全文获取类型
收费全文 | 180篇 |
免费 | 31篇 |
出版年
2024年 | 2篇 |
2023年 | 1篇 |
2022年 | 9篇 |
2021年 | 12篇 |
2020年 | 2篇 |
2019年 | 7篇 |
2018年 | 9篇 |
2017年 | 2篇 |
2016年 | 13篇 |
2015年 | 9篇 |
2014年 | 11篇 |
2013年 | 11篇 |
2012年 | 30篇 |
2011年 | 13篇 |
2010年 | 9篇 |
2009年 | 10篇 |
2008年 | 8篇 |
2007年 | 10篇 |
2006年 | 13篇 |
2005年 | 6篇 |
2003年 | 1篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 1篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1996年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有211条查询结果,搜索用时 15 毫秒
1.
S. R. Saif 《Plant and Soil》1987,97(1):25-35
Summary Growth and mineral uptake of twenty-four tropical forage legumes and grasses were compared under glasshouse conditions in a sterile low P oxisol, one part inoculated and the other not inoculated with mycorrhizal fungi. Shoot and root dry weights and total uptake of P, N, K, Ca, and Mg of all the test plants were significantly increased by mycorrhizal inoculation. Mycorrhizal inoculation, with few exceptions, decreased the root/shoot ratio. Non-mycorrhizal plants contained always lower quantities of mineral elements than mycorrhizal plants. Plant species showed differences in percentage mycorrhizal root length and there was no correlation between percentage mycorrhizal infection and plant growth parameters. A great variation in dependence on mycorrhiza was observed among forage species. Total uptake of all elements by non-mycorrhizal legumes and uptake of P, N and K by non-mycorrhizal grasses correlated inversely with mycorrhizal dependency. Mycorrhizal plants of all species used significantly greater quantities of soil P than the nonmycorrhizal plants. Utilization of soil P by non-mycorrhizal plants was correlated inversely with mycorrhizal dependency. 相似文献
2.
3.
A quantitative and qualitative survey of the indigenous Endogone population in wheat field soil and vesicular-arbuscular mycorrhiza in wheat roots as influenced by season and by the stage of development of the wheat plant was made. The number of Endogone spores in wheat field soil remained relatively unchanged in winter until January during the period of maximum root growth. The extent of formation of arbuscules was influenced by the stage of development of the wheat plants. 相似文献
4.
T Chiyomaru S Yamamura MS Zaman S Majid G Deng V Shahryari S Saini H Hirata K Ueno I Chang Y Tanaka ZL Tabatabai H Enokida M Nakagawa R Dahiya 《PloS one》2012,7(8):e43812
Genistein has been shown to suppress the growth of several cancers through modulation of various pathways. However, the effects of genistein on the regulation of oncogenic microRNA-151 (miR-151) have not been reported. In this study, we investigated whether genistein could alter the expression of oncogenic miR-151 and its target genes that are involved in the progression and metastasis of prostate cancer (PCa). Real-time RT-PCR showed that the expression of miR-151 was higher in PC3 and DU145 cells compared with RWPE-1 cells. Treatment of PC3 and DU145 cells with 25 μM genistein down-regulated the expression of miR-151 compared with vehicle control. Inhibition of miR-151 in PCa cells by genistein significantly inhibited cell migration and invasion. In-silico analysis showed that several genes (CASZ1, IL1RAPL1, SOX17, N4BP1 and ARHGDIA) suggested to have tumor suppressive functions were target genes of miR-151. Luciferase reporter assays indicated that miR-151 directly binds to specific sites on the 3'UTR of target genes. Quantitative real-time PCR analysis showed that the mRNA expression levels of the five target genes in PC3 and DU145 were markedly changed with miR-151 mimics and inhibitor. Kaplan-Meier curves and log-rank tests revealed that high expression levels of miR-151 had an adverse effect on survival rate. This study suggests that genistein mediated suppression of oncogenic miRNAs can be an important dietary therapeutic strategy for the treatment of PCa. 相似文献
5.
Tianyuan Li Saif Ullah He Liang Izhar Ali Quan Zhao Anas Iqbal Shanqing Wei Tariq Shah Yuqiong Luo Ligeng Jiang 《Phyton》2021,90(1):223-243
Readily available chemical fertilizers have resulted in a decline in the
use of organic manure (e.g., green manures), a traditionally sustainable source
of nutrients. Based on this, we applied urea at the rate of 270 kg ha−1 with and
without green manure in order to assess nitrogen (N) productivity in a double rice
cropping system in 2017. In particular, treatment combinations were as follows:
winter fallow rice-rice (WF-R-R), milk vetch rice-rice (MV-R-R), oil-seed rape
rice-rice (R-R-R) and potato crop rice-rice (P-R-R). Results revealed that green
manure significantly (p ≤ 0.05) improved the soil chemical properties and net soil
organic carbon content increased by an average 117.47%, total nitrogen (N) by
28.41%, available N by 26.64%, total phosphorus (P) by 37.77%, available P
by 20.48% and available potassium (K) by 33.10% than WF-R-R, however pH
was reduced by 3.30% across the seasons. Similarly, net dry matter accumulation
rate enhanced in green manure applied treatments and ranked in order: P-R-R >
R-R-R > MV-R-R > WF-R-R. Furthermore, the total leaf dry matter transport
(t ha−1
) for the P-R-R in both seasons was significantly higher by an average
11.2%, 7.2% and 36 % than MV-R-R, R-R-R, and WF-R-R, respectively. In addition, net total nitrogen accumulation (kg ha−1
) was found higher in green manure
applied plots compared to the control. Yield and yield attributed traits were
observed maximum in green manure applied plots, with treatments ranking as follows: P-R-R > R-R-R > MV-R-R > WF-R-R. Thus, results obtained highlight
ability of green manure to sustainably improve soil quality and rice yield. 相似文献
6.
Jianfan Sun Susan Rutherford Muhammad Saif Ullah Ikram Ullah Qaiser Javed Ghulam Rasool Muhammad Ajmal Ahmad Azeem Muhammad Junaid Nazir Daolin Du 《Journal of Plant Ecology》2022,15(3):610
生物入侵过程中的植物-土壤反馈:一种入侵植物的凋落物分解对其本地近缘植物的影响
植物入侵可通过正或负的植物-土壤反馈效应改变土壤的生物和非生物性质,从而影响入侵栖息地的土壤理化性质。许多入侵物种的凋落物分解可增加土壤养分,降低本地植物多样性,并导致进一步的植物入侵。关于入侵植物凋落物在不同土壤类型及深度分解及反馈效应的研究依然很少。本研究旨在明确入侵植物南美蟛蜞菊(Sphagneticola trilobata)凋落物在不同土壤类型和不同土壤深度条件下的分解情 况及其对本地近缘植物蟛蜞菊(S. calendulacea)生理生长的影响。将装有南美蟛蜞菊凋落物的尼龙袋加入到不同深度(即0、2、4 和6 cm)的砂土、营养土和粘土中,经6个月的分解后,回收凋落物袋并计算分解速率,随后在凋落物分解处理后的土壤中种植本地蟛蜞菊,并在生长期结束时测量其生理生态指标。研究结果表明,所有处理土壤类型中,凋落物在土壤深度为2和4 cm处分解后显著增加了土壤养分,而对本 地蟛蜞菊的叶片叶绿素、叶氮含量等生长指标表现为负效应。因此,入侵植物南美蟛蜞菊凋落物分解对土壤养分表现为正的反馈效应,而对本地植物蟛蜞菊的生长表现为负效应。我们的研究结果还表明,入侵植物的凋落物分解对土壤和本地物种的影响还因凋落物分解所在的土壤深度而显著不同。未来的研究应侧重于入侵栖息地中更多本地和入侵物种的植物-土壤反馈效应,以及更多土壤类型和土壤深度的入侵植物凋落物效应。 相似文献
7.
8.
Feng Zhu Anil Kalra Tal Saif Zaihan Yang King H. Yang Albert I. King 《Computer methods in biomechanics and biomedical engineering》2016,19(10):1053-1059
Traumatic brain injury due to primary blast loading has become a signature injury in recent military conflicts and terrorist activities. Extensive experimental and computational investigations have been conducted to study the interrelationships between intracranial pressure response and intrinsic or ‘input’ parameters such as the head geometry and loading conditions. However, these relationships are very complicated and are usually implicit and ‘hidden’ in a large amount of simulation/test data. In this study, a data mining method is proposed to explore such underlying information from the numerical simulation results. The heads of different species are described as a highly simplified two-part (skull and brain) finite element model with varying geometric parameters. The parameters considered include peak incident pressure, skull thickness, brain radius and snout length. Their interrelationship and coupling effect are discovered by developing a decision tree based on the large simulation data-set. The results show that the proposed data-driven method is superior to the conventional linear regression method and is comparable to the nonlinear regression method. Considering its capability of exploring implicit information and the relatively simple relationships between response and input variables, the data mining method is considered to be a good tool for an in-depth understanding of the mechanisms of blast-induced brain injury. As a general method, this approach can also be applied to other nonlinear complex biomechanical systems. 相似文献
9.
Singh Shweta Hans Sandeep Ahmad Aijaz Fatima Zeeshan Hameed Saif 《International microbiology》2022,25(4):769-779
International Microbiology - Infections caused by Candida albicans are rising due to increment in drug resistance and a limited arsenal of conventional antifungal drugs. Thus, elucidating the novel... 相似文献
10.
The Rickettsia ~1800-amino-acid autotransporter protein surface cell antigen 2 (Sca2) promotes actin polymerization on the surface of the bacterium to drive its movement using an actin comet-tail mechanism. Sca2 mimics eukaryotic formins in that it promotes both actin filament nucleation and elongation and competes with capping protein to generate filaments that are long and unbranched. However, despite these functional similarities, Sca2 is structurally unrelated to eukaryotic formins and achieves these functions through an entirely different mechanism. Thus, while formins are dimeric, Sca2 functions as a monomer. However, Sca2 displays intramolecular interactions and functional cooperativity between its N- and C-terminal domains that are crucial for actin nucleation and elongation. Here, we map the interaction of N- and C- terminal fragments of Sca2 and their contribution to actin binding and nucleation. We find that both the N- and C-terminal regions of Sca2 interact with actin monomers but only weakly, whereas the full-length protein binds two actin monomers with high affinity. Moreover, deletions at both ends of the N- and C-terminal regions disrupt their ability to interact with each other, suggesting that they form a contiguous ring-like structure that wraps around two actin subunits, analogous to the formin homology-2 domain. The discovery of Sca2 as an actin nucleator followed the identification of what appeared to be a repeat of three Wiskott-Aldrich syndrome homology 2 (WH2) domains in the middle of the molecule, consistent with the presence of WH2 domains in most actin nucleators. However, we show here that contrary to previous assumptions, Sca2 does not contain WH2 domains. Instead, our analysis indicates that the region containing the putative WH2 domains is folded as a globular domain that cooperates with other parts of the Sca2 molecule for actin binding and nucleation. 相似文献