Perhaps you should try some spelling variations:
thuoc sach » nuoc sach, thuat sach, thuoc sinh
phap thong » phap phong, phap chong, pho thong
khau sach » hau sach, khoa sach, pham sach
khoa phap » khoa phau, khoan phai, khong phap
hoc sach » hoc sinh, hoc cac, hoc anh
tu sach » thu sach, su sach, te sach

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((((tu sach) or (thu hoach))) or (khau sach)) tai ((thuoc sach) OR (hoc sach)) khoa phap thong~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((((tu sach) OR (thu hoach))) OR (khau sach)) tai ((thuoc sach) OR (hoc sach)) khoa phap thong.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((tu sach) or (thu hoach))) or (khau sach)) tai ((thuoc sach) OR (hoc sach)) khoa phap thong".
• Adding a wildcard symbol may retrieve word variants: ((((tu sach) or (thu hoach))) or (khau sach)) tai ((thuoc sach) OR (hoc sach)) khoa phap thong*.