Perhaps you should try some spelling variations:
van thac » van hac, van than, van thuc
van tham » van thanh, van tuan, van chat
hanh hai » thanh hai, nhanh hai, hang hai
van hanh » van thanh, ban hanh, van anh
hai cua » thai cua, dai cua, hoi cua
toc van » hoc van, toc san, tac van
sach ky » sach y, sach ty, sach kem
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
sac ky » cac ky, sai ky

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 ky) or (sac ky)) nang ma hoi. hieu ((van thac) OR (van tham)) toc van hanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu ((sach ky) OR (sac ky)) nang ma hoi. hieu ((van thac) OR (van tham)) toc van hanh hai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu ((sach ky) or (sac ky)) nang ma hoi. hieu ((van thac) OR (van tham)) toc van hanh hai cua tre*".