Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
cau tren » cu tren, dau tren, cau treo
dan hanh » dang hanh, dan khanh, dan thanh
tham hoc » thai hoc, tham hoa, than hoc
va tham » van tham, va cham, va thanh
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
tu sach » su sach, te sach, tu cach
ca tren » cu tren, la tren, co tren

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