Perhaps you should try some spelling variations:
thuoc sach » nuoc sach, thuat sach, thuoc sinh
hoc sach » hoc sinh, hoc cac, hoc anh
cac nuoc » cap nuoc, hoc nuoc, cua nuoc
nang thi » dang thi, tang thi, nang tai
thi van » thi lan, thi hanh, thi nang
va nang » van nang, da nang, cam nang
thi cua » thai cua, thi cuc, tri cua
cua tre » cua te, cuu tre, cua triet
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: ((thuoc sach) OR (hoc sach)) ky nang x hoi. thi van ((cac nuoc) or (dat nuoc)) va nang thi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (hoc sach)) ky nang x hoi. thi van ((cac nuoc) OR (dat nuoc)) va nang thi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) OR (hoc sach)) ky nang x hoi. thi van ((cac nuoc) or (dat nuoc)) va nang thi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) OR (hoc sach)) ky nang x hoi. thi van ((cac nuoc) or (dat nuoc)) va nang thi cua tre*.