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51.
Shun HIRASAWA Miki SHIMIZU Yuumi MARUI Miori KISHIMOTO Seiichi OKUNO 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2014,76(12):1603-1607
We designed a new method of
measuring the length of the ulnar nerve and determining standard values for F-wave
parameters of the ulnar nerve in clinically normal beagles. Nerve length must be precisely
measured to determine F-wave latency and conduction velocity. The length of the forelimb
has served as the length of the ulnar nerve for F-wave assessments, but report indicates
that F-wave latency is proportional to the length of the pathway traveled by nerve
impulses. Therefore, we measured the surface distance from a stimulus point to the spinous
process of the first thoracic vertebra (nerve length 1) and the anterior horn of the
scapula (nerve length 2) as landmarks through the olecranon and the shoulder blade
acromion. The correlation coefficients between the shortest F-wave latency and the length
of nerves 1, 2 or the forelimb were 0.61, 0.7 and 0.58. Nerve length 2 generated the
highest value. Furthermore, the anterior horn of the scapula was easily palpated in any
dog regardless of well-fed body. We concluded that nerve length 2 was optimal for
measuring the length of the ulnar nerve. 相似文献
52.
This study quantifies the impact of four different grazing regimes (heavy, moderate, light and ungrazed) on the vegetation dynamics of rangeland ecosystems along the southern boundary area of the Mu Us Desert, China. As the grazing intensities decreased, the soil quality, canopy cover, height, density, above‐ and below‐ground biomass, litter, root/shoot ratio and native plant (Aneurolepidium dasystachys) and grass abundances significantly increased; the above‐ground biomass of grasses increased, but the above‐ground biomass of forbs decreased. Ungrazed grassland has significantly improved from grasslands experiencing three other levels of grazing pressure, especially in the grassland biomass. Species richness increased as the grazing intensity decreased in the grazing grasslands, but peak species richness appeared under moderate and light grazing against lower productivity. Grazing exclusion causes desirable transitions in plant communities of desert steppe rangelands. Therefore, appropriate and efficient grazing exclusion is an available way to counteract local grassland degradation and promote rangeland sustainability. 相似文献
53.
M. Necpálová D. Li G. Lanigan I. A. Casey W. Burchill J. Humphreys 《Grass and Forage Science》2014,69(4):611-624
This study investigated changes in soil organic carbon (SOC) in a poorly drained clay loam soil under (i) permanent grassland (PG) over 7 years and (ii) after PG renovation over 2·5 years. The experimental area was divided into four blocks with four paddocks per block. Composite soil samples from each PG block were taken to 30‐cm depth on five occasions between 2004 and 2011. In June 2008, one paddock per block was renovated by ploughing and reseeding and sampled as above on the latter four occasions. Renovation decreased SOC (P < 0·05) by 32·2 t ha?1 in the 2·5 years following ploughing; the difference developed almost entirely (86%) in the first four months. Renovation had no effect on above‐ground productivity, standing root and stubble phytomass or on dissolved organic matter leaching. Therefore, soil respiration was considered to be a single potential pathway responsible for the SOC loss from renovated grassland. Although a simple linear regression indicated a tendency for PG to accumulate SOC, there was no evidence of recovery in SOC to previous levels following renovation during the study period. These results could have implications for greenhouse gas inventories in countries where PG is an important land‐use type. 相似文献
54.
研究米曲霉和酿酒酵母混合固态发酵热榨花生粕同步提取花生非淀粉多糖和抗氧化肽,为花生粕的高值化利用提供理论基础。以发酵产物的可溶性氮浓度、1,1-二苯基苦基苯肼(DPPH)自由基清除率、羟自由基清除率和非淀粉多糖得率为考察指标,研究了菌种比例、接种量、营养盐溶液量、发酵温度、发酵时间、水浴温度和水浴时间对发酵效果的影响,确定最佳工艺条件为:菌种比例1∶2,接种量3mL,营养盐溶液添加量30mL,发酵温度33℃,发酵时间42h,水浴温度40℃,水浴时间6h。此工艺下发酵产物的可溶性氮浓度为46.32mg/mL、DPPH自由基清除率为71.90%、羟自由基清除率为96.96%、非淀粉多糖得率为4.36%。发酵产物经乙醇沉淀和超滤分离得到的花生非淀粉多糖和抗氧化肽产品具有清除自由基、抑制脂质过氧化、金属离子螯合力和还原力等4大类抗氧化活性。 相似文献
55.
R. K. NARESH S. S. TOMAR Dipender KUMAR Samsher Purushottam S. P. SINGH Ashish DWIVEDI Vineet KUMAR 《水稻科学》2014,21(3):170-180
In recent years, conventional rice production technologies have been leading to deterioration of soil health and declining farm profitability due to high inputs of water and labor. Conservation agriculture(CA) based resource-conserving technologies i.e. zero-tillage(ZT), raised-bed planting and direct-seeded rice(DSR) have shown promise as alternatives to conventional production technologies to overcome these problems. Present study was undertaken during 2009–2012 to establish an understanding of how permanent raised bed cropping system could be practiced to save water at the field application level to improve water productivity and also have the capability to enhance productivity, profitability and soil physical quality. The results showed that among different crop establishment techniques, conventional-tilled puddle transplanted rice(CT-TPR) required 14%-25% more water than other techniques. Compared with the CT-TPR system, zero till direct-seeded rice(ZT-DSR) consumed 6%–10% less water with almost equal system productivity and demonstrated higher water productivity. Wide raised beds saved about 15%–24% water and grain yield decrease of about 8%. Direct-seeded rice after ZT or reduced tillage or on unpuddled soil provided more net income than CT-TPR. The CTTPR system had higher bulk density and penetration resistance due to compaction caused by the repeated wet tillage in rice. The steady-state infiltration rate and soil aggregation( 0.25 mm) were higher under permanent beds and ZT and lower in the CT-TPR system. Under CT-TPR, soil aggregation was static across seasons, whereas it improved under no-till and permanent beds. Similarly, mean weight diameter of aggregates was higher under ZT and permanent beds and increased over time. The study reveals that to sustain the rice productivity, CA-based planting techniques can be more viable options. However, the long-term effects of these alternative technologies need to be studied under varying agro-ecologies in western Uttar Pradesh, India. 相似文献
56.
57.
段亚东 《林业机械与木工设备》2012,(1):43-45
在深入研究我国割草机技术的基础上,设计了简单实用的园林便携式割草机。该割草机采用无刷电动机,与传统有刷电动机相比,其主要技术性能大幅提升。以无刷直流电动机专用驱动芯片IR2130为控制芯片,以功率器件MOSFET为开关器件,可实现对无刷直流电动机的控制。 相似文献
58.
利用ANSYS软件对永磁式缓速器的电磁场进行计算。基于数值计算结果,重点分析了材料区和气隙的磁感应强度的分布特性,并对理论计算结果进行分析,以深入了解其电磁场特性及工作机理,同时还对车用永磁式缓速器电磁场进行了参数设计。 相似文献
59.
以滑块椭圆机构原理设计数控椭圆专用铣床,该机构不需计算长短轴和焦距,用步进电机作为动力源可提高椭圆的加工精度,实现大批量自动化生产。 相似文献
60.
对交流电动机的功率因数进行负反馈控制可使其功率因数恒定。通过对交流电动机稳态数学模型的分析可知,最优效率对应的功率因数由转差频率控制,且电动机功率因数在小范围内变化时所引起效率变化小。因此,可以用恒功率因数控制替代最优功率因数控制。 相似文献