全文获取类型
收费全文 | 1796篇 |
免费 | 95篇 |
国内免费 | 23篇 |
出版年
2023年 | 17篇 |
2022年 | 18篇 |
2021年 | 32篇 |
2020年 | 42篇 |
2019年 | 64篇 |
2018年 | 32篇 |
2017年 | 38篇 |
2016年 | 45篇 |
2015年 | 55篇 |
2014年 | 149篇 |
2013年 | 166篇 |
2012年 | 128篇 |
2011年 | 178篇 |
2010年 | 120篇 |
2009年 | 74篇 |
2008年 | 84篇 |
2007年 | 73篇 |
2006年 | 86篇 |
2005年 | 59篇 |
2004年 | 52篇 |
2003年 | 52篇 |
2002年 | 43篇 |
2001年 | 25篇 |
2000年 | 11篇 |
1999年 | 24篇 |
1998年 | 16篇 |
1997年 | 21篇 |
1996年 | 21篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 14篇 |
1992年 | 16篇 |
1991年 | 6篇 |
1990年 | 10篇 |
1989年 | 11篇 |
1988年 | 12篇 |
1987年 | 22篇 |
1986年 | 3篇 |
1985年 | 9篇 |
1984年 | 11篇 |
1983年 | 5篇 |
1982年 | 7篇 |
1980年 | 5篇 |
1979年 | 10篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1973年 | 3篇 |
排序方式: 共有1914条查询结果,搜索用时 15 毫秒
91.
Fouling-release coatings prevent fouling of ships' hulls through hydrodynamic forces generated as the ship moves through the water. The effectiveness of such coatings may be evaluated by measuring the adhesion strength of settled organisms, e.g. barnacles. The influence of desiccation of the barnacle adhesive on such measurements was investigated. Shear forces required to remove barnacles of the genus Balanus increased during the course of desiccation up to the point when the barnacles suddenly self-detached. The increase was thought to be due to the rising cohesive strength of the adhesive. Growing tensile forces within the weakly cross-linked adhesive, however, are suggested to have led to self-detachment. The shear forces required to remove barnacles of the genus Elminius were generally low and did not differ significantly during the course of desiccation. The different results may be attributed to specific base morphologies. It was concluded that measuring the adhesion strength of members of the Balanidae on non-stick surfaces in air could produce flawed results due to the influence of desiccation of the barnacle adhesive. The investigations have also provided new insights into the characteristics of barnacle adhesive. 相似文献
92.
93.
94.
旋覆花素抑制血管内皮剥脱诱导的粘附分子表达 总被引:2,自引:0,他引:2
目的观察旋覆花素对内皮剥脱诱导的新生内膜形成过程中血管壁粘附分子OPN、ICAM-1、ILK表达的影响,为寻找该药物抑制新生内膜形成的作用靶标提供实验依据。方法采用主动脉球囊损伤后血管狭窄动物模型,用免疫组织化学和Western Blot方法分别检测血管壁中骨桥蛋白(osteopontin,OPN)、细胞间粘附分子-1(intercellular adhesion molecule-1,ICAM-1)、整合素偶联激酶(integrin-linked kinase,ILK)的表达变化及旋覆花素对其的影响。结果血管内皮剥脱可诱导血管壁平滑肌细胞大量增生,新生内膜呈弥漫性增厚,血管损伤局部组织中OPN、ICAM-1、ILK的表达均比正常对照组明显升高(P<0.05)。旋覆花素治疗组在球囊损伤后,血管内膜增生程度显著减轻,血管壁OPN、ICAM-1、ILK的表达均比模型组明显降低(P<0.05)。结论旋覆花素减缓新生内膜形成的效应与其抑制粘附分子的表达、阻断粘附分子信号传递有关。 相似文献
95.
Kamila Myszka Katarzyna Czaczyk Marcin T. Schmidt Anna M. Olejnik 《World journal of microbiology & biotechnology》2007,23(11):1605-1612
The purpose of these investigations was to evaluate the influence of limited nutrient availability in the culture medium on
Proteus vulgaris biofilm formation on surfaces of stainless steel. The relationship between the P. vulgaris adhesion to the abiotic surfaces, the cellular ATP levels, cell surface hydrophobicity and changes in the profiles of extracellular
proteins and lipopolysaccharides was examined. In all experimental variants the starvation conditions induced the bacterial
cells to adhere to the surfaces of stainless steel. Higher ATP content and lower cell surface hydrophobicity of P. vulgaris cells was observed upon nutrient-limited conditions. Under starvation conditions a reduction in the levels of extracellular
low molecular weight proteins was noticed. High molecular weight proteins formed the conditioning layer on stainless steel
plates, making the bacteria adhesion process more favorable. The production of low molecular weight carbohydrates promoted
more advanced stages of P. vulgaris biofilm formation process on the surfaces of stainless steel upon starvation. 相似文献
96.
Root extract from Pelargonium sidoides DC is used therapeutically as antimicrobial agent against infections of the respiratory system. In order to elucidate possible modes of actions we investigated the influence of P. sidoides root extract on microbial adhesion with Helicobacter pylori as model microorganism, a germ with a strong adherence to human stomach tissue. In an in-situ anti-adhesion assay intact human stomach tissue from patient resectates was incubated with fluorescent-labelled bacteria. Epithelial adhesion occurred in untreated samples and was quantified by fluorescent microscopy. Pre-treatment of the bacteria with Pelargonium extract showed good anti-adhesive activity. The antiadhesive effect was clearly dose-dependent in a range from 0.001 to 10 mg/ml. Within agar diffusion-test the extract had no direct cytotoxicity against H. pylori. The results show that the root extract from Pelargonium sidoides is a potent anti-adhesive agent against H. pylori and could therefore be a useful choice to avoid the first step of a bacterial infection. 相似文献
97.
Annelies Mortier Eduardo V. Soares 《World journal of microbiology & biotechnology》2007,23(10):1401-1407
Separation of yeast cells using a co-flocculation process was investigated. Co-flocculation is a fast process (within few
minutes), occurs in a broad pH range (3.0–8.0) and requires a small amount of calcium (0.1 mM). Agitation affects yeast aggregation;
however, an agitation between 60 rev/min and 160 rev/min has only a little influence on the co-flocculation process. The ratio
flocculent/non-flocculent cells that induced the settling of 50 and 90% of the cells of S. cerevisiae was 1:7 and 1:1, respectively. Separation of non-flocculent cells can be carried out at any time of the growth cycle. No
difference in the efficiency of co-flocculation carried out in buffer (pH 4.0 with 10 mM calcium) or in 48 h-fermented broth
was observed. Flocculent cells of Saccharomyces cerevisiae had the ability to sediment non-flocculent cells of S. cerevisiae and
Kluyveromyces marxianus, which shows the suitability of the co-flocculation process for separation of different kinds of non-flocculent cells. 相似文献
98.
Robert G. Moody Mary K. Phillips-Jones Mike P. Williamson 《Biomolecular NMR assignments》2007,1(1):11-12
We report the almost complete assignment of 1H, 13C and 15N nuclei in the 137-residue his-tagged fasciclin domain protein (Fdp) from Rhodobacter sphaeroides. Fdp is homologous to fasciclin I domains, including Drosophila FAS1 and M. tuberculosis MPB70 and plays a role in cell adhesion. 相似文献
99.
Using the paper disc-agar plate method, a number of fatty and related acids have been tested for tested activity for inhibiting the growth of Chlorella pyrenoidosa Chick. Of the saturated acids, a peak in growth inhibiting activity wax observed in the C7–C12 range, where inhibition wax observed when solutions down to 0.02 M were applied to the discs. Most of the unsaturated acids tested showed greater inhibition than did the corresponding saturated acids. Acrylic acid showed detectable inhibition at 0.001 M concentration. 相似文献
100.
椎间盘退变是一种年龄相关的退行性疾病,是引起下腰痛的主要因素,严重影响病人的生活质量,并显著增加家庭的经济负担。目前,缺少椎间盘退变的有效干预和治疗手段,部分原因是其发病机制尚未阐明。椎间盘退变动物模型的构建对于阐明该疾病的病理机制至关重要。椎间盘退变是一个复杂的过程,受机械应力、结构损伤、生物化学与基因表达等多种因素的影响。本文总结了应用异常机械应力、结构损伤、生物化学或化学诱导和基因敲除等方式构建的椎间盘退变动物模型。生物力学是维持椎间盘稳态的重要因素,异常的机械应力会导致椎间盘退变。同时,椎间盘退变常伴随结构性损伤,椎间盘结构破坏也会导致椎间盘发生退变。此外,生物化学或化学诱导和关键基因敲除也会导致椎间盘退变。本文按照造成异常机械应力的因素将机械应力模型分为加压模型和失稳模型;按照椎间盘结构将结构损伤模型分为髓核与纤维环损伤模型和软骨终板损伤模型。总结了生物化学或化学诱导模型以及新型的基因敲除模型。讨论了不同类型椎间盘退变动物模型的可能应用和局限性。 相似文献