Perhaps you should try some spelling variations:
chinh dinh » hinh dinh, chinh minh, chinh hinh
van chinh » va chinh, lan chinh, van thinh
cau tren » cu tren, dau tren, ca tren
dinh cau » dinh chau, dinh cuu, dinh cu
sach ty » sach y, sach tu, sach thu
duc van » duc va, duc tan, duc manh
ve chat » va chat, van chat
tu sach » thu sach, su sach, te sach
ty nang » ky nang, ty xang, ty hang
ve chim » va chim, ve cham, ve chinh
so hoc » co hoc, mo hoc, so hoa
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ty nang ((o hoi) or (so hoc)). hieu ((ve chim) or (ve chat)) duc van chinh dinh cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang ((o hoi) OR (so hoc)). hieu ((ve chim) OR (ve chat)) duc van chinh dinh cau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang ((o hoi) or (so hoc)). hieu ((ve chim) or (ve chat)) duc van chinh dinh cau tren*.