Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
chat lua » chat cua, chat va, chat huu
cham luu » cham cuu, phap luu, cham lai
vu sach » vu bach, su sach, vu khach
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach y ((nang xa) or (nang ma)) hoi. lieu va ((cham luu) OR (chat lua)) van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach y ((nang xa) OR (nang ma)) hoi. lieu va ((cham luu) OR (chat lua)) van hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach y ((nang xa) or (nang ma)) hoi. lieu va ((cham luu) OR (chat lua)) van hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: vu sach y ((nang xa) or (nang ma)) hoi. lieu va ((cham luu) OR (chat lua)) van hanh vi cua tre*.