全文获取类型
收费全文 | 3000篇 |
免费 | 215篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 297篇 |
妇产科学 | 71篇 |
基础医学 | 398篇 |
口腔科学 | 35篇 |
临床医学 | 295篇 |
内科学 | 429篇 |
皮肤病学 | 67篇 |
神经病学 | 112篇 |
特种医学 | 49篇 |
外科学 | 370篇 |
综合类 | 130篇 |
预防医学 | 223篇 |
眼科学 | 111篇 |
药学 | 368篇 |
中国医学 | 29篇 |
肿瘤学 | 229篇 |
出版年
2023年 | 33篇 |
2022年 | 47篇 |
2021年 | 80篇 |
2020年 | 73篇 |
2019年 | 65篇 |
2018年 | 79篇 |
2017年 | 62篇 |
2016年 | 57篇 |
2015年 | 80篇 |
2014年 | 104篇 |
2013年 | 129篇 |
2012年 | 243篇 |
2011年 | 214篇 |
2010年 | 117篇 |
2009年 | 93篇 |
2008年 | 116篇 |
2007年 | 120篇 |
2006年 | 137篇 |
2005年 | 110篇 |
2004年 | 117篇 |
2003年 | 88篇 |
2002年 | 101篇 |
2001年 | 60篇 |
2000年 | 69篇 |
1999年 | 72篇 |
1998年 | 44篇 |
1997年 | 25篇 |
1996年 | 29篇 |
1994年 | 20篇 |
1993年 | 22篇 |
1992年 | 54篇 |
1991年 | 43篇 |
1990年 | 34篇 |
1989年 | 30篇 |
1988年 | 39篇 |
1987年 | 29篇 |
1986年 | 40篇 |
1985年 | 35篇 |
1984年 | 25篇 |
1983年 | 26篇 |
1979年 | 15篇 |
1978年 | 15篇 |
1977年 | 12篇 |
1976年 | 16篇 |
1974年 | 14篇 |
1973年 | 15篇 |
1972年 | 12篇 |
1971年 | 17篇 |
1970年 | 20篇 |
1968年 | 12篇 |
排序方式: 共有3228条查询结果,搜索用时 15 毫秒
61.
Saha Soma Pal Dey Poushali Mitra Souvik 《Proceedings of the National Academy of Sciences, India. Section B.》2021,91(4):919-927
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - Microbial association is considered as a significant innovation for land colonization of mosses. Plagiomnium... 相似文献
62.
Can F. Koyuncu Cheng Lu Kaustav Bera Zelin Zhang Jun Xu Paula Toro German Corredor Deborah Chute Pingfu Fu Wade L. Thorstad Farhoud Faraji Justin A. Bishop Mitra Mehrad Patricia D. Castro Andrew G. Sikora Lester D.R. Thompson R.D. Chernock Krystle A. Lang Kuhs Jingqin Luo Vlad Sandulache David J. Adelstein Shlomo Koyfman James S. Lewis Jr. Anant Madabhushi 《The Journal of clinical investigation》2021,131(8)
BACKGROUNDPatients with p16+ oropharyngeal squamous cell carcinoma (OPSCC) are potentially cured with definitive treatment. However, there are currently no reliable biomarkers of treatment failure for p16+ OPSCC. Pathologist-based visual assessment of tumor cell multinucleation (MN) has been shown to be independently prognostic of disease-free survival (DFS) in p16+ OPSCC. However, its quantification is time intensive, subjective, and at risk of interobserver variability.METHODSWe present a deep-learning–based metric, the multinucleation index (MuNI), for prognostication in p16+ OPSCC. This approach quantifies tumor MN from digitally scanned H&E-stained slides. Representative H&E-stained whole-slide images from 1094 patients with previously untreated p16+ OPSCC were acquired from 6 institutions for optimization and validation of the MuNI.RESULTSThe MuNI was prognostic for DFS, overall survival (OS), or distant metastasis–free survival (DMFS) in p16+ OPSCC, with HRs of 1.78 (95% CI: 1.37–2.30), 1.94 (1.44–2.60), and 1.88 (1.43–2.47), respectively, independent of age, smoking status, treatment type, or tumor and lymph node (T/N) categories in multivariable analyses. The MuNI was also prognostic for DFS, OS, and DMFS in patients with stage I and stage III OPSCC, separately.CONCLUSIONMuNI holds promise as a low-cost, tissue-nondestructive, H&E stain–based digital biomarker test for counseling, treatment, and surveillance of patients with p16+ OPSCC. These data support further confirmation of the MuNI in prospective trials.FUNDINGNational Cancer Institute (NCI), NIH; National Institute for Biomedical Imaging and Bioengineering, NIH; National Center for Research Resources, NIH; VA Merit Review Award from the US Department of VA Biomedical Laboratory Research and Development Service; US Department of Defense (DOD) Breast Cancer Research Program Breakthrough Level 1 Award; DOD Prostate Cancer Idea Development Award; DOD Lung Cancer Investigator-Initiated Translational Research Award; DOD Peer-Reviewed Cancer Research Program; Ohio Third Frontier Technology Validation Fund; Wallace H. Coulter Foundation Program in the Department of Biomedical Engineering; Clinical and Translational Science Award (CTSA) program, Case Western Reserve University; NCI Cancer Center Support Grant, NIH; Career Development Award from the US Department of VA Clinical Sciences Research and Development Program; Dan L. Duncan Comprehensive Cancer Center Support Grant, NIH; and Computational Genomic Epidemiology of Cancer Program, Case Comprehensive Cancer Center. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH, the US Department of VA, the DOD, or the US Government. 相似文献
63.
Kyu-Sun Lee Zhihao Wu Yan Song Siddhartha S. Mitra Abdullah H. Feroze Samuel H. Cheshier Bingwei Lu 《Genes & development》2013,27(24):2642-2647
The self-renewal versus differentiation choice of Drosophila and mammalian neural stem cells (NSCs) requires Notch (N) signaling. How N regulates NSC behavior is not well understood. Here we show that canonical N signaling cooperates with a noncanonical N signaling pathway to mediate N-directed NSC regulation. In the noncanonical pathway, N interacts with PTEN-induced kinase 1 (PINK1) to influence mitochondrial function, activating mechanistic target of rapamycin complex 2 (mTORC2)/AKT signaling. Importantly, attenuating noncanonical N signaling preferentially impaired the maintenance of Drosophila and human cancer stem cell-like tumor-forming cells. Our results emphasize the importance of mitochondria to N and NSC biology, with important implications for diseases associated with aberrant N signaling. 相似文献
64.
In this paper a frequency plane analysis of both normal and diseased ECG signals is performed specifically for disease identification. Image processing techniques are used to develop an automated data acquisition package of 12 lead ECG signals from paper records. A regeneration domain is also developed to check the captured pattern with the original wave shape. A QRS complex detector with an accuracy level ~98.4% in up to 30% signal to noise level is developed. Discrete Fourier transform (DFT) is performed to obtain the frequency spectrum of every ECG signal. Some interesting amplitude and phase response properties of chest lead V2, V3, V4, V6 and limb lead I, II, III, AVL, AVF are seen. Both amplitude and phase properties are different for normal and diseased subjects and can serve an important role in disease identification. A statistical analysis of amplitude property is carried out to show that this property is significantly different for normal and diseased subjects. 相似文献
65.
Liu Gengbo Mitra Debasis Jones Ella F. Franc Benjamin L. Behr Spencer C. Nguyen Alex Bolouri Marjan S. Wisner Dorota J. Joe Bonnie N. Esserman Laura J. Hylton Nola M. Seo Youngho 《Journal of digital imaging》2021,34(3):630-636
Journal of Digital Imaging - In this proof-of-concept work, we have developed a 3D-CNN architecture that is guided by the tumor mask for classifying several patient-outcomes in breast cancer from... 相似文献
66.
67.
In order to develop effective laser-based therapeutics, the extent of laser-induced damage must be quantified for given laser parameters. Therefore, we want to determine the spatiotemporal expression patterns of heat shock proteins, both to understand the roles of heat shock proteins in laser-induced tissue damage and repair and to develop heat shock proteins as tools to illustrate the extent of laser-induced damage and wound healing following irradiation. We exposed anesthetized mice to the focused beam of a short-pulse Nd:YAG laser (1064 nm; 200 ns pulsewidth) for 15 s, while measuring temperature distribution in the skin using an infrared thermal camera. Following irradiation, we examined expression of HSP47 and HSP70 over time (0–24 h) as indicators of the heat shock response and recovery from damage in the laser-irradiated region. Expression patterns of HSP70 and HSP47 as detected by immunohistochemistry and confocal microscopy delineate the extent of damage and the process of healing in tissue. Both HSP70 and HSP47 were expressed in dermis and epidermis following laser irradiation, and the spatial and temporal changes in HSP expression patterns define the laser-induced thermal damage zone and the process of healing in tissues. HSP70 may define biochemically the thermal damage zone in which cells are targeted for destruction, and HSP47 may illustrate the process of recovery from thermally induced damage. Studying the effects of different laser parameters on the expression of HSPs will allow development of effective laser therapies that provide accurate and precise tissue ablation and may promote rapid wound healing following laser-based surgery. 相似文献
68.
Asadollah Bafekry Fazel Shojaei Mohammed M. Obeid Mitra Ghergherehchi C. Nguyen Mohammad Oskouian 《RSC advances》2020,10(53):31894
Using density functional theory, we investigate a novel two-dimensional silicon bismotide (SiBi) that has a layered GaSe-like crystal structure. Ab initio molecular dynamic simulations and phonon dispersion calculations suggest its good thermal and dynamical stability. The SiBi monolayer is a semiconductor with a narrow indirect bandgap of 0.4 eV. Our results show that the indirect bandgap decreases as the number of layers increases, and when the number of layers is more than six layers, direct-to-indirect bandgap switching occurs. The SiBi bilayer is found to be very sensitive to an E-field. The bandgap monotonically decreases in response to uniaxial and biaxial compressive strain, and reaches 0.2 eV at 5%, while at 6%, the semiconductor becomes a metal. For both uniaxial and biaxial tensile strains, the material remains a semiconductor and indirect-to-direct bandgap transition occurs at a strain of 3%. Compared to a SiBi monolayer with a layer thickness of 4.89 Å, the bandgap decreases with either increasing or decreasing layer thickness, and at a thicknesses of 4.59 to 5.01 Å, the semiconductor-to-metal transition happens. In addition, under pressure, the semiconducting character of the SiBi bilayer with a 0.25 eV direct bandgap is preserved. Our results demonstrate that the SiBi nanosheet is a promising candidate for designing high-speed low-dissipation devices.The modulation of the electronic properties of SiBi monolayer via external means, including layer thickness, electric field and mechanical strain are explored with DFT method. 相似文献
69.
Gerard M O'Reilly Rob D Mitchell Biswadev Mitra Hamed Akhlaghi Viet Tran Jeremy S Furyk Paul Buntine Holly Bannon‐Murphy Timothy Amos Maushmi Udaya Kumar Emma Perkins Alexandra Prentice Olivia Szwarcberg Ashley Loughman Nicole Lowry Steven Colwell Michael P Noonan Ryan Hiller Andrew Paton De Villiers Smit Peter A Cameron 《Emergency medicine Australasia : EMA》2021,33(1):114-124
70.
Reza Barati rashvanlou Abbas Rezaee Mahdi Farzadkia Mitra Gholami Majid Kermani 《RSC advances》2020,10(59):35718
Micro-aeration as a pretreatment method improves the efficiency of anaerobic digestion of municipal sewage sludge and consequently promotes the methane production. In this study, adenosine triphosphate (ATP) and flow cytometry (FCM) were employed to monitor the performance of the micro-aerobic process and investigate the survival of bacterial cells within the process. At first, the effect of air flow rate (AFR) (0.1, 0.2, 0.3 and 0.5 vvm) on hydrolysis of mixed sludge in 5 aeration cycles (20, 30, 40, 48 and 60 hours) was examined. Then, the effects of the micro aerobic process on methane (CH4) production in anaerobic digestion were surveyed. The highest VSS reduction was 30.6% and 10.4% for 40 hours in the reactor and control, respectively. Soluble COD also fluctuated between 40.87 and 65.14% in micro-aerobic conditions; the highest SCOD was achieved at the time of 40 h. Microbial activities were increased by 597%, 170% and 79.4% for 20, 30 and 40 h pretreatment with the micro-aerobic process, respectively. Apoptosis assay showed that micro-aerobic pre-treatment at 20, 30 and 40 h increased the percentage of living cells by 57.4, 62.8 and 67.9%, respectively. On the other hand, FCM results showed that the highest percentage of viable bacteria (i.e., 67.9%) was observed at 40 h pretreating which was approximately 40% higher the ones for the control. Variation in cumulative methane production shows that methane production was increased by 221% compared to anaerobic digestion (control group). Therefore, ATP and FCM can be employed as two appropriate, accurate, relatively specific indicators for monitoring the process and bacteria viability.Micro-aeration as a pretreatment method improves the efficiency of anaerobic digestion of municipal sewage sludge and consequently promotes the methane production. 相似文献