Perhaps you should try some spelling variations:
dau tren » dau tien, dat tren, dau tieng
van hanh » van thanh, ban hanh, van anh
nang doc » nang luc
vu cham » va cham, vu kham, tu cham
hanh va » hang va, hanh vi
duc van » duc va, duc tan, duc manh
ve cham » va cham, ve chat, ve chim
doc hoc » duoc hoc, toc hoc, duc hoc
tu sach » thu sach, su sach, te sach
y nang » ky nang, ly nang, v nang
va dau » va dao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu hoach) or (tu sach)) y nang doc hoc. hieu ((ve cham) or (vu cham)) duc van hanh va dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu hoach) OR (tu sach)) y nang doc hoc. hieu ((ve cham) OR (vu cham)) duc van hanh va dau tren.
• Adding a wildcard symbol may retrieve word variants: ((thu hoach) or (tu sach)) y nang doc hoc. hieu ((ve cham) or (vu cham)) duc van hanh va dau tren*.