Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
tao nano » tao nganh, cao nang, tao nhan
van hanh » ban hanh, van anh, van ban
su sach » so sach, vu sach
cac duc » cac du, cao duc, cac dac
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
tao cao » bao cao, toan cao
va cua » va chua, via cua, ca cua
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ((tao nano) OR (tao cao)) cau hoi. hieu ve cac duc ((van hanh) or (van thanh)) va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((tao nano) OR (tao cao)) cau hoi. hieu ve cac duc ((van hanh) OR (van thanh)) va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((tao nano) OR (tao cao)) cau hoi. hieu ve cac duc ((van hanh) or (van thanh)) va cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((tao nano) OR (tao cao)) cau hoi. hieu ve cac duc ((van hanh) or (van thanh)) va cua tre*.