Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
van hanh » van thanh, ban hanh, van anh
cham sat » cham mat, cham soc, khao sat
hanh va » hang va, hanh vi
sat van » sat va, hat van, hoat van
ca tren » cau tren, cu tren, la tren
hieu va » hieu qua
nang xa » nang x, lang xa, nang ma
ty nang » ky nang, ty xang, ty hang
va ca » va cac, va cao, va cai

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