全文获取类型
收费全文 | 4989篇 |
免费 | 375篇 |
国内免费 | 3篇 |
出版年
2023年 | 19篇 |
2022年 | 10篇 |
2021年 | 78篇 |
2020年 | 75篇 |
2019年 | 98篇 |
2018年 | 143篇 |
2017年 | 107篇 |
2016年 | 179篇 |
2015年 | 257篇 |
2014年 | 329篇 |
2013年 | 359篇 |
2012年 | 463篇 |
2011年 | 451篇 |
2010年 | 275篇 |
2009年 | 250篇 |
2008年 | 317篇 |
2007年 | 316篇 |
2006年 | 249篇 |
2005年 | 233篇 |
2004年 | 252篇 |
2003年 | 193篇 |
2002年 | 166篇 |
2001年 | 102篇 |
2000年 | 105篇 |
1999年 | 69篇 |
1998年 | 27篇 |
1997年 | 25篇 |
1996年 | 18篇 |
1995年 | 18篇 |
1994年 | 15篇 |
1993年 | 11篇 |
1992年 | 19篇 |
1991年 | 24篇 |
1990年 | 18篇 |
1989年 | 10篇 |
1988年 | 13篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 7篇 |
1982年 | 5篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1976年 | 5篇 |
1975年 | 3篇 |
1973年 | 4篇 |
1972年 | 3篇 |
1971年 | 5篇 |
1967年 | 3篇 |
排序方式: 共有5367条查询结果,搜索用时 15 毫秒
1.
Seung Hak Lee Chiyul Yoon Sun Gun Chung Hee Chan Kim Youngbin Kwak Hee-won Park Keewon Kim 《PloS one》2015,10(6)
Range of motion (ROM) measurements are essential for the evaluation for and diagnosis of adhesive capsulitis of the shoulder (AC). However, taking these measurements using a goniometer is inconvenient and sometimes unreliable. The Kinect (Microsoft, Seattle, WA, USA) is gaining attention as a new motion detecting device that is nonintrusive and easy to implement. This study aimed to apply Kinect to measure shoulder ROM in AC; we evaluated its validity by calculating the agreement of the measurements obtained using Kinect with those obtained using goniometer and assessed its utility for the diagnosis of AC. Both shoulders of 15 healthy volunteers and affected shoulders of 12 patients with AC were included in the study. The passive and active ROM of each were measured with a goniometer for flexion, abduction, and external rotation. Their active shoulder motions for each direction were again captured using Kinect and the ROM values were calculated. The agreement between the two measurements was tested with the intraclass correlation coefficient (ICC). Diagnostic performance using the Kinect ROM was evaluated with Cohen’s kappa value. The cutoff values of the limited ROM were determined in the following ways: the same as passive ROM values, reflecting the mean difference, and based on receiver operating characteristic curves. The ICC for flexion/abduction/external rotation between goniometric passive ROM and the Kinect ROM were 0.906/0.942/0.911, while those between active ROMs and the Kinect ROMs were 0.864/0.932/0.925. Cohen’s kappa values were 0.88, 0.88, and 1.0 with the cutoff values in the order above. Measurements of the shoulder ROM using Kinect show excellent agreement with those taken using a goniometer. These results indicate that the Kinect can be used to measure shoulder ROM and to diagnose AC as an alternative to goniometer. 相似文献
2.
Kang Yerin Lee Woonwoo Jang Geupil Kim Bong-Gyu Yoon Youngdae 《Applied microbiology and biotechnology》2018,102(11):4863-4872
Applied Microbiology and Biotechnology - Despite the large number of bioreporters developed to date, the ability to detect heavy metal(loid)s with bioreporters has thus far been limited owing to... 相似文献
3.
Simulating the fidelity and the three Mg mechanism of pol η and clarifying the validity of transition state theory in enzyme catalysis 下载免费PDF全文
Pol η belongs to the important Y family of DNA polymerases that can catalyze translesion synthesis across sites of damaged DNA. This activity involves the reduced fidelity of Pol η for 8‐oxo‐7,8‐dhyedro‐2′‐deoxoguanosin(8‐oxoG). The fundamental interest in Pol η has grown recently with the demonstration of the importance of a 3rd Mg2+ ion. The current work explores both the fidelity of Pol η and the role of the 3rd metal ion, by using empirical valence bond (EVB) simulations. The simulations reproduce the observed trend in fidelity and shed a new light on the role of the 3rd metal ion. It is found that this ion does not lead to a major catalytic effect, but most probably plays an important role in reducing the product release barrier. Furthermore, it is concluded, in contrast to some implications, that the effect of this metal does not violate transition state theory, and the evaluation of the catalytic effect must conserve the molecular composition upon moving from the reactant to the transition state. Proteins 2017; 85:1446–1453. © 2017 Wiley Periodicals, Inc. 相似文献
4.
Contribution of autophagy and regulation of related proteins to the degeneration of retinal pigment epithelium (RPE) in age-related macular degeneration (AMD) remain unknown. We report that upregulation of KRT8 (keratin 8) as well as its phosphorylation are accompanied with autophagy and attenuated with the inhibition of autophagy in RPE cells under oxidative stress. KRT8 appears to have a dual role in RPE pathophysiology. While increased expression of KRT8 following autophagy provides a cytoprotective role in RPE, phosphorylation of KRT8 induces pathologic epithelial-mesenchymal transition (EMT) of RPE cells under oxidative stress, which is mediated by MAPK1/ERK2 (mitogen-activated protein kinase 1) and MAPK3/ERK1. Inhibition of autophagy further promotes EMT, which can be reversed by inhibition of MAPK. Thus, regulated enhancement of autophagy with concurrent increased expression of KRT8 and the inhibition of KRT8 phosphorylation serve to inhibit oxidative stress-induced EMT of RPE cells as well as to prevent cell death, suggesting that pharmacological manipulation of KRT8 upregulation through autophagy with combined inhibition of the MAPK1/3 pathway may be attractive therapeutic strategies for the treatment of AMD. 相似文献
5.
6.
7.
8.
9.
The first observations regarding the control of translation initiation in the yeast Saccharomyces cerevisiae were made by Fred Sherman and his colleagues in 1971. Elegant genetic studies of the CYC1 gene resulted in the formulation of 'Sherman's Rules' for translation initiation as follows: (i) AUG is the only initiator codon. (ii) the most proximal AUG from the 5' end of a message will serve as the start site of translation; and (iii) if the upstream AUG codon is mutated then initiation begins at the next available AUG in the message. Hidden within these rules is the mechanism of eukaryotic translation initiation, as these very same rules were later shown to apply to higher eukaryotic organisms and were formulated into the scanning model. However, only in the past five years has yeast been taken seriously as an organism for studying the mechanism of eukaryotic translation initiation. The basis for this is that the yeast genes for at least four mammalian translation initiation factor homologues have been identified and the number is growing. Similar factors suggest similar mechanisms for translation initiation between yeast and mammals. For some translation initiation factors, the genetics of yeast has provided new insights into their function. A mechanism for regulating translation initiation in mammalian cells is now evident in yeast. It seems clear that the molecular genetics of yeast coupled with the available in vitro translation system will provide a wealth of information in the future regarding translational control and regulatory mechanisms. The purpose of this review is to summarize what is known about translational control in S. cerevisiae. 相似文献
10.
Il Sang Yoon 《Analytical biochemistry》2010,407(2):205-210
Parkinson’s disease (PD) is a neurodegenerative disease featured by selective loss of substantia nigra neurons. Rotenone administration in animals induces neurodegeneration accompanied by α-synuclein-positive Lewy body-like inclusions, recapturing typical histopathological features of PD. In an effort to screen for small-molecule agents to reverse rotenone-induced cytotoxicity, we developed and validated a sensitive and robust assay with neuroblastoma SK-N-SH cells. This assay was amenable to a high-throughput screening format with Z′ factor of 0.56. Robotic screening of a bioactive compound library led to the identification of carnosic acid that can effectively protect cells from rotenone treatment. Using a high-content image-based assay and Western blot analysis, we demonstrated that carnosic acid protects cells from rotenone stress by significant induction of HSP70 expression. Therefore, the assay reported here can be used to identify novel cytoprotective agents for clinical therapeutics of PD. 相似文献