全文获取类型
收费全文 | 487篇 |
免费 | 21篇 |
专业分类
林业 | 12篇 |
农学 | 29篇 |
基础科学 | 2篇 |
43篇 | |
综合类 | 30篇 |
农作物 | 19篇 |
水产渔业 | 40篇 |
畜牧兽医 | 293篇 |
园艺 | 6篇 |
植物保护 | 34篇 |
出版年
2022年 | 5篇 |
2021年 | 13篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 7篇 |
2017年 | 10篇 |
2016年 | 7篇 |
2015年 | 13篇 |
2014年 | 17篇 |
2013年 | 20篇 |
2012年 | 23篇 |
2011年 | 31篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 17篇 |
2007年 | 27篇 |
2006年 | 27篇 |
2005年 | 24篇 |
2004年 | 25篇 |
2003年 | 15篇 |
2002年 | 20篇 |
2001年 | 14篇 |
2000年 | 17篇 |
1999年 | 23篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 9篇 |
1991年 | 12篇 |
1990年 | 7篇 |
1989年 | 4篇 |
1988年 | 11篇 |
1987年 | 13篇 |
1986年 | 8篇 |
1985年 | 2篇 |
1984年 | 7篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 3篇 |
1976年 | 1篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1972年 | 2篇 |
1971年 | 3篇 |
1970年 | 2篇 |
1969年 | 2篇 |
1968年 | 2篇 |
1926年 | 1篇 |
排序方式: 共有508条查询结果,搜索用时 156 毫秒
91.
Fujiwara Y Hayashida A Tsurushima K Nagai R Yoshitomi M Daiguji N Sakashita N Takeya M Tsukamoto S Ikeda T 《Journal of agricultural and food chemistry》2011,59(9):4544-4552
Because foam cell formation in macrophages is believed to play an essential role in the progression of early atherosclerotic lesions in vivo, prevention of foam cell formation is considered to be one of the major targets for the treatment of atherosclerosis. The present study examined the inhibitory effect of 50 crude plant extracts on foam cell formation. Among those crude extracts, Zizyphi Fructus (ZF) and Zizyphi Semen (ZS) extracts significantly inhibited the foam cell formation induced by acetylated LDL. Furthermore, triterpenoids such as oleanonic acid, pomolic acid, and pomonic acid were the major active compounds, and triterpenoids containing a carboxylic acid at C-28 play an important role in the inhibitory effect on foam cell formation in human macrophages. These data suggest that triterpenoids in Zizyphus jujuba , the plant source of ZF and ZS, may therefore be useful for the prevention of atherosclerosis. 相似文献
92.
The paddy field is being recognised as a biodiversity hotspot fostering a variety of organisms. However, there are few studies on the ecology of paddy field nematodes. We characterised nematode communities in rice paddy fields by comparing them with upland fields of rice or soybean. We examined nematode communities of the top (0-15 mm) and second (15-50 mm) soil layers before flooding (March or April), during flooding (June or July) and during the draining period (October) 2007-2009. We found that the nematode community in the paddy was different than that in the upland fields during all periods. Rhabdolaimus, Tobrilus, Mesodorylaims and Monhysteridae characterised the top of the paddy and Hirschmanniella characterised the second layer of the paddy. Total nematode density was generally lower in the paddy than in the upland field. However, the density in the paddy top layer increased with time from the flooding period to the draining period, during which time it was about the same as (or even greater than) the peak density in the upland fields. The density in the second layer of the paddy remained lower than that in the top layer of the paddy throughout the time course. Community diversity values were generally greater in the paddy top layer than in the paddy second layer across the six sampling periods, but periodic differences between the paddy and upland fields or between soil layers were not significant. During the flooding period, the F/(F + B) (13-37) and Enrichment Index (17-38) values were lower in the paddy than in the upland fields (32-47, 37-74, respectively) to reflect that bacteria dominate over fungi with slow decomposition due to anaerobic conditions in the flooded paddy field. In addition, particularly in the top layer, the Maturity (2.0-2.4) and Structure Index (23-72) values were greater in the paddy than in the upland fields (1.7-2.1, 9-15, respectively), indicating a well-developed ecosystem under water. These unique nematode communities persisted during the draining period, but there was a rapid increase in opportunistic bacterivores, which increased the EI values. We suggest that bactivorous nematodes in the families Cephalobidae and Chronogasteridae, herbivores in the genus Hirschmanniella, and fungivores in the genus Filenchus may be specific to paddy field soil rather than to pond and lake sediments. 相似文献
93.
Akari Fukuda Yoshihisa Okada Nobuo Suzui Toru Fujiwara Tadakatsu Yoneyama Hiroaki Hayashi 《Soil Science and Plant Nutrition》2013,59(8):1255-1262
The N-terminal amino-acid sequence of a major rice phloem-sap protein, designated as RPP23, was determined. The complete amino-acid sequence of RPP23 was deduced from the corresponding rice EST- clone and contained an extra 46 amino acids at the N-terminus, that was apparently cleaved off to form mature RPP23 in sieve tubes. RPP23 shared a similarity to plant small heat-shock proteins (smHSPs), though the N-terminal region of RPP23 was distinct from that of known smHSPs. Immunocytological analyses using leaf sections showed that RPP23 was located only in the phloem regions of leaves, and was present in non-stressed plants. In mature leaves, stronger immunocytological signals were detected in sieve elements than in companion cells. 相似文献
94.
Haruto Sasaki Takahiro Hara Satoshi Ito Naoko Uehara Han-Yong Kim Mark Lieffering Masumi Okada Kazuhiko Kobayashi 《Field Crops Research》2007
Increasing global atmospheric CO2 concentrations are expected to influence crop production. To investigate the effect on rice (Oryza sativa L.), plants were grown under ambient CO2 (AMB) or free-air CO2-enrichment (FACE) at CO2 concentrations ranged from 275 to 365 μmol mol−1 above AMB. We supplied 13CO2 to the plants at different growth stages so we could examine the contribution of carbohydrate stored during the vegetative stage or newly fixed carbohydrate produced during the grain-filling stage to ear weight at grain maturity. In plants supplied with 13C at the panicle-initiation or pre-heading stages, plants grown under FACE had more starch in the stems at heading, but there was no difference in stem 13C content. Furthermore, there were no differences between treatments in whole-plant 13C contents at heading and grain maturity. In contrast, plants supplied with 13C at the grain-filling stage had more 13C in the whole plant and the ears at grain maturity under FACE than under AMB, indicating that the increased amount of photosynthate produced at the grain-filling stage under CO2 enrichment might be effectively stored in the grains. Furthermore, regardless of when the 13C was supplied, plants had more 13C in starch in the ears at grain maturity under FACE than under AMB. Therefore, CO2 enrichment appears to promote partitioning of photosynthate produced during both vegetative and grain-filling stages to the grains. 相似文献
95.
Planning improvement of an irrigation project often depends on irrigation professionals who conduct the initial survey of the irrigation project. Accordingly, activities for improvement will be different depending on who evaluates the status quo of the irrigation project, because of the diversity of expertise and experience of professionals. A questionnaire survey was conducted to examine how irrigation professionals evaluate an irrigation project, that is, on what evaluation factors (EFs) they place the importance. In the questionnaire, professionals ranked the relative importance of EFs derived from internal process indicators of the Rapid Appraisal Process (RAP). Answers to the questionnaire were processed by the Analytic Hierarchy Process (AHP, Part I), and then local weights of EFs were obtained as a measure of relative importance of EFs. Those local weights were statistically analyzed by the Anderson-Darling normality test, the F-test and the t-test. Then, they were modeled by probability density functions. The results implied (a) that irrigation professionals give the first priority to water delivery services project-wide and (b) that they consider that irrigation infrastructure (hardware) of primary canals is more important than that of secondary canals. These findings infer that irrigation professionals first consider how well water is controlled and distributed project-wide and second how appropriately primary canals are designed and maintained. Also, their views are divided into two regarding importance of hardware and management, namely some insist that hardware is more important than management and the others insist that management is more important than hardware. 相似文献
96.
In many disaster settings, top‐down responses emphasise ‘expert‐led’ solutions that often involve relocating disaster‐affected communities. While the intention might be to move people from harm's way and facilitate recovery, failure to attend to local pre‐disaster circumstances as well as the interplay between power, resilience and vulnerability within and around affected communities often sees resettlement reconfigure as displacement or disconnection. This oversight may even usher in a new phase of dispossession and disadvantage for marginalised groups (particularly in colonial settings). This paper explores experiences in Australia, Japan and Taiwan to reflect on what issues of local sociality, local culture and local resilience need to be attended to in framing ‘better’ disaster responses. 相似文献
97.
Takanari Tanabata Kunihiro Kodama Takuyu Hashiguchi Daisuke Inomata Hidenori Tanaka Sachiko Isobe 《Breeding Science》2022,72(1):85
Plant phenotyping technology has been actively developed in recent years, but the introduction of these technologies into the field of agronomic research has not progressed as expected, in part due to the need for flexibility and low cost. “DIY” (Do It Yourself) methodologies are an efficient way to overcome such obstacles. Devices with modular functionality are critical to DIY experimentation, allowing researchers flexibility of design. In this study, we developed a plant conveyance system using a commercial AGV (Automated Guided Vehicle) as a case study of DIY plant phenotyping. The convey module consists of two devices, a running device and a plant-handling device. The running device was developed based on a commercial AGV Kit. The plant-handling device, plant stands, and pot attachments were originally designed and fabricated by us and our associates. Software was also developed for connecting the devices and operating the system. The run route was set with magnetic tape, which can be easily changed or rerouted. Our plant delivery system was developed with low cost and having high flexibility, as a unit that can contribute to others’ DIY’ plant research efforts as well as our own. It is expected that the developed devices will contribute to diverse phenotype observations of plants in the greenhouse as well as to other important functions in plant breeding and agricultural production. 相似文献
98.
Nobuo Kochi Atsushi Hayashi Yota Shinohara Takanari Tanabata Kunihiro Kodama Sachiko Isobe 《Breeding Science》2022,72(1):75
In this study, we developed an all-around 3D plant modeling system that operates using images and is capable of measuring plants non-destructively without any contact. During the fabrication of this device, we selected a method capable of performing 3D model reconstruction from multiple images. We then developed an improved SfM-MVS (Structure from Motion / Multi-View-Stereo) method that enables 3D reconstruction by simply capturing images with a camera. The resulting image-based method offers a high degree of freedom because the hardware and software can comprise commercially available products, and it permits the use of one or more cameras according to the shape and size of the plant. The advantages of the image-based method are that 3D reconstruction can be conducted at any time as long as the images are already taken, and that the desired locations can be observed, measured, and analyzed from 2D images and a 3D point cloud. The device we developed is capable of 3D measurements and modeling of plants from a few millimeters to 2.4 m of height using this method. This article explains this device, the principles of its composition, and the accuracy of the models obtained from it. 相似文献
99.
Okada Y Iimure T Takoi K Kaneko T Kihara M Hayashi K Ito K Sato K Takeda K 《Journal of agricultural and food chemistry》2008,56(4):1458-1464
The foam stability of beer is one of the important key factors in evaluating the quality of beer. The purpose of this study was to investigate the relationship between the level of malt modification (degradation of protein, starch, and so on) and the beer foam stability. This was achieved by examining foam-promoting proteins using two-dimensional gel electrophoresis (2DE). We found that the foam stability of beer samples brewed from the barley malts of cultivars B and C decreased as the level of malt modification increased; however, the foam stability of cultivar A did not change. To identify the property providing the increased foam stability of cultivar A, we analyzed beer proteins using 2DE. We analyzed three fractions that could contain beer foam-promoting proteins, namely, beer whole proteins, salt-precipitated proteins, and the proteins concentrated from beer foam. As a result, we found that in cultivar A, some protein spots did not change in any of these three protein fractions even when the level of malt modification increased, although the corresponding protein spots in cultivars B and C decreased. We analyzed these protein spots by peptide mass finger printing using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. As a result, all of these spots were identified as barley dimeric alpha-amylase inhibitor-I (BDAI-I). These results suggest that BDAI-I is an important contributor to beer foam stability. 相似文献
100.
C-cell Distribution in Ovine Thyroid Gland 总被引:1,自引:0,他引:1
The number and percentage of C-cells per unit area were investigated in 2-3-year-old sheep by an immunoperoxidase technique, using a digital-image analysis. C-cells were distributed throughout the thyroid lobes but were not present in either the isthmus or the superior and inferior poles of the thyroid. C-cells were more concentrated in the deep central region of the lobes and decreased gradually toward the periphery. There was a high correlation between the number and the percentage of C-cells per unit area of thyroid gland in sheep. Significant differences were not present between male and female sheep of 2-3 years of age. 相似文献