Perhaps you should try some spelling variations:
doanh khoa » toan khoa
van thanh » ban thanh, van tuan
thanh van » thanh san, thanh toan, thanh phan
thu sach » thuat sach, thuoc sach, thu hoach
cuu long » cuu cong, cuu tong, cuu nang
so doanh » so danh, su doanh, hoa doanh
khoa hoc » hoa hoc
thai van » thi van, thai vung, thai den
tu sach » su sach, te sach, tu cach
long so » long soc, cong so, dong so
da thai » dao thai, do thai, ca thai
hoc da » hoc dan, hoc dai, hoc dat

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) or (tu sach)) hoc tap, nghien cuu long so doanh khoa hoc da thai van thanh van~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) hoc tap, nghien cuu long so doanh khoa hoc da thai van thanh van.
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) hoc tap, nghien cuu long so doanh khoa hoc da thai van thanh van*.