Perhaps you should try some spelling variations:
dac khanh » dat khanh, dan khanh, duc khanh
phong hoc » phong ho, phuong hoa, phong khoa
thong hoc » thuong hoc, tuong hoc, thong hoa
sach hoi » sach doi, sach moi, cach thoi
cuu cong » cua cong, thu cong, cac cong
cong dac » cong tac, cong dan, cong cac
tu sach » thu sach, su sach, te sach
hoi tap » hoi dap, hoc tap, hoi tai
nhan va » nhan tai, nhan dan, nhan tao
hoi ca » hoi cua, hoi cac, hoi cau

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 hoi tap, nghien cuu cong dac khanh ((phong hoc) OR (thong hoc)) xa hoi ca nhan va~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach hoi tap, nghien cuu cong dac khanh ((phong hoc) OR (thong hoc)) xa hoi ca nhan va".
• Adding a wildcard symbol may retrieve word variants: tu sach hoi tap, nghien cuu cong dac khanh ((phong hoc) OR (thong hoc)) xa hoi ca nhan va*.