全文获取类型
收费全文 | 1617087篇 |
免费 | 134290篇 |
国内免费 | 18527篇 |
专业分类
耳鼻咽喉 | 20120篇 |
儿科学 | 48590篇 |
妇产科学 | 43753篇 |
基础医学 | 225396篇 |
口腔科学 | 41151篇 |
临床医学 | 155813篇 |
内科学 | 314938篇 |
皮肤病学 | 35392篇 |
神经病学 | 128331篇 |
特种医学 | 61625篇 |
外国民族医学 | 602篇 |
外科学 | 230699篇 |
综合类 | 67572篇 |
现状与发展 | 58篇 |
一般理论 | 505篇 |
预防医学 | 122551篇 |
眼科学 | 37779篇 |
药学 | 120238篇 |
195篇 | |
中国医学 | 15580篇 |
肿瘤学 | 99016篇 |
出版年
2022年 | 13173篇 |
2021年 | 22105篇 |
2020年 | 15264篇 |
2019年 | 18993篇 |
2018年 | 24292篇 |
2017年 | 19506篇 |
2016年 | 20636篇 |
2015年 | 25910篇 |
2014年 | 34681篇 |
2013年 | 43656篇 |
2012年 | 60721篇 |
2011年 | 65191篇 |
2010年 | 38326篇 |
2009年 | 34943篇 |
2008年 | 54871篇 |
2007年 | 57372篇 |
2006年 | 58073篇 |
2005年 | 56672篇 |
2004年 | 50354篇 |
2003年 | 47944篇 |
2002年 | 45352篇 |
2001年 | 77031篇 |
2000年 | 79028篇 |
1999年 | 66594篇 |
1998年 | 20370篇 |
1997年 | 18797篇 |
1996年 | 18301篇 |
1995年 | 17312篇 |
1994年 | 15466篇 |
1993年 | 13894篇 |
1992年 | 47405篇 |
1991年 | 44840篇 |
1990年 | 42564篇 |
1989年 | 40422篇 |
1988年 | 37007篇 |
1987年 | 36084篇 |
1986年 | 33453篇 |
1985年 | 31703篇 |
1984年 | 24078篇 |
1983年 | 20220篇 |
1982年 | 12316篇 |
1979年 | 20796篇 |
1978年 | 14605篇 |
1977年 | 12116篇 |
1976年 | 11382篇 |
1975年 | 11654篇 |
1974年 | 14023篇 |
1973年 | 13560篇 |
1972年 | 12651篇 |
1971年 | 11487篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Improvement in Tricuspid Annular Plane Systolic Excursion with Pulmonary Hypertension Therapy in Pediatric Patients
下载免费PDF全文
![点击此处可从《Echocardiography (Mount Kisco, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
43.
O. Ieromina C. J. M. Musters P. M. Bodegom W. J. G. M. Peijnenburg M. G. Vijver 《Ecotoxicology (London, England)》2016,25(6):1170-1180
Analyzing functional species’ characteristics (species traits) that represent physiological, life history and morphological characteristics of species help understanding the impacts of various stressors on aquatic communities at field conditions. This research aimed to study the combined effects of pesticides and other environmental factors (temperature, dissolved oxygen, dissolved organic carbon, floating macrophytes cover, phosphate, nitrite, and nitrate) on the trait modality distribution of aquatic macrofauna communities. To this purpose, a field inventory was performed in a flower bulb growing area of the Netherlands with significant variation in pesticides pressures. Macrofauna community composition, water chemistry parameters and pesticide concentrations in ditches next to flower bulb fields were determined. Trait modalities of nine traits (feeding mode, respiration mode, locomotion type, resistance form, reproduction mode, life stage, voltinism, saprobity, maximum body size) likely to indicate pesticides impacts were analyzed. According to a redundancy analysis, phosphate -and not pesticides- constituted the main factor structuring the trait modality distribution of aquatic macrofauna. The functional composition could be ascribed for 2–4 % to pesticides, and for 3–11 % to phosphate. The lack of trait responses to pesticides may indicate that species may have used alternative strategies to adapt to ambient pesticides stress. Biomass of animals exhibiting trait modalities related to feeding by predation and grazing, presence of diapause form or dormancy, reproduction by free clutches and ovoviviparity, life stage of larvae and pupa, was negatively correlated to the concentration of phosphate. Hence, despite the high pesticide pollution in the area, variation in nutrient-related stressors seems to be the dominant driver of the functional composition of aquatic macrofauna assembly in agricultural ditches. 相似文献
44.
Shasha Yuan Fang Wang Yan Zhao Yun Liu 《The International journal of health planning and management》2020,35(1):e196-e209
Since the new round of health care reform in 2009, the vertical integration of hospitals and primary health institutions has become widely implemented in China as an efficient method for improving quality of primary care. This study aimed to answer the following questions: (a) What is the perceived quality of township health centres (THCs) under integration? (B) What differences could be observed among the three typical integration models, namely, private hospital-THC integration, public hospital-THC integration, and loose collaboration? Two rounds of cross-sectional surveys were conducted from November 2016 to June 2018. The Chinese version of the Primary Care Assessment Tool was used to evaluate perceived quality of sample THCs, and 1118 adult patients were interviewed in total. Multiple linear regressions were employed to compare the quality scores between two survey rounds and among different integration models after controlling for potential confounders. The results revealed that the quality of care significantly improved under private hospital-THC integration as observed by comparing two survey rounds, while no change or slight changes were observed in the other two models. The difference observed among the three models was that the perceived quality of THCs integrated with private hospitals was worse than that of THCs integrated with public hospitals and THCs under loose collaboration, while no significant difference was observed between public hospital-THC integration and loose collaboration. Increased attention should be given to highlighting the tight integration between hospitals and THCs and the different roles played by private and public hospitals in the current reform. 相似文献
45.
46.
47.
48.
Unconditional Positivity-Preserving and Energy Stable Schemes for a Reduced Poisson-Nernst-Planck System
下载免费PDF全文
![点击此处可从《Communications In Computational Physics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hailiang Liu & Wumaier Maimaitiyiming 《Communications In Computational Physics》2020,27(5):1505-1529
The Poisson-Nernst-Planck (PNP) system is a widely accepted model for
simulation of ionic channels. In this paper, we design, analyze, and numerically validate a second order unconditional positivity-preserving scheme for solving a reduced
PNP system, which can well approximate the three dimensional ion channel problem.
Positivity of numerical solutions is proven to hold true independent of the size of time
steps and the choice of the Poisson solver. The scheme is easy to implement without
resorting to any iteration method. Several numerical examples further confirm the
positivity-preserving property, and demonstrate the accuracy, efficiency, and robustness of the proposed scheme, as well as the fast approach to steady states. 相似文献
49.
Recurrent Oral and Genital Ulcers in an Infant: Neonatal Presentation of Pediatric Behçet Disease
下载免费PDF全文
![点击此处可从《Pediatric dermatology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Emma F. Johnson M.D. Danielle M. Hawkins M.D. Laura K. Gifford M.D. Aimee C. Smidt M.D. 《Pediatric dermatology》2015,32(5):714-717
Behçet disease is a complex, multisystem disease characterized by recurrent oral and genital ulcerations. It rarely occurs in infants or children. Neonatal Behçet disease has been reported in infants whose ulcers resolve at or before 9 weeks of age. Few cases of neonatal Behçet disease persisting into childhood have previously been reported. We report the case of a 1‐month‐old infant who presented with severe recurrent genital ulcerations and at 6 months developed recurrent oral ulcerations. Her orogenital ulcerations continue to recur. Human leukocyte antigen testing revealed HLA‐B51 and B44 positivity. This is a case of pediatric Behçet disease in the neonatal period. Behçet disease should be considered in the differential diagnosis of recurrent genital and oral ulcerations in infants and children. 相似文献
50.
Dermoscopic difficult lesions: an objective evaluation of reflectance confocal microscopy impact for accurate diagnosis
下载免费PDF全文
![点击此处可从《Journal of the European Academy of Dermatology and Venereology》网站下载免费的PDF全文](/ch/ext_images/free.gif)