Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
doanh van » doanh va, doanh ban, doanh nhan
doan van » doan va, hoang van, luan van
danh vai » danh sai, danh va, dang van
su sach » so sach, vu sach
thuc xa » thuc xay, tuc xa, thuc va
sach ta » sach tai, sach xa, sach ha
ve tham » va tham, ve cham, vi tham
hieu ve » hieu va, hieu van
tang ha » lang ha, tang ma, trung ha
ta tang » ta trang, tay tang, ha tang
cuu tre » cua tre, cau tren, cau treo
ha hoi » hoa hoi, ha noi, xa hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ta tang ha hoi. hieu ve tham thuc xa ((danh vai) or (((doanh van) OR (doan van)))) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ta tang ha hoi. hieu ve tham thuc xa ((danh vai) OR (((doanh van) OR (doan van)))) cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ta tang ha hoi. hieu ve tham thuc xa ((danh vai) or (((doanh van) OR (doan van)))) cuu tre*".