首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   131篇
  免费   7篇
  国内免费   10篇
  148篇
  2023年   1篇
  2022年   5篇
  2021年   5篇
  2020年   6篇
  2019年   6篇
  2018年   5篇
  2017年   2篇
  2016年   8篇
  2015年   7篇
  2014年   3篇
  2013年   5篇
  2012年   6篇
  2011年   10篇
  2010年   2篇
  2009年   6篇
  2008年   9篇
  2007年   4篇
  2006年   4篇
  2005年   4篇
  2004年   2篇
  2003年   12篇
  2002年   5篇
  2001年   2篇
  2000年   4篇
  1999年   3篇
  1998年   1篇
  1997年   7篇
  1996年   3篇
  1994年   2篇
  1992年   1篇
  1991年   2篇
  1989年   1篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1983年   1篇
  1982年   1篇
排序方式: 共有148条查询结果,搜索用时 0 毫秒
111.
目的 探讨岗位设置与绩效管理相结合在消毒供应中心应用的效果。方法 本研究于2015年1月1日开始实行,为期1年,2015年12月31日结束。将消毒供应中心的56人分为四个层次、三个级别制定岗位职责,进行理论和技能培训,并对培训结果进行对比分析;另一方面,制订量化的绩效考核标准,建立绩效考核与个人奖惩相结合的绩效考核方法,加强绩效反馈,对56名工作人员干预前后工作质量与自评情况、理论和实操考核情况、各临床科室满意率进行比较。 结果 在干预前和干预12个月后进行数据统计发现,岗位设置与绩效管理在实施干预后与实施干预前相比在中心工作质量与效率、员工专业素质及临床科室满意率等方面均有显著提高,差异有统计学意义(P <0.05)。其中干预后消毒供应中心员工高质高效率由14.29%上升至80.36%,效果显著。干预后,不同层级的中心工作人员理论考核与操作技能考核优秀率上升20%~50%不等。 干预后各临床科室满意度由干预前的65%左右提高至80%及其以上。结论 岗位设置与绩效管理有助于消毒中心工作人员提高工作热情,持续改善提高工作绩效,提升工作人员专业素质和各临床科室的满意率。  相似文献   
112.
春化处理控制冬小麦的小穗发育   总被引:8,自引:0,他引:8  
春化作用是决定冬性及二年草本植物成花和穗化的一个关键生理过程,通过用不同时间的前期低温处理,观察对冬小麦(Triticum aestivum L.)后期形态建成中穗分化启动,小花发育及结实率的影响,发现前期低温处理对穗启动分化的早晚具有决定作用,春化时间越长,穗分化启动越早,较长时间低温有利于促进穗分化,在实验室低温处理条件下,促进小花分化和提高结实率的最佳春化处理时间是45d左右,实验观察表明,春化处理促进小麦生长锥分化启动时间和分化速率,减少小穗退化,这一结果表明了春化处理不仅是冬小麦开花启动过程所必需的,而且是花序正常发育过程和顶部与基部小穗完全结实所不可缺少的。  相似文献   
113.
Polysaccharides were sequentially extracted from Australian Pterocladia lucida at 50 °C, to give the Warm Water (WW) fraction, and at 95 °C. The 95 °C extract was further separated into gelling (GF) and thaw water (TW) fractions by freezing-thawing. Fourier Transform infrared (FTIR) spectroscopy, compositional and linkage analyses, and physico-chemical properties indicated that the GF contained an agar with nearly idealized repeating structure and low levels of sulfate and pyruvate substitution. By contrast, the WW and TW contained heterogeneous, highly sulfated galactans with relatively low levels of 3,6-anhydrogalactose and higher levels of pyruvate and glycosyl branching and impurities, such as starch and protein. The properties of the gels formed from the GF and two commercially available agars (Sigma High Gel Strength agar and Sigma Type A agar) were investigated with a texture analyser. The GF from P. lucida had a gel strength intermediate between that of the commercial agars. The gel setting temperature of a 0.8% (w/v) solution formed from the GF was 2 °C below that of comparable solutions of the two commercial agars. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   
114.
115.

Background and Aims

Although the apical development of wheat has been widely described, studies analysing how genetic breeding over the 20th century influenced the developmental phases and its consequences on yield generation are lacking, especially for durum wheat under field conditions in Mediterranean environments. The aims of this study were to analyse the effects of breeding in Spain and Italy on crop development during the last century, to determine whether or not breeding significantly altered the developmental phases between sowing and maturity, and to evaluate the importance of each phase in determining the number of grains per spike of durum wheat (Triticum durum) cultivars representing the germplasm grown throughout the 20th century in Spain and Italy.

Methods

Eight field experiments were carried out during 4 years in two contrasting latitudes (Lleida and Granada, Spain). Plant material consisted of 24 durum wheat cultivars (12 Italian and 12 Spanish) grown throughout the 20th century in Spain and Italy.

Key Results

In Spanish materials, breeding reduced the duration of the period from sowing to anthesis, placing the grain-filling period in better conditions. In those cultivars, the sub-phase sowing–terminal spikelet formation was reduced while the duration of the period from booting to anthesis was increased. The number of grains per spike increased by 23 % from old to modern cultivars, by changes in the number of grains per spikelet in both Spanish and Italian cultivars. Floral abortion from booting to anthesis diminished by 24 % from old to modern cultivars, and grain setting increased by 13 %.

Conclusions

The results suggest that breeding reduced not only plant height, but also the time to anthesis. By extending the duration of the phase from booting to anthesis, which was associated with an increase in spike dry weight and grains per spike, it suggests that future increases in spike fertility could be achieved by enlarging that phase.  相似文献   
116.
通过对黑龙江省东宁地区的4年生平欧杂交榛(Corylus heterophylla×Corylus avellana)联合施用不同浓度的硼(0.2%、0.3%、0.4%)、锌(0.3%、0.4%、0.5%)肥处理,研究两种微量元素对平欧杂交榛光合生理、结实、果仁和叶片营养状态的影响。研究结果表明:(1)硼、锌对净光合速率影响显著,其交互作用对净光合速率影响极显著。(2)硼对出仁率影响极显著,对果仁重影响显著,对单果重和座果率影响不显著。锌对单果重和果仁重影响极显著,对出仁率影响显著,对座果率影响不显著。硼、锌交互作用对出仁率影响显著,对单果重、果仁重和座果率影响不显著。(3)硼、锌和其交互作用对果仁脂肪酸含量、果仁蛋白质含量影响不显著。硼、锌和其交互作用对4年生平欧杂交榛的生理和结实影响明显,提高了平欧杂交榛叶片的净光合速率,同时对果仁重、出仁率和单果重有不同程度的促进作用。本地区4年生平欧杂交榛硼、锌叶面施肥的浓度分别以0.3%和0.4%为宜。  相似文献   
117.
Friedman A 《Bioethics》2008,22(2):101-112
This paper is a critique of Norman Daniels' and James Sabin's 'Accountability for Reasonableness' framework for making priority-setting decisions in health care in the face of widespread disagreement about values. Accountability for Reasonableness has been rapidly gaining worldwide acceptance, arguably to the point of becoming the dominant paradigm in the field of health policy. The framework attempts to set ground rules for a procedure that ensures that whatever decisions result will be fair, reasonable, and legitimate to the extent that even those who would be adversely affected will have reason to abide by them. I argue that the framework's four conditions are inadequate to this task. While we certainly require a fair and legitimate procedure for making priority setting decisions in health care despite a lack of consensus on relevant ethical and political issues, we must significantly revise the four conditions, and we cannot avoid facing our substantive disagreements head on if we hope to arrive at decisions that would (and should) be acceptable to everyone. I offer two suggestions. First, there is need for greater public involvement in all stages of deliberation. Second, we should give up on the idea that we can simplify the task of democratic deliberation by disallowing particular kinds or reasons and types of reasoning. Reasons of all kinds should be on the table, but then should be judged on their merits, such as consistency, plausibility and explanatory power, without any regard for their alleged sources of authority.  相似文献   
118.
Scaling‐up ecological restoration demands the involvement of private sector actors. Experience regarding science‐based habitat restoration programs in the sector should be made available to support further joint projects. In our case, hierarchical restoration prioritization was applied to select best target for habitat reconstruction at a Hungarian industrial area. Multiple potential natural vegetation model, a novel approach, supported restoration prioritization satisfying both ecological (sustainability and nature conservation value) and other needs (feasibility, rapid green surface, amenity, and education value). The target that met all priorities was the open steppe forest that has a mosaic arrangement with open and closed sand steppes. The potential area of this xero‐thermophile oak wood is expected to expand in Hungary with climate change, therefore the selected target has a likelihood of long‐term sustainability, if established. A matrix of sand steppes was created first at the factory area in 2014–2015, and tree and shrub saplings were planted in this matrix. The seeding induced rapid changes in vegetation composition: the second year samples became close to reference sand steppes in the principal component analysis ordination space. Tree and shrub survival was species dependent, reaching a maximum of 52 and 73% for tree and shrub species, respectively. One tree and 2 shrub species did not survive at all. Altogether 53 of 107 target species have established. So far, restored vegetation development confirmed the suitability of the applied hierarchical prioritization framework at factory scale.  相似文献   
119.
The trophic state of many streams is likely to deteriorate in the future due to the continuing increase in human‐induced nutrient availability. Therefore, it is of fundamental importance to understand how nutrient enrichment affects plant litter decomposition, a key ecosystem‐level process in forest streams. Here, we present a meta‐analysis of 99 studies published between 1970 and 2012 that reported the effects of nutrient enrichment on litter decomposition in running waters. When considering the entire database, which consisted of 840 case studies, nutrient enrichment stimulated litter decomposition rate by approximately 50%. The stimulation was higher when the background nutrient concentrations were low and the magnitude of the nutrient enrichment was high, suggesting that oligotrophic streams are most vulnerable to nutrient enrichment. The magnitude of the nutrient‐enrichment effect on litter decomposition was higher in the laboratory than in the field experiments, suggesting that laboratory experiments overestimate the effect and their results should be interpreted with caution. Among field experiments, effects of nutrient enrichment were smaller in the correlative than in the manipulative experiments since in the former the effects of nutrient enrichment on litter decomposition were likely confounded by other environmental factors, e.g. pollutants other than nutrients commonly found in streams impacted by human activity. However, primary studies addressing the effect of multiple stressors on litter decomposition are still few and thus it was not possible to consider the interaction between factors in this review. In field manipulative experiments, the effect of nutrient enrichment on litter decomposition depended on the scale at which the nutrients were added: stream reach > streamside channel > litter bag. This may have resulted from a more uniform and continuous exposure of microbes and detritivores to nutrient enrichment at the stream‐reach scale. By contrast, nutrient enrichment at the litter‐bag scale, often by using diffusing substrates, does not provide uniform controllable nutrient release at either temporal or spatial scales, suggesting that this approach should be abandoned. In field manipulative experiments, the addition of both nitrogen (N) and phosphorus (P) resulted in stronger stimulation of litter decomposition than the addition of N or P alone, suggesting that there might be nutrient co‐limitation of decomposition in streams. The magnitude of the nutrient‐enrichment effect on litter decomposition was higher for wood than for leaves, and for low‐quality than for high‐quality leaves. The effect of nutrient enrichment on litter decomposition may also depend on climate. The tendency for larger effect size in colder regions suggests that patterns of biogeography of invertebrate decomposers may be modulating the effect of nutrient enrichment on litter decomposition. Although studies in temperate environments were overrepresented in our database, our meta‐analysis suggests that the effect of nutrient enrichment might be strongest in cold oligotrophic streams that depend on low‐quality plant litter inputs.  相似文献   
120.
不同化学试剂组合对四季花龙眼枝梢生长和成花座果研究表明,不同时期成熟的枝梢对四季花龙眼成花座果无重大的影响;乙烯利、多效唑和赤霉素三者共同作用可促进成花座果;当枝梢充分成熟时,树冠喷施乙烯利250mg·L-1+多效唑450mg·L-1,谢花3/4时再喷施赤霉素50mg·L-1,可以有效抑制四季花龙眼植株新梢的萌发,促使植株100%成花,并且花穗和果穗性状的综合表现最好。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号