Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
khoi cua » hoi cua, khi cua, kho cua
te sach » toc sach
sach ky » sac ky, sach y, sach ty
cam tuc » cam xuc, nam thuc, dam thuc
va sinh » va kinh, va tinh, hoa sinh
cua tre » cua te, cuu tre, cua triet
cam tu » cam thu, nam tu, dam tu
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ky nang x hoi. hieu van ((cam tuc) or (cam tu)) ((va sinh) OR (vi sinh)) khoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ky nang x hoi. hieu van ((cam tuc) OR (cam tu)) ((va sinh) OR (vi sinh)) khoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ky nang x hoi. hieu van ((cam tuc) or (cam tu)) ((va sinh) OR (vi sinh)) khoi cua tre".
• Adding a wildcard symbol may retrieve word variants: te sach ky nang x hoi. hieu van ((cam tuc) or (cam tu)) ((va sinh) OR (vi sinh)) khoi cua tre*.