Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
van hanh » van thanh, ban hanh, van anh
hieu van » hieu va, thien van, lieu va
tu sach » su sach, te sach, tu cach
hanh va » hang va, hanh vi
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
cam ly » tam ly, cam ky, cam lo
va cua » va chua, via cua, ca cua

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) or (thu sach)) ty nang ma hoi. hieu van ((cam lyc) or (cam ly)) van hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ty nang ma hoi. hieu van ((cam lyc) OR (cam ly)) van hanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ty nang ma hoi. hieu van ((cam lyc) or (cam ly)) van hanh va cua tre*.