Perhaps you should try some spelling variations:
vien cac » vien bach, vien dai, vien da
cau tren » cu tren, ca tren, cau treo
dau tren » dau tien, dat tren, dau tieng
te sach » toc sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, co hoi, cao hoc
ve cac » va cac
xa dan » ca dan, xa dai, va dan

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang cao hoi. hieu ((ve cac) OR (vien cac)) tuc xa dan ca ((cau tren) or (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang cao hoi. hieu ((ve cac) OR (vien cac)) tuc xa dan ca ((cau tren) OR (dau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang cao hoi. hieu ((ve cac) OR (vien cac)) tuc xa dan ca ((cau tren) or (dau tren))".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang cao hoi. hieu ((ve cac) OR (vien cac)) tuc xa dan ca ((cau tren) or (dau tren))*.