Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cham luc » cham soc, nhan luc, cham cuu
van hanh » van thanh, ban hanh, van anh
lang xa » dang xay, lang van
lang ha » long ha
va cham » va chat, va tham
luc van » luoc van, luu van, duc van
cuu tre » cau tren, cau treo
cua tre » cua te, cua triet, dua tren

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 y ((lang xa) or (lang ha)) hoi. lieu va cham luc van hanh vi ((cuu tre) or (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y ((lang xa) OR (lang ha)) hoi. lieu va cham luc van hanh vi ((cuu tre) OR (cua tre)).
• Adding a wildcard symbol may retrieve word variants: toc sach y ((lang xa) or (lang ha)) hoi. lieu va cham luc van hanh vi ((cuu tre) or (cua tre))*.