Perhaps you should try some spelling variations:
cach thoi » cac thoi, cach thuc, cach noi
thoi tap » toi tap, hoc tap, thoi dai
cuu dong » cuu cong, cuu tong, cuu long
dong hoc » dong co, dong luc
hoc hanh » hoc nhanh, hoc thanh, hoc anh
hanh hoa » thanh hoa, khanh hoa, hang hoa
nhan van » nhan dan, nhan va, phan van
te cach » ve cach, te sach, tu cach

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

• Performing a fuzzy search may retrieve terms with similar spellings: te cach thoi tap, nghien cuu dong hoc hanh hoa hoc ma ((hoa vo) OR (hoa co)) nhan van~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te cach thoi tap, nghien cuu dong hoc hanh hoa hoc ma ((hoa vo) OR (hoa co)) nhan van".
• Adding a wildcard symbol may retrieve word variants: te cach thoi tap, nghien cuu dong hoc hanh hoa hoc ma ((hoa vo) OR (hoa co)) nhan van*.