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   56237篇
  免费   4526篇
  国内免费   153篇
耳鼻咽喉   511篇
儿科学   1508篇
妇产科学   1075篇
基础医学   7449篇
口腔科学   953篇
临床医学   6232篇
内科学   10772篇
皮肤病学   804篇
神经病学   4844篇
特种医学   2193篇
外科学   9373篇
综合类   782篇
一般理论   57篇
预防医学   5587篇
眼科学   1261篇
药学   4040篇
  1篇
中国医学   53篇
肿瘤学   3421篇
  2023年   320篇
  2022年   450篇
  2021年   1154篇
  2020年   654篇
  2019年   1086篇
  2018年   1305篇
  2017年   951篇
  2016年   1025篇
  2015年   1228篇
  2014年   1797篇
  2013年   2491篇
  2012年   3800篇
  2011年   3887篇
  2010年   2105篇
  2009年   1868篇
  2008年   3392篇
  2007年   3639篇
  2006年   3537篇
  2005年   3436篇
  2004年   3180篇
  2003年   3026篇
  2002年   2853篇
  2001年   881篇
  2000年   838篇
  1999年   835篇
  1998年   642篇
  1997年   517篇
  1996年   486篇
  1995年   514篇
  1994年   431篇
  1993年   401篇
  1992年   543篇
  1991年   486篇
  1990年   504篇
  1989年   467篇
  1988年   431篇
  1987年   376篇
  1986年   384篇
  1985年   428篇
  1984年   370篇
  1983年   301篇
  1982年   255篇
  1981年   232篇
  1980年   212篇
  1979年   242篇
  1978年   234篇
  1974年   210篇
  1973年   194篇
  1972年   188篇
  1968年   185篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
The hypothesis that the release of vasopressin-associated neurophysin (hNpI) or oxytocin-associated neurophysin (hNpII) is modified by a course of electroconvulsive therapy (ECT) was tested by the measurement of serum neurophysins before and after the first and last ECTs given to 17 unipolar depressed patients. Neither basal nor ECT-induced neurophysin release changed between the first and last ECTs. Data from the present study were combined with data from a previous published study to provide a sample of 29 unipolar depressed patients. In this extended sample, the release of hNpII after the first ECT was significantly correlated with improvement in symptoms of depression over a course of ECT as measured by the Hamilton Rating Scale for Depression and the Montgomery-Asberg Depression Rating Scale.  相似文献   
93.
94.
Many recent improvements in the management of patients with malignancy would have been impossible without parallel improvements in our ability to support patients through periods of severe bone marrow aplasia produced by the disease or aggressive therapy of the disease. The purpose of this article is to review the use of transfusion of platelets, erythrocytes, and granulocytes in the treatment of these patients.
Resumen Muchos de los recientes adelantos en el manejo de pacientes con neoplasias malignas habrían sido imposibles sin un desarrollo paralelo en la capacidad de proveer soporte en el curso de severa aplasia de la medula ósea producida por la enfermedad misma o por terapia antineoplásica agresiva. El propósito de este artículo es revisar el uso de las transfusiones de plaquetas, eritrocitos, y granulocitos en el manejo de estos pacientes.

Résumé De nombreuses améliorations récentes du traitement des malades atteints d'une affection maligne auraient été impossibles sans des améliorations parallèles du traitement des épisodes d'aplasie médullaire grave produits par l'affection elle-même ou par les agents thérapeutiques agressifs employés pour les traiter. Le but de l'article est de passer en revue l'emploi respectif des plaquettes, des érythrocytes et des granulocytes pour traiter ces malades.
  相似文献   
95.
96.
The purpose of this study was to test the hypothesis that specific cytokines are involved in the initiation and evolution of the fibrotic process in adhesive capsulitis of the shoulder. After approval from the Institutional Review Board, biopsies of shoulder capsule and synovium were collected during shoulder arthroscopy from 19 patients with adhesive capsulitis, 14 patients with nonspecific synovitis and no fibrosis or clinical evidence of adhesive capsulitis, and seven patients undergoing surgery for another pathology who had a normal capsule and synovium. Immunohistochemical localization with monoclonal antibodies to transforming growth factor-β and its receptor, platelet-derived growth factor and its receptor, basic fibroblast growth factor, interleukin-1β, tumor necrosis factor-α, and hepatocyte growth factor was performed using standard immunoperoxidase techniques. The frequency of cytokine staining was correlated with the clinical diagnosis Synovial cells, fibroblasts, T-cells, and B-cells were identified with specific antibodies, and newly synthesized matrix was examined for type-I and type-III collagen by immunohistochemical staining. The predominant cell types present were synovial cells and fibroblasts. Staining for type-III collagen in adhesive capsulitis tissues indicated new deposition of collagen in the capsule. There was staining for transforming growth factor-β and its receptor, platelet-derived growth factor and its receptor, interleukin-1β, and tumor necrosis factor-α in adhesive capsulitis and nonspecific synovitis tissues, compared with minimal staining in normal capsule. Staining was more frequent in snovial cells than in capsular cells. The frequency of cell and matrix staining for transforming growth factor-β, platelet-derived growth factor, and hepatocyte growth factor was greater in adhesive capsulitis tissues than in those from patients with nonspecific synovitis. No difference in the frequency of staining between primary (idiopathic) and secondary adhesive capsulitis was found. The results of this study indicate that adhesive/capsulitis involves both synovial hyperplasia and capsular fibrosis. Cytokines such as transforming growth factor-β and platelet-derived growth factor may be involved in the inflammatory and fibrotic processes in adhesive capsulitis. Matrix-bound transforming growth factor-β may act as a persistent stimulus, resulting in capsular fibrosis. Understanding the basic pathophysiology of adhesive capsulitis is an important step in the development of clinically useful antifibrotic agents that may serve as novel treatments for patients with this condition.  相似文献   
97.
The objective of this study was to determine the frequency and significance of the MR findings of incomplete shell collapse for detecting implant rupture in a series of surgically removed breast prostheses. MR images of 86 breast implants in 44 patients were studied retrospectively and correlated with surgical findings at explanation. MR findings included (a) complete shell collapse (linguine sign), 21 implants; (b) incomplete shell collapse (subcapsular line sign, teardrop sign, and keyhole sign), 33 implants; (c) radial folds, 31 implants; and (d) normal, 1 implant. The subcapsular line sign was seen in 26 implants, the teardrop sign was seen in 27 implants, and the keyhole sign was seen in 23 implants. At surgery, 48 implants were found to be ruptured and 38 were intact. The MR findings of ruptured implants showed signs of incomplete collapse in 52% (n = 25), linguine sign in 44% (n = 21), and radial folds in 4% (n = 2). The linguine sign perfectly predicted implant rupture, but sensitivity was low. Findings of incomplete shell collapse improved sensitivity and negative predictive values, and the subcapsular line sign produced a significant incremental increase in predictive ability. MRI signs of incomplete shell collapse were more common than the linguine sign in ruptured implants and are significant contributors to the high sensitivity and negative predictive values of MRI for evaluating implant integrity.  相似文献   
98.
In the current era of functional surgery for movement disorders, deep brain stimulation (DBS) of the globus pallidus internus (GPi) is emerging as the favoured intervention for patients with dystonia. Here we report our results in 20 patients with medically intractable dystonia treated with GPi stimulation. The series comprised 14 patients with generalized dystonia and six with spasmodic torticollis. Although comparisons were limited by differences in their respective neurological rating scales, chronic DBS clearly benefited both patient groups. Data conveying the rate of change in neurological function following intervention are also presented, demonstrating the gradual but progressive and sustained nature of improvement following stimulation of the GPi in dystonic patients.  相似文献   
99.
Success of meniscal repair with early or immediate motion depends on the ability of the suture fixation to withstand the loads applied. Vertical and horizontal mattress suture techniques were tested using 2-0 Ethibond, and 0-PDS and 1-PDS sutures (Ethicon, Somerville, NJ). Mulberry knot technique was tested with 0-PDS and 1-PDS sutures. Twenty menisci (60 sutures) were tested for each suture material. Sutures were placed 3 to 4 mm from the peripheral edge of the meniscus with double barreled cannulas for vertical and horizontal mattress techniques or a spinal needle for the mulberry knot technique, reproducing clinical techniques of meniscal repair. Mechanical testing of suture fixation was performed to failure at a rate of 10 mm/min on a MTS material testing system (MTS Systems Corp. Minneapolis, MN). Suture pullouts were reported as the load displacement to failure from the inner fragment only, because clinical failure would ensue should a suture pull through the inner fragment of a tear. Vertical mattress technique with 1-PDS suture had significantly greater load to failure than any other combination (P < .05). Analysis of variance showed that the vertical mattress technique had statistically superior pullout strength (P < .0001) compared with the horizontal mattress and mulberry knot techniques, which were statistically similar. There were significant differences (P < .0001) between suture types, with 1-PDS proving best compared with 0-PDS, which was stronger than 2-0 Ethibond. Selection of suture material had the greatest impact on vertical mattress load to failure and was not important to the strength of the other techniques.  相似文献   
100.
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