全文获取类型
收费全文 | 1948856篇 |
免费 | 148628篇 |
国内免费 | 10305篇 |
专业分类
耳鼻咽喉 | 25413篇 |
儿科学 | 61869篇 |
妇产科学 | 54382篇 |
基础医学 | 283035篇 |
口腔科学 | 52507篇 |
临床医学 | 178235篇 |
内科学 | 374909篇 |
皮肤病学 | 44411篇 |
神经病学 | 150737篇 |
特种医学 | 72543篇 |
外国民族医学 | 563篇 |
外科学 | 285655篇 |
综合类 | 58587篇 |
现状与发展 | 23篇 |
一般理论 | 592篇 |
预防医学 | 152059篇 |
眼科学 | 44960篇 |
药学 | 145100篇 |
116篇 | |
中国医学 | 10530篇 |
肿瘤学 | 111563篇 |
出版年
2021年 | 18467篇 |
2019年 | 17748篇 |
2018年 | 23850篇 |
2017年 | 18814篇 |
2016年 | 20410篇 |
2015年 | 24296篇 |
2014年 | 33421篇 |
2013年 | 47166篇 |
2012年 | 64807篇 |
2011年 | 69221篇 |
2010年 | 41779篇 |
2009年 | 38845篇 |
2008年 | 62168篇 |
2007年 | 65527篇 |
2006年 | 65912篇 |
2005年 | 63339篇 |
2004年 | 59240篇 |
2003年 | 56351篇 |
2002年 | 54108篇 |
2001年 | 92974篇 |
2000年 | 95055篇 |
1999年 | 78980篇 |
1998年 | 22434篇 |
1997年 | 20158篇 |
1996年 | 20243篇 |
1995年 | 19164篇 |
1994年 | 17554篇 |
1993年 | 16221篇 |
1992年 | 58934篇 |
1991年 | 57322篇 |
1990年 | 55584篇 |
1989年 | 53081篇 |
1988年 | 48750篇 |
1987年 | 47804篇 |
1986年 | 44642篇 |
1985年 | 42568篇 |
1984年 | 32215篇 |
1983年 | 27204篇 |
1982年 | 16080篇 |
1979年 | 28995篇 |
1978年 | 20668篇 |
1977年 | 17199篇 |
1976年 | 16400篇 |
1975年 | 17423篇 |
1974年 | 21020篇 |
1973年 | 20036篇 |
1972年 | 18984篇 |
1971年 | 17634篇 |
1970年 | 16539篇 |
1969年 | 15556篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Maggie L. Westfal David C. Chang Cassandra M. Kelleher 《Journal of pediatric surgery》2019,54(1):140-144
Purpose
The purpose of this study was to evaluate trends in demographics and outcomes of pediatric breast cancer in a United States population-based cohort.Methods
The Surveillance, Epidemiology, and End Results (SEER) database was utilized to identify all pediatric patients with malignant breast tumors between 1973 and 2014. Analysis was performed using Stata Statistical Software version 13.1. Associations between categorical variables were made using X2 test. Log-rank test was used for univariate survival analysis. Kaplan–Meier analysis investigated five-year survival rates across several variables. Adjusted analysis was performed using a Cox Proportional-Hazards regression.Results
134 patients with breast malignancies were identified. Carcinoma was the most prevalent histology (48.5%), followed by fibroepithelial tumors (FETs) (35.1%), and sarcoma (14.2%). FETs were twice as common in black compared to nonblack patients (56.3% vs. 29.0%, p?<?0.01). Analyzing histology by stage revealed that 100% of FETs were early stage disease (p?<?0.0001). 46.7% of the tumors tested were ER/PR negative, more than twice as many compared to the published adult estimate of 20.0%. Unadjusted survival analysis revealed worse survival for patients with adenocarcinoma/sarcomas, advanced stage, and high grade disease, without a survival difference between races.Conclusion
Breast cancer remains a rare malignancy among pediatric patients. Although black patients were found to have more noncarcinomatous tumors with less advanced disease, this did not confer a survival advantage.Type of study
Retrospective cohort study.Level of evidence
Level III. 相似文献22.
A. Ríos A.I. López-Navas M.A. Ayala G. Garrido M.J. Sebastián J. Carrillo Á. Sánchez J. Flores-Medina J.J. Ruiz-Manzanera A.M. Hernández P. Ramírez P. Parrilla 《Transplantation proceedings》2019,51(2):258-260
The Latin American population has a double way of immigration, one toward the United States by proximity and another toward Spain by sociocultural affinity. This population increase is affecting organ donation and transplantation in receiving countries.
Objective
To analyze the brain death (BD) concept knowledge in the Dominican Republic immigrant population in Florida (United States) and Spain.Method
Population under study: Population born in the Dominican Republic, resident in Florida (United States) and in Spain. Inclusion criteria: Population older than 15 years stratified by age and sex. Assessment instrument: Donation attitude questionnaire PCID-DTO-Ríos. Fieldwork: Random selection based on stratification. Immigration support association collaboration in Florida and Spain was needed to locate potential respondents. Completion was anonymous and self-administered, with verbal consent.Results
A total of 123 respondents, 57 residents in Spain and 66 in Florida, have been included in the study. The 27% (n = 33) of the respondents knowledgeable of the BD concept consider it the death of an individual. Of the remainder, 52% (n = 64) do not know about it, and the remaining 21% (n = 26) believe it does not mean the death of a patient. No differences were observed regarding migration countries (P > .05). There was no association of the BD concept with other psychosocial factors analyzed or with the attitude toward organ donation.Conclusions
Knowledge of the BD concept among the Dominican immigrant population is similar in Spain and Florida, and, unlike most studies, there is no objective association with the attitude toward organ donation. 相似文献23.
24.
Béla Nagy Zsolt Bene Zsolt Fejes Sonya L. Heltshe David Reid Nicola J. Ronan Yvonne McCarthy Daniel Smith Attila Nagy Elizabeth Joseloff György Balla János Kappelmayer Milan Macek Scott C. Bell Barry J. Plant Margarida D. Amaral István Balogh 《Journal of cystic fibrosis》2019,18(2):271-277
Background
We have recently shown that human epididymis protein 4 (HE4) levels correlate with the severity of cystic fibrosis (CF) lung disease. However, there are no data on how HE4 levels alter in patients receiving CFTR modulating therapy.Methods
In this retrospective clinical study, 3 independent CF patient cohorts (US-American: 29, Australian: 12 and Irish: 19 cases) were enrolled carrying at least one Class III CFTR CF-causing mutation (p.Gly551Asp) and being treated with CFTR potentiator ivacaftor. Plasma HE4 was measured by immunoassay before treatment (baseline) and 1–6?months after commencement of ivacaftor, and were correlated with FEV1 (% predicted), sweat chloride, C-reactive protein (CRP) and body mass index (BMI).Results
After 1?month of therapy, HE4 levels were significantly lower than at baseline and remained decreased up to 6?months. A significant inverse correlation between absolute and delta values of HE4 and FEV1 (r?=??0.5376; P?<?.001 and r?=??0.3285; P?<?.001), was retrospectively observed in pooled groups, including an independent association of HE4 with FEV1 by multiple regression analysis (β?=??0.57, P?=?.019). Substantial area under the receiver operating characteristic curve (ROC-AUC) value was determined for HE4 when 7% mean change of FEV1 (0.722 [95% CI 0.581–0.863]; P?=?.029) were used as classifier, especially in the first 2?months of treatment (0.806 [95% CI 0.665–0.947]; P?<?.001).Conclusions
This study shows that plasma HE4 levels inversely correlate with lung function improvement in CF patients receiving ivacaftor. Overall, this potential biomarker may be of value for routine clinical and laboratory follow-up of CFTR modulating therapy. 相似文献25.
目的:综述运动系统软组织损伤引起慢性疼痛的各种治疗方法的研究进展。资料来源:应用计算机检索Medline1980—01/2006—04与运动系统软组织损伤引起慢性疼痛的治疗相关文章,检索词“Soft tissue injury,pain.chronic,comprehensive therapy”,并限定文章语言种类为“English”;同时计算机检索中国期刊全文数据库1994—01/2006-04期间的相关文章,检索词“软组织损伤、慢性疼痛、治疗方法”,并限定语言种类为中文。同时手工查阅相关书籍。资料选择:对资料进行初审,所选文献内容符合:①软组织损伤引起的慢性疼痛药物治疗的研究。②软组织损伤引起的慢性疼痛微创治疗的研究。③软组织损伤引起的慢性疼痛运动疗法的研究。④软组织损伤引起的慢性疼痛心理治疗的研究。⑤软组织损伤引起的慢性疼痛其他疗法的研究。排除重复性研究的文献。资料提炼:共收集到40篇关于软组织损伤引起的慢性疼痛治疗方法的文献,均为全文,23篇符合纳入标准,排除17篇重复性研究。同时录入书籍3本。资料综合:软组织损伤引起的慢性疼痛的产生是生理、心理及社会因素复杂结合的结果,个体表现差异较大,目前尚无特效治疗方法,常用的治疗方法有:药物治疗、微创治疗、运动疗法、心理治疗、物理疗法及其他疗法。结论:对于软组织损伤引起的慢性疼痛的治疗必须以整体的观点对其进行合理的评估和个体化治疗,才能收到良好的效果。 相似文献
26.
Chronic transplant dysfunction is a complex dynamic pathogenic process. Clinically, a decrease in glomerular filtration rate (GFR) becomes apparent leading to chronic renal insufficiency and dialysis or death from cardiovascular events. Chronic transplant dysfunction can develop into a chronic alIograft nephropathy (CAN) as a specific entity with dynamic progression. CAN includes a collection of immunologic and non-immunologic factors, rejection, ischemia time, donor and recipient characteristics and toxicity of calcineurin inhibitors. Despite improvements in immunosuppression, the long-range prognosis of renal allografts has not improved. Whether modern immunosuppressive concepts with reduction or avoidance of calcineurin inhibitors and a therapy based on antimetabolites, such as mycophenolate or mTOR-inhibitors could lead to a prolongation of transplant survival, remains to be seen. 相似文献
27.
N. SUVAJD
I V. EMERIKI‐MARTINOVI . ARANOVI M. PETROVI M. POPOVI V. ARTIKO M. UPI I. ELEZOVI 《International journal of laboratory hematology》2006,28(5):317-320
We report the case of a littoral‐cell angioma of the spleen, a recently described benign vascular tumour, whose imaging and pathological characteristics have been discussed only by a few authors. The diagnosis was made after elective splenectomy. The CT images, scintigraphy and histological specimens are presented, and differential diagnoses discussed. 相似文献
28.
29.
G Steinitz M C Martín N Gazit-Yaari M L Quesada J de la Nuez R Casillas U Malik Z B Begin 《Applied radiation and isotopes》2006,64(4):520-524
Multi-day signals, generally with duration of 2-10 days, are a prominent temporal variation type of radon (Rn) in geogas in the unsaturated zone. Rare multi-day Rn signals have been found which are characterized by: (a) a declining limb lasting up to 10 days which conforms to the radioactive decay of Rn, (b) recurs at the same location and (c) is recorded in diverse situations-volcanic and seismogenic. It suggested that a Rn blob is injected at a lower level on a steady upward flow of geogas whereby the rise and final fall of the signal are attributed to the edges of the blob while the central Rn-decay segment records the passing of the decaying blob itself. Rn-decay signals are a small subset of multi-day Rn signals which are considered as highly irregular and unusable for the understanding of geophysical processes. In difference, it is concluded that multi-day Rn signals are probably proxies of subtle geodynamic processes at upper crustal levels and are therefore significant for studying such processes. 相似文献
30.
ZusammenfassungHintergrund Bedingt durch die intraoperative Katecholaminsekretion mit hämodynamischen Veränderungen, einem größeren Tumordurchmesser und einer deutlichen Neovaskularisation ist die Adrenalektomie beim Phäochromozytom im Vergleich zu anderen Nebennierenerkrankungen schwieriger und potenziell komplikationsträchtiger. Ziel unserer Studie war die Frage, ob das Risiko intraoperativer kardiovaskulärer Komplikationen durch das minimal-invasive Vorgehen potenziert wird.Patienten und Methodik Im Zeitraum zwischen Februar 1992 und Mai 2005 wurden in unserer Klinik 82 Eingriffe wegen eines Phäochromozytoms bei 71 Patienten durchgeführt. Davon wurden 8 (1) Patient(en) bi-(tri-)lateral adrenalektomiert und bei 2 Patienten erfolgte eine ipsilaterale Rezidivoperation. Eingeschlossen sind 5 weitere Patienten mit Rezidiv nach Erstoperation vor 1992. Sechsunddreißig Eingriffe erfolgten konventionell (transperitoneal n=35, retroperitoneal n=1) und 46 Operationen endoskopisch (transperitoneal n=28, retroperitoneal n=18), davon keine Konversion zum offenen Vorgehen.Ergebnisse Das mediane Alter zum Zeitpunkt der Operation betrug 45 (24–75) Jahre bei einer Anamnesedauer von 12 (0–180) Monaten. Die offen operierten Phäochromozytome waren mit 5,5 (1–19) cm vs. 3,5 (0,5–8) cm (endoskopisch) signifikant größer (p=0,0011). Patienten mit endoskopischer, insbesondere mit retroperitoneoskopischer Adrenalektomie hatten im Vergleich zum konventionellen Vorgehen intraoperativ höhere systolische und diastolische maximale Blutdruckwerte sowie Spitzen über 200 mmHg (statistisch nicht signifikant). Faktoren mit möglichem Einfluss auf intraoperative hämodynamische Veränderungen waren in der multivariaten Analyse das Geschlecht (p=0,0107), der operative Zugangsweg (p=0,0153), das Patientenalter (p=0,0364) und die Tumorgröße (p=0,0484). Die postoperative stationäre Verweildauer war nach endoskopischer Operation signifikant kürzer (p<0,0001).Schlussfolgerung Die endoskopische Adrenalektomie beim Phäochromozytom ist in der Routine ohne vermehrtes Risiko kardiovaskulärer Komplikationen die Methode der Wahl. Das offene Vorgehen sollte extraadrenalen Befunden oder sehr großen Tumoren mit Malignitätsverdacht vorbehalten bleiben. 相似文献