Perhaps you should try some spelling variations:
khoan phai » khong phai, khoan hoi, khoan nhoi
khong phap » chong phap, khong phai, phuong phap
tham thuc » nham thuc, pham thuc, thai thuc
khoa phau » hoa phan, khoa kham, khoa than
thu sach » tu sach, thuat sach, thuoc sach
tam thuc » am thuc, nam thuc, dam thuc

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach ((tham thuc) OR (tam thuc)) bach ((((khoan phai) or (khoa phau))) or (khong phap)) thong~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((tham thuc) OR (tam thuc)) bach ((((khoan phai) OR (khoa phau))) OR (khong phap)) thong.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((tham thuc) OR (tam thuc)) bach ((((khoan phai) or (khoa phau))) or (khong phap)) thong".
• Adding a wildcard symbol may retrieve word variants: thu sach ((tham thuc) OR (tam thuc)) bach ((((khoan phai) or (khoa phau))) or (khong phap)) thong*.