Perhaps you should try some spelling variations:
sach nganh » sach ngan, sach tranh, cac nganh
sach ngang » sach nang, sach ngan, sach ngon
cong thai » cong hai, hong thai, cong thanh
ngang cho » nang cho, ngang tho, sang cho
thu sach » tu sach, thuat sach, thuoc sach
cong khi » khong khi, co khi, cong ha
cho khi » co khi, cho ghi, cao khai

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 nganh ((cong khi) OR (cong thai)) đong luc ) or ( thu sach ngang cho khi đong luc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( thu sach nganh ((cong khi) OR (cong thai)) đong luc ) OR ( thu sach ngang cho khi đong luc )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( thu sach nganh ((cong khi) OR (cong thai)) đong luc ) or ( thu sach ngang cho khi đong luc ))".
• Adding a wildcard symbol may retrieve word variants: (( thu sach nganh ((cong khi) OR (cong thai)) đong luc ) or ( thu sach ngang cho khi đong luc ))*.