Device-to-device　(D2D)　communication　raises　new　transmission　secrecy　protection　challenges,　since　conventional　physical　layer　security　approaches,　such　as　multiple　antennas　and　cooperation　techniques,　are　invalid　due　to　its　resource/size　constraints.　The　full-duplex　(FD)　jamming　receiver,　which　radiates　jamming　signals　to　confuse　eavesdroppers　when　receiving　the　desired　signal　simultaneously,　is　a　promising　candidate.　Unlike　existing　endeavors　that　assume　the　FD　jamming　receiver　always　improves　the　secrecy　performance　compared　with　the　half-duplex　(HD)　receiver,　we　show　that　this　assumption　highly　depends　on　the　instantaneous　residual　self-interference　cancellation　level　and　may　be　invalid.　We　propose　an　adaptive　jamming　receiver　operating　in　a　switched　FD/HD　mode　for　a　D2D　link　in　random　networks.　Subject　to　the　secrecy　outage　probability　constraint,　we　optimize　the　transceiver　parameters,　such　as　signal/jamming　powers,　secrecy　rates,　and　mode　switch　criteria,　to　maximize　the　secrecy　throughput.　Most　of　the　optimization　operations　are　taken　off-line　and　only　very　limited　on-line　calculations　are　required　to　make　the　scheme　with　low　complexity.　Furthermore,　some　interesting　insights　are　provided,　such　as　the　secrecy　throughput　is　a　quasi-concave　function.　Numerical　results　are　demonstrated　to　verify　our　theoretical　findings,　and　to　show　its　superiority　compared　with　the　receiver　operating　in　the　FD　or　HD　mode　only.