用显微镜的一个目镜分别与4个不同倍数的物镜组合观察临时装片,形成清晰物像时,每一

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问题:

用显微镜的一个目镜分别与4个不同倍数的物镜组合观察临时装片,形成清晰物像时,每一物镜与载玻片的距离如下图示。在一个视野中看到的细胞数目最多的是

考点:显微镜的构造和使用
题型:选择题
等比数列{an}(n∈N*)中,若a2=
1
16
a5=
1
2
,则a12=______.
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用同一种正多边形地砖镶嵌成平整的地面,那么这种正多边形地砖的形状可以是        . (只需写出一种即可)

题型:选择题

D,yn11连接组的变压器,二次线电压与一线电压之间的相位差为()。

A、0℃

B、30℃

C、60℃

D、110℃

题型:选择题

抗胆碱药是我国首创的抗感染性休克的药物,其作用机制是什么?

题型:选择题

Silicon Valley is a magnet to which numerous talented engineers, scientists and entrepreneurs from overseas flock in search of fame, fast money and to participate in a technological revolution whose impact on mankind will surely surpass the epoch-making European Renaissance and Industrial Revolution of the bygone age.
(46) With the rapid spread of the Internet since the early 1990s, and the relentless technological innovations generated through it, the information era is truly upon us, profoundly influencing and changing not only our lifestyle, but also the way we work, do business, think and communicate with others.
(47) The unprecedented success of the Valley is a testimony to the concerted international endeavors and contributions by people from diverse cultural and racial backgrounds, made possible by the favorable political, economic and intellectual climate prevailing, as well as the farsighted policies of the US government.
Many countries have, or are in the process of creating, their own "Silicon Valley". So far, none has as yet threatened the preeminence of the US prototype. What makes Silicon Valley such a Unique entity There are several crucial factors.
(48) First and foremost, it has the largest concentration of brilliant computer professionals and the best supporting services in the world, and easy access to world-class research institutions, like Stanford University, which continually nurtures would-be that the industry needs in order to move forward. Without these advantages, the Valley would be a different place.
Secondly, it actively encourages, or even exalts, risk taking. Hence, failure holds no terror and there is no shame attached to a failed effort. On the contrary, they will try even harder next time round. Such never-say-die approach is the sine qua non for the ultimate triumph in entrepreneurship and technological breakthrough.
(49) A third decisive factor is the vital role of venture capitalists who willingly support promising start-ups with urgently needed initial capital to get them started. Some would even give failed entrepreneurs a second chance if convinced that a fresh concept might lead to ultimate success.
(50) Of equal importance, bright young people and middle level professionals are keen to work for a new venture at substantially reduced remuneration, as it offers more scope for entrepreneurship and job satisfaction than the established companies. There is also a pride of achievement if their efforts contribute to its fruition.
Intellectual challenges aside, it is a common practice for start-ups to offer generous share options to employees in order to attract the right talent into their folds. This is a powerful incentive to motivate the staff to do their utmost and to share in the company’s prosperity if it reaches its goal Many regard this as the foundation of a successful enterprise.

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