全文获取类型
收费全文 | 2709篇 |
免费 | 111篇 |
专业分类
耳鼻咽喉 | 19篇 |
儿科学 | 119篇 |
妇产科学 | 27篇 |
基础医学 | 335篇 |
口腔科学 | 31篇 |
临床医学 | 181篇 |
内科学 | 562篇 |
皮肤病学 | 58篇 |
神经病学 | 298篇 |
特种医学 | 101篇 |
外科学 | 329篇 |
综合类 | 42篇 |
预防医学 | 114篇 |
眼科学 | 171篇 |
药学 | 137篇 |
中国医学 | 3篇 |
肿瘤学 | 293篇 |
出版年
2023年 | 21篇 |
2022年 | 54篇 |
2021年 | 104篇 |
2020年 | 62篇 |
2019年 | 64篇 |
2018年 | 96篇 |
2017年 | 54篇 |
2016年 | 51篇 |
2015年 | 62篇 |
2014年 | 89篇 |
2013年 | 124篇 |
2012年 | 185篇 |
2011年 | 184篇 |
2010年 | 97篇 |
2009年 | 91篇 |
2008年 | 146篇 |
2007年 | 158篇 |
2006年 | 138篇 |
2005年 | 112篇 |
2004年 | 139篇 |
2003年 | 128篇 |
2002年 | 84篇 |
2001年 | 43篇 |
2000年 | 62篇 |
1999年 | 58篇 |
1998年 | 15篇 |
1997年 | 14篇 |
1996年 | 16篇 |
1995年 | 11篇 |
1994年 | 17篇 |
1993年 | 12篇 |
1992年 | 26篇 |
1991年 | 29篇 |
1990年 | 20篇 |
1989年 | 21篇 |
1988年 | 27篇 |
1987年 | 36篇 |
1986年 | 26篇 |
1985年 | 22篇 |
1984年 | 13篇 |
1983年 | 9篇 |
1982年 | 8篇 |
1980年 | 5篇 |
1979年 | 10篇 |
1977年 | 5篇 |
1975年 | 8篇 |
1973年 | 10篇 |
1972年 | 13篇 |
1971年 | 13篇 |
1970年 | 5篇 |
排序方式: 共有2820条查询结果,搜索用时 288 毫秒
91.
92.
A heterostructure of WS2/WO3·H2O has been prepared by partial oxidation of WS2 nanosheets by exposing bulk WS2 micron powder to ultrasonic waves in a bath sonicator. The as-prepared nanomaterial was used as a sensing film in an interdigitated electrode-based gas detecting device. The device was found to be specific towards ammonia gas among a group oxidizing and reducing gases. In particular, a response of as high as 11.36–254.66% was recorded for ammonia concentrations of 50 ppb to 2 ppm with excellent repeatability and reproducibility at room temperature. The response time and recovery time of the device was found to be a few tens of seconds suggesting its practicability. A plausible mechanism based on different active sites present in the receptor film is proposed and a logical reason behind its specificity towards ammonia gas is also inferred based on the Lewis acidic centers on the nano-surfaces. Overall, this proposed nanomaterial has very high potential for practical use as a room temperature ammonia sensor.A tungsten sulfide/tungstite heterostructure is prepared via a modified liquid exfoliation technique. A chemiresistive sensor based on this nanomaterial demonstrates excellent sensitivity and selectivity towards ammonia gas even at room temperature. 相似文献
93.
Victoria Hallett Luc Lecavalier Denis G. Sukhodolsky Noreen Cipriano Michael G. Aman James T. McCracken Christopher J. McDougle Elaine Tierney Bryan H. King Eric Hollander Linmarie Sikich Joel Bregman Evdokia Anagnostou Craig Donnelly Lily Katsovich Kimberly Dukes Benedetto Vitiello Kenneth Gadow Lawrence Scahill 《Journal of autism and developmental disorders》2013,43(10):2341-2352
This study explores the manifestation and measurement of anxiety symptoms in 415 children with ASDs on a 20-item, parent-rated, DSM-IV referenced anxiety scale. In both high and low-functioning children (IQ above vs. below 70), commonly endorsed items assessed restlessness, tension and sleep difficulties. Items requiring verbal expression of worry by the child were rarely endorsed. Higher anxiety was associated with functional language, IQ above 70 and higher scores on several other behavioral measures. Four underlying factors emerged: Generalized Anxiety, Separation Anxiety, Social Anxiety and Over-arousal. Our findings extend our understanding of anxiety across IQ in ASD and provide guidance for improving anxiety outcome measurement. 相似文献
94.
95.
Brainstem auditory evoked potentials and middle latency auditory evoked potentials in young children
Jin Jun Luo Divya S. Khurana Sanjeev V. Kothare 《Journal of clinical neuroscience》2013,20(3):383-388
Measurements of brainstem auditory evoked potentials (BAEP) and middle latency auditory evoked potentials (MLAEP) are readily available neurophysiologic assessments. The generators for BAEP are believed to involve the structures of cochlear nerve, cochlear nucleus, superior olive complex, dorsal and rostral pons, and lateral lemniscus. The generators for MLAEP are assumed to be located in the subcortical area and auditory cortex. BAEP are commonly used in evaluating children with autistic and hearing disorders. However, measurement of MLAEP is rarely performed in young children. To explore the feasibility of this procedure in young children, we retrospectively reviewed our neurophysiology databank and charts for a 3-year period to identify subjects who had both BAEP and MLAEP performed. Subjects with known or identifiable central nervous system abnormalities from the history, neurologic examination and neuroimaging studies were excluded. This cohort of 93 children up to 3 years of age was divided into 10 groups based on the age at testing (upper limits of: 1 week; 1, 2, 4, 6, 8, 10 and 12 months; 2 years; and 3 years of age). Evolution of peak latency, interpeak latency and amplitude of waveforms in BAEP and MLAEP were demonstrated. We concluded that measurement of BAEP and MLAEP is feasible in children, as early as the first few months of life. The combination of both MLAEP and BAEP may increase the diagnostic sensitivity of neurophysiologic assessment of the integrity or functional status of both the peripheral (acoustic nerve) and the central (brainstem, subcortical and cortical) auditory conduction systems in young children with developmental speech and language disorders. 相似文献
96.
97.
Regenhardt Robert W. Turner Ashby C. Hirsch Joshua A. Young Michael J. Alotaibi Naif M. Stapleton Christopher J. Patel Aman B. Leslie-Mazwi Thabele M. Rost Natalia S. Etherton Mark R. 《Journal of neurology》2022,269(1):307-315
Journal of Neurology - Sex-specific differences in ischemic stroke outcomes are prevalent. We sought to investigate sex differences in the determinants of reperfusion and functional outcomes after... 相似文献
98.
Paul M. Bunch Scott E. Sheehan George S. Dyer Aaron Sodickson Bharti Khurana 《Emergency radiology》2016,23(2):175-185
Distal radius fractures are the most common upper extremity fracture and account for approximately one sixth of all fractures treated in US emergency departments. These fractures are associated with significant morbidity and have a major economic impact. Radiographic evaluation of distal radius fractures is frequently performed in the emergency department setting, has a profound impact on initial management, and is essential to assessing the quality and relative success of the initial reduction. While the most appropriate definitive management of distal radius fractures remains controversial, overarching treatment principles reflect distal radius injury mechanisms and biomechanics. An intuitive understanding of the biomechanics of the distal radius and of common mechanisms of injury informs and improves the emergency radiologist’s ability to identify key imaging findings with important management implications and to communicate the critical information that emergency physicians and orthopedic surgeons need to best manage distal radius fractures. 相似文献
99.
Sharma A Wanchu A Bansal V Singh S Varma S 《Indian journal of pathology & microbiology》2007,50(4):905-907
A decrease in CD4 counts in HIV positive patients with concomitant tuberculosis leads to an increase in the morbidity and mortality. Little data exists about the use of antiretroviral drugs along with antitubercular drugs on the improvement in CD4 counts from this part of country. The records of 119 HIV and TB positive patients were obtained from immunodeficiency clinic of tertiary care centre of North India who were on drug treatment for both the diseases and were analysed for demographic profile and effects on CD4 counts. There was a statistically significant improvement in the CD4 counts of the patients as compared to their baseline values mean (SD) as 120.03 (124.1) at visit one to 270.2 (141.3) at visit two (p < 0.01) and 320.9 (184.3) at visit three (p < 0.05). Six patients died during the period of evaluation. Concomitant use of antitubercular drugs with antiretroviral drugs has resulted in a significant improvement in the CD4 counts which is a marker of delay in disease progression. 相似文献