Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
toc sach » hoc sach, doc sach, nuoc sach
cua viet » ca viet, hoa viet, cua vat
thi van » thi lan, thi hanh, thi nang
va lang » va nang, hoa lang
lang di » lang dai, hang di, lang du
y nang » ky nang, ly nang, v nang
cam lo » nam lo, cam ly, cam o
di cua » dai cua, doi cua, de cua
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: ((toc sach) OR (thuoc sach)) y nang x hoi. thi van ((cam loc) or (cam lo)) va lang di cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (thuoc sach)) y nang x hoi. thi van ((cam loc) OR (cam lo)) va lang di cua viet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (thuoc sach)) y nang x hoi. thi van ((cam loc) or (cam lo)) va lang di cua viet*".