieu va chat soc ((van hanh) OR (ban hanh)) vi cuu tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ty ((nang xa) or (nang x)) hoi. hieu va chat soc ((van hanh) or (ban hanh)) vi cuu tre*.