Perhaps you should try some spelling variations:
sach tham » sach nha
thu sach » tu sach, thuat sach, thuoc sach
luc nhan » luc nhat, tue nhan, luc luan
dat tren » dat trong, dua tren
hieu ve » hieu va, hieu van
cu nhan » ca nhan
nang xa » lang xa, nang ma, mang xa
hang vi » hang va, hanh vi, hang di
vi dat » voi dat, vi dai, va dat
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: thu sach tham ((nang xa) OR (nang x)) hoi. hieu ve cam ((luc nhan) or (cu nhan)) hang vi dat tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach tham ((nang xa) OR (nang x)) hoi. hieu ve cam ((luc nhan) OR (cu nhan)) hang vi dat tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach tham ((nang xa) OR (nang x)) hoi. hieu ve cam ((luc nhan) or (cu nhan)) hang vi dat tren".
• Adding a wildcard symbol may retrieve word variants: thu sach tham ((nang xa) OR (nang x)) hoi. hieu ve cam ((luc nhan) or (cu nhan)) hang vi dat tren*.