Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
van hanh » ban hanh, van anh, van ban
cuu tre » cua tre, cau tren, cau treo
sach ty » sach y, sach tu, sach thu
cao hoi » cau hoi, co hoi, cao hoc
hieu ve » hieu va, hieu van
cam duc » cam xuc, cao duc, pham duc
di cuu » di cau, di cua, dinh cuu
sac ky » cac ky, sai ky
ve cam » ve cham, ve cac, va cam

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sac ky) or (sach ty)) nang cao hoi. hieu ve cam duc ((van hanh) or (van thanh)) di cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (sach ty)) nang cao hoi. hieu ve cam duc ((van hanh) OR (van thanh)) di cuu tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) or (sach ty)) nang cao hoi. hieu ve cam duc ((van hanh) or (van thanh)) di cuu tre*.