Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
thu nang » thi nang, thu bang, tho nang
thu hang » thi hang, thuc hanh, thu huong
luc nhan » luc nhat, cu nhan, tue nhan
luc ngan » luc nganh, luat ngan, vu ngan
hang vi » hang va, hanh vi, hang di
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
vi dau » vi dai, va dau, bi dau
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: tu sach ((thu nang) OR (thu hang)) xa hoi. hieu ve cam ((luc ngan) or (luc nhan)) hang vi dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((thu nang) OR (thu hang)) xa hoi. hieu ve cam ((luc ngan) OR (luc nhan)) hang vi dau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((thu nang) OR (thu hang)) xa hoi. hieu ve cam ((luc ngan) or (luc nhan)) hang vi dau tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ((thu nang) OR (thu hang)) xa hoi. hieu ve cam ((luc ngan) or (luc nhan)) hang vi dau tren*.