There are two main types of glucose, $\alpha$-D-(+)-glucose and $\beta$-D-(+)-glucose.
Can anyone please explain what is $\alpha$,D or (+)?
So (maybe by permutation and combination), how many types of glucose are there?
Glucose can exist in the open form or cyclic form.
In the open form, there are only two types, D-glucose (illustrated in Fischer projection above) and L-glucose which is the mirror image of the above.
Experimentally, D-glucose rotates plane polarize light clockwise, hence the symbol "+", and L-glucose rotates plane polarize light counterclockwise, hence the minus symbol. For more information on the meaning of + versus - see: http://en.wikipedia.org/wiki/Dextrorotation_and_levorotation
In the cyclic form, there is an additional chiral center, so there is alpha (where 3 OH groups are on the same side of the ring) vs beta (where 2 OH groups are on each side of the ring) as ilustrated in the drawing of the question.
Each of alpha and beta have a D and an L form, so there are 4 types in the cyclic form.
So in summary, there are only two types in the open form, but 4 types in the cyclic form.