Perhaps you should try some spelling variations:
dung trung » dung trong, quang trung, dung ung
hanh truc » hang truc, nhanh thuc, hanh thuoc
dung tren » dung trong
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
vu sach » vu bach, su sach, vu khach
cuu tre » cua tre, cau tren, cau treo
sach ky » sac ky, sach y, sach ty
truc va » thuc va, thuc vat, trung va
nang ma » tang ma, sang ma, nang cao
dan vi » doan vi, don vi, dan va
ma hoi » mai hoi, xa hoi, ma hoa
va dan » ca dan, va dao, va dau

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 nang ma hoi. hieu van hanh truc va dan vi ((((dung tren) OR (dung trung))) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky nang ma hoi. hieu van hanh truc va dan vi ((((dung tren) OR (dung trung))) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky nang ma hoi. hieu van hanh truc va dan vi ((((dung tren) OR (dung trung))) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: vu sach ky nang ma hoi. hieu van hanh truc va dan vi ((((dung tren) OR (dung trung))) or (cuu tre))*.