This gives a overview:
List of Domain operators: ! (Not), | (Or), & (And)
List of Term operators: '=', '!=', '<=', '<', '>', '>=', '=?', '=like', '=ilike', 'like', 'not like', 'ilike', 'not ilike', 'in', 'not in', 'child_of'
Usage:
Input records:
Record 1: Openerp
Record 2: openerp
Record 3: Opensource
Record 4: opensource
Record 5: Open
Record 6: open
Record 7: Odoo
Record 8: odoo
Record 9: Odooopenerp
Record 10: OdooOpenerp
'like': [('input', 'like', 'open')] -  Returns case sensitive (wildcards - '%open%') search. O/p: open, opensource, openerp, Odooopenerp
'not like': [('input', 'not like', 'open')] -  Returns results not matched with case sensitive (wildcards - '%open%') search. O/p: Openerp, Opensource, Open, Odoo, odoo, OdooOpenerp
'=like': [('name', '=like', 'open')] - Returns exact (=  'open') case sensitive search. O/p: open
'ilike': [('name', 'ilike', 'open')] - Returns exact case insensitive (wildcards - '%open%') search. O/p: Openerp, openerp, Opensource, opensource, Open, open, Odooopenerp, OdooOpenerp
'not ilike': [('name', 'not ilike', 'open')] - Returns results not matched with exact case insensitive (wildcards - '%open%') search. O/p: Odoo, odoo
'=ilike': [('name', '=ilike', 'open')] - Returns exact (=  'open' or 'Open') case insensitive search. O/p: Open, open
'=?':
name = 'odoo'
parent_id = False
[('name', 'like', name), ('parent_id', '=?', parent_id)] - Returns name domain result & True
name = 'odoo'
parent_id = 'openerp'
[('name', 'like', name), ('parent_id', '=?', parent_id)] - Returns name domain result & parent_id domain result
'=?' is a short-circuit that makes the term TRUE if right is None or False, '=?' behaves like '=' in other cases
'in':
[('value1', 'in', ['value1', 'value2'])] - in operator will check the value1 is present or not in list of right term
'not in':
[('value1', 'not in', ['value2'])] - not in operator will check the value1 is not present in list of right term
While these 'in' and 'not in' works with list/tuple of values, the latter '=' and '!=' works with string
'=':
value = 10
[('value','=',value)] - term left side has 10 in db and term right our value 10 will match
'!=':
value = 15
[('value','!=',value)] - term left side has 10 in db and term right our value 10 will not match
'child_of':
parent_id = '1' #Agrolait
'child_of':
[('partner_id', 'child_of', parent_id)] - return left and right list of partner_id for given parent_id
'<=', '<', '>', '>=':
These operators are largely used in openerp for comparing dates - [('date', '>=', date_begin), ('date', '<=', date_end)]. You can use these operators to compare int or float also.