全文获取类型
收费全文 | 10133篇 |
免费 | 483篇 |
国内免费 | 180篇 |
出版年
2023年 | 107篇 |
2022年 | 150篇 |
2021年 | 230篇 |
2020年 | 212篇 |
2019年 | 273篇 |
2018年 | 283篇 |
2017年 | 157篇 |
2016年 | 207篇 |
2015年 | 234篇 |
2014年 | 430篇 |
2013年 | 572篇 |
2012年 | 244篇 |
2011年 | 348篇 |
2010年 | 343篇 |
2009年 | 440篇 |
2008年 | 531篇 |
2007年 | 459篇 |
2006年 | 398篇 |
2005年 | 363篇 |
2004年 | 334篇 |
2003年 | 301篇 |
2002年 | 247篇 |
2001年 | 179篇 |
2000年 | 177篇 |
1999年 | 166篇 |
1998年 | 181篇 |
1997年 | 155篇 |
1996年 | 138篇 |
1995年 | 144篇 |
1994年 | 150篇 |
1993年 | 132篇 |
1992年 | 133篇 |
1991年 | 106篇 |
1990年 | 99篇 |
1989年 | 104篇 |
1988年 | 84篇 |
1987年 | 86篇 |
1986年 | 89篇 |
1985年 | 105篇 |
1984年 | 104篇 |
1982年 | 98篇 |
1981年 | 91篇 |
1980年 | 112篇 |
1979年 | 124篇 |
1978年 | 146篇 |
1977年 | 139篇 |
1976年 | 191篇 |
1974年 | 101篇 |
1973年 | 254篇 |
1972年 | 135篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Lambert W Koeck PJ Ahrman E Purhonen P Cheng K Elmlund D Hebert H Emanuelsson C 《Protein science : a publication of the Protein Society》2011,20(2):291-301
Unfolding proteins are prevented from irreversible aggregation by small heat shock proteins (sHsps) through interactions that depend on a dynamic equilibrium between sHsp subunits and sHsp oligomers. A chloroplast-localized sHsp, Hsp21, provides protection to client proteins to increase plant stress resistance. Structural information is lacking concerning the oligomeric conformation of this sHsp. We here present a structure model of Arabidopsis thaliana Hsp21, obtained by homology modeling, single-particle electron microscopy, and lysine-specific chemical crosslinking. The model shows that the Hsp21 subunits are arranged in two hexameric discs, similar to a cytosolic plant sHsp homolog that has been structurally determined after crystallization. However, the two hexameric discs of Hsp21 are rotated by 25° in relation to each other, suggesting a role for global dynamics in dodecamer function. 相似文献
993.
Marcin Gr?zBo?ena Pawlikowska-Pawl?ga Anna Jarosz-Wilko?azka 《International biodeterioration & biodegradation》2011,65(1):124-129
When Abortiporus biennis was grown on PbO-amended media, Pb (II) ions accumulated near fungal membrane structures, in the cell wall, and in the cytoplasm of the fungal cells, and their presence caused cell vacuolization. Increased concentration of PbO in the growth media caused a decline in fungal accumulation capacity. Neither PbO solubilization nor an increased level of organic acids underneath the mycelium was found. 相似文献
994.
Taldone T Gomes-DaGama EM Zong H Sen S Alpaugh ML Zatorska D Alonso-Sabadell R Guzman ML Chiosis G 《Bioorganic & medicinal chemistry letters》2011,21(18):5347-5352
Fluorescent ligands for the heat shock protein 90 (Hsp90) were synthesized containing either fluorescein isothiocyanate (FITC), 4-nitrobenzo[1,2,5]oxadiazole (NBD) or the red shifted dye sulforhodamine 101 (Texas Red) conjugated to PU-H71. Two of the compounds, PU-H71-FITC2 (9) and PU-H71-NBD1 (8), were shown to be suitable for fluorescence-activated flow cytometry and fluorescence microscopy. Thus these molecules serve as useful probes for studying Hsp90 in heterogeneous live cell populations. 相似文献
995.
New BODIPY-based pH probes have been designed with excitation and emission wavelengths suitable for fluorescence microscopy and flow cytometry. These pH probes are cell-permeable, selectively label lysosomes, and can be used for noninvasive monitoring of lysosomal pH changes during physiological and pathological processes. 相似文献
996.
介绍了蛋白质电子晶体学和单颗粒分析技术这两种低温电子显微技术在膜蛋白和膜蛋白复合体结构研究中的具体方法和近10~20年来的实际应用,并分别分析了这两种方法的优势和瓶颈。此外,还介绍了Amphipol替代、Streptavidin二维晶体锚定脂质体和纳米球包被脂质体等近两年来出现的新的用于低温电镜成像的膜蛋白样品制备方法。最后对膜蛋白的低温电子显微研究的未来发展做了展望。 相似文献
997.
998.
New and emerging therapeutic approaches focus on the targeted delivery of therapeutic agents to cell mitochondria with high specificity. Herein we present a novel mitotropic nanocarrier based on an oligolysine scaffold by addition of two triphenylphosphonium cations per oligomer. Although the parent oligolysine failed to enter healthy cells, the triphenylphosphonium modified carrier, with or without d-Luciferin, attached as cargo molecule, demonstrated striking mitochondrial specificity. Furthermore, the oligolysine bound d-Luciferin exhibited chemiluminescence, of lower intensity than free d-Luciferin, yet of remarkably longer steady-state temporal profile. 相似文献
999.
Dechkrong P Jiwajinda S Dokchan P Kongtungmon M Chomsaeng N Chairuangsri T Yu CC Hsiao CN Shiojiri M 《Journal of structural biology》2011,176(1):75-82
Wing scales of male Euploea mulciber (E. mulciber) and Troides aeacus (T. aeacus) butterflies were investigated from interest in photonic crystal by scanning electron microscopy and optical reflectance measurement. On the basis of the structural observation, the colouration in different areas in their wings was discussed. It was particularly deduced that a violet-green iridescence characteristic of E. mulciber’s forewing is caused only in a wavelength range from ∼380 to ∼510 nm by multiple interference from a highly tilted, triple-layered cuticle arrangement on the brown scales. It was also found that T. aeacus does not produce a blue-green sheen such as observed by Troides magellanus because its scales have no multiple cuticle layers but microrib layers unable to produce any backscattering diffraction. 相似文献
1000.
In this work, we examined structural changes of actin filaments interacting with myosin visualized by quick freeze deep-etch replica electron microscopy (EM) by using a new method of image processing/analysis based on mathematical morphology.In order to quantify the degree of structural changes, two characteristic patterns were extracted from the EM images. One is the winding pattern of the filament shape (WP) reflecting flexibility of the filament, and the other is the surface pattern of the filament (SP) reflecting intra-molecular domain-mobility of actin monomers constituting the filament. EM images were processed by morphological filtering followed by box-counting to calculate the fractal dimensions for WP (DWP) and SP (DSP). The result indicates that DWP was larger than DSP irrespective of the state of the filament (myosin-free or bound) and that both parameters for myosin-bound filaments were significantly larger than those for myosin-free filaments. Overall, this work provides the first quantitative insight into how conformational disorder of actin monomers is correlated with the myosin-induced increase in flexibility of actin filaments along their length as suggested by earlier studies with different techniques. Our method is yet to be improved in details, but promising as a powerful tool for studying the structural change of protein molecules and their assemblies, which can potentially be applied to a wide range of biological and biomedical images. 相似文献