全文获取类型
收费全文 | 3942篇 |
免费 | 206篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 47篇 |
儿科学 | 98篇 |
妇产科学 | 123篇 |
基础医学 | 386篇 |
口腔科学 | 121篇 |
临床医学 | 311篇 |
内科学 | 975篇 |
皮肤病学 | 62篇 |
神经病学 | 118篇 |
特种医学 | 148篇 |
外国民族医学 | 2篇 |
外科学 | 856篇 |
综合类 | 97篇 |
一般理论 | 2篇 |
预防医学 | 209篇 |
眼科学 | 70篇 |
药学 | 246篇 |
中国医学 | 25篇 |
肿瘤学 | 299篇 |
出版年
2023年 | 47篇 |
2022年 | 132篇 |
2021年 | 216篇 |
2020年 | 119篇 |
2019年 | 159篇 |
2018年 | 197篇 |
2017年 | 121篇 |
2016年 | 126篇 |
2015年 | 119篇 |
2014年 | 185篇 |
2013年 | 204篇 |
2012年 | 337篇 |
2011年 | 351篇 |
2010年 | 184篇 |
2009年 | 153篇 |
2008年 | 203篇 |
2007年 | 168篇 |
2006年 | 174篇 |
2005年 | 194篇 |
2004年 | 169篇 |
2003年 | 136篇 |
2002年 | 117篇 |
2001年 | 37篇 |
2000年 | 41篇 |
1999年 | 52篇 |
1998年 | 25篇 |
1997年 | 15篇 |
1996年 | 23篇 |
1995年 | 8篇 |
1994年 | 14篇 |
1993年 | 8篇 |
1992年 | 12篇 |
1991年 | 17篇 |
1990年 | 15篇 |
1989年 | 13篇 |
1988年 | 17篇 |
1987年 | 12篇 |
1986年 | 13篇 |
1985年 | 23篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1970年 | 1篇 |
1966年 | 1篇 |
1965年 | 3篇 |
1964年 | 1篇 |
排序方式: 共有4195条查询结果,搜索用时 15 毫秒
121.
Sven Rainer Kantelhardt Naureen Keric Jens Conrad Amr Nimer Raymund Woo Laura Varich Alf Giese 《Acta neurochirurgica》2014,156(9):1799-1805
Background
Two-dimensional image guidance and navigation can help to reduce the number of misplaced pedicle screws, but do not completely prevent misplacement. This experimental, retrospective, non-inferiority study was designed to evaluate and compare the efficacy of a novel 3D imaging technique versus conventional postoperative CT-scan, for intra-operative determination of pedicle screw position accuracy.Methods
The capacity of C-OnSite® to intraoperatively assess screw placement was evaluated in 28 clinical cases and 23 deliberately misplaced screws in a cadaver model, and compared to placement accuracy determined by standard CT. The position of each implant, as viewed by both modalities, was graded by three neurosurgeons, one orthopaedic-surgeon and one radiologist. The intermodal variance determined the difference between CT- and C-OnSite® results for each observer, while the inter-observer variance measured the difference between ratings of the same modality by different observers.Results
C-OnSite® successfully assessed 120/138 screws (25/28 cases). Mean procedural fluoroscopy time was 132?±?51s, and 40?±?16s per C-OnSite® scan. The average inter-modality variance was ,15 % with mismatches >1° between C-OnSite® and the gold-standard imaging technique in only 2 % of the comparisons. Average inter-observer variances were about similar (12 % for CT and 18 % for C-OnSite®), with deviations of >1° reaching 1 % for CT and 3 % for C-OnSite®. Individual variances between experienced only observers differed even less.Conclusions
C-OnSite® is a feasible, reliable and intuitive means of intraoperatively visualizing pedicle screw positions and might render the majority of postoperative CTs superfluous. C-OnSite® might help avoid re-operations for screw re-positioning. 相似文献122.
123.
Aras Jamal Talabani Stian Lydersen Birger H. Endreseth Tom-Harald Edna 《International journal of colorectal disease》2014,29(8):937-945
Purpose
Hospitalization for acute colonic diverticulitis has become more and more frequent. We studied the changes in the rate of admission and incidence of the disease during the last 25 years.Methods
We performed a retrospective analysis of all cases treated for acute diverticulitis during 1988–2012 at one hospital serving a defined population in Mid-Norway. The study made a distinction between admission rates and incidence rates. The admission rates defined the total number of cases admitted, while the incidence rates defined the number of new patients hospitalized for acute diverticulitis (first admission). Poisson regression was used to analyse factors associated with diverticulitis incidence rates.Results
A total of 851 admissions in 650 different patients were identified, with an overall admission rate of 38.5 (CI 35.9 to 41.1) per 100,000 person-years. The admission rate increased from 17.9 (CI 14.1 to 22.3)/100,000 during 1988–1992 to 51.1 (CI 44.8 to 58.0)/100,000 during 2008–2012. Poisson regression analysis showed a significant increase in admission rates with a factor of 2.8 (C.I. 2.2 to 3.5) during 25 years. The overall incidence rate (IRR) of new patients was 29.4 (CI 27.1 to 31.7)/100,000 person-years. IRR increased significantly with a factor of 2.6 (CI 1.96 to 3.34) during 25 years, while IRR for perforations increased even more, by a factor of 3.3 (CI 1.24 to 8.58).Conclusion
The hospital admission rates as well as incidence rates for acute colonic diverticulitis increased significantly during the 25-year time span. 相似文献124.
Yusof Khairunnisa’ Md Makpol Suzana Fen Lye Siew Jamal Rahman Wan Ngah Wan Zurinah 《Journal of natural medicines》2019,73(4):745-760
Journal of Natural Medicines - Our previous study reported that combined treatment of γ-tocotrienol with 6-gingerol showed promising anticancer effects by synergistically inhibiting... 相似文献
125.
Mahmoud Mohamed Saleh Tamer Moustafa Abdelrahman Youusef Madney Ghada Mohamed Ahmed Mohammed Shokry Amr Farouk Moustafa 《The British journal of radiology》2020,93(1115)
Objective:To evaluate the multiparametric MRI in predicting chemotherapy response in pathologically proven cases of osteosarcoma and Ewing’s sarcoma. Correlation between the tumor size changes and internal breakdown using RECIST 1.1, modified RECIST, quantitative apparent diffusion coefficient (ADC) and tumor volume as well as dynamic contrast-enhanced MRI (DCE-MRI).Methods:The study included 104 patients pathologically proved osteosarcoma (53) and Ewing`s sarcoma (51) underwent MRI examinations; before and after chemotherapy. All patients were assessed using the RECIST 1.1 criteria, m-RECIST, quantitative ADC, and tumor volume evaluation. 21 patients underwent DCE-MRI curve type with quantitative parameters. Correlation between the different evaluations was carried out. Results were correlated with the post-operative pathology in 42 patients who underwent surgery and for statistical evaluation, Those patients were classified into responders (≥90% necrosis) and non-responders (<90% necrosis).Results:The initial mean ADC of 104 patients of osteosarcoma and Ewing’s sarcoma (0.90 ± 0.29) and (0.71 ± 0.16) respectively, differed significantly from that after treatment (1.62 ± 0.46) and (1.6 ± 0.39) respectively with (p<0.001).ADC variations (ADC%) in the non-progressive group were higher than those of the progressive group (128.3 ± 63.49 vs 36.34 ± 78.7) % with (p<0.001).ADC values and ADC variations were inversely correlated with morphologic changes, regardless of the effectiveness of chemotherapy expressed as changes in tumor size based on (RECIST 1.1, RECIST, and 3D volume). Linear regression analysis revealed a Pearson correlation coefficient of r=-0.427, -0.498 and -0.408, respectively with (p<0.001).An increase in the ADC value was not always associated with a reduction in tumor volume. The disease control rate (defined as the percentage of CR+PR+SD patients) was 89.4% and 93.9% according to RECIST 1.1 and m-RECIST respectively.42 out of the 104 patients had postsurgical histological evaluation as regards the chemotherapeutic response divided into two groups. ADC values showed a statistically significant difference between Group A and Group B being more evident with minimum ADC% (p<0.001).Conclusion:Quantitative diffusion-weighted imaging with ADC mapping and ADC % after chemotherapy allows a detailed analysis of the treatment response in osteosarcoma and Ewing’s sarcoma. The therapeutic response can be underestimated using RECIST 1.1, so the modified RECIST should be also considered.Advances in knowledge:Quantitative ADC especially ADC% provided an accurate non-invasive tool in the assessment of post-therapeutic cases of osteosarcoma and Ewing''s sarcoma 相似文献
126.
Hesham R. El-Seedi Rehan M. El-Shabasy Shaden A. M. Khalifa Aamer Saeed Afzal Shah Raza Shah Faiza Jan Iftikhar Mohamed M. Abdel-Daim Abdelfatteh Omri Nahid H. Hajrahand Jamal S. M. Sabir Xiaobo Zou Mohammed F. Halabi Wessam Sarhan Weisheng Guo 《RSC advances》2019,9(42):24539
Nanoparticles (NPs) are new inspiring clinical targets that have emerged from persistent efforts with unique properties and diverse applications. However, the main methods currently utilized in their production are not environmentally friendly. With the aim of promoting a green approach for the synthesis of NPs, this review describes eco-friendly methods for the preparation of biogenic NPs and the known mechanisms for their biosynthesis. Natural plant extracts contain many different secondary metabolites and biomolecules, including flavonoids, alkaloids, terpenoids, phenolic compounds and enzymes. Secondary metabolites can enable the reduction of metal ions to NPs in eco-friendly one-step synthetic processes. Moreover, the green synthesis of NPs using plant extracts often obviates the need for stabilizing and capping agents and yields biologically active shape- and size-dependent products. Herein, we review the formation of metallic NPs induced by natural extracts and list the plant extracts used in the synthesis of NPs. In addition, the use of bacterial and fungal extracts in the synthesis of NPs is highlighted, and the parameters that influence the rate of particle production, size, and morphology are discussed. Finally, the importance and uniqueness of NP-based products are illustrated, and their commercial applications in various fields are briefly featured.Nanoparticles (NPs) are new inspiring clinical targets that have emerged from persistent efforts with unique properties and diverse applications. 相似文献
127.
Clinical Rheumatology - A 49-year-old African American male with multiorgan sarcoidosis presented with recurrent episodes of dactylitis and arthritis. Imaging had shown sarcoid osseous involvement... 相似文献
128.
129.
130.
Ahmed E. Lasheen Reda Ezz Khaled Safwat Ayman Salem Wesam Amr 《Surgical endoscopy》2014,28(7):2086-2089