Perhaps you should try some spelling variations:
sach nang » cach mang, sach dung, sach danh
cham hoc » cham soc, chat hoc, cham hoi
dieu cua » dieu tra
nang mai » nang ma, nang tai, lang mai
dien cua » dien cuc, dien cu, tien cua
va danh » va dinh, va dan, va hanh
hieu vu » hieu va, hieu ve, hieu su
vu cham » va cham, vu kham, tu cham
mai hoi » mai khoi, dai hoi, lai hoi

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 y) or (sach nang)) nang mai hoi. hieu vu cham hoc va danh ((dien cua) or (dieu cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach y) OR (sach nang)) nang mai hoi. hieu vu cham hoc va danh ((dien cua) OR (dieu cua)) tre.
• Adding a wildcard symbol may retrieve word variants: te ((sach y) or (sach nang)) nang mai hoi. hieu vu cham hoc va danh ((dien cua) or (dieu cua)) tre*.