全文获取类型
收费全文 | 27144篇 |
免费 | 15646篇 |
国内免费 | 3篇 |
专业分类
42793篇 |
出版年
2024年 | 3篇 |
2023年 | 27篇 |
2022年 | 116篇 |
2021年 | 459篇 |
2020年 | 2213篇 |
2019年 | 3736篇 |
2018年 | 3861篇 |
2017年 | 4128篇 |
2016年 | 4140篇 |
2015年 | 4105篇 |
2014年 | 3735篇 |
2013年 | 4192篇 |
2012年 | 1867篇 |
2011年 | 1574篇 |
2010年 | 3086篇 |
2009年 | 1821篇 |
2008年 | 748篇 |
2007年 | 374篇 |
2006年 | 345篇 |
2005年 | 356篇 |
2004年 | 337篇 |
2003年 | 318篇 |
2002年 | 313篇 |
2001年 | 288篇 |
2000年 | 208篇 |
1999年 | 150篇 |
1998年 | 28篇 |
1997年 | 22篇 |
1996年 | 24篇 |
1995年 | 20篇 |
1994年 | 19篇 |
1993年 | 11篇 |
1992年 | 31篇 |
1991年 | 19篇 |
1990年 | 21篇 |
1989年 | 14篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 13篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 9篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1978年 | 3篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1970年 | 3篇 |
1965年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
992.
993.
994.
995.
Deborah F. Tate Leslie Lytle Kristen Polzien Molly Diamond Kelsey R. Leonard John M. Jakicic Karen C. Johnson Christine M. Olson Kevin Patrick Laura P. Svetkey Rena R. Wing Pao‐Hwa Lin Mathilda Coday Melissa N. Laska Gina Merchant Sara J. Czaja Richard Schulz Steven H. Belle 《Obesity (Silver Spring, Md.)》2019,27(7):1085-1098
996.
Faris M. Zuraikat Elsa Thomas Devon Roeshot Dympna Gallagher Marie‐Pierre St‐Onge 《Obesity (Silver Spring, Md.)》2019,27(11):1769-1771
Healthy sleep is associated with lower body weight and could improve and sustain weight loss following bariatric surgery. To support this premise, preliminary data on the relation between sleep duration and quality and long‐term weight change in a subsample of participants from the Longitudinal Assessment of Bariatric Surgery are presented. Results indicate a relation between sleep duration and BMI and percent weight loss 9 years after surgery. Additionally, sleep quality explained 25% of the variance in weight change between 6‐ and 9‐year follow‐up visits. These data from a small exploratory study, in combination with the known effects of sleep on energy balance, suggest that sleep may play an important role in both immediate and sustained weight loss following bariatric surgery. Herein, a model of the proposed bidirectional relation between sleep and weight loss is presented as well as a call for systematic investigations of the influence of sleep on long‐term weight management following bariatric surgery. 相似文献
997.
998.
Photoacoustic microscopy (PAM) is a noninvasive imaging technique and is excellent to study structural and functional changes in the microcirculation. In this work, a lipopolysaccharide (LPS)‐induced inflammation model in mice is noninvasively evaluated by PAM. PAM is used to image the microvascular structural changes in mice for 8 hours after the LPS with different concentrations is applied. Quantitative analysis of five vessel parameters is conducted, which shows that the rate of reduction in microvasculature is highly dependent on the applied LPS concentrations. For low‐concentration LPS, changes in the microvasculature are not obvious over the observation period, whereas for high‐concentration LPS, quick and marked reduction in the microvasculature is observed. In addition, changes in capillaries are more significant than those in relatively large vessels. The results show that PAM is able to evaluate the inflammation mouse model by studying structural (and potentially functional) changes in the microcirculation. Furthermore, PAM may have potential for early intervention and treatment plan optimization of sepsis by monitoring the microcirculation and inflammatory response. 相似文献
999.
Polona
nidari
‐Plazl 《Biotechnology journal》2019,14(8)
The challenges of transition toward the postpetroleum world shed light on the biocatalysis as the most sustainable way for the valorization of biobased raw materials. However, its industrial exploitation strongly relies on integration with innovative technologies such as microscale processing. Microflow devices remarkably accelerate biocatalyst screening and engineering, as well as evaluation of process parameters, and intensify biocatalytic processes in multiphase systems. The inherent feature of microfluidic devices to operate in a continuous mode brings additional interest for their use in chemoenzymatic cascade systems and in connection with the downstream processing units. Further steps toward automation and analytics integration, as well as computer‐assisted process development, will significantly affect the industrial implementation of biocatalysis and fulfill the promises of the bioeconomy. This review provides an overview of recent examples on implementation of microfluidic devices into various stages of biocatalytic process development comprising ultrahigh‐throughput biocatalyst screening, highly efficient biocatalytic process design including specific immobilization techniques for long‐term biocatalyst use, integration with other (bio)chemical steps, and/or downstream processing. 相似文献
1000.
Pasquale D'Acunzo Tal Hargash Monika Pawlik Chris N. Goulbourne Rocío Prez‐Gonzlez Efrat Levy 《Developmental neurobiology》2019,79(7):656-663
Down syndrome (DS) is a human genetic disease caused by trisomy of chromosome 21 and characterized by early developmental brain abnormalities. Dysfunctional endosomal pathway in neurons is an early event of DS and Alzheimer's disease. Recently, we have demonstrated that exosome secretion is upregulated in human DS postmortem brains, in the brain of the trisomic mouse model Ts[Rb(12.1716)]2Cje (Ts2) and by DS fibroblasts as compared with disomic controls. High levels of the tetraspanin CD63, a regulator of exosome biogenesis, were observed in DS brains. Partially blocking exosome secretion by DS fibroblasts exacerbated a pre‐existing early endosomal pathology. We thus hypothesized that enhanced CD63 expression induces generation of intraluminal vesicles (ILVs) in late endosomes/multivesicular bodies (MVBs), increasing exosome release as an endogenous mechanism to mitigate endosomal abnormalities in DS. Herein, we show a high‐resolution electron microscopy analysis of MVBs in neurons of the frontal cortex of 12‐month‐old Ts2 mice and littermate diploid controls. Our quantitative analysis revealed that Ts2 MVBs are larger, more abundant, and contain a higher number of ILVs per neuron compared to controls. These findings were further corroborated biochemically by Western blot analysis of purified endosomal fractions showing higher levels of ILVs proteins in the same fractions containing endosomal markers in the brain of Ts2 mice compared to controls. These data suggest that upregulation of ILVs production may be a key homeostatic mechanism to alleviate endosomal dysregulation via the endosomal–exosomal pathway. 相似文献