首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4809篇
  免费   274篇
  国内免费   17篇
耳鼻咽喉   61篇
儿科学   114篇
妇产科学   119篇
基础医学   652篇
口腔科学   567篇
临床医学   387篇
内科学   980篇
皮肤病学   137篇
神经病学   314篇
特种医学   210篇
外科学   496篇
综合类   24篇
一般理论   1篇
预防医学   530篇
眼科学   92篇
药学   250篇
中国医学   38篇
肿瘤学   128篇
  2023年   47篇
  2022年   91篇
  2021年   179篇
  2020年   135篇
  2019年   134篇
  2018年   191篇
  2017年   119篇
  2016年   139篇
  2015年   170篇
  2014年   231篇
  2013年   276篇
  2012年   413篇
  2011年   417篇
  2010年   186篇
  2009年   186篇
  2008年   296篇
  2007年   290篇
  2006年   254篇
  2005年   229篇
  2004年   164篇
  2003年   142篇
  2002年   139篇
  2001年   105篇
  2000年   79篇
  1999年   58篇
  1998年   29篇
  1997年   23篇
  1996年   17篇
  1995年   22篇
  1994年   17篇
  1993年   12篇
  1992年   12篇
  1991年   25篇
  1990年   22篇
  1989年   20篇
  1988年   13篇
  1987年   14篇
  1986年   23篇
  1985年   14篇
  1984年   9篇
  1983年   11篇
  1982年   9篇
  1981年   7篇
  1980年   15篇
  1977年   7篇
  1976年   7篇
  1973年   11篇
  1971年   9篇
  1970年   16篇
  1969年   12篇
排序方式: 共有5100条查询结果,搜索用时 31 毫秒
11.
Pulmonary embolism (PE) is an important health problem and often a major clinical challenge, not only because of the low specificity of its clinical manifestations but also because of the increasing number of medical circumstances that are risk factors for this illness and the importance of early identification, since prompt and appropriate treatment can decrease mortality from this disease by about 25%. In recent years research on PE has been extensive, directed mainly at trying to determine and characterize its risk factors, establish new clinical probability algorithms, develop new diagnostic methods and put existing ones into perspective, seek new therapeutic approaches (pharmacological and non-pharmacological), and above all establish protocols that can guide the clinician from the stage of clinical suspicion to measures to prevent recurrence. It was the authors' aim to review the most significant literature on this subject, in order to produce a text that reflects the state of the art concerning PE and that can be used as a guide in the clinical approach to this pathology.  相似文献   
12.
New techniques of sling placement may be associated with infectious complications. Slings through the obturator foramen and thigh can lead to a significant abscess formation within the thigh adductor muscles. A large thigh abscess associated with a transobturator sling was diagnosed and treated. The authors report the evaluation and treatment of a unique infectious complication of transobturator slings.  相似文献   
13.
Haughton  VM; Prost  R 《Radiology》1986,158(2):461-462
The effect of chemical shift on magnetic resonance (MR) imaging of the pituitary fossa was studied. Healthy volunteers underwent conventional MR imaging of the pituitary fossa and then imaging with the frequency-encoding gradient reversed or with the phase- and frequency-encoding gradients interchanged. Comparison of the image pairs in each subject showed that the thin, black stripe evident at the water-fat interface within the pituitary fossa was altered when the gradients were changed. Therefore, the low-intensity signal within the pituitary fossa is a chemical shift misregistration effect.  相似文献   
14.
15.
PURPOSE: A prospective radiographic study analyzed condylar position in patients who had undergone orthodontic treatment and isolated maxillary advancement after Le Fort I osteotomy. PATIENTS AND METHODS: Eleven patients were selected and radiographic images were taken in the immediate preoperative, immediate postoperative (1-2 weeks), and late postoperative periods (minimum of 6 months). Tracings were done on acetate paper for the submento-vertex radiograph, to measure the axial angulation of the condyles, and for the tomographic images of both sides, in the maximal intercuspation, rest position, and maximal opening, for the 3 periods. Linear measurements were taken for the tomograms over the posterior, superior, and anterior articular spaces. These images with the tracings were digitized and measured by means of computer software (UTHSCSA Image Tool 3.0; University of Texas Health Science Center at San Antonio, San Antonio, TX), after it had been adequately calibrated. RESULTS: The analysis of variance (ANOVA; 5% of significance) demonstrated 1) that there was no statistically significant difference for the linear measurements of the articular spaces in any of the periods, and 2) also not for the angular measure of the condyles (P > .05). In the maximal opening, there was a significant difference for the immediate postoperative period for both sides (P = .003). CONCLUSION: Le Fort I osteotomy for maxillary advancement did not cause any significant changes in this specific group of patients evaluated.  相似文献   
16.
Anulus fibrosus in bulging intervertebral disks   总被引:1,自引:0,他引:1  
Yu  SW; Haughton  VM; Sether  LA; Wagner  M 《Radiology》1988,169(3):761-763
In this investigation the association of radial tears of the anulus fibrosus and bulging of the intervertebral disk was studied. An index of disk bulging was measured in sagittal anatomic sections in 149 lumbar disks from 31 cadavers. The indexes of disk bulging were correlated with stages of disk development and the presence of an annular tear. The largest disk-bulging indexes were always associated with radial tears of the anulus. Eighty-four percent of the disks with radial tears had disk-bulging indexes greater than 2.5 mm. Most normal adult disks had an index of less than 2.5 mm. The results challenge the concept that the anulus fibrosus is intact in bulging disks, although ruptured in herniated disks.  相似文献   
17.
This study evaluated the effects of [D-Leu1]Microcystin-LR variants, by the exposure of Hypophthalmichthys molitrix to Microcystis aeruginosa NPLJ4. Fish was placed in aquariums and exposed to 105 cells mL−1. For 15 days, 05 individuals were removed every 05 days, and tissue samples of liver, skeletal muscle and intestinal tract were collected for histopathologic analyses. Following exposure, those surviving were placed in clean water for 15 days to evaluate their recovery. A control without toxins was maintained in the same conditions and exhibited normal histology and no tissue damage. In exposed fish, samples were characterized by serious damages that similarly affected the different organs, such as dissociation of cells, necrosis and haemorrhage. Samples showed signs of recovery but severe damages were still observed. The results should be valuable to analyze the potency of microcystin toxicity and to help in the diagnosis of fish deaths.  相似文献   
18.
Allelic frequencies of eight autosomal short‐tandem repeat (STR) loci (TH01, TPOx, CSF1PO, vWA, FES/FPS, F13A1, F13B, and CD4) were determined in 400 individuals born in the State of São Paulo. No significant deviations from Hardy‐Weinberg equilibrium were found in any loci analyzed. The Unweighted Pair‐Group Method with Arithmetic Mean (UPGMA) tree constructed based on genetic distances revealed that the present population was grouped with Europeans, and separated from African and Amerindian populations. Estimates of admixture components based on the gene identity method revealed 79% European, 14% African, and 7% Amerindian contributions to this Brazilian population sample. Am. J. Hum. Biol. 18:702–705, 2006. © 2006 Wiley‐Liss, Inc.  相似文献   
19.
The point of penetration of the recurrent laryngeal nerve into the larynx is recognized as the most frequent site of injury to the nerve during surgical procedures of the thyroid gland. The anatomical relationships of 25 right and left recurrent laryngeal nerves in 25 anatomical blocks from formalin-fixed human corpses have been studied. In 34 cases (68%), the recurrent laryngeal nerve penetrated into the larynx below the lower fibers of the inferior constrictor muscle of the pharynx (type 1 of penetration). In the remaining 16 cases (32%), the nerve crossed through those muscle fibers to penetrate into the larynx (type 2 of penetration). The thyroid gland was found to involve the recurrent laryngeal nerve at the penetration point into the larynx in 19 of 50 cases (38%).  相似文献   
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号