Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
cua viet » ca viet, hoa viet, cua vat
tu sach » su sach, te sach, tu cach
nang xa » nang x, lang xa, nang ma
cac luc » cau luc, cac nuoc, cac cuoc
y nang » ky nang, ly nang, v nang
va dan » ca dan, va dao, va dau
dan va » doan va, dan ca, ban va
va cua » va chua, via cua, ca 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) OR (thu sach)) y nang xa hoi. hieu qua ((cac luc) or (coc luc)) va dan va cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) y nang xa hoi. hieu qua ((cac luc) OR (coc luc)) va dan va cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) OR (thu sach)) y nang xa hoi. hieu qua ((cac luc) or (coc luc)) va dan va cua viet".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) OR (thu sach)) y nang xa hoi. hieu qua ((cac luc) or (coc luc)) va dan va cua viet*.