全文获取类型
收费全文 | 351703篇 |
免费 | 20631篇 |
国内免费 | 659篇 |
专业分类
耳鼻咽喉 | 4875篇 |
儿科学 | 11551篇 |
妇产科学 | 11599篇 |
基础医学 | 52892篇 |
口腔科学 | 9174篇 |
临床医学 | 30138篇 |
内科学 | 67652篇 |
皮肤病学 | 7285篇 |
神经病学 | 26492篇 |
特种医学 | 13507篇 |
外国民族医学 | 45篇 |
外科学 | 53367篇 |
综合类 | 8127篇 |
现状与发展 | 1篇 |
一般理论 | 208篇 |
预防医学 | 24040篇 |
眼科学 | 7766篇 |
药学 | 24639篇 |
1篇 | |
中国医学 | 861篇 |
肿瘤学 | 18773篇 |
出版年
2021年 | 3420篇 |
2019年 | 3303篇 |
2018年 | 4907篇 |
2017年 | 3791篇 |
2016年 | 4416篇 |
2015年 | 4883篇 |
2014年 | 6405篇 |
2013年 | 9868篇 |
2012年 | 13046篇 |
2011年 | 13630篇 |
2010年 | 8593篇 |
2009年 | 7817篇 |
2008年 | 12144篇 |
2007年 | 13268篇 |
2006年 | 12739篇 |
2005年 | 12419篇 |
2004年 | 11851篇 |
2003年 | 11143篇 |
2002年 | 10506篇 |
2001年 | 13937篇 |
2000年 | 14206篇 |
1999年 | 12060篇 |
1998年 | 3662篇 |
1997年 | 3308篇 |
1996年 | 3107篇 |
1995年 | 2935篇 |
1994年 | 2690篇 |
1992年 | 8659篇 |
1991年 | 8810篇 |
1990年 | 8591篇 |
1989年 | 8390篇 |
1988年 | 7600篇 |
1987年 | 7321篇 |
1986年 | 6978篇 |
1985年 | 6823篇 |
1984年 | 5029篇 |
1983年 | 4331篇 |
1982年 | 2692篇 |
1979年 | 4572篇 |
1978年 | 3373篇 |
1977年 | 2893篇 |
1976年 | 2612篇 |
1975年 | 2952篇 |
1974年 | 3455篇 |
1973年 | 3454篇 |
1972年 | 3189篇 |
1971年 | 3007篇 |
1970年 | 2894篇 |
1969年 | 2623篇 |
1968年 | 2595篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
FDA’S Perspectives on Cardiovascular Devices 总被引:1,自引:0,他引:1
Eric A. Chen Sonna M. Patel-Raman Kathryn O’Callaghan Matthew G. Hillebrenner 《Journal of cardiovascular translational research》2009,2(2):143-146
The Food and Drug Administration (FDA) decision process for approving or clearing medical devices is often determined by a
review of robust clinical data and extensive preclinical testing of the device. The mission statement for the Center for Devices
and Radiological Health (CDRH) is to review the information provided by manufacturers so that it can promote and protect the
health of the public by ensuring the safety and effectiveness of medical devices deemed appropriate for human use (Food, Drug
& Cosmetic Act, §903(b)(1, 2(C)), December 31, 2004; accessed December 17, 2008 ). For high-risk devices, such as ventricular assist devices (VADs), mechanical heart valves, stents, cardiac resynchronization
therapy (CRT) devices, pacemakers, and defibrillators, the determination is based on FDA’s review of extensive preclinical
bench and animal testing followed by use of the device in a clinical trial in humans. These clinical trials allow the manufacturer
to evaluate a device in the intended use population. FDA reviews the data from the clinical trial to determine if the device
performed as predicted and the clinical benefits outweigh the risks. This article reviews the regulatory framework for different
marketing applications related to cardiovascular devices and describes the process of obtaining approval to study a cardiovascular
device in a U.S. clinical trial. 相似文献
94.
H. J. J. Kars Juha M. Hijmans Jan H. B. Geertzen Wiebren Zijlstra 《Journal of diabetes science and technology》2009,3(4):931-943
The objective of this review is to identify and review publications describing the impact of reduced somatosensation on balance. Based on knowledge of the association between specific somatosensory loss and deterioration of balance, conclusions can be made about role of somatosensation in standing balance.A systematic literature review is presented in which publications from the years 1993 through 2007 were searched in Medline and Embase. Medical Subject Headings (MESH) terms and free text words (related to balance, somatosensory loss, and lower limb) were used to perform the searches. Fifteen articles were selected for detailed review based on predetermined inclusion criteria, and three of the included articles described the effect of experimentally reduced somatosensation on balance in healthy subjects. Ten of the articles described balance in diabetic neuropathy (DN). The last two included articles described balance in Charcot-Marie-Tooth (CMT) disease type 1A (CMT1A) or type 2 (CMT2).The literature indicates that the tactile sensation is reduced in DN, CMT1A, and CMT2 and when the plantar surface of the feet was hypothermically anesthetized. Joint motion sensation seems to be impaired in patients with DN, and passive joint position sensation appears to be reduced in healthy subjects with anesthesia of ankle and foot from prolonged ischemia. This reduced somatosensation seems to have a negative effect on balance in patients with DN and CMT2; however, this appeared not to be the case in patients with CMT1A and in healthy subjects. 相似文献
95.
Loa Clausen Kristian Rokkedal Jan H. Rosenvinge 《European eating disorders review》2009,17(6):462-467
The Eating Disorder Inventory, Version 2 (EDI‐2) is a questionnaire used clinically and in research all over the world. EDI‐2 is cross‐culturally valid, yet normative values may depend on culture. Norms and reliability of the Danish version have to date been lacking, and will be presented in this article, comparing patients (N = 575) and controls (N = 881). Also, internal reliability of scales is tested for both groups. Differences between norms of the Danish and the North American version of EDI were small but significant for all scales except asceticism (eating disorder patients) and ineffectiveness, interpersonal distrust and maturity fears (normal controls). For both groups the internal consistency was >0.70 for all subscales except asceticism. Although differences across the eating disorder diagnostic groups were dubious, the EDI‐2 is useful to screen for eating problems in the general population as well as to rate progress and outcome among eating disorder patients. Copyright © 2009 John Wiley & Sons, Ltd and Eating Disorders Association. 相似文献
96.
Ludger Grote MD PhD Lena Leissner MD Jan Hedner MD PhD Jan Ulfberg MD PhD 《Movement disorders》2009,24(10):1445-1452
Iron deficiency may exacerbate symptoms in the Restless Legs Syndrome (RLS). We investigated the effect of intravenous iron sucrose or placebo on symptoms in patients with RLS and mild to moderate iron deficit. Sixty patients with primary RLS (seven males, age 46 (9) years, S‐ferritin ≤45 μg/L) recruited from a cohort of 231 patients were randomly assigned in a 12‐months double‐blind, multi‐centre study of iron sucrose 1000 mg (n = 29) or saline (n = 31). The primary efficacy variable was the RLS severity scale (IRLS) score at week 11. Median IRLS score decreased from 24 to 7 (week 11) after iron sucrose and from 26 to 17 after placebo (P = 0.123, N.S. for between treatment comparison). The corresponding scores at week 7 were 12 and 20 in the two groups (P = 0.017). Drop out rate because of lack of efficacy at 12 months was 19/31 after placebo and 5/29 patients after iron sucrose (Kaplan–Meier estimate, log rank test P = 0.0006) suggesting an iron induced superior long term RLS symptom control. Iron sucrose was well tolerated. This study showed a lack of superiority of iron sucrose at 11 weeks but found evidence that iron sucrose reduced RLS symptoms both in the acute phase (7 weeks) and during long‐term follow up in patients with variable degree of iron deficiency. Further studies on target patient groups, dosing and dosing intervals are warranted before iron sucrose could be considered for treatment of iron deficient patients with RLS. © 2009 Movement Disorder Society 相似文献
97.
Hong Wang Venkatraman Siddharthan Jeffery O. Hall John D. Morrey 《Journal of neurovirology》2009,15(4):293-299
Prior findings led us to hypothesize that West Nile virus (WNV) preferentially transports along motor axons instead of sensory
axons. WNV is known to undergo axonal transport in cell culture and in infected hamsters to infect motor neurons in the spinal
cord. To investigate this hypothesis, WNV was injected directly into the left sciatic nerve of hamsters. WNV envelope-staining
in these hamsters was only observed in motor neurons of the ipsilateral ventral horn of the spinal cord, but not in the dorsal
root ganglion (DRG). To evaluate the consequence of motor neuron infection by WNV, the authors inoculated wheat germ agglutinin—horseradish
peroxidase (WGA-HRP) 9 days after WNV sciatic nerve injection, and stained the spinal cord and the DRG for HRP activity 3
days later. The degree of HRP-staining in DRG was the same in WNV- and sham-infected animals, but the HRP-staining in the
motor neuron in the ventral horn was considerably less for WNV-infected hamsters. To investigate the mechanism of WNV transport,
hamsters were treated with colchicine, an inhibitor of membranous microtubule-mediated transport. The intensity of the WNV-stained
area in the spinal cord of colchicine-treated hamsters at 6 days after WNV infection were significantly reduced (P≤.05) compared to the placebo-treated hamsters. These data suggest that WNV is preferentially transported through the motor
axons, but not the sensory axons, to subsequently infect motor neurons and cause motor weakness and paralysis. 相似文献
98.
Marieke Peeters Ludo Verhoeven Jan de Moor Hans van Balkom 《Research in developmental disabilities》2009,30(4):712-726
The goal of this longitudinal study was to investigate the precursors of early reading development in 52 children with cerebral palsy at kindergarten level in comparison to 65 children without disabilities. Word Decoding was measured to investigate early reading skills, while Phonological Awareness, Phonological Short-term Memory (STM), Speech Perception, Speech Production and Nonverbal Reasoning were considered reading precursors. Children with cerebral palsy lag behind on all reading precursors at the beginning of the second year of kindergarten. For the children without disabilities, early reading skills in Grade 1 were best predicted by Phonological Awareness and Phonological STM while Speech Production was the most important predictor of early reading success for the children with cerebral palsy, followed by Phonological Awareness and Speech Perception. Furthermore, for children with cerebral palsy, Speech Production appears to dominate reading development, as Speech Production measured at the beginning of the second year of kindergarten was strongly predictive of all other reading precursors measured at the end of the second year of kindergarten. The results of this study reveal that children with cerebral palsy with additional speech impairments are at risk for limited literacy development. Clinical implications are discussed. 相似文献
99.
100.
D.E. Hilling J.K.R.A. Rijkelijkhuizen H.A.M. Töns O.T. Terpstra E. Bouwman 《Transplantation proceedings》2009,41(1):316
When studying histological characteristics of human and porcine pancreata in relation to islet isolation, we encountered a remarkably high number of hyperemic islets. The abnormalities observed in these islets ranged from a single dilated vessel through multiple widely dilated vessels to hemorrhages extending into the surrounding exocrine tissue. We determined their possible relevance for outcomes of islet isolation. This study involved a histological examination of 143 porcine pancreata (72 juvenile and 71 adult) and islet isolation from 48 adult pancreata. Human pancreata obtained from 71 multiple organ donors yielded islet isolation in 24 cases. To determine their endocrine content, tissue samples were stained with Aldehyde Fuchsin. The presence of hyperemic islets was scored semiquantitatively with pancreata allotted to categories based on the severity. In humans and pigs we observed hyperemic islets in 48% of pancreata, but only 4.0 ± 2.4% of the islets were hyperemic. In both humans and pigs, significantly higher endocrine content was found in the most severely affected pancreata. When the higher endocrine content was taken into account and isolation results were expressed as ratios of yield and content, we observed significantly lower yields in the most affected pancreata in pigs with a trend toward lower yields in humans. A substantial proportion of human and porcine pancreata contain hyperemic islets. Although the results in humans are preliminary, our data suggest that this phenomenon may contribute to the unpredictable, highly variable islet yields in pigs and humans. 相似文献