Perhaps you should try some spelling variations:
thanh toan » thanh hoa, thanh san, tinh toan
thanh tay » thanh tai, thanh thuy, thanh san
van hanh » van thanh, ban hanh, van anh
luc van » luoc van, luu van, duc van
tu sach » thu sach, su sach, te sach
cam luc » cam xuc, cau luc
sach ky » sac ky, sach y, sach ty
ve cai » va cai, ve cac, ve tai
va cam » va cham, va cac, va cao
ve ca » ve cac, ve cau, ve cua

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 ky ((thanh tay) or (thanh toan)) hoi. lieu va cam luc van hanh ((ve ca) OR (ve cai)) tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((thanh tay) OR (thanh toan)) hoi. lieu va cam luc van hanh ((ve ca) OR (ve cai)) tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((thanh tay) or (thanh toan)) hoi. lieu va cam luc van hanh ((ve ca) OR (ve cai)) tren".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((thanh tay) or (thanh toan)) hoi. lieu va cam luc van hanh ((ve ca) OR (ve cai)) tren*.