全文获取类型
收费全文 | 5847篇 |
免费 | 393篇 |
国内免费 | 50篇 |
专业分类
耳鼻咽喉 | 59篇 |
儿科学 | 127篇 |
妇产科学 | 179篇 |
基础医学 | 902篇 |
口腔科学 | 105篇 |
临床医学 | 469篇 |
内科学 | 1407篇 |
皮肤病学 | 108篇 |
神经病学 | 665篇 |
特种医学 | 140篇 |
外科学 | 647篇 |
综合类 | 20篇 |
一般理论 | 3篇 |
预防医学 | 361篇 |
眼科学 | 81篇 |
药学 | 493篇 |
中国医学 | 11篇 |
肿瘤学 | 513篇 |
出版年
2023年 | 58篇 |
2022年 | 130篇 |
2021年 | 199篇 |
2020年 | 119篇 |
2019年 | 159篇 |
2018年 | 159篇 |
2017年 | 122篇 |
2016年 | 180篇 |
2015年 | 171篇 |
2014年 | 201篇 |
2013年 | 309篇 |
2012年 | 427篇 |
2011年 | 439篇 |
2010年 | 248篇 |
2009年 | 204篇 |
2008年 | 391篇 |
2007年 | 397篇 |
2006年 | 333篇 |
2005年 | 371篇 |
2004年 | 354篇 |
2003年 | 292篇 |
2002年 | 279篇 |
2001年 | 61篇 |
2000年 | 41篇 |
1999年 | 49篇 |
1998年 | 47篇 |
1997年 | 48篇 |
1996年 | 33篇 |
1995年 | 42篇 |
1994年 | 33篇 |
1993年 | 20篇 |
1992年 | 25篇 |
1991年 | 25篇 |
1990年 | 30篇 |
1989年 | 30篇 |
1988年 | 22篇 |
1987年 | 26篇 |
1986年 | 21篇 |
1985年 | 14篇 |
1984年 | 16篇 |
1983年 | 12篇 |
1982年 | 10篇 |
1981年 | 9篇 |
1980年 | 16篇 |
1979年 | 14篇 |
1978年 | 13篇 |
1976年 | 8篇 |
1973年 | 8篇 |
1971年 | 10篇 |
1966年 | 11篇 |
排序方式: 共有6290条查询结果,搜索用时 15 毫秒
1.
Gian Eugenio Tontini Guido Manfredi Stefania Orlando Helmut Neumann Maurizio Vecchi Elisabetta Buscarini Luca Elli 《Digestive endoscopy》2019,31(6):627-643
Over the last decade, impressive technological advances have occurred in ultrasonography and small‐bowel endoscopy. Nowadays, endoscopic ultrasonography is an essential diagnostic tool and a therapeutic weapon for pancreatobiliary disorders. Capsule endoscopy and device‐assisted enteroscopy have quickly become the reference standard for the diagnosis of small‐bowel luminal diseases, thereby leading to radical changes in diagnostic and therapeutic pathways. We herein provide an up‐to‐date overview of the latest advances in endoscopic ultrasonography and small‐bowel endoscopy, focusing on the emerging paradigms and technological innovations that might improve clinical practice in the near future. 相似文献
2.
3.
Massimo Porena Sauro Biscotto Elisabetta Costantini Ettore Mearini Livio Verdini 《Neurourology and urodynamics》2003,22(3):206-222
AIMS: The aim of this study is to compare PUMA curves with different pathologic conditions causing bladder dysfunction in 158 men and 83 women. METHODS: PUMA results in terms of bladder outlet obstruction and detrusor contractility were compared in 92 men with benign prostatic hypertrophy (BPH) and p(ves) congruent with p(det) (i.e., p(abd) congruent with 0) with the results of the urodynamics operator's opinion, the provisional International Continence Society method, Abrams and Griffith's diagram, urethral resistence factor (URA), Sch?fer's diagram, and Watt factor. PUMA curves correlated reliably with different pathologic conditions such as obstructive BPH, orthotopic bladder, cystocele, the neurological bladder, and bladder diverticulum. Statistical analysis indicated excellent agreement between PUMA and URA; agreement with other methods was good in cases of obstruction and nonobstruction. In doubtful cases, as diagnosed by standard methods, PUMA agreed only with the Abrams and Griffith's diagram. PUMA and Wmax were in good agreement on detrusor con traction force. Agreement between PUMA and Sch?fer's diagram was excellent for patients with detrusor hypercontractility and good for patients with detrusor hypocontractility and normocontractility. PUMA is the only method applicable to women. It is easy to perform. When integrated with other diagnostic tests, it provides realistic data for diagnosis, medical or surgical therapy, and outcome. 相似文献
4.
Vigilio Ballabeni Massimiliano Tognolini Simona Bertoni Renato Bruni Alessandra Guerrini Gabriela Moreno Rueda Elisabetta Barocelli 《Pharmacological research》2007,55(1):23-30
Ocotea quixos essential oil was shown to possess significant inhibitory activity of platelet aggregation and clot retraction in rodent plasma. This study is aimed at fully characterizing the antiplatelet activity of the whole essential oil and its main components trans-cinnamaldehyde and methyl cinnamate also in human plasma, at investigating the mechanism underlying such activity and at evaluating the potential antithrombotic activity of subacute treatment of mice with Ocotea essential oil. In vitro Ocotea essential oil and trans-cinnamaldehyde inhibited arachidonic acid-, U46619-, ADP-, phorbol12-myristate13-alcetate-, collagen-induced platelet aggregation and thrombin-induced clot retraction in human and rodent plasma; Ocotea oil and trans-cinnamaldehyde competitively antagonized contractions induced by thromboxane A2 receptor agonist U46619 in rat isolated aortic ring (K(B) = 18 and 3.2 microg ml(-1), respectively). In vivo Ocotea oil, orally administered in a subacute treatment (30-100 mg kg(-1) day(-1) for 5 days) to mice, prevented acute thrombosis induced by collagen-epinephrine intravenous injection. This antithrombotic activity was not accompanied by pro-haemorragic side effect, as detected by the inactivity in bleeding test, thus showing a favourable safety profile compared to the conventional antiplatelet agent, acetylsalicylic acid. Present findings indicate that Ocotea essential oil possesses potent and safe antithrombotic activity attributable to its antiplatelet and vasorelaxant effects. The main constituent trans-cinnamaldehyde seems to be the primary responsible for this activity through a putative mechanism involving the inhibition of thromboxane A2 receptors. 相似文献
5.
6.
Silvia Miano Oliviero Bruni Vincenzo Leuzzi Maurizio Elia Elisabetta Verrillo Raffaele Ferri 《Clinical neurophysiology》2004,115(4):938-945
OBJECTIVE: Sleep disturbances are frequent in Angelman syndrome (AS); however, beside the few studies which have investigated sleep disorders in AS by means of questionnaires, to our knowledge, no systematic polysomnographic recordings have been carried out in AS patients. The present study represents the first attempt to study sleep patterns of AS by polysomnography, to evaluate the influences of sleep on the paroxysmal electroencephalogram (EEG) patterns of AS and to assess the eventual age-related changes of sleep architecture and of sleep EEG abnormalities in children and adolescents with AS. METHODS: Fifteen children with AS (7 males and 8 females, mean age 7.2 years, range 3-16 years), attending the Sleep Center of the Department of Child Neurology and Psychiatry of the University of Rome 'La Sapienza' and the Sleep Research Centre of the Oasi Institute (IRCCS) of Troina were included and subdivided into two subgroups by age: subgroup 1, aged 3-5 years, and subgroup 2, aged 9-17 years. Two control groups of age-matched normal subjects were also included: one aged less than 8 years and another aged more than 8 years; additionally, two other groups of age-matched children with epilepsy and mental retardation of different origin, one aged less and one aged more than 9 years were taken into consideration. The statistical comparison between the sleep parameters obtained from the patients and those from the other groups was carried out by means of the non-parametric Kruskal-Wallis ANOVA and the Mann-Whitney U test. RESULTS: The most frequent EEG abnormality found in AS patients appeared to be the 2-3 c/s poorly defined spike/waves complexes. This pattern was influenced by sleep stages; the duration of the runs showed an increasing length with sleep deepening from sleep stage 1 to slow-wave sleep (SWS). Moreover, the 2-3 c/s bursts activity present in sleep stage 2 showed a slowing to 1-2 c/s during SWS. Regarding sleep architecture, in subjects with AS aged <8 year there was a significant reduction in sleep efficiency as compared to normal controls, while the percentage and duration of REM sleep was significantly lower and the percentage of SWS was significantly higher. REM sleep time was reduced in AS subjects aged >8 years than in normal controls. The comparison between AS groups and mental retardation with epilepsy groups did not show significant differences. CONCLUSIONS: Similarly to other types of genetically determined mental retardation syndromes, also subjects with AS seems to show important abnormalities of their sleep polysomnographic patterns. SIGNIFICANCE: This is the first study which reports, in detail, these abnormalities and opens a new path for further insight into the knowledge of additional sleep-related disturbances which are reported in sleep questionnaires by the caregivers of AS subjects. 相似文献
7.
Between 1981-88, 223 surgical interventions were performed in cases of pathologic breast secretion after exclusion of extra-mammary aetiology. The milk duct was identified by pre-operative chromogalactography, followed by a selective excision of the ductal-lobular unit. In 36 cases (16.1%), however, neither spontaneous nor provocable secretion remained after diagnostic galactography, so that a segment resection was required. In all tissue specimens, the cause of the pathologic secretion was found histologically; most often, it was fibrocystic disease or solitary intraductal papilloma (21.5% each). In 32.3% of the specimens, findings with a prospective significance (papillomatosis, carcinoma in situ or invasive carcinoma) were discovered and further operative treatment was initiated. The colour of the discharge allowed no prediction of the histological findings. In 28.6% (8/28) of the carcinomas, secretion was bilateral. In 46.4% of the specimens containing carcinoma, papillomatosis was also detected; vice versa, papillomatosis was associated with carcinoma in 22.8%. The recurrence rate of 1.6% indicates the efficiency of this method in removing the pathology. The diagnostic value of galactography for the prediction of findings with a prospective significance was considerably reduced by a rate of 37.5% false-negatives; therefore, we have decided to omit diagnostic galactography in our patients. Now, provided extra-mammary causes of the nipple discharge have been excluded and mammography has been inconspicuous, a selective excision of the ductal-lobular unit is performed after preoperative chromogalactography. 相似文献
8.
9.
Pedro Moral Elisabetta Marini Esther Estebanup Giuseppa Elisa Mameli Valeria Succa Giuseppe Vona 《American journal of human biology》2002,14(1):21-28
Four communities from Guahibo of Venezuela were analyzed for the genetic variants of nine erythrocyte enzymes and five serum proteins. Of the 14 loci determined, four were monomorphic. Significant frequency differentiation among communities, was present for ESD and TF markers. In general, Guahibo allele frequencies are in the variation ranges described for South American groups. The analysis indicates a relatively higher affinity of Guahibos with other Venezuelan groups within an irregular pattern of genetic distances that are likely related to the complex demographic history of the South American groups. Genetic diversity estimates reveal a moderate degree of genetic structure between the four Guahibo communities. This intra‐tribal variability in Guahibo appears to be lower than in Venezuelan Piaroa but higher than in other Amerindians and could be attributed to a combined effect of low population size and relative isolation of communities. At a continental level, the distribution of genetic diversity is consistent with preferential population movements along the eastern and western coastal areas. Am. J. Hum. Biol. 14:21–28, 2002. © 2002 Wiley‐Liss, Inc. 相似文献
10.
†Francesco Mari Carlo Di Bonaventura ‡Nicola Vanacore Jinane Fattouch Anna Elisabetta Vaudano Gabriella Egeo †Alfredo Berardelli †Mario Manfredi Massimiliano Prencipe †Anna Teresa Giallonardo 《Epilepsia》2006,47(S5):64-67
Summary: Purpose: Psychogenic nonepileptic seizures (PNES) are episodes that may resemble epileptic seizures (ES) but are not associated with abnormal electrical discharges in the brain. Video-EEG recording of a typical episode is considered the best diagnostic tool available. PNES are, however, also documented in patients with epilepsy (PNES/ES). The purpose of this study was to assess this comorbid population, focusing on the differences between patients with PNES/ES and patients with PNES alone.
Methods: We reviewed 110 PNES episodes, occurring spontaneously or induced by means of suggestion techniques, recorded in our video-EEG laboratory over a period of eight years. We identified two subgroups of patients, consisting of 85 PNES cases and 25 PNES/ES cases, and assessed any differences in their characteristics by reviewing a number of variables (age, sex, clinical features, antiepileptic therapy, age of onset, time to diagnosis, pathological history, and length of follow-up).
Results: The comparison between the two subgroups revealed that PNES/ES patients displayed some statistically significant differences when compared with PNES alone patients, i.e., younger age, a higher percentage of spontaneously activated events, a shorter disease duration, a longer time to PNES diagnosis, and a lower percentage lost at follow-up.
Conclusions: This study confirms that PNES is a common, though probably underestimated, occurrence in epilepsy services. Our results shed light on some different characteristics between PNES and PNES/ES patients. 相似文献
Methods: We reviewed 110 PNES episodes, occurring spontaneously or induced by means of suggestion techniques, recorded in our video-EEG laboratory over a period of eight years. We identified two subgroups of patients, consisting of 85 PNES cases and 25 PNES/ES cases, and assessed any differences in their characteristics by reviewing a number of variables (age, sex, clinical features, antiepileptic therapy, age of onset, time to diagnosis, pathological history, and length of follow-up).
Results: The comparison between the two subgroups revealed that PNES/ES patients displayed some statistically significant differences when compared with PNES alone patients, i.e., younger age, a higher percentage of spontaneously activated events, a shorter disease duration, a longer time to PNES diagnosis, and a lower percentage lost at follow-up.
Conclusions: This study confirms that PNES is a common, though probably underestimated, occurrence in epilepsy services. Our results shed light on some different characteristics between PNES and PNES/ES patients. 相似文献