Perhaps you should try some spelling variations:
sang lap » sang tao, sang ma, sang tai
vien cac » vien dai, vien da, gian cac
sach ky » sach y, sach ty, sach kem
lap lai » lap tai, lay lai, lam lai
sac ky » cac ky, sai ky
luc va » duc va, tuc va, loc va
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
vi cua » vai cua, di cua
cua te » cua tu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach ky) OR (sac ky)) sang lap lai. hieu ((vien cac) OR (vien bach)) luc va dan vi cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach ky) or (sac ky)) sang lap lai. hieu ((vien cac) OR (vien bach)) luc va dan vi cua te~".
• Adding a wildcard symbol may retrieve word variants: su ((sach ky) or (sac ky)) sang lap lai. hieu ((vien cac) OR (vien bach)) luc va dan vi cua te*.