Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
thien van » thi van
hieu van » hieu va, lieu va, hieu ve
cau tren » cu tren, dau tren, ca tren
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
lao luc » bao luc
va kinh » va tinh
i cau » di cau, _ cau, 2 cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuoc sach ky nang xa hoi. ((hieu van) or (thien van)) lao luc ((va kinh) OR (qua kinh)) i cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ky nang xa hoi. ((hieu van) OR (thien van)) lao luc ((va kinh) OR (qua kinh)) i cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ky nang xa hoi. ((hieu van) or (thien van)) lao luc ((va kinh) OR (qua kinh)) i cau tren".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ky nang xa hoi. ((hieu van) or (thien van)) lao luc ((va kinh) OR (qua kinh)) i cau tren*.