It might be something simple like the tap is worn out inside and when you think it is open it is still almost closed. Don't forget that the kitchen tap is usually direct from the main supply but all the other taps are fed from the water tank in the roof, so maybe that pipe is blocked or something.You will have to test it by turning off the main water supply and removing the top of the tap as though changing the washer and then carefully (Means very slowy!) open the main water supply and see if water comes out, if yes then just change the tap, if no then its time to get somebody in.