Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
van hanh » van thanh, ban hanh, van anh
tham soc » cham soc, tham nuoc, thai son
cau tren » cu tren, dau tren, ca tren
nang xa » nang x, lang xa, mang xa
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
tu sach » su sach, te sach, tu cach
soc van » hoc van, oc van, sac van
nang ma » tang ma, sang ma, nang cao
vi cau » va cau, ve cau, di cau

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) or (tu sach)) ty ((nang xa) OR (nang ma)) hoi. hieu va tham soc van hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) ty ((nang xa) OR (nang ma)) hoi. hieu va tham soc van hanh vi cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (tu sach)) ty ((nang xa) OR (nang ma)) hoi. hieu va tham soc van hanh vi cau tren".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) ty ((nang xa) OR (nang ma)) hoi. hieu va tham soc van hanh vi cau tren*.