Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
dang thai » dang thi, dang khai, lang thai
dang hai » dang khai, hang hai, dung hai
bac nuoc » cac nuoc, bach tuoc, sach nuoc
lan bac » dan bac, la bac, van bac
thi lan » thi hanh, thi nang, thi lien
tu nong » tu dong, tu cong, tu tong
tu nang » tru nang, tu nano, tu lang
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 ((tu nang) OR (tu nong)) x hoi. thi lan bac nuoc va ((dang thai) or (dang hai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ((tu nang) OR (tu nong)) x hoi. thi lan bac nuoc va ((dang thai) OR (dang hai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ((tu nang) OR (tu nong)) x hoi. thi lan bac nuoc va ((dang thai) or (dang hai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ((tu nang) OR (tu nong)) x hoi. thi lan bac nuoc va ((dang thai) or (dang hai)) cua tre*.