全文获取类型
收费全文 | 1257篇 |
免费 | 62篇 |
出版年
2023年 | 8篇 |
2022年 | 17篇 |
2021年 | 43篇 |
2020年 | 15篇 |
2019年 | 24篇 |
2018年 | 34篇 |
2017年 | 17篇 |
2016年 | 32篇 |
2015年 | 59篇 |
2014年 | 70篇 |
2013年 | 118篇 |
2012年 | 115篇 |
2011年 | 89篇 |
2010年 | 48篇 |
2009年 | 40篇 |
2008年 | 57篇 |
2007年 | 67篇 |
2006年 | 59篇 |
2005年 | 44篇 |
2004年 | 42篇 |
2003年 | 33篇 |
2002年 | 29篇 |
2001年 | 20篇 |
2000年 | 18篇 |
1999年 | 11篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1992年 | 11篇 |
1991年 | 6篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 9篇 |
1987年 | 9篇 |
1986年 | 9篇 |
1985年 | 11篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 5篇 |
1975年 | 7篇 |
1974年 | 11篇 |
1973年 | 14篇 |
1972年 | 10篇 |
1971年 | 5篇 |
1970年 | 4篇 |
1969年 | 6篇 |
排序方式: 共有1319条查询结果,搜索用时 31 毫秒
31.
32.
Reema Khurana Hitesh Kathuria Arnab Mukhopadhyay Sanjay Kapoor Akhilesh K. Tyagi 《Biotechnology letters》2013,35(3):455-462
OSIPP3 gene (coding for pectin methylesterase inhibitor protein) was isolated from a pre-pollinated inflorescence-specific cDNA library by differential screening of stage-specific libraries from Oryza sativa. OSIPP3 is present in the genome of rice as a single copy gene. OSIPP3 gene was expressed exclusively in the pre-pollinated spikelets of rice. Upstream regulatory region (URR) of OSIPP3 was isolated and a series of 5′-deletions were cloned upstream of GUS reporter gene and were used to transform Arabidopsis. OSIPP3_del1 and del2 transgenic plants showed GUS expression in root, anther and silique, while OSIPP3_del3 showed GUS activity only in anthers and siliques. Pollen-specific expression was observed in case of plants harboring OSIPP3_del4 construct. It can, therefore, be concluded that the OSIPP3 URR between ?178 and +108 bp is necessary for conferring pollen-specific expression in Arabidopsis. 相似文献
33.
Jason Yi Xufeng Wu Andrew H. Chung James K. Chen Tarun M. Kapoor John A. Hammer 《The Journal of cell biology》2013,202(5):779-792
T cells rapidly reposition their centrosome to the center of the immunological synapse (IS) to drive polarized secretion in the direction of the bound target cell. Using an optical trap for spatial and temporal control over target presentation, we show that centrosome repositioning in Jurkat T cells exhibited kinetically distinct polarization and docking phases and required calcium flux and signaling through both the T cell receptor and integrin to be robust. In “frustrated” conjugates where the centrosome is stuck behind the nucleus, the center of the IS invaginated dramatically to approach the centrosome. Consistently, imaging of microtubules during normal repositioning revealed a microtubule end-on capture-shrinkage mechanism operating at the center of the IS. In agreement with this mechanism, centrosome repositioning was impaired by inhibiting microtubule depolymerization or dynein. We conclude that dynein drives centrosome repositioning in T cells via microtubule end-on capture-shrinkage operating at the center of the IS and not cortical sliding at the IS periphery, as previously thought. 相似文献
34.
Manpreet Kaur Rawal Mohammad Firoz Khan Khyati Kapoor Neha Goyal Sobhan Sen Ajay Kumar Saxena Andrew M. Lynn Joel D. A. Tyndall Brian C. Monk Richard D. Cannon Sneha Sudha Komath Rajendra Prasad 《The Journal of biological chemistry》2013,288(34):24480-24493
The fungal ATP-binding cassette (ABC) transporter Cdr1 protein (Cdr1p), responsible for clinically significant drug resistance, is composed of two transmembrane domains (TMDs) and two nucleotide binding domains (NBDs). We have probed the nature of the drug binding pocket by performing systematic mutagenesis of the primary sequences of the 12 transmembrane segments (TMSs) found in the TMDs. All mutated proteins were expressed equally well and localized properly at the plasma membrane in the heterologous host Saccharomyces cerevisiae, but some variants differed significantly in efflux activity, substrate specificity, and coupled ATPase activity. Replacement of the majority of the amino acid residues with alanine or glycine yielded neutral mutations, but about 42% of the variants lost resistance to drug efflux substrates completely or selectively. A predicted three-dimensional homology model shows that all the TMSs, apart from TMS4 and TMS10, interact directly with the drug-binding cavity in both the open and closed Cdr1p conformations. However, TMS4 and TMS10 mutations can also induce total or selective drug susceptibility. Functional data and homology modeling assisted identification of critical amino acids within a drug-binding cavity that, upon mutation, abolished resistance to all drugs tested singly or in combinations. The open and closed Cdr1p models enabled the identification of amino acid residues that bordered a drug-binding cavity dominated by hydrophobic residues. The disposition of TMD residues with differential effects on drug binding and transport are consistent with a large polyspecific drug binding pocket in this yeast multidrug transporter. 相似文献
35.
36.
37.
Hyun Seok Kim Saurabh Mendiratta Jiyeon Kim Chad Victor Pecot Jill E. Larsen Iryna Zubovych Bo Yeun Seo Jimi Kim Banu Eskiocak Hannah Chung Elizabeth McMillan Sherry Wu Jef De Brabander Kakajan Komurov Jason E. Toombs Shuguang Wei Michael Peyton Noelle Williams Adi F. Gazdar Bruce A. Posner Rolf A. Brekken Anil K. Sood Ralph J. Deberardinis Michael G. Roth John D. Minna Michael A. White 《Cell》2013
38.
Saurabh Sudha Dhiman Dayanand Kalyani Sujit Sadashiv Jagtap Jung-Rim Haw Yun Chan Kang Jung-Kul Lee 《Applied microbiology and biotechnology》2013,97(3):1081-1091
Enhanced catalytic activities of different lignocellulases were obtained from Armillaria gemina under statistically optimized parameters using a jar fermenter. This strain showed maximum xylanase, endoglucanase, cellobiohydrolase, and β-glucosidase activities of 1,270, 146, 34, and 15 U mL?1, respectively. Purified A. gemina xylanase (AgXyl) has the highest catalytic efficiency (k cat/K m?=?1,440 mg?mL?1?s?1) ever reported for any fungal xylanase, highlighting the significance of the current study. We covalently immobilized the crude xylanase preparation onto functionalized silicon oxide nanoparticles, achieving 117 % immobilization efficiency. Further immobilization caused a shift in the optimal pH and temperature, along with a fourfold improvement in the half-life of crude AgXyl. Immobilized AgXyl gave 37.8 % higher production of xylooligosaccharides compared to free enzyme. After 17 cycles, the immobilized enzyme retained 92 % of the original activity, demonstrating its potential for the synthesis of xylooligosaccharides in industrial applications. 相似文献
39.
40.
Xiang Li Emily A. Foley Shigehiro A. Kawashima Kelly R. Molloy Yinyin Li Brian T. Chait Tarun M. Kapoor 《Protein science : a publication of the Protein Society》2013,22(3):287-295
Post‐translational modifications (PTM) of proteins can control complex and dynamic cellular processes via regulating interactions between key proteins. To understand these regulatory mechanisms, it is critical that we can profile the PTM‐dependent protein–protein interactions. However, identifying these interactions can be very difficult using available approaches, as PTMs can be dynamic and often mediate relatively weak protein–protein interactions. We have recently developed CLASPI (cross‐linking‐assisted and stable isotope labeling in cell culture‐based protein identification), a chemical proteomics approach to examine protein–protein interactions mediated by methylation in human cell lysates. Here, we report three extensions of the CLASPI approach. First, we show that CLASPI can be used to analyze methylation‐dependent protein–protein interactions in lysates of fission yeast, a genetically tractable model organism. For these studies, we examined trimethylated histone H3 lysine‐9 (H3K9Me3)‐dependent protein–protein interactions. Second, we demonstrate that CLASPI can be used to examine phosphorylation‐dependent protein–protein interactions. In particular, we profile proteins recognizing phosphorylated histone H3 threonine‐3 (H3T3‐Phos), a mitotic histone “mark” appearing exclusively during cell division. Our approach identified survivin, the only known H3T3‐Phos‐binding protein, as well as other proteins, such as MCAK and KIF2A, that are likely to be involved in weak but selective interactions with this histone phosphorylation “mark”. Finally, we demonstrate that the CLASPI approach can be used to study the interplay between histone H3T3‐Phos and trimethylation on the adjacent residue lysine 4 (H3K4Me3). Together, our findings indicate the CLASPI approach can be broadly applied to profile protein–protein interactions mediated by PTMs. 相似文献