目的探讨超声在产道隐蔽性血肿诊断中的应用价值。

Objective to discuss the applicative value in ultrasonic diagnosis of concealed hematoma of birth canal.

由于目标的隐蔽性和机动性，反潜作战被列为世界海军三大难题之首。

Due to the concealment and mobility of targets, anti-submarine warfare is listed as the top of three difficulties faced by world navies.

关于这些行为最显著的特征是其常常带有自毁倾向和隐蔽性。

What is most striking about these behaviours is that they are often self-destructive and hidden.

辽河盆地热欧地区勘探程度低，取心资料少，砂体与油气分布具有较强的隐蔽性。

Re_Ou area of Liao basin has the features of low exploration degree, lack cored data, and the indecision of sandy hydrocarbon reservoirs.

潜艇因具有优良的战术性能、良好的隐蔽性、较强的自给力和续航力、较大的突击力而受到世界各国海军的普遍重视。

The submarine receives all around the world attention of navy because of its fine tactical performance, good disguise, stronger self-sufficiency strength, endurance and greater assault strength.