全文获取类型
收费全文 | 1406篇 |
免费 | 98篇 |
国内免费 | 2篇 |
出版年
2024年 | 3篇 |
2023年 | 10篇 |
2022年 | 21篇 |
2021年 | 37篇 |
2020年 | 13篇 |
2019年 | 21篇 |
2018年 | 48篇 |
2017年 | 33篇 |
2016年 | 47篇 |
2015年 | 58篇 |
2014年 | 75篇 |
2013年 | 110篇 |
2012年 | 117篇 |
2011年 | 142篇 |
2010年 | 63篇 |
2009年 | 61篇 |
2008年 | 87篇 |
2007年 | 70篇 |
2006年 | 77篇 |
2005年 | 79篇 |
2004年 | 75篇 |
2003年 | 54篇 |
2002年 | 39篇 |
2001年 | 20篇 |
2000年 | 20篇 |
1999年 | 18篇 |
1998年 | 10篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 13篇 |
1990年 | 4篇 |
1989年 | 10篇 |
1988年 | 3篇 |
1987年 | 6篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1970年 | 2篇 |
排序方式: 共有1506条查询结果,搜索用时 15 毫秒
81.
Arabidopsis CROOKED encodes for the smallest subunit of the ARP2/3 complex and controls cell shape by region specific fine F-actin formation 总被引:7,自引:0,他引:7
Mathur J Mathur N Kirik V Kernebeck B Srinivas BP Hülskamp M 《Development (Cambridge, England)》2003,130(14):3137-3146
The generation of a specific cell shape requires differential growth, whereby specific regions of the cell expand more relative to others. The Arabidopsis crooked mutant exhibits aberrant cell shapes that develop because of mis-directed expansion, especially during a rapid growth phase. GFP-aided visualization of the F-actin cytoskeleton and the behavior of subcellular organelles in different cell-types in crooked and wild-type Arabidopsis revealed that localized expansion is promoted in cellular regions with fine F-actin arrays but is restricted in areas that maintain dense F-actin. This suggested that a spatiotemporal distinction between fine versus dense F-actin in a growing cell could determine the final shape of the cell. CROOKED was molecularly identified as the plant homolog of ARPC5, the smallest sub-unit of the ARP2/3 complex that in other organisms is renowned for its role in creating dendritic arrays of fine F-actin. Rescue of crooked phenotype by the human ortholog provides the first molecular evidence for the presence and functional conservation of the complex in higher plants. Our cell-biological and molecular characterization of CROOKED suggests a general actin-based mechanism for regulating differential growth and generating cell shape diversity. 相似文献
82.
Kamal A Ramulu P Srinivas O Ramesh G 《Bioorganic & medicinal chemistry letters》2003,13(22):3955-3958
The synthesis of new A-C8/C-C2 alkoxyamido-linked pyrrolo[2,1-c][1,4]-benzodiazepine dimers have been described in this report. These dimers exhibit significant DNA-binding ability with moderate anticancer activity. 相似文献
83.
Berries of steroid-bearingSolanum viarum Dunal are exploited commercially in India as raw material by steroid industries for solasodine, a glycoalkaloid, present
in the mucilaginous exotesta of the seed. Comparative ontogeny of exotesta studied through histochemical studies in diploid,
autotetraploid and trisomic plants indicated similarity in the histochemical changes occurring during ontogeny of the outermost
seed coat layer which culminated in the transformation of this layer into the mucilage layer. The increased cell size in this
layer in the autotetraploid plants probably accounts for the higher steroid content reported. Corroborative evidences for
histochemical changes observed in the mucilage layer were obtained from studies of ultrastructure using transmission electron
microscopy. 相似文献
84.
Chlorantraniliprole seed treatments in rice provide effective suppression of rice water weevil populations in the United States; however, heavy reliance on prophylactic insecticide treatments as a sole strategy could destabilize management programs for this insect. The present research evaluated the compatibility of seed treatments with two other potential management tactics—plant resistance and shallow flooding–by conducting two split‐plot experiments in 2009 and 2011. In both experiments, no substantial antagonism was found among the 3 different tactics. Statistical interactions in these experiments arose from the strong and persistent effects of chlorantraniliprole on larval densities rather than incompatibility of tactics. In 2009, weevil densities differed among varieties and were significantly lower on the cultivar “Jefferson.” In 2011, weevil densities were reduced significantly in shallow‐flooded plots compared to deep‐flooded plots. Significant reductions in weevil numbers by chlorantraniliprole seed treatments, even at application rates 5 fold lower than commercially recommended rates, demonstrated the potential to reduce application rates of this highly potent larvicide. These latter results suggest that future studies on the relationship between chlorantraniliprole seed treatment rate and weevil fitness are warranted. 相似文献
85.
86.
87.
88.
Nanako Tokuda Mitsuru Hattori Kota Abe Yoshinori Shinohara Yusuke Nagano Takao Itino 《Ecology and evolution》2015,5(6):1271-1277
Plant–plant interspecific competition via pollinators occurs when the flowering seasons of two or more plant species overlap and the pollinator fauna is shared. Negative sexual interactions between species (reproductive interference) through improper heterospecific pollen transfer have recently been reported between native and invasive species demonstrating pollination‐driven competition. We focused on two native Impatiens species (I. noli‐tangere and I. textori) found in Japan and examined whether pollinator‐mediated plant competition occurs between them. We demonstrate that I. noli‐tangere and I. textori share the same pollination niche (i.e., flowering season, pollinator fauna, and position of pollen on the pollinator's body). In addition, heterospecific pollen grains were deposited on most stigmas of both I. noli‐tangere and I. textori flowers that were situated within 2 m of flowers of the other species resulting in depressed fruit set. Further, by hand‐pollination experiments, we show that when as few as 10% of the pollen grains are heterospecific, fruit set is decreased to less than half in both species. These results show that intensive pollinator‐mediated competition occurs between I. noli‐tangere and I. textori. This study suggests that intensive pollinator‐mediated competition occurs in the wild even when interacting species are both native and not invasive. 相似文献
89.
So Kato Yasushi Oshima Hiroyuki Oka Hirotaka Chikuda Yujiro Takeshita Kota Miyoshi Naohiro Kawamura Kazuhiro Masuda Junichi Kunogi Rentaro Okazaki Seiichi Azuma Nobuhiro Hara Sakae Tanaka Katsushi Takeshita 《PloS one》2015,10(4)
Objectives
The Japanese Orthopaedic Association (JOA) score is widely used to assess the severity of clinical symptoms in patients with cervical compressive myelopathy, particularly in East Asian countries. In contrast, modified versions of the JOA score are currently accepted as the standard tool for assessment in Western countries. The objective of the present study is to compare these scales and clarify their differences and interchangeability and verify their validity by comparing them to other outcome measures.Materials and Methods
Five institutions participated in this prospective multicenter observational study. The JOA and modified JOA (mJOA) proposed by Benzel were recorded preoperatively and at three months postoperatively in patients with cervical compressive myelopathy who underwent decompression surgery. Patient reported outcome (PRO) measures, including Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), the Short Form-12 (SF-12) and the Neck Disability Index (NDI), were also recorded. The preoperative JOA score and mJOA score were compared to each other and the PRO values. A Bland-Altman analysis was performed to investigate their limits of agreement.Results
A total of ninety-two patients were included. The correlation coefficient (Spearman’s rho) between the JOA and mJOA was 0.87. In contrast, the correlations between JOA/mJOA and the other PRO values were moderate (|rho| = 0.03 – 0.51). The correlation coefficient of the recovery rate between the JOA and mJOA was 0.75. The Bland-Altman analyses showed that limits of agreement were 3.6 to -1.2 for the total score, and 55.1% to -68.8% for the recovery rates.Conclusions
In the present study, the JOA score and the mJOA score showed good correlation with each other in terms of their total scores and recovery rates. Previous studies using the JOA can be interpreted based on the mJOA; however it is not ideal to use them interchangeably. The validity of both scores was demonstrated by comparing these values to the PRO values. 相似文献90.
Sudeep Chenna Narendra Jaya Prakash Chalise Mattias Magnusson Srinivas Uppugunduri 《PloS one》2015,10(10)