#1	MeSH descriptor Venous Thrombosis explode all trees
#2	MeSH descriptor Venous Thromboembolism explode all trees
#3	MeSH descriptor Thrombosis explode all trees
#4	MeSH descriptor Pulmonary Embolism explode all trees
#5	thrombol* or thrombot* or thrombu* or thromboemb*
#6	DVT or deep near (vein* or ven*) near thromb*
#7	PE or Pulmonary near emb*
#8	(#1 OR #2 OR #3 OR #4 OR #5 OR #6 OR #7)
#9	MeSH descriptor Anticoagulants explode all trees
#10	anticoagulant* or unfractionated hep* or UFH or low molecular weight hep* or LMWH or warfarin
#11	(#9 OR #10)
#12	MeSH descriptor Placebos explode all trees
#13	placebo*
#14	(#12 OR #13)
#15	(#8 AND #11 AND #14)