全文获取类型
收费全文 | 2109篇 |
免费 | 116篇 |
国内免费 | 1篇 |
专业分类
2226篇 |
出版年
2023年 | 15篇 |
2022年 | 27篇 |
2021年 | 55篇 |
2020年 | 32篇 |
2019年 | 40篇 |
2018年 | 55篇 |
2017年 | 31篇 |
2016年 | 70篇 |
2015年 | 61篇 |
2014年 | 91篇 |
2013年 | 158篇 |
2012年 | 157篇 |
2011年 | 124篇 |
2010年 | 91篇 |
2009年 | 83篇 |
2008年 | 86篇 |
2007年 | 98篇 |
2006年 | 101篇 |
2005年 | 85篇 |
2004年 | 75篇 |
2003年 | 71篇 |
2002年 | 74篇 |
2001年 | 56篇 |
2000年 | 55篇 |
1999年 | 41篇 |
1998年 | 13篇 |
1997年 | 11篇 |
1996年 | 14篇 |
1995年 | 15篇 |
1994年 | 18篇 |
1992年 | 23篇 |
1991年 | 16篇 |
1990年 | 22篇 |
1989年 | 34篇 |
1988年 | 10篇 |
1987年 | 17篇 |
1986年 | 15篇 |
1985年 | 17篇 |
1984年 | 10篇 |
1983年 | 14篇 |
1982年 | 10篇 |
1981年 | 14篇 |
1980年 | 6篇 |
1979年 | 15篇 |
1978年 | 9篇 |
1977年 | 11篇 |
1976年 | 12篇 |
1975年 | 12篇 |
1970年 | 7篇 |
1968年 | 9篇 |
排序方式: 共有2226条查询结果,搜索用时 15 毫秒
31.
Satpute RM Kashyap RS Kainthla RP Purohit HJ Taori GM Daginawala HF 《Indian journal of experimental biology》2006,44(5):367-370
Neurite outgrowth is essential for the communication of the nervous system. The rat Pheochromocytoma (PC12) cells are commonly used in the neuronal cell study. It is well known that exogenous stimuli such as Nerve Growth Factor (NGF) induce neurite outgrowth. In the present study it has been investigated whether or not the conditioned medium from human neuroblastoma cell line (IMR-32) and human glioblastoma cell line (U87MG) may augment neurite outgrowth in PC12 cells. PC12 were cultured with and without conditioned media of IMR-32 and U87MG. The result showed that both the conditioned media induce neurite outgrowth within 48 hr and stops further proliferation of PC12 cells. However no outgrowth was noted in PC12 cells incubated without conditioned medium. In conclusion, it is shown that both the conditioned media (IMR-32 and U87MG) have the potential to induce the neurite outgrowth in the PC12 cells. 相似文献
32.
33.
Savita Rani Sanjeev Kumar Syed Mudassir Jeelani Raghbir Chand Gupta Santosh Kumari 《Plant Systematics and Evolution》2012,298(2):485-497
At present 14 species of Potentilla L. have been cytologically worked out from different geographical areas of Kashmir and Himachal Pradesh in the Western Himalayas.
New chromosome numbers in nine species—Potentilla argyrophylla (n = 14), P. atrosanguinea (n = 7, 14), P. desertorum (n = 7), P. gerardiana (n = 14), P. indica (n = 14), P. micropetala (n = 14), P. nepalensis (n = 14), P. sibbaldia (n = 14) and P. thomsonii (n = 7)—have been reported on a worldwide basis for the first time. Additional chromosomal races of polyploid cytotypes for
P. argyrophylla (n = 28) and P. desertorum (n = 14) along with a diploid cytotype for P. micropetala (n = 7) plus diploid cytotypes for the five species as P. fulgens (n = 7), P. gelida (n = 7), P. kleiniana (n = 7), P. sibbaldia (n = 7) and P. sundaica (n = 7) as well as a tetraploid cytotype for P. fruticosa (n = 14) all have been cytologically worked out from India for the first time. The course of meiosis varies from normal to abnormal
in different populations of the majority of the species, such as P. argyrophylla, P. atrosanguinea, P. desertorum, P. fruticosa, P. fulgens, P. gelida, P. indica, P. nepalensis, P. sibbaldia and P. sundaica, except for normal meiosis observed in P. gerardiana, P. kleiniana, P. micropetala and P. thomsonii. The anomalous taxa are marked with meiotic abnormalities in the form of cytomixis, chromosomal stickiness, unoriented bivalents,
formation of laggards and bridges resulting in abnormal microsporogenesis, and production of heterogenous-sized fertile pollen
grains along with reduced pollen fertility. All the taxa with normal meiotic courses show nearly one hundred percent pollen
fertility. 相似文献
34.
The analysis of primary sequences from a protein sequence data base suggests that the sequences can be considered as examples
of constrained random fractals. Fractal dimensions of the positional distributions of the 20 residues along the chain have
been calculated. These fractal dimensions can be used as indices of intrinsic preferences of various residues. 相似文献
35.
The aggregation of biotherapeutics is a major hindrance to the development of successful drug candidates; however, the propensity to aggregate is often identified too late in the development phase to permit modification to the protein's sequence. Incorporating rational design for the stability of proteins in early discovery has numerous benefits. We engineered out aggregation-prone regions on the Fab domain of a therapeutic monoclonal antibody, bevacizumab, to rationally design a biobetter drug candidate. With the purpose of stabilizing bevacizumab with respect to aggregation, 2 strategies were undertaken: single point mutations of aggregation-prone residues and engineering a glycosylation site near aggregation-prone residues to mask these residues with a carbohydrate moiety. Both of these approaches lead to comparable decreases in aggregation, with an up to 4-fold reduction in monomer loss. These single mutations and the new glycosylation pattern of the Fab domain do not modify binding to the target. Biobetters with increased stability against aggregation can therefore be generated in a rational manner, by either removing or masking the aggregation-prone region or crowding out protein-protein interactions. 相似文献
36.
Wan Yun Ho Jer-Cherng Chang Kenneth Lim Amaury Cazenave-Gassiot Aivi T. Nguyen Juat Chin Foo Sneha Muralidharan Ashley Viera-Ortiz Sarah J.M. Ong Jin Hui Hor Ira Agrawal Shawn Hoon Olubankole Aladesuyi Arogundade Maria J. Rodriguez Su Min Lim Seung Hyun Kim John Ravits Shi-Yan Ng Markus R. Wenk Edward B. Lee Greg Tucker-Kellogg Shuo-Chien Ling 《The Journal of cell biology》2021,220(9)
37.
38.
Satish Mohan Gunasekar Palanikumar Asensio Juan A. Agrawal Devendra K. 《Molecular and cellular biochemistry》2020,474(1-2):219-228
Molecular and Cellular Biochemistry - Intracoronary stenting is a common procedure in patients with coronary artery disease (CAD). Stent deployment stretches and denudes the endothelial layer,... 相似文献
39.
Jung YH Jeong SH Kim SH Singh R Lee JE Cho YS Agrawal GK Rakwal R Jwa NS 《Proteomics》2012,12(6):878-900
Magnaporthe oryzae is a devastating blast fungal pathogen of rice (Oryza sativa L.) that causes dramatic decreases in seed yield and quality. During the early stages of infection by this pathogen, the fungal spore senses the rice leaf surface, germinates, and penetrates the cell via an infectious structure known as an appressorium. During this process, M. oryzae secretes several proteins; however, these proteins are largely unknown mainly due to the lack of a suitable method for isolating secreted proteins during germination and appressoria formation. We examined the secretome of M. oryzae by mimicking the early stages of infection in vitro using a glass plate (GP), PVDF membrane, and liquid culture medium (LCM). Microscopic observation of M. oryzae growth revealed appressorium formation on the GP and PVDF membrane resembling natural M. oryzae-rice interactions; however, appresorium formation was not observed in the LCM. Secreted proteins were collected from the GP (3, 8, and 24 h), PVDF membrane (24 h), and LCM (48 h) and identified by two-dimensional gel electrophoresis (2DE) followed by tandem mass spectrometry. The GP, PVDF membrane, and LCM-derived 2D gels showed distinct protein patterns, indicating that they are complementary approaches. Collectively, 53 nonredundant proteins including previously known and novel secreted proteins were identified. Six biological functions were assigned to the proteins, with the predominant functional classes being cell wall modification, reactive oxygen species detoxification, lipid modification, metabolism, and protein modification. The in vitro system using GPs and PVDF membranes applied in this study to survey the M. oryzae secretome, can be used to further our understanding of the early interactions between M. oryzae and rice leaves. 相似文献
40.
Arun Agrawal 《Human ecology: an interdisciplinary journal》1993,21(3):261-279
This paper describes and then analyzes the decision-making arrangements that prevail among the Raikas—nomadic shepherds from Western India. The paper suggests, using a simple analytical framework, that the existing distribution of decision-making during migration helps the Raikasto utilize available economies of scale, represent the different interest groups in their collectives, and control their decision-makers. At the same time, the ordinary shepherds in the camp are able to extract a comfortable subsistence from a complex and harsh environment by delegating much of their decision-making responsibilities to the leaders in the camp. To the extent shepherds in other parts of the world migrate over long distances and must confront similar issues of delegation of responsibilities and control over decision-makers, the analysis holds general relevance. 相似文献