Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
van tham » van thanh, van tuan, van chat
tham soc » cham soc, tham nuoc, thai son
va danh » va dinh, va dan, dia danh
cuu tre » cau tren, cau treo
va hanh » van hanh, va thanh, ban hanh
xay hoi » xa hoi, tay hoi, cay phoi
cua tre » cua te, cua triet, dua tren
y dang » ky dang, 2 dang, _ dang

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y dang xay hoi. hieu van tham soc ((va hanh) or (va danh)) vi ((cuu tre) OR (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y dang xay hoi. hieu van tham soc ((va hanh) OR (va danh)) vi ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y dang xay hoi. hieu van tham soc ((va hanh) or (va danh)) vi ((cuu tre) OR (cua tre))".
• Adding a wildcard symbol may retrieve word variants: toc sach y dang xay hoi. hieu van tham soc ((va hanh) or (va danh)) vi ((cuu tre) OR (cua tre))*.