затруднять

. усложнять

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Internal conversion hampers (or hinders) the use of IR emitting dyes as laser materials.

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One difficulty that plagues the investigation of cosmic jets is that it is not known how much ...

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This makes further substitution difficult (or hard).

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Затруднять -- to make difficult, to render difficult; to impede, to hamper (препятствовать)

 The highly polished surfaces in a ball bearing make microscope examination difficult.

 Both of these features render it difficult to state explicitly what energy is available to be dissipated by flow.

—затруднять обеспечение

—затруднять проведение

—затруднять проведение испытаний

—затрудняя тем самым

—очень затрудняет