Perhaps you should try some spelling variations:
cau theo » cau thi, cau tao
cau treo » cau tren, cau triet, cau trieu
hieu ve » hieu va, hieu van
nang xa » nang x, lang xa, nang ma
cac lao » ca lao, cac loai, cac giao
ve cac » va cac, vien cac
sac ky » sai ky
lao va » tao va, cao va, bao va
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc ((sac ky) or (cac ky)) nang xa hoi. hieu ve cac lao va dan vi ((cau treo) OR (cau theo))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sac ky) OR (cac ky)) nang xa hoi. hieu ve cac lao va dan vi ((cau treo) OR (cau theo)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sac ky) or (cac ky)) nang xa hoi. hieu ve cac lao va dan vi ((cau treo) OR (cau theo))".
• Adding a wildcard symbol may retrieve word variants: toc ((sac ky) or (cac ky)) nang xa hoi. hieu ve cac lao va dan vi ((cau treo) OR (cau theo))*.