全文获取类型
收费全文 | 23573篇 |
免费 | 2526篇 |
国内免费 | 468篇 |
专业分类
耳鼻咽喉 | 128篇 |
儿科学 | 672篇 |
妇产科学 | 244篇 |
基础医学 | 2956篇 |
口腔科学 | 253篇 |
临床医学 | 2726篇 |
内科学 | 1491篇 |
皮肤病学 | 129篇 |
神经病学 | 2669篇 |
特种医学 | 842篇 |
外科学 | 806篇 |
综合类 | 4757篇 |
现状与发展 | 2篇 |
一般理论 | 7篇 |
预防医学 | 5120篇 |
眼科学 | 408篇 |
药学 | 1855篇 |
17篇 | |
中国医学 | 968篇 |
肿瘤学 | 517篇 |
出版年
2024年 | 72篇 |
2023年 | 427篇 |
2022年 | 967篇 |
2021年 | 1229篇 |
2020年 | 1090篇 |
2019年 | 889篇 |
2018年 | 807篇 |
2017年 | 937篇 |
2016年 | 973篇 |
2015年 | 1028篇 |
2014年 | 1859篇 |
2013年 | 2011篇 |
2012年 | 1630篇 |
2011年 | 1619篇 |
2010年 | 1241篇 |
2009年 | 1151篇 |
2008年 | 1292篇 |
2007年 | 1104篇 |
2006年 | 969篇 |
2005年 | 782篇 |
2004年 | 646篇 |
2003年 | 579篇 |
2002年 | 457篇 |
2001年 | 384篇 |
2000年 | 315篇 |
1999年 | 240篇 |
1998年 | 227篇 |
1997年 | 231篇 |
1996年 | 194篇 |
1995年 | 153篇 |
1994年 | 122篇 |
1993年 | 96篇 |
1992年 | 120篇 |
1991年 | 101篇 |
1990年 | 73篇 |
1989年 | 77篇 |
1988年 | 55篇 |
1987年 | 67篇 |
1986年 | 42篇 |
1985年 | 54篇 |
1984年 | 44篇 |
1983年 | 51篇 |
1982年 | 23篇 |
1981年 | 31篇 |
1980年 | 29篇 |
1979年 | 18篇 |
1978年 | 18篇 |
1977年 | 10篇 |
1976年 | 14篇 |
1974年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
171.
We evaluated the effects of rowing on the morphology and function of the leg extensor muscle in old people. The area and
the power of the leg extensor muscle were measured in 15 oarsmen – age [mean (SD)] 65 (3) years; height 171 (4) cm, body mass
68 (6) kg – and in 15 sedentary men – age 66 (4) years, height 170 (4) cm, body mass 67 (7) kg – who were matched on the basis
of their body size. The leg extensor muscle area of the oarsmen was larger than that of the sedentary men [77.8 (5.4) vs 68.4
(5.1) cm2, P<0.05]. Also the bilateral leg extension power of the oarsmen was larger than that of the sedentary men [1,624 (217) vs 1,296
(232) W, P<0.05]. Thus, the leg extension power per the leg extensor muscle area was not significantly different between two groups
[20.9 (2.0) vs 19.9 (2.1) W·cm–2) and leg extension power was correlated to the leg extensor muscle area (59–89 cm2, r=0.74, P<0.001). Also the 2,000-m rowing ergometer time of the oarsmen [495 (14) s; range 479–520 s] was related to leg extensor muscle
area (68–89 cm2, r=0.63, P<0.01). The results suggest that rowing prevents age-related muscle wasting and weakness.
Electronic Publication 相似文献
172.
华南地区质粒介导超广谱β-内酰胺酶的基因分型研究 总被引:59,自引:4,他引:59
目的:了解华南地区质粒介导超广谱β-内酰胺酶(ESBLs)的发生率及基因型特征。方法:收集2001年4月-9月革兰阴性菌临床分离无重复株共1184株,采用NCCLS表型筛选和确认试验进行了ESBLs产酶的识别,E-test法检测各亚型ESBLs的MICs值,质粒接合及电转化实验,耐药质粒提取及酶切指纹分析,等电聚焦电泳,PCR通用引物扩增TEM、SHV、CTX-M、VEB、PER、SFO基因及其克隆测序进行ESBLs基因分型和质粒定位。结果:革兰阴性苗ESBLs的检出率为14.6%(173/1184);获得产ESBLs接合子67株,电转化子11株,其中产CTX-M-14型ESBLs为33.3%(26/78)、CTX-M-3为23.1%(18/78)、CTX-M-9为14.1%(11/78)及SHV-2a为2.6%(2/78),未定型为5.1%(4/78);29.5%(23/78)野生株伴广谱酶TEM-1或SHV-1型;各型ESBLs基因约定位在35-190kb大小的可接合性低执行者拷贝数天然质粒上;CTX-M型ESBLs以对头孢噻肟高水平高耐为特征。结论:华南地区质粒介导的ESBLs以CTX-M型衍生酶为主,其次是SHV型酶。 相似文献
173.
Taoka M Toda T Iriki A Tanaka M Iwamura Y 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2000,134(2):139-146
Single-neuron activities were recorded in the hindlimb region of the primary somatosensory cortex and part of area 5 in awake Japanese monkeys. A total of 1050 units were isolated from five hemispheres of four animals. Receptive fields (RFs) and submodalities were identified for 90% of isolated neurons in areas 3a and 3b. The percentage decreased as the recoding site moved to the more caudal areas. Deep or skin submodality neurons were dominant in area 3a or area 3b, respectively. Deep submodality neurons increased in more caudal areas and were the majority in areas 2 and 5. These observations were consistent with those in the hand and/or digit or arm and/or trunk region. The identified neurons were classified by their RF positions into four types: the foot, leg, foot and leg, or hindlimb and other body parts type. Among 831 identified neurons, 33 neurons had bilateral RFs, 14 had ipsilateral RFs, and the rest (N=784) had contralateral RFs. The relative incidence of neurons with bilateral or ipsilateral RFs among identified neurons was less than 1% in areas 3a, 3b, and 1, and 16% or 25% in areas 2 or 5, respectively. Within areas 2 and 5, the percentage of neurons with bilateral or ipsilateral RFs was significantly smaller in the foot type (5%) than in other RF types (24-57%). RFs of the foot type were on the sole or single toe but never on multiple toes. These observations contrasted with the previous findings that neurons with bilateral RFs were more frequently seen in the hand and/or digit region and that RFs on multiple digit tips were dominant there. The present study thus demonstrated that neurons with bilateral RFs do exist in the hindlimb region. Similarly to the forelimb region, they were found mostly in areas 2 and 5, the caudalmost areas of the postcentral gyrus and hierarchically higher stages in information processing. The relative paucity of neurons with bilateral RFs on the foot, especially those with RFs on multiple toes, may reflect functional differences between the foot and the hand. 相似文献
174.
S. Szava Dr. P. Valdes R. Biscay L. Galan J. Bosch I. Clark J. C. Jimenez 《Brain topography》1994,6(3):211-219
Summary High resolution spectral methods are explored as an alternative to broad band spectral parameters (BBSP) in quantitative EEG analysis. In a previous paper (Valdes et al. 1990b) regression equations (Developmental surfaces) were introduced to characterize the age-frequency distribution of the mean and standard deviation of the log spectral EEG power in a normative sample. These normative surfaces allow the calculation of z transformed spectra for all derivations of the 10/20 system and z maps for each frequency. Clinical material is presented that illustrates how these procedures may pinpoint frequencies of abnormal brain activity and their topographic distribution, avoiding the frequency and spatial smearing that may occur using BBSP. The increased diagnostic accuracy of high resolution spectral methods is demonstrated by means of receiver operator characteristic (ROC) curve analysis. Procedures are introduced to avoid type I error inflation due to the use of more variables in this type of procedure. 相似文献
175.
为探讨“军字1号”工程使用前后的病案首页质量变化,本文通过作者所在医院近八年病案首页的质量调查统计,对“军字1号”工程使用前后的病案首页质量作了详细的对照分析比较,为进一步加强“军字1号”工程中的病案首页质量管理提供经验。 相似文献
176.
177.
In three factorial experiments, auditory vs visual vs tactile feedback, analog feedback vs analog feedback which was anchored, and sex, were varied to assess the effects of these variables on performance in short-term biofeedback training of heart rate reduction, hand temperature increase, and forehead muscle tension reduction. A total of 108 subjects served in the study. Moderate but reliable changes were found during the course of the training session for all three physiological responses. The ability to reduce heart rate in a single training session did not appear to be a function of any of the variables manipulated in this study, but rather could be attributed to adaptation. In both muscle tension and temperature training, however, there were significant interactions between sex and sensory modality of the feedback stimulus and, in the case of muscle tension training, between information content of the feedback signal and sex. The overall pattern of results indicated that performance during biofeedback training is a complicated function of sex and the type of signal used to provide feedback, and that this function is not constant across physiological response systems. 相似文献
178.
S. S. Kanj J. E. Corkill Z. A. Kanafani G. F. Araj C. A. Hart R. Jaafar G. M. Matar 《Clinical microbiology and infection》2008,14(5):501-504
The prevalence of bla CTX-M , bla TEM and bla SHV genes among extended-spectrum β-lactamase (ESBL)-producing clinical isolates of Escherichia coli ( n = 50) and Klebsiella spp. ( n = 50) from Lebanon was 96%, 57% and 67%, and 40%, 82% and 84%, respectively. Genotyping revealed that the clonal diversity was unrelated to the presence of bla genes. Sequence analysis of 16 selected isolates identified the bla CTX-M-15 , bla TEM-1 , bla OXA-1 and six bla SHV genes, as well as the gene encoding the quinolone-modifying enzyme AAC(6')-Ib-cr. The genes encoding CTX-M-15 and AAC(6')-Ib-cr were carried on a 90-kb plasmid of the pC15-1a or pCTX-15 type, which transferred both ESBL production and quinolone resistance from donors to transconjugants. 相似文献
179.
K. Hkkinen W. J. Kraemer R. U. Newton M. Alen 《Acta physiologica (Oxford, England)》2001,171(1):51-62
The effects of a 6‐month resistance training (2 day/week) designed to develop both strength and power on neural activation by electromyographic activity (EMG) of the agonist and antagonist knee extensors, muscle fibre proportion and areas of type I, IIa, and IIb of the vastus lateralis (VL) as well as maximal concentric one repetition maximum (1 RM) strength and maximal and explosive isometric strength of the knee extensors were examined. A total of 10 middle‐aged men (M40; 42 ± 2), 11 middle‐aged women (W40; 39 ± 3), 11 elderly men (M70; 72 ± 3) and 10 elderly women (W70; 67 ± 3) served as subjects. Maximal and explosive strength values remained unaltered during a 1‐month control period. After the 6‐month training maximal isometric and 1RM strength values increased in M40 by 28 ± 14 and 27 ± 7% (P < 0.001), in M70 by 27 ± 17 and 21 ± 9% (P < 0.001), in W40 by 27 ± 19 and 35 ± 14% (P < 0.001) and in W70 by 26 ± 14 and 31 ± 14% (P < 0.001), respectively. Explosive strength improved in M40 by 21 ± 41% (P < 0.05), in M70 by 21 ± 24% (P < 0.05), in W40 by 32 ± 45% (NS) and in W70 by 22 ± 28% (P < 0.05). The iEMGs of the VL and vastus medialis (VM) muscles increased during the training in M40 (P < 0.001 and 0.05), in M70 (P < 0.001 and 0.05), in W40 (P < 0.001 and 0.05) and in W70 (P < 0.001 and 0.05). The antagonist biceps femoris (BF) activity during the isometric knee extension remained unaltered in M40, in W40, and in M70 but decreased in W70 (from 42 ± 34 to 32 ± 26%; P < 0.05) during the first 2 months of training. Significant increases occurred during the training in the mean fibre areas of type I in W70 (P < 0.05) and of overall type II along with a specific increase in IIa in both W40 (P < 0.05) and in W70 (P < 0.05), while the changes in the male groups were not statistically significant. The individual percentage values for type II fibres at pretraining correlated with the individual values for 1 RM strength in both W70 (r=0.80; P < 0.05) and M70 (r=0.61; P < 0.05) and also at post‐training for maximal isometric torque in W70 (r=0.77, P < 0.05). The findings support the concept of the important role of neural adaptations in strength and power development in middle‐aged and older men and women. The muscle fibre distribution (percentage type II fibres) seems to be an important contributor on muscle strength in older people, especially older women. Women of both age groups appear to be hypertrophically responsive to the total body strength training protocol performed two times a week including heavier and lower (for fast movements) loads designed for both maximal strength and power development, while such a programme has limited effects on muscle hypertrophy in men. 相似文献
180.
《The Knee》2021
BackgroundAs knee osteotomy surgery becomes increasingly accessible, more patients may turn to the Internet for information. This study examined the source, quality, content and readability of online information regarding osteotomy around the knee.MethodsThe first 70 websites returned by the top four search engines were identified using the key words: “knee osteotomy” and “high tibial osteotomy.” The websites were categorised by type and assessed using the DISCERN score, Journal of the American Medical Association (JAMA) benchmark criteria and a novel Knee Osteotomy-Specific Score (KOSS). The presence of the Health On the Net (HON) code accreditation seal was noted. Readability of each website was assessed using eight readability formulae. The mean reading grade level (RGL) was compared to the 6th and 8th grade reading levels. The mean RGL of each category was also compared.ResultsOf the 45 unique websites analysed, the majority were Physician (33%) and Journal websites (31%). The mean DISCERN score was 36.7 (±8.9) which is classified as ‘poor.’ The mean JAMA benchmark criteria score was 2.04 (±1.5) and Physician websites were most likely to be scored zero. The mean KOSS was 15.4 (±5.7). The highest scoring website was a Commercial site but, overall, Journal category sites provided the best quality information. Websites that bore the HONcode seal obtained higher DISCERN, JAMA benchmark criteria and Knee Osteotomy - Specific Scores.The cumulative mean RGL was 13.2 (±2.2) which exceeded the 6th grade level by an average of 7.2 grade levels and the 8th grade level by an average of 5.2 grade levels. No website (0%) was written at or below either the 6th or the 8th grade reading levels. The mean Flesch Reading Ease Score of all websites was 41.13 (±14.7) which is classified as ‘difficult.’ Journal websites had the highest RGL.ConclusionThe information available online regarding osteotomy around the knee varies tremendously in quality and completeness. Physician sites predominate, but these were among the lowest scoring of all websites. Even where high quality information is available, it is set at too high a level to be easily understood.Level of evidenceSurvey of materials – Internet. 相似文献