全文获取类型
收费全文 | 2186259篇 |
免费 | 157436篇 |
国内免费 | 4728篇 |
专业分类
耳鼻咽喉 | 28525篇 |
儿科学 | 71836篇 |
妇产科学 | 58781篇 |
基础医学 | 317676篇 |
口腔科学 | 63596篇 |
临床医学 | 196988篇 |
内科学 | 423929篇 |
皮肤病学 | 49642篇 |
神经病学 | 166223篇 |
特种医学 | 81691篇 |
外国民族医学 | 316篇 |
外科学 | 329153篇 |
综合类 | 49815篇 |
现状与发展 | 5篇 |
一般理论 | 663篇 |
预防医学 | 161893篇 |
眼科学 | 52198篇 |
药学 | 161211篇 |
9篇 | |
中国医学 | 6146篇 |
肿瘤学 | 128127篇 |
出版年
2021年 | 16602篇 |
2019年 | 17280篇 |
2018年 | 25128篇 |
2017年 | 19235篇 |
2016年 | 21121篇 |
2015年 | 23905篇 |
2014年 | 33071篇 |
2013年 | 48552篇 |
2012年 | 66703篇 |
2011年 | 70288篇 |
2010年 | 41660篇 |
2009年 | 38991篇 |
2008年 | 65230篇 |
2007年 | 69586篇 |
2006年 | 70066篇 |
2005年 | 66832篇 |
2004年 | 64564篇 |
2003年 | 61410篇 |
2002年 | 59115篇 |
2001年 | 114094篇 |
2000年 | 116244篇 |
1999年 | 95949篇 |
1998年 | 25122篇 |
1997年 | 21787篇 |
1996年 | 22004篇 |
1995年 | 21228篇 |
1994年 | 19481篇 |
1993年 | 17940篇 |
1992年 | 72516篇 |
1991年 | 70734篇 |
1990年 | 68069篇 |
1989年 | 65784篇 |
1988年 | 59967篇 |
1987年 | 58326篇 |
1986年 | 55193篇 |
1985年 | 52090篇 |
1984年 | 38377篇 |
1983年 | 32609篇 |
1982年 | 18243篇 |
1979年 | 34001篇 |
1978年 | 23683篇 |
1977年 | 20062篇 |
1976年 | 18892篇 |
1975年 | 20101篇 |
1974年 | 24083篇 |
1973年 | 23199篇 |
1972年 | 21702篇 |
1971年 | 20041篇 |
1970年 | 18841篇 |
1969年 | 17528篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Christopher N. Cooley Tyler J. Beranek Matthew A. Warpinski Robert Alexander Amanda O. Esquivel 《The American journal of emergency medicine》2019,37(2):199-203
Introduction
In the United States there has been a large increase in participation in lacrosse for both males and females. The purpose of this study was to analyze the number of head injuries, injury rates (calculated using the reported number of participants) and types of head injuries that are seen in emergency departments in the United States.Methods
We compared injuries between male and female lacrosse participants. This was a retrospective study using a publicly available database produced by the US Consumer Product Safety Commission and information about lacrosse participation from US Lacrosse.Results
A linear regression was performed and showed a positive correlation between number of head injuries to males and time from 2002 to 2010 (R2?=?0.823; p?=?0.001). While the number of injuries to the head in female lacrosse participants was not significant. There was a negative correlation between the number of head injuries to males from 2010 to 2016 (R2?=?0.800; p?=?0.007), but again, there was no significance for female injury count (R2?=?0.417; p?=?0.117). Other significant differences between head injuries in males and females included the mechanism of injury and the type of injury recorded.Conclusion
The most recent data from 2010 to 2016, suggest that both males and females have had a decrease in injury rate. However the total number of female head injuries is not significantly decreasing and as the sport continues to grow there will likely be more total head injuries and visits to the emergency department. 相似文献32.
33.
Laparoscopic surgery has several advantages over traditional surgery because it has been shown to be less invasive. The next logical step in the evolution of minimally invasive surgery may be to eliminate all abdominal incisions. The natural orifices provide a port of entry via the gastrointestinal tract to the peritoneal cavity. This approach would require the creation of a perforation, which is considered to be a major complication of endoscopy with significant morbidity and mortality. However, there are several recent studies that have described the technical feasibility and safety of a per‐oral transgastric approach to the peritoneal cavity using conventional endoscopes. Theoretically, this approach could reduce postoperative abdominal wall pain, wound infection, hernia formation, and adhesions. This article aims to summarize the current status of transgastric surgery, currently referred to as natural orifice transluminal endoscopic surgery (NOTES), and to address some of its future challenges. 相似文献
34.
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
35.
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
36.
37.
38.
39.
A Kotsiou M Tsamouri S Anagnostopoulou M Tzivras E Vairactaris C Tesseromatis 《European journal of drug metabolism and pharmacokinetics》2006,31(2):97-101
Liver disease alters the pharmacokinetic and pharmacodynamic properties of hepatically eliminated drugs. The main factors influenced are plasma albumin levels, enzyme balance (induction & inhibition) and drug binding to tissue proteins. The influence of lidocaine on serum, heart and liver propranolol levels in Wistar rats after liver injury induced by carbon tetrachloride CCl4 0.4 ml/kg x 2/wkl, was investigated. 40 male Wistar rats were divided into four groups (I, II, III, IV; n=10), Group I animals received only propranolol (labelled + cold substance) 40 mg/kg/12 h p.o., group II propranolol plus lidocaine in a single dose of 4mg/kg s.c., group III was treated with CCl4 for 6 weeks and received propranolol x2 at the same dosage as group I, while group VI was treated with CCl4 and the same drug dosage as group II. The simultaneous administration of H3-propranolol and lidocaine increased propranolol levels in the serum and tissues. The liver in damaged animals showed an increase of propranolol level under lidocaine co-administration, probably due to CCl4 induced liver enzyme activity, resulting in a rapid propranolol metabolism or to competition between both drug protein binding sites. The increased propranolol levels in the heart after lidocaine administration were probably due to attributed to its high affinity for heart tissue. Consequently, as regards the therapeutic approach for patients with liver disease receiving propranolol their propranolol dosage should be reduced when lidocaine is co-administered. 相似文献
40.
A-C Koschker M Fassnacht S Hahner D Weismann B Allolio 《Experimental and clinical endocrinology & diabetes》2006,114(2):45-51
BACKGROUND: Adrenocortical carcinoma (ACC) is a rare and highly malignant tumour with a poor prognosis. Patients present with signs of steroid hormone excess (e.g., Cushing's syndrome) or symptoms due to an abdominal mass. DIAGNOSIS: In case of an adrenal mass, hormonal workup before surgery is required for differential diagnosis, perioperative management, and for follow-up. The imaging of choice is CT or MRI with MRI being of additional use when invasion of big vessels is suspected. Apart from that, the use of 18-FDG-PET is becoming increasingly established. TREATMENT: Surgical resection is the therapeutic option of choice in stages 1 - 3. In stage 4, the adrenolytic compound mitotane is part of the first-line treatment, but often needs to be combined with cytotoxic chemotherapy. Most patients will eventually have a recurrence, so adjuvant treatment (mitotane/tumour bed radiation) has to be considered in high risk patients, even if randomized controlled trials on adjuvant treatment are still lacking. STRUCTURAL PROGRESS: Several national and European structures have recently been established in order to increase our knowledge of ACC, improve therapeutic options and diagnostic procedures, and promote research. GANIMED, as a Germany-wide network of experts on adrenal diseases, has been founded allowing for improved gathering of data and joint studies. ENSAT (European Network for the Study of Adrenal Tumours) has been brought to life, aiming at European standards for therapy, diagnosis and tumour banking. Since 2003, patients can be enrolled in the German ACC Registry. France and Italy have also developed a central registry to collect nationwide data from patients with ACC. For the first time, patients with metastatic/unresectable ACC can participate in a prospective controlled randomized trial comparing two different cytotoxic chemotherapy regimes (FIRM-ACT). 相似文献