全文获取类型
收费全文 | 9008篇 |
免费 | 734篇 |
国内免费 | 30篇 |
专业分类
耳鼻咽喉 | 113篇 |
儿科学 | 182篇 |
妇产科学 | 196篇 |
基础医学 | 1546篇 |
口腔科学 | 312篇 |
临床医学 | 1015篇 |
内科学 | 1765篇 |
皮肤病学 | 323篇 |
神经病学 | 905篇 |
特种医学 | 309篇 |
外科学 | 1197篇 |
综合类 | 67篇 |
一般理论 | 2篇 |
预防医学 | 589篇 |
眼科学 | 114篇 |
药学 | 520篇 |
中国医学 | 9篇 |
肿瘤学 | 608篇 |
出版年
2023年 | 61篇 |
2022年 | 114篇 |
2021年 | 188篇 |
2020年 | 128篇 |
2019年 | 167篇 |
2018年 | 209篇 |
2017年 | 181篇 |
2016年 | 233篇 |
2015年 | 246篇 |
2014年 | 325篇 |
2013年 | 423篇 |
2012年 | 632篇 |
2011年 | 644篇 |
2010年 | 380篇 |
2009年 | 361篇 |
2008年 | 509篇 |
2007年 | 547篇 |
2006年 | 492篇 |
2005年 | 500篇 |
2004年 | 465篇 |
2003年 | 421篇 |
2002年 | 412篇 |
2001年 | 155篇 |
2000年 | 138篇 |
1999年 | 135篇 |
1998年 | 105篇 |
1997年 | 66篇 |
1996年 | 61篇 |
1995年 | 68篇 |
1994年 | 50篇 |
1993年 | 42篇 |
1992年 | 97篇 |
1991年 | 70篇 |
1990年 | 80篇 |
1989年 | 74篇 |
1988年 | 63篇 |
1987年 | 78篇 |
1986年 | 52篇 |
1985年 | 66篇 |
1984年 | 46篇 |
1983年 | 44篇 |
1982年 | 32篇 |
1981年 | 32篇 |
1979年 | 37篇 |
1978年 | 35篇 |
1976年 | 33篇 |
1975年 | 28篇 |
1974年 | 45篇 |
1973年 | 53篇 |
1972年 | 31篇 |
排序方式: 共有9772条查询结果,搜索用时 15 毫秒
31.
Torkel Falk Lennart J?nsson Lisbeth H Olsen Henrik D Pedersen 《Cardiovascular pathology》2006,15(4):185-193
BACKGROUND: The occurrence of small vessel arteriosclerosis in the myocardium, kidney, and lung in dogs with naturally occurring myxomatous mitral valve disease has not been previously investigated systematically. METHODS: Twenty-one dogs with naturally occurring congestive heart failure and 21 age-matched, sex-matched, and weight-matched control dogs underwent extensive pathological and histopathological examination. Morphometry and scoring of tissue sections were used to measure arterial narrowing and fibrosis in the myocardium, kidney, and lung; and intimal thickness and plaque formation in the aorta and pulmonary artery. RESULTS: Dogs with congestive heart failure had significantly more arterial narrowing in the left ventricle (P < .003), lung (P < .0001), and kidney (P < .02); intimal-medial thickening in the pulmonary artery (P = .04); and fibrosis in the left ventricle (P < .0001) than control dogs. However, they did not have more plaque formation or intimal-medial thickening in the aorta than controls. There was significantly more arterial narrowing in papillary muscles than in all other locations in dogs with congestive heart failure (P < .002). In control dogs, arterial changes were less pronounced and did not differ in different locations. CONCLUSIONS: Dogs with naturally occurring myxomatous mitral valve disease have significantly more arterial changes in the myocardium, lung, and kidney, and significantly more fibrosis in the myocardium than control dogs. This could have important implications in the management of myxomatous mitral valve disease and raises interesting questions about the occurrence and importance of intramural small vessel disease in humans with primary mitral valve prolapse. 相似文献
32.
M. Bar-Eli S. Sachs G. Tenenbaum J. S. Pie B. Falk 《Scandinavian journal of medicine & science in sports》1996,6(5):313-321
This study presents a unique observational approach to basketball, based on the theory of psychological performance crisis in competition. The approach used takes into account the responses of a player's actions to significant social factors such as team-mates, spectators, the coach and the referees. The contribution of this approach beyond traditional observational techniques is discussed. In our investigation, a single case design was used, in which a professional basketball player was observed during 10 home and 3 away games of the regular season. The relations between the observations and the crisis concept are discussed in detail. In addition, some relevant methodological and applied aspects are presented. 相似文献
33.
P. S. Karnes A. T. Shamban D. R. Olsen M. J. Fazio R. E. Falk 《American journal of medical genetics. Part A》1992,42(1):29-34
Several “progeroid” syndromes have now been identified. The De Barsy syndrome is an autosomal recessive syndrome of dwarfism, mental deficiency, an “aged” appearance at birth, abnormal elastic fibers on skin biopsy, and lax skin, large helices, eye abnormalities, lax joints, hypotonia, and athetoid posturing. We report one case and review 11 cases from the literature. To understand the abnormal appearance of the elastic fibers on biopsy, we performed elastin gene expression studies on fibroblasts cultured from our patient's skin. Molecular hybridization studies revealed reduced elastin mRNA steady-state levels as compared with age matched control individuals. Assuming normal rates of mRNA translation, reduced elastin synthesis would occur. Diminished dermal elastin content could explain the altered cutaneous elasticity, decreased elastic fibers in the skin, and many clinical manifestations of individuals with this condition. 相似文献
34.
An outbreak of hypervitaminosis D associated with the overfortification of milk from a home-delivery dairy. 总被引:3,自引:1,他引:2
下载免费PDF全文
![点击此处可从《American journal of public health》网站下载免费的PDF全文](/ch/ext_images/free.gif)
OBJECTIVES. The purpose of the study was to identify cases of hypervitaminosis D caused by the inadvertent overfortification of milk from a home-delivery dairy and to identify risk factors for this illness. METHODS. Hospital discharge, laboratory, and state health department data were used to define, identify, and describe cases of hypervitaminosis D diagnosed in the exposed communities between January 1, 1985, and June 30, 1991. To identify disease risk factors, community-based sex- and age-matched controls were used in a case-control study. RESULTS. Of the 56 case patients identified, at least 41 were hospitalized; 2 died. The study included 33 case patients and 93 control subjects. Nineteen of the 33 case patients had been customers of the implicated dairy. Risk of illness rose with increasing consumption of the dairy's milk and was also associated with vitamin D supplement use, sunburn susceptibility, and cancer history. Accounting for these factors did not alter the association between drinking the dairy's milk and developing hypervitaminosis D. CONCLUSIONS. Overfortification of milk with vitamin D can lead to hypervitaminosis D, manifested by severe illness and death. The episode highlights the need for monitoring the fortification process and enforcing the upper limit for vitamin D addition to milk. 相似文献
35.
36.
37.
Daniel L. Rubin Karen L. Falk Malcolm J. Sperling Michael Ross Sanjay Saini Barry Rothman Frank Shellock Elias Zerhouni David Stark Eric K. Outwater Udo Schmiedl Louis C. Kirby Judith Chezmar Terry Coates Miles Chang Jeffery M. Silverman Neil Rofsky Keith Burnett Julie Engel Stuart W. Young 《Journal of magnetic resonance imaging : JMRI》1997,7(5):865-872
The purpose of this study was to assess the effectiveness and safety of Gadolite Oral Suspension as a gastrointestinal (GI) contrast agent for MRI in a phase II and two phase III multicenter clinical trials. Gadolite was administered to 306 patients with known or suspected abdominal and/or pelvic disease. MRI with T1- and T2-weighted sequences was performed before and after ingestion. Efficacy was evaluated by having two masked readers rate the certainty of their MR diagnosis (0 = uncertain, 1 = probable, 2 = definite) on randomly presented pre- and post-Gadolite Oral Suspension enhanced images. Principal investigators also evaluated the images and established the final diagnosis. Vital signs, clinical chemistries, and adverse events were documented. Blood and urine samples were analyzed for gadolinium content to determine whether Gadolite Oral Suspension was absorbed systemically. Certainty in MR diagnosis increased significantly (P < .001) for both blinded readers between pre- and post-Gadolite images (.49–1.18 for reader 1; .46–1.53 for reader 2). Sensitivity, specificity, and accuracy also increased for both masked readers. No gadolinium was detected in blood or urine samples. There were no serious adverse events and no apparent drug-related trends in mean vital signs or laboratory values. Gadolite is a highly effective, safe, and well tolerated contrast agent for clinical use with MRI. 相似文献
38.
Andreas Machner Harry Merk Roland Becker Kerstin Rohkohl Heiko Wissel G za Pap 《Acta orthopaedica》2003,74(1):85-88
A proprioceptive deficit is an important determinant of disability in various shoulder disorders, such as instability and osteoarthrosis. In 15 patients with impingement syndrome stage II (Neer 1983), who were treated by arthroscopic subacromial decompression, we measured movement sense by determining threshold levels for the perception of motion of the shoulder. The patients were placed in a specially designed chair allowing continuous passive motion of the shoulder joint, while avoiding cutaneous, auditory and visual stimuli. To assess movement detection thresholds, passive abduction movements of the shoulder were performed at a starting angle of 60°, an amplitude of 10° and an angular velocity of 1.3°/s. Before surgery, all patients had higher threshold levels for the perception of motion in their affected shoulders then in the other side. After decompression, proprioception had improved on the decompressed side, but was unchanged on the other side. 相似文献
39.
40.
New perspectives of avalanche disasters. Phase classification using pathophysiologic considerations]
This study comprises an analysis of the data on 332 persons totally buried by avalanches in Switzerland between 1981 and 1989. The survival rate was calculated with the aid of a computer-assisted estimation procedure according to Turnbull. The curve pattern was interpreted according to pathophysiological considerations, on the basis of which the time course of the battle for survival was divided into 4 phases: 1) Survival phase: until 15 minutes after burial under the snow masses. The survival probability amounts to 93% and is, thus, higher than so far assumed. Almost all those buried survived this period of the time provided they were not fatally injured and received first aid. 2) Asphyxia phase: duration of burial under the avalanche from 15 to 45 minutes. The probability of survival sank dramatically during this period from 93% to about 25% (fatal kink of the survival probability curve). Those buried under the snow without an air pocket die of acute asphyxia (the point of no return) and the mortality rate reaches its maximum in this phase. 3) Latent phase: the period as from 45 minutes following the avalanche until the time of rescue. This phase is survived only in the presence of an air pocket. With sufficient oxygen reserves and freedom of thoracic movement a "phase of relative safety" occurs, whereby the survival probability diminishes further only slowly. The first deaths due to hypothermia arise after 90 minutes. 4) Rescue phase: from the time of extrication from the snow until arrival in hospital. There is an increased risk of a fatal outcome during the rescue procedure and immediately afterwards through augmented hypothermia.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献