全文获取类型
| 收费全文 | 832篇 |
| 免费 | 29篇 |
| 国内免费 | 32篇 |
专业分类
| 测绘学 | 210篇 |
| 大气科学 | 41篇 |
| 地球物理 | 46篇 |
| 地质学 | 123篇 |
| 海洋学 | 59篇 |
| 天文学 | 8篇 |
| 综合类 | 73篇 |
| 自然地理 | 333篇 |
出版年
| 2024年 | 1篇 |
| 2023年 | 10篇 |
| 2022年 | 40篇 |
| 2021年 | 38篇 |
| 2020年 | 41篇 |
| 2019年 | 28篇 |
| 2018年 | 32篇 |
| 2017年 | 41篇 |
| 2016年 | 41篇 |
| 2015年 | 27篇 |
| 2014年 | 43篇 |
| 2013年 | 63篇 |
| 2012年 | 32篇 |
| 2011年 | 29篇 |
| 2010年 | 30篇 |
| 2009年 | 15篇 |
| 2008年 | 43篇 |
| 2007年 | 40篇 |
| 2006年 | 36篇 |
| 2005年 | 44篇 |
| 2004年 | 35篇 |
| 2003年 | 37篇 |
| 2002年 | 22篇 |
| 2001年 | 15篇 |
| 2000年 | 30篇 |
| 1999年 | 18篇 |
| 1998年 | 17篇 |
| 1997年 | 7篇 |
| 1996年 | 9篇 |
| 1995年 | 6篇 |
| 1994年 | 7篇 |
| 1993年 | 4篇 |
| 1992年 | 3篇 |
| 1991年 | 2篇 |
| 1990年 | 1篇 |
| 1989年 | 2篇 |
| 1988年 | 1篇 |
| 1986年 | 1篇 |
| 1983年 | 1篇 |
| 1979年 | 1篇 |
排序方式： 共有893条查询结果，搜索用时 283 毫秒
1.
PatMoore 《成都信息工程学院学报》2002,17(4):289-299
尽管语法在交际教学法鼎盛时期一度遭到冷遇，但现在又重新被英语语言教学所接纳，作为一种新的语法教学方式，发现原则综合了传统归纳发和演绎法的长处，概述了发现原则的理论依据，指出发现原则旨在鼓励学习者积极参与而非被动接受，符合当前认知主义对二语学习的认识。 相似文献
2.
3.
Generally, the underwater flight vehicle (UFV) depth control system operates with the following problems: it is a multi-input multi-output (MIMO) system, it requires robustness, a continuous control input, and further, it has the speed dependency of controller parameters. To solve these problems, an expanded adaptive fuzzy sliding mode controller (EAFSMC), which is based on the decomposition method designed by using an expert knowledge and the decoupled sub-controllers and composition method designed by using the fuzzy basis function expansions (FBFEs), is proposed. To verify the performance of the EAFSMC, the depth control of UFV in various operating conditions is performed. Simulation results show that the EAFSMC solves all problems experienced in the UFV depth control system online. 相似文献
4.
本文对用于模式分类、函数逼近、参数估计的多层感知器 (MLPs)给出 1个清晰的关于内部行为的解释。作者以单隐层的 MLP为例 ,论述了关于 MLP的内部行为的半线性分析理论。对受训的MLP,将隐层单元的输出分别定义为网络输出的正、负“内部分量”;定义内部分量的连接权重集为给定问题的“内部判别模式”;建立了 MLP和模糊集相结合的新模型 ;分析了 MLP的结构为 N- 2 - 1和N- H- 1 ,给出权重初始化的方法 ;提出了 1种从受训神经 -模糊模型 (NFMs)中提取知识的全新的具有实用价值的方法。 相似文献
5.
在基于启发式内插等高线算法的基础上提出了一种局部内插方法。首先利用Douglas-Peucker算法提取等高线的特征点,根据特征点判断等高线之间的相似性程度,找出导致等高线出现异常的特征点;然后将相似性程度很低的两条等高线自动分解为若干简单等高线再进行内插。有效地解决了局部弯曲很大、马鞍型地貌等复杂等高线的内插问题。算法已经在以Microstation为平台的数字制图系统中实现并逐渐实用化。 相似文献
6.
7.
8.
A decision support system (DSS) has been developed to assist expert and non-expert users in the evaluation and selection of
eco-engineering strategies for slope protection. This DSS combines a qualitative hazard assessment of erosion and mass movements
with a detailed catalogue of eco-engineering strategies for slope protection of which the suitability is evaluated in relation
to the data entered. The slope decision support system (SDSS) is a knowledge based DSS in which knowledge is stored in frames
containing rules that can evaluate the available information for a project, stored as project specific information (PSI) in
a data file. The advantages of such a system are that it accepts incomplete information and that the qualitative nature of
the information does not instil the user with a sense of unjustified exactitude. By its multidisciplinary and progressive
nature, the DSS will be of value during the initial stages of an eco-engineering project when data collection and the potential
of different eco-engineering strategies are considered. The accent of the output of the DSS is on the application of eco-engineering
strategies for slope protection as an environmentally-friendly solution aiding sustainable development. For its acceptance
within the engineering community, the DSS needs to prove its predictive capacity. Therefore, its performance has been benchmarked
against successful and unsuccessful cases of slope stabilisation using eco-engineering. The target audience and the areas
of application of this DSS are reviewed and the strategies for further development in this area suggested. 相似文献
9.
10.
In this article we make a case for a renewed emphasis upon some of the generic, albeit often tacit, spaces of practice that we share across our sub–disciplinary boundaries. In this we seek to emphasize the ways in which everyday actions make up the grander facades of institutional agendas, empirical projects and disciplinary schools of thought. To achieve this we trace the performance of disciplinary contours and identities across three important sites: the field, the body and the act of dissemination. There are, we will argue, significant commonalities that bind us as disciplinary practitioners in terms of how we perform within and across these sites, and indeed, how we join them up through our practices. 相似文献