全文获取类型
收费全文 | 205975篇 |
免费 | 3294篇 |
国内免费 | 55篇 |
专业分类
耳鼻咽喉 | 1418篇 |
儿科学 | 7753篇 |
妇产科学 | 3941篇 |
基础医学 | 20501篇 |
口腔科学 | 1952篇 |
临床医学 | 16505篇 |
内科学 | 36146篇 |
皮肤病学 | 1118篇 |
神经病学 | 19713篇 |
特种医学 | 9458篇 |
外国民族医学 | 4篇 |
外科学 | 31506篇 |
综合类 | 2631篇 |
一般理论 | 45篇 |
预防医学 | 22364篇 |
眼科学 | 3216篇 |
药学 | 11519篇 |
中国医学 | 646篇 |
肿瘤学 | 18888篇 |
出版年
2024年 | 32篇 |
2023年 | 263篇 |
2022年 | 434篇 |
2021年 | 1120篇 |
2020年 | 681篇 |
2019年 | 1045篇 |
2018年 | 22901篇 |
2017年 | 18048篇 |
2016年 | 20340篇 |
2015年 | 1878篇 |
2014年 | 2079篇 |
2013年 | 2577篇 |
2012年 | 9565篇 |
2011年 | 23718篇 |
2010年 | 20146篇 |
2009年 | 12693篇 |
2008年 | 21658篇 |
2007年 | 23846篇 |
2006年 | 2615篇 |
2005年 | 4107篇 |
2004年 | 5096篇 |
2003年 | 5817篇 |
2002年 | 3996篇 |
2001年 | 456篇 |
2000年 | 561篇 |
1999年 | 349篇 |
1998年 | 497篇 |
1997年 | 431篇 |
1996年 | 251篇 |
1995年 | 272篇 |
1994年 | 225篇 |
1993年 | 174篇 |
1992年 | 104篇 |
1991年 | 129篇 |
1990年 | 168篇 |
1989年 | 112篇 |
1988年 | 89篇 |
1987年 | 72篇 |
1986年 | 55篇 |
1985年 | 44篇 |
1984年 | 37篇 |
1983年 | 49篇 |
1982年 | 48篇 |
1980年 | 50篇 |
1938年 | 60篇 |
1937年 | 25篇 |
1935年 | 22篇 |
1934年 | 31篇 |
1932年 | 56篇 |
1930年 | 46篇 |
排序方式: 共有10000条查询结果,搜索用时 250 毫秒
1.
Hommes Franziska Mohsenpour Amir Kropff Dana Pilgram Lisa Matusall Svenja von Philipsborn Peter Sell Kerstin 《Bundesgesundheitsblatt, Gesundheitsforschung, Gesundheitsschutz》2022,65(1):96-106
Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Akteure der öffentlichen Gesundheit (Public Health) tragen wesentlich zu Gesundheitsschutz, -förderung und... 相似文献
2.
3.
Kuo-yi Jade Chang MHealthEc MHM BSc Lisa Lorraine Dillon MSpecEd BPsych Lil Deverell COMS PhD MEd GradDipO&M BEd Mei Ying Boon PhD BOptom FAAO Lisa Keay PhD MPH BOptom 《Clinical & experimental optometry》2020,103(4):434-448
Despite orientation and mobility (O&M) being a significant factor determining quality of life of people with low vision or blindness, there are no gold standard measures or agreement on how to measure O&M performance. In the first part of this systematic review, an inventory of O&M outcome measures used by recent studies to assess the performance of orientation and/or mobility of adults with vision impairment (low vision and blindness) is presented. A wide variety of O&M outcome measures have been implemented in different fields of study, such as epidemiologic research and interventional studies evaluating training, assistive technology, vision rehabilitation and vision restoration. The most frequent aspect of outcome measures is efficiency such as time, distance, speed and percentage of preferred walking speed, followed by obstacle contacts and avoidance, and dis/orientation and veering. Other less commonly used aspects are target identification, safety and social interaction and self-reported outcome measures. Some studies employ sophisticated equipment to capture and analyse O&M performance in a laboratory setting, while others carry out their assessment in real-world indoor or outdoor environments. In the second part of this review, the appropriateness of implementing the identified outcome measures to assess O&M performance in clinical and functional O&M practice is evaluated. Nearly a half of these outcome measures meet all four criteria of face validity (either clinical or functional), responsiveness, reliability and feasibility and have the potential to be implemented in clinical or functional O&M practice. The findings of this review confirm the complicated and dynamic nature of O&M. Multiple measures are required in any evaluation of O&M performance to facilitate holistic assessment of O&M abilities and limitations of each individual. 相似文献
4.
5.
Metabolism describes the series of chemical reactions that are concerned with the provision of energy to biological systems. They may be divided into reactions involved in energy yield (catabolism: demand exceeds supply), and energy storage (anabolism: supply exceeds demand). Regulation of these pathways is critical for homeostasis, and derangements in metabolism are seen in a wide variety of pathological processes. Understanding metabolism is key to the treatment of many diseases, notably diabetes, as well as underpinning clinical nutritional support. 相似文献
6.
Seyed Mehdi BagheriMofidi Majid Pouladian Seyed Behnamedin Jameie Ali Abbaspour Tehrani-Fard 《Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine》2016,39(3):717-726
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation. 相似文献
7.
8.
9.
10.