全文获取类型
收费全文 | 112034篇 |
免费 | 2112篇 |
国内免费 | 3496篇 |
专业分类
117642篇 |
出版年
2024年 | 79篇 |
2023年 | 408篇 |
2022年 | 783篇 |
2021年 | 1202篇 |
2020年 | 924篇 |
2019年 | 1106篇 |
2018年 | 12607篇 |
2017年 | 11221篇 |
2016年 | 8319篇 |
2015年 | 1952篇 |
2014年 | 1909篇 |
2013年 | 1977篇 |
2012年 | 6117篇 |
2011年 | 14479篇 |
2010年 | 13021篇 |
2009年 | 9087篇 |
2008年 | 10782篇 |
2007年 | 12193篇 |
2006年 | 1008篇 |
2005年 | 1139篇 |
2004年 | 1454篇 |
2003年 | 1426篇 |
2002年 | 1153篇 |
2001年 | 520篇 |
2000年 | 392篇 |
1999年 | 252篇 |
1998年 | 162篇 |
1997年 | 174篇 |
1996年 | 152篇 |
1995年 | 116篇 |
1994年 | 117篇 |
1993年 | 119篇 |
1992年 | 126篇 |
1991年 | 109篇 |
1990年 | 84篇 |
1989年 | 61篇 |
1988年 | 58篇 |
1987年 | 47篇 |
1986年 | 35篇 |
1985年 | 35篇 |
1984年 | 29篇 |
1983年 | 34篇 |
1982年 | 17篇 |
1979年 | 11篇 |
1975年 | 13篇 |
1972年 | 247篇 |
1971年 | 277篇 |
1965年 | 15篇 |
1962年 | 24篇 |
1944年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
Pawan K. Dhar 《Journal of biosciences》2007,32(1):1005-1008
Systems biology is an approach to explain the behaviour of a system in relation to its individual components. Synthetic biology uses key hierarchical and modular concepts of systems biology to engineer novel biological systems. In my opinion the next step in biology is to use molecule-to-phenotype data using these approaches and integrate them in the form a periodic table. A periodic table in biology would provide chassis to classify, systematize and compare diversity of component properties vis-a-vis system behaviour. Using periodic table it could be possible to compute higher-level interactions from component properties. This paper examines the concept of building a bio-periodic table using protein fold as the fundamental unit. 相似文献
113.
Ferruh Aşçi 《Biologia》2009,64(6):1146-1149
In this study, the structural characteristics, unique features, various organ measurements of males and females of the water
mite Atractides (Atractides) turcicus sp. n. from Turkey are described. In addition, the study compares their characteristics with related species. 相似文献
114.
115.
Andrew Leask 《Journal of cell communication and signaling》2010,4(1):73-74
Connective tissue growth factor (CTGF/CCN2) is overexpressed in diabetes. Diabetic rats possess myocardial and cardiomyocyte hypertrophy. In a recent report, Wang and colleagues (Am J Physiol Cell Physiol. 2009 Jul 22. [Epub ahead of print]) show that CCN2 directly mediates cardiomyocyte hypertrophy as well as that induced by high glucose and fatty acid. CCN2 acted via the TrkA receptor. These data are the subject of this commentary, and emphasize that CCN2 may be an excellent target for therapy in diabetes. 相似文献
116.
117.
Cassandre Leverrier Giana Almeida Lucia Espinosa-Mu noz Gérard Cuvelier 《Food biophysics》2016,11(3):235-247
This work investigates the impact of structural parameters on the rheological behaviour of apple purees. Reconstructed apple purees from 0 g/100 g up to 2.32 g/100 g of insoluble solids content and varying in particle size were prepared. Three different particle size distributions were obtained by mechanical treatment only, to modify both size and morphology of the particles without modifying the intrinsic rigidity of the cell walls. Rheological measurements showed that the insoluble solids content have a first order effect on the rheological behaviour of the suspensions: three concentrations domains were observed in both dynamic and flow measurements. A model is proposed for each domain. The existence of a weak network between particles is clearly shown over a critical concentration of insoluble solids (cell walls) depending on particle size distribution (semi-diluted domain). In a concentrated domain, particles are on close packing conditions and their apparent volume begin to shrink. Particle size and shape also play an important role on the rheological behaviour of reconstructed apple puree. Due to their irregular shape, cell clusters clog the medium at lower concentration compared to individual cells. 相似文献
118.
119.
A general in vitro cloning system was established for four Helleborus species: H. argutifolius, H. foetidus, H. niger and H. orientalis. The plant material was introduced in vitro from axillary buds. A Murashige and Skoog (MS)—based medium (Murashige and Skoog
1962) was used supplemented with 2% (w/v) sucrose, 2-isopentenyladenine (2-iP) and 6-benzylaminopurine (BA). Multiplication
rates depended on the genotype and varied from 1.3 for H. foetidus till 3.8 for H. niger. The first results showed that the rooting phase could be done ex vitro. Rooting was induced by a drench for one week in
a solution of indole-3-butyric acid (IBA -3 mg l−1) and 1-naphthaleneacetic acid (NAA-1 mg l−1) at 5°C. 相似文献
120.