Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh doc » than doc, thanh do, nhanh doc
hieu van » hieu va, thien van, lieu va
sinh cua » manh cua, dinh cuu, sinh va
vinh cuu » dinh cuu, dinh cu, tinh cua
va hanh » van hanh, va thanh, va danh
te sach » toc sach
sach ky » sac ky, sach y, sach ty
ky dang » ky nang, ky danh
doc va » duoc va, hoc va, duc va
ha hoi » hoa hoi, ha noi, va hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky dang ((ha hoi) OR (xa hoi)). hieu van thanh doc va hanh ((vinh cuu) or (sinh cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky dang ((ha hoi) OR (xa hoi)). hieu van thanh doc va hanh ((vinh cuu) OR (sinh cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky dang ((ha hoi) OR (xa hoi)). hieu van thanh doc va hanh ((vinh cuu) or (sinh cua)) tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky dang ((ha hoi) OR (xa hoi)). hieu van thanh doc va hanh ((vinh cuu) or (sinh cua)) tre*.