Shift register, unit thereof, and display device

A shift register, comprising at least one shift register unit which includes:

• driving module, configured to transmit a first clock signal to a signal output terminal of the shift register unit by switching on/off state of a controlling terminal, to output a scanning signal;
• inputting module, configured to control the on/off state of the controlling terminal of the driving module;
• and
• low voltage level maintaining module, including:
• a first maintaining unit configured to maintain a signal output terminal and/or the controlling terminal of the driving module at low voltage level when a first maintain-enabling terminal receives an effective level;
• a second maintaining unit, configured to maintain the signal output terminal and/or the controlling terminal of the driving module at low voltage level when a second maintain-enabling terminal receives an effective level;
• wherein, the shift register unit further includes:
• threshold voltage sensing module, having a sensing input terminal coupled to the first maintain-enabling terminal and a signal output terminal coupled to the second maintain-enabling terminal, configured to control its signal output terminal to provide an effective level to the second maintain-enabling terminal according to shifted threshold voltage sensed at its sensing input terminal.