Perhaps you should try some spelling variations:
nang hoa » nang hoat, hang hoa, nang hoc
cau tren » cu tren, dau tren, ca tren
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
hoa hoi » khoa hoi, hoa hoc, hoa doi
ve cam » ve cham, ve cac, va cam
loc va » luc va
vi cau » va cau, ve cau, di cau

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: vu sach ky nang hoa hoi. hieu ((ve cam) OR (va cac)) ((loc va) OR (hoc va)) hanh vi cau tren~.
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang hoa hoi. hieu ((ve cam) or (va cac)) ((loc va) or (hoc va)) hanh vi cau tren*.