全文获取类型
收费全文 | 41220篇 |
免费 | 2620篇 |
国内免费 | 1357篇 |
专业分类
耳鼻咽喉 | 642篇 |
儿科学 | 998篇 |
妇产科学 | 698篇 |
基础医学 | 4165篇 |
口腔科学 | 709篇 |
临床医学 | 4115篇 |
内科学 | 6254篇 |
皮肤病学 | 1849篇 |
神经病学 | 2525篇 |
特种医学 | 995篇 |
外国民族医学 | 2篇 |
外科学 | 1753篇 |
综合类 | 5844篇 |
现状与发展 | 3篇 |
预防医学 | 4549篇 |
眼科学 | 496篇 |
药学 | 6232篇 |
29篇 | |
中国医学 | 2141篇 |
肿瘤学 | 1198篇 |
出版年
2024年 | 62篇 |
2023年 | 465篇 |
2022年 | 996篇 |
2021年 | 1440篇 |
2020年 | 1230篇 |
2019年 | 1112篇 |
2018年 | 1170篇 |
2017年 | 1210篇 |
2016年 | 1202篇 |
2015年 | 1295篇 |
2014年 | 2470篇 |
2013年 | 2836篇 |
2012年 | 2513篇 |
2011年 | 2665篇 |
2010年 | 2177篇 |
2009年 | 2025篇 |
2008年 | 2048篇 |
2007年 | 2137篇 |
2006年 | 1782篇 |
2005年 | 1678篇 |
2004年 | 1356篇 |
2003年 | 1196篇 |
2002年 | 975篇 |
2001年 | 913篇 |
2000年 | 775篇 |
1999年 | 741篇 |
1998年 | 582篇 |
1997年 | 587篇 |
1996年 | 526篇 |
1995年 | 522篇 |
1994年 | 464篇 |
1993年 | 369篇 |
1992年 | 413篇 |
1991年 | 374篇 |
1990年 | 304篇 |
1989年 | 313篇 |
1988年 | 300篇 |
1987年 | 274篇 |
1986年 | 227篇 |
1985年 | 252篇 |
1984年 | 195篇 |
1983年 | 159篇 |
1982年 | 177篇 |
1981年 | 138篇 |
1980年 | 119篇 |
1979年 | 88篇 |
1978年 | 77篇 |
1977年 | 63篇 |
1976年 | 48篇 |
1975年 | 37篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
The cold pressor test: Vascular and myocardial response patterns and their stability 总被引:2,自引:0,他引:2
PATRICE G. SAAB MARIA M. LLABRE BARRY E. HURWITZ NEIL SCHNEIDERMAN WILLIAM WOHLGEMUTH LYNN A. DUREL CLIFFORD MASSIE JOACHIM NAGEL 《Psychophysiology》1993,30(4):366-373
The purposes of the present study were to compare the cardiovascular response patterns evoked by three versions of the cold pressor test (either forehead stimulation or hand or foot immersion) and to determine the reproducibility of the responses over a 2-week interval. Blood pressure, heart rate, stroke volume, cardiac output, total peripheral resistance, and systolic time intervals were obtained during rest and during the cold pressor test in 42 young men. Across conditions, the pressor response was supported by peripheral resistance increases with concomitant stroke volume decreases. Although the response panerns were generally similar across sites, exceptions were apparent for heart rate. Forehead stimulation was characterized by no significant change in heart rate, whereas limb (hand or foot) immersion was associated with significant heart rate acceleration. The responses elicited by the three cold pressor test conditions were reliable and showed little evidence of attenuation over the test-retest interval. 相似文献
102.
Background: People with abnormal colour vision often report difficulty seeing coloured berries and flowers in foliage, which suggests they will have a diminished capacity for visual search when target objects are marked out by colour. There is very little experimental evidence of the effect of abnormal colour vision on visual search and none relating to search for objects in natural foliage. Method: We showed 79 subjects with abnormal colour vision (seven protanopes, 10 deuteranopes, 16 protanomals and 46 deuteranomals) and 20 subjects with normal colour vision photographs of natural scenes and asked them to locate clumps of red berries, to trace the length of a red string on grass and to name the season depicted in a photograph taken in the Autumn and the same scene photographed in the Summer. Colour vision was assessed using the Ishihara, the Medmont C100, the Farnsworth D15, the Richmond HRR and the Nagel anomaloscope. Results: All the subjects with abnormal colour vision located fewer clumps of red berries than those with normal colour vision. The subjects who failed the Farnsworth D15 performed significantly worse than those who passed but the distribution of scores in the two groups overlaps. The majority of subjects with abnormal colour vision could not trace the full length of the string: only 38 per cent of anomalous trichromats who passed the Farnsworth D15 test and three per cent of those who failed it were able to trace the full length of the string. Fifty‐five per cent of those classed as having a mild deficiency by the HRR test could trace the whole string. Most dichromats were unable to identify the Autumn season and those who did may have been assisted by guessing. Most (94 per cent) of those who passed the Farnsworth D15 test and all those classified as having a ‘mild’ deficiency by the HRR test could identify the season. Conclusions: All people with abnormal colour vision, even those with a very mild deficiency, have some degree of impairment of their ability to see coloured objects in natural surroundings. A pass at the Farnsworth D15 test or a ‘mild’ classification with the Richmond HRR test identifies those likely to have the least problems with visual search and identification tasks. The results have practical implications for the selection of personnel in occupations that involve visual search in natural terrain. 相似文献
103.
宣肺清热颗粒剂稳定性研究 总被引:1,自引:0,他引:1
目的:研究宣肺清热颗粒剂中橙皮甙热稳定性变化,为该颗粒剂有效期的确定、制剂生产、贮存条什提供实验参考依据。方法:采用加速实验法对橙皮甙热稳定性进行研究,用甲醇超声提取样品,HPLC进行含量测定。根据Arrhenius公式处理数据。结果:Arrhenius公式得室温下的速度常数K298=3.38×10-5/h,得出常温下该颗粒剂以橙皮甙为指标的有效期为3.6年。结论:宣肺清热颗粒剂稳定性好,初步符合中药稳定性要求。 相似文献
104.
Michael J Radcliffe George T Lewith Philip Prescott Martin K Church Stephen T Holgate 《Clinical and experimental allergy》2006,36(12):1488-1493
BACKGROUND: In the investigation of seasonal allergic rhinoconjunctivitis (SAR), quantitative skin and conjunctival allergen challenge tests are used to measure individual allergen sensitivity. These tests are reproducible and relate well to prevalence but their relationship to symptom severity is less well established. OBJECTIVE: We wished to determine if quantitative skin prick tests (QSPT) and conjunctival provocation tests (CPTs) using a single grass pollen allergen extract are reproducible and predict symptom severity in SAR. METHODS: We retrospectively analysed data from 91 participants in a previously published randomized placebo controlled study of low dosage allergen immunotherapy who were randomized to receive placebo treatment. We examined the relationship between pre-seasonal QSPT, CPT and SAR symptoms. RESULTS: We found a high level of reproducibility when repeated measures were compared for both the QSPT (P < 0.001) and the CPT (P < 0.001) and moderate correlation (0.49) between the standard skin prick test (SPT) and the QSPT (P < 0.001). We found weak negative correlation (-0.27) between the QSPT and the CPT (P < 0.001). We found no correlation between seasonal symptom, use of rescue medication or quality of life (QOL) scores and pre-seasonal QSPT or CPT. Conclusion In the assessment of seasonal rhinoconjunctivitis, quantitative skin and conjunctival allergen challenge tests are strongly reproducible, although there is no correlation between these tests and seasonal symptom, use of rescue medication or QOL scores. 相似文献
105.
噪声作业人员职业体验研究 总被引:1,自引:1,他引:0
采用华西医科大学劳动卫生教研室研制的系统化职业心理测验(OPT)软件,对四川第一棉纺织厂织布车间噪声(101.2dB(A))作业女工98人职业体验进行考察。以OPT常模女性工人组为对照(年龄、工龄、文化程度等与观察组同),按标准化OPT方法实施测验和统计分析。结果提示噪声作业女工职业体验欠佳,职业满意度、工作生活质量均低于常模。 相似文献
106.
昆明种小鼠56只,在两个海拔高度上(300m和5000m)各分为两个组(对照组和复合组),分别给予相应的处理因素后,检测其血浆ANP水平和游泳时间。结果表明,小鼠在海拔5000m生活48h后,其血浆ANP较海拔300m小鼠降低52.87%,而其游泳时间则增长91.59%;在两个海拔高度上,复合组血浆ANP都较对照组降低,而游泳时间都长于对照组.提示复合方案提高高原劳动能力的机理,可能与降低体内血浆ANP水平有关。 相似文献
107.
目的:测定肺结核、肺肿瘤及非特异性炎症患者注射结核菌素前后痰巨噬细胞的不同数量变化,由此提供一种新的鉴别诊断方法。方法:皮内注射结核菌素、收集注射前、后痰液,测定痰巨噬细胞在不同时间的数量变化。结果:肺结核病人在结核菌素试验后痰巨噬细胞明显增加,肺部肿瘤及非特异性炎症则无显著性变化。结论:肺部患者测定结核菌素前后痰巨噬细胞变化,可作为菌阴肺结核与肺部肿瘤及非特异性炎症鉴别诊断依据之一。 相似文献
108.
Postictal Language Dysfunction in Patients with Right or Bilateral Hemispheric Language Localization 总被引:2,自引:1,他引:1
Summary: Purpose : As shown previously, when temporal lobe complex partial seizures (TLCPS) originate from the language dominant hemisphere, patients cannot read a test phrase correctly within 60 s of the end of the ictal discharge. We wished to assess whether postictal language testing results discordant with this pattern identified patients with non-left (right hemisphere or mixed) language dominance.
Methods : Since 1988, all patients undergoing video/EEG monitoring at our institution have been given a test phrase to read aloud as soon as a seizure is detected. Inclusion criteria for this study were (a) postictal language testing within 60 s of seizure end for at least one TLCPS, (b) >90% seizure reduction after anterior temporal lobectomy with 2-year minimum follow- follow- up, and (c) language localization by either intracarotid amobarbital test (IAT) or direct electrical stimulation of left hemisphere cortex.
Results : Two hundred twenty-four seizures in 64 patients were analyzed. Discordant postictal language patterns were noted in 10 of 11 patients with IAT documented non-left language dominance and in 15 of 53 with left dominance (p = 0.006; sensitivity 90.9%, specificity 71.7%).
Conclusions : Postictal language testing accurately identifies patients with non-left language dominance and may be useful in selecting appropriate patients for IAT. 相似文献
Methods : Since 1988, all patients undergoing video/EEG monitoring at our institution have been given a test phrase to read aloud as soon as a seizure is detected. Inclusion criteria for this study were (a) postictal language testing within 60 s of seizure end for at least one TLCPS, (b) >90% seizure reduction after anterior temporal lobectomy with 2-year minimum follow- follow- up, and (c) language localization by either intracarotid amobarbital test (IAT) or direct electrical stimulation of left hemisphere cortex.
Results : Two hundred twenty-four seizures in 64 patients were analyzed. Discordant postictal language patterns were noted in 10 of 11 patients with IAT documented non-left language dominance and in 15 of 53 with left dominance (p = 0.006; sensitivity 90.9%, specificity 71.7%).
Conclusions : Postictal language testing accurately identifies patients with non-left language dominance and may be useful in selecting appropriate patients for IAT. 相似文献
109.
110.
T. Eger L. Zller H.-P. Müller S. Hoffmann D. Lobinsky 《European journal of oral sciences》1996,104(2):112-117
Actinobacillus actinomycetemcomitans has been implicated in the pathogenesis of several forms of early onset and refractory adult periodontitis. Early diagnosis of colonization of the oral cavity might be of importance in order to initiate preventive measures. The aim of the present study was to determine the potential diagnostic value of oral mucosal and salivary tests to identify, among healthy young men with no or minor periodontal disease, individuals colonized by A. actinomycetemcomitans. Two hundred and one male recruits. 18–25 yr of age, took part in the present study. Mean values of periodontal parameters suggested only minor periodontal disease. Of the sites, 64.8±17.6% (mean ± SD) had a periodonta) probing depth (PPD) of 1 or 2 mm. only 1.6±2.9% deep sites of 5 mm were detected. More than 1000 subgingival and extracrevicular samples were selectively cultivated for A. actinomycetemcomitans. The organism was isolated in 55 subjects (21%). The odds for presence of at least 1 deep site of 5 mm was increased by a factor 1.99 if A. actinomycetemcomitans could be recovered. In identifying subjects colonized by A. actinomycetemcomitans. diagnostic test parameters sensitivity and predictive value for a negative test were 74.5±5.9% and 91.1±2.3%', respectively, for both saliva and dorsum of tongue samples. In contrast, pooled subgingival plaque from mesial surfaces of 1st molars was only 34.5±6.4% sensitive: the negative predictive value was 80.2±3.0%. The results point to a high diagnostic value of oral mucosal and especially saliva samples to identify young adult individuals colonized by A. actinomycetemcomitans. 相似文献