Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
tren thuoc » trien thuoc, trung thuoc, tin thuoc
khau thong » khau thuong, khap thong, khau tong
tren thuc » trien thuc, tron thuc, trinh thuc
sach khoa » bach khoa, sach nha, anh khoa
phu thong » pho thong, phap thong, phan thong

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

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