Perhaps you should try some spelling variations:
cau tren » cu tren, ca tren, cau treo
dau tren » dau tien, dat tren, dau tieng
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cac lao » ca lao, cac loai, cac giao
sac ky » sai ky
lao va » tao va, cao va, bao va
va dan » ca dan, va dao, va dau
dan ve » ban ve, dan va, dan viet

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