Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
ly nang » ky nang, ly hang, ly vang
hieu va » lieu va, hieu qua
luu tre » luu tru, cuu tre, luy tre
y nang » ky nang, may nang, day nang
v nang » va nang, vu nang, van nang
va cam » va cham, va cac, va cao
cam tu » cam thu, nam tu, dam tu
va dan » ca dan, va dao, va dau
dan vi » doan vi, don vi, dan va
vi luu » vi lua

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ((((y nang) OR (ly nang))) or (v nang)) xa hoi. hieu va cam tu va dan vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((((y nang) OR (ly nang))) OR (v nang)) xa hoi. hieu va cam tu va dan vi luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc sach ((((y nang) OR (ly nang))) or (v nang)) xa hoi. hieu va cam tu va dan vi luu tre".
• Adding a wildcard symbol may retrieve word variants: hoc sach ((((y nang) OR (ly nang))) or (v nang)) xa hoi. hieu va cam tu va dan vi luu tre*.