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941.
  1. The ocean is the linchpin supporting life on Earth, but it is in declining health due to an increasing footprint of human use and climate change. Despite notable successes in helping to protect the ocean, the scale of actions is simply not now meeting the overriding scale and nature of the ocean's problems that confront us.
  2. Moving into a post-COVID-19 world, new policy decisions will need to be made. Some, especially those developed prior to the pandemic, will require changes to their trajectories; others will emerge as a response to this global event. Reconnecting with nature, and specifically with the ocean, will take more than good intent and wishful thinking. Words, and how we express our connection to the ocean, clearly matter now more than ever before.
  3. The evolution of the ocean narrative, aimed at preserving and expanding options and opportunities for future generations and a healthier planet, is articulated around six themes: (1) all life is dependent on the ocean; (2) by harming the ocean, we harm ourselves; (3) by protecting the ocean, we protect ourselves; (4) humans, the ocean, biodiversity, and climate are inextricably linked; (5) ocean and climate action must be undertaken together; and (6) reversing ocean change needs action now.
  4. This narrative adopts a ‘One Health’ approach to protecting the ocean, addressing the whole Earth ocean system for better and more equitable social, cultural, economic, and environmental outcomes at its core. Speaking with one voice through a narrative that captures the latest science, concerns, and linkages to humanity is a precondition to action, by elevating humankind's understanding of our relationship with ‘planet Ocean’ and why it needs to become a central theme to everyone's lives. We have only one ocean, we must protect it, now. There is no ‘Ocean B’.
  相似文献   
942.
In recent years, more than 130 extinctions have been estimated to have occurred in the marine realm. Here we review this body of evidence and show that this figure may actually be overestimated by as much as 50%. We argue that previous estimates have not fully taken into account critical uncertainties such as naturally variable geographical distributions, and have misinterpreted documentary evidence. However, current evidence indicates that some sharks, rays and reef‐associated species, although not necessarily geographically restricted, are particularly vulnerable to anthropogenic impacts and now occur in very low numbers. Overestimating extinctions is of concern because it could reduce confidence in the credibility of the ‘extinct’ category in threatened species lists and, ultimately, be used to question the integrity of conservation and management policies. We suggest that when integrating future checklists of marine extinct species, there needs to be a more rigorous use of the terminology of extinction, and participation by specialists in each of the particular taxonomic groups involved.  相似文献   
943.
The influence of global greenhouse warming on the ocean's biological productivity may be more complicated and weaker than that proposed by Bakun (1990). A doubled carbon dioxide simulation made with the Canadian Climate Centre atmospheric general circulation model coupled to a simplified mixed layer ocean model suggests that the midlatitude continents do not all follow the Bakun scenario in developing anomalous low pressure in summer and enhancing coastal winds favorable to upwelling. In the open ocean the equatorial and subpolar zonal upwelling bands and the subtropical downwelling bands generally weaken as winds diminish owing to the weakening of the equator-to-pole temperature gradient in the lower troposphere under global warming. With a weakening of open ocean upwelling and an absence of enhanced coastal upwelling, the overall effect of global warming could be to decrease the global biological productivity.  相似文献   
944.
Fishing down the deep   总被引:7,自引:2,他引:7  
Global landings of demersal marine fishes are demonstrated to have shifted to deeper water species over the last 50 years. Our analysis suggests deep‐water fish stocks may be at serious risk of depletion, as their life histories render them highly vulnerable to overfishing with little resilience to over‐exploitation. Deep‐sea fisheries are exploiting the last refuges for commercial fish species and should not be seen as a replacement for declining resources in shallower waters. Instead, deep‐water habitats are new candidates for conservation.  相似文献   
945.
We conducted a global systematic literature review of climate change adaptation in fisheries. We addressed three specific questions: (i) What are fisheries adapting to? (ii) How are fisheries adapting? and (iii) What research gaps need to be addressed? We identified, characterized and examined case studies published between 1990 and 2019 that lie at the intersection of the domains of climate change, adaptation and fisheries. We characterized the documented climate change effects in fisheries that are being adapted to multiple stressors, general climate impacts, extreme events, ocean conditions, marine system shifts, climate variability, fishery dynamics, species distribution and atmospheric warming. Three categories of adaptive responses came to light: coping mechanisms (e.g. changing fishing location, use of traditional knowledge); adaptive strategies (e.g. livelihood diversification, incorporation of technology); and management responses (e.g. adaptive management, adaptation planning). We identified key potential areas for future research, including studies on the limits and barriers for adaptation, studies using specific conceptual and methodological approaches, and studies focussing on the top-producing countries such as China, Indonesia, Peru and Russia. This analysis gives broader insights to the fisheries industry and to climate change adaptation research to proceed in the face of new global challenges.  相似文献   
946.
陈忠 《长江大学学报》2014,(3):I0001-I0003
非线性共轭梯度法由于其迭代简单和储存量小,且搜索方向不需要满足正割条件,在求解大规模无约束优化问题时占据及其重要的地位.提出了一类新的共轭梯度法,其搜索方向是目标函数的下降方向.若假设目标函数连续可微且梯度满足Lipschitz条件,线性搜索满足Wolfe原则,讨论了所设计算法的全局收敛性.  相似文献   
947.
通过对渭北旱塬区永寿、风翔、蒲城、旬邑4个农业气象试验站1971年到2010年冬小麦观测数据以及30个县市区同期气象资料同步观测分析,得出渭北旱塬区气候近40年来增温明显,且以冬季和春季增温最为显著。受气候变化影响,本区域冬小麦播种期、越冬期推迟,返青期、拔节期、抽穗期、成熟期等发育期普遍提前,以返青期提前最为显著,相关性分析显示,除了冬前生长期,冬小麦越冬期以及春季各发育期间隔和发育期平均气温相关显著,而且春季的相关性明显比冬季显著,但表现在发育期间隔方面,却是冬小麦越冬期呈显著缩短趋势,而返青后各发育期间隔没有明显变化。结论认为:气候变暖一方面有利于越冬农作物安全越冬,减少冻害对农业生产的影响,而且温度升高,也增加了农业生产积温,使农作物可生长期延长,有利于提高复种指数;另一方面,由于旱塬区春季气温变率较大,发育期提前将导致作物受冻害的气候风险增大,尤其果树开花期遭受冻害,将对产量构成严重威胁。冬季气温持续上升,将导致冬小麦条锈病孢子和林果病虫害等安全越冬,对病虫害防治工作带来很大难度。因此,气候变暖对旱塬农业生产将产生深刻的影响,应引起高度关注。  相似文献   
948.
Based on uniform access and shared memory system,the conception of "balancing permutation" and corresponding methods for Do Loop parallelization are given in this paper.By combining element group and balancing permutation,and effective parallel algorithm for assembling the global stiffness matrix of structures of beam system is put forward.  相似文献   
949.
《保鲜与加工》2003,(10):120-123
Some ideas of uniform design in the test design are introduced into Simulated Annealing Arithmetic and a new method of design based on uniform design is discussed. The global optimal solutions of nonlinear multi-peak function can be found by this method. A series of uniformly distributed points are generated by the principle of the uniform design in variable design space. These points are regarded as a series of start points of the optimization model. The Simulated Annealing Arithmetic is chosen to compute and a series of local minimum values can be gained. Before compared with each other, the best value of all local minimum values can be found out, the value is thought as the global minimum in some degree. According to the method, a program is compiled and an example of design is implemented. The result of the example testifies that the method is feasible.  相似文献   
950.
Abstract: This paper explores the theme of governance as it relates to the evolution of global commodity chains in agro‐industry and their incorporation of wine firms in two countries of the semi‐periphery, New Zealand and Chile. The paper goes on to specifically examine the upstream and downstream relationships of selected New Zealand and Chilean wine firms to the wider commodity chains in which they are involved. Brief case studies will analyse the downstream and upstream links to the commodity chain of key wine firms in both countries. Such cases provide indicative evidence of the underlying processes of the commodity chain that are constantly changing.  相似文献   
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