全文获取类型
收费全文 | 1106篇 |
免费 | 50篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 35篇 |
妇产科学 | 7篇 |
基础医学 | 181篇 |
口腔科学 | 25篇 |
临床医学 | 72篇 |
内科学 | 158篇 |
皮肤病学 | 36篇 |
神经病学 | 69篇 |
特种医学 | 64篇 |
外科学 | 104篇 |
综合类 | 142篇 |
一般理论 | 1篇 |
预防医学 | 58篇 |
眼科学 | 26篇 |
药学 | 108篇 |
中国医学 | 3篇 |
肿瘤学 | 67篇 |
出版年
2023年 | 8篇 |
2022年 | 45篇 |
2021年 | 40篇 |
2020年 | 24篇 |
2019年 | 28篇 |
2018年 | 27篇 |
2017年 | 21篇 |
2016年 | 21篇 |
2015年 | 27篇 |
2014年 | 45篇 |
2013年 | 64篇 |
2012年 | 81篇 |
2011年 | 82篇 |
2010年 | 45篇 |
2009年 | 43篇 |
2008年 | 74篇 |
2007年 | 53篇 |
2006年 | 44篇 |
2005年 | 30篇 |
2004年 | 38篇 |
2003年 | 24篇 |
2002年 | 25篇 |
2001年 | 36篇 |
2000年 | 27篇 |
1999年 | 18篇 |
1998年 | 27篇 |
1997年 | 36篇 |
1996年 | 25篇 |
1995年 | 6篇 |
1994年 | 12篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 8篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 9篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1975年 | 3篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有1164条查询结果,搜索用时 15 毫秒
31.
D. Sahoo P. Priyadarshini A. Aparimita D. Alagarasan R. Ganesan S. Varadharajaperumal R. Naik 《RSC advances》2020,10(45):26675
The present work shows the effect of annealing conditions on the linear and nonlinear optical properties of two-year-old thermally evaporated 800 nm As40Se50Ge10 thin films. The aging effect in this film is clearly noticeable as compared with the old observation. The two-year-old films were annealed at different temperatures like 373, 413, 453 and 493 K for 1 h. The optical parameters were calculated from the optical transmittance and reflectance spectra measured at normal incidence of light by spectrometer in the 500–1000 nm range. The linear refractive index (n) and extinction coefficient (k) were decreased with annealing temperature. The observation reveals the increase in optical band gap with increase in annealing temperature while the width of the tail in the gap has an opposite behaviour. The oscillator energy, dispersion energy, dielectric constant, the loss factor, and optical conductivity were discussed in detail. The nonlinear refractive index and optical susceptibility were calculated by using Miller''s formula which decreased with annealing temperature. The changes in both linear and nonlinear optical parameters with annealing temperature showed that annealing temperature can be considered as a useful factor for controlling the optical properties of As40Se50Ge10 chalcogenide films which could be the candidate for numerous photonic applications. The structural study was done by X-ray diffraction and Raman spectroscopy.The present work shows the effect of annealing conditions on the linear and nonlinear optical properties of two-year-old thermally evaporated 800 nm As40Se50Ge10 thin films. 相似文献
32.
33.
34.
N. Mohan Rangan N. K. Sahoo K. Tomar P. K. Chattopadhyay 《Journal of maxillofacial and oral surgery》2015,14(3):754-760
Introduction
The patients with cranial deformity suffer from headache, dizziness, irritability, loss of concentration, depression, anxiety, intolerance to noise and vibration and neuromotor weakness. It is therefore essential to restore the calvarium.Material and Method
This study was conducted in the Department of Oral and Maxillofacial Surgery, Armed Forces Medical College, Pune between Oct 2010 and Mar 2012. The study population was selected from the outpatient department and from the referred cases. The aim was to study the uptake of split thickness calvarial graft in the management of residual cranial defect. After applying the inclusion and exclusion criterions, ten cases were selected with residual cranial deformity, operated for cranioplasty using split thickness calvarial graft and evaluated.Conclusion
It was concluded that cranioplasty using autogenous split thickness calvarial graft for restoring cranial defects is a useful technique and this procedure allows the surgeon to reconstruct a moderate-to-large cranial defect, without breaching the inner cortical plate. 相似文献35.
Willingham SB Volkmer JP Gentles AJ Sahoo D Dalerba P Mitra SS Wang J Contreras-Trujillo H Martin R Cohen JD Lovelace P Scheeren FA Chao MP Weiskopf K Tang C Volkmer AK Naik TJ Storm TA Mosley AR Edris B Schmid SM Sun CK Chua MS Murillo O Rajendran P Cha AC Chin RK Kim D Adorno M Raveh T Tseng D Jaiswal S Enger PØ Steinberg GK Li G So SK Majeti R Harsh GR van de Rijn M Teng NN Sunwoo JB Alizadeh AA Clarke MF Weissman IL 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(17):6662-6667
CD47, a "don't eat me" signal for phagocytic cells, is expressed on the surface of all human solid tumor cells. Analysis of patient tumor and matched adjacent normal (nontumor) tissue revealed that CD47 is overexpressed on cancer cells. CD47 mRNA expression levels correlated with a decreased probability of survival for multiple types of cancer. CD47 is a ligand for SIRPα, a protein expressed on macrophages and dendritic cells. In vitro, blockade of CD47 signaling using targeted monoclonal antibodies enabled macrophage phagocytosis of tumor cells that were otherwise protected. Administration of anti-CD47 antibodies inhibited tumor growth in orthotopic immunodeficient mouse xenotransplantation models established with patient tumor cells and increased the survival of the mice over time. Anti-CD47 antibody therapy initiated on larger tumors inhibited tumor growth and prevented or treated metastasis, but initiation of the therapy on smaller tumors was potentially curative. The safety and efficacy of targeting CD47 was further tested and validated in immune competent hosts using an orthotopic mouse breast cancer model. These results suggest all human solid tumor cells require CD47 expression to suppress phagocytic innate immune surveillance and elimination. These data, taken together with similar findings with other human neoplasms, show that CD47 is a commonly expressed molecule on all cancers, its function to block phagocytosis is known, and blockade of its function leads to tumor cell phagocytosis and elimination. CD47 is therefore a validated target for cancer therapies. 相似文献
36.
Volkmer JP Sahoo D Chin RK Ho PL Tang C Kurtova AV Willingham SB Pazhanisamy SK Contreras-Trujillo H Storm TA Lotan Y Beck AH Chung BI Alizadeh AA Godoy G Lerner SP van de Rijn M Shortliffe LD Weissman IL Chan KS 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(6):2078-2083
Current clinical judgment in bladder cancer (BC) relies primarily on pathological stage and grade. We investigated whether a molecular classification of tumor cell differentiation, based on a developmental biology approach, can provide additional prognostic information. Exploiting large preexisting gene-expression databases, we developed a biologically supervised computational model to predict markers that correspond with BC differentiation. To provide mechanistic insight, we assessed relative tumorigenicity and differentiation potential via xenotransplantation. We then correlated the prognostic utility of the identified markers to outcomes within gene expression and formalin-fixed paraffin-embedded (FFPE) tissue datasets. Our data indicate that BC can be subclassified into three subtypes, on the basis of their differentiation states: basal, intermediate, and differentiated, where only the most primitive tumor cell subpopulation within each subtype is capable of generating xenograft tumors and recapitulating downstream populations. We found that keratin 14 (KRT14) marks the most primitive differentiation state that precedes KRT5 and KRT20 expression. Furthermore, KRT14 expression is consistently associated with worse prognosis in both univariate and multivariate analyses. We identify here three distinct BC subtypes on the basis of their differentiation states, each harboring a unique tumor-initiating population. 相似文献
37.
38.
39.
Herein we developed a rapid, cheap, and water-soluble ultra-sensitive ZnO quantum dot (QD) based metal sensor for detecting different hazardous metal ions up to the picomolar range in water. Various spectroscopic and microscopic techniques confirmed the formation of 2.15 ± 0.46 μm of ZnO QD conjugated CMC microspheres (ZCM microspheres) which contain 5.5 ± 0.5 nm fluorescent zinc oxide (ZnO) QDs. Our system, as a promising sensor, exhibited excellent photostability and affinity towards various heavy metal ions. The detection limits were calculated to be 16 pM for Cu2+ and 0.18 nM for Cr6+ ions which are better than previously reported values. The simple fluorescence ‘turn off’ property of our ZCM microsphere sensor system can serve a two-in-one purpose by not only detecting the heavy metals but also quantifying them. Nonetheless, pattern recognition for different heavy metals helped us to detect and identify multiple heavy metal ions. Finally, their practical applications on real samples also demonstrated that the ZCM sensor can be effectively utilized for detection of Cr6+, Fe3+, Cu2+ present in the real water samples. This study may inspire future research and design of target fluorescent metal oxide QDs with specific functions.Herein we developed a rapid, cheap, and water-soluble ultra-sensitive ZnO quantum dot (QD) based metal sensor for detecting different hazardous metal ions up to the picomolar range in water. 相似文献
40.
Ujjwal Neogi Anita Shet Pravat Nalini Sahoo Irene Bontell Maria L Ekstrand Akhil C Banerjea Anders Sonnerborg 《Journal of the International AIDS Society》2013,16(1)