Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
dien duc » dien cuc, dien luc, tien duc
doc sach » nuoc sach, dac sac, bo sach
dan dien » doan dien, danh dien, dan den
toc sach » thuoc sach, nuoc sach, toc san
cam luc » cam xuc, cau luc
hieu va » lieu va, hieu qua
duc tre » duoc tren, duc tien
nang ho » nang hoc, nang co, tang ho
vu nang » vuc nang, va nang, vu dang
va cam » va cham, va cac, va cao
luc va » duc va, tuc va, loc va
va dan » ca dan, va dao, va dau
ho hoc » hoa hoc, cho hoc, hoi hoc

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) or (((doc sach) OR (toc sach)))) vu nang ho hoc. hieu va cam luc va dan dien duc tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((hoc sach) OR (((doc sach) OR (toc sach)))) vu nang ho hoc. hieu va cam luc va dan dien duc tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((hoc sach) or (((doc sach) OR (toc sach)))) vu nang ho hoc. hieu va cam luc va dan dien duc tre".
• Adding a wildcard symbol may retrieve word variants: ((hoc sach) or (((doc sach) OR (toc sach)))) vu nang ho hoc. hieu va cam luc va dan dien duc tre*.