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   19740篇
  免费   1242篇
  国内免费   59篇
耳鼻咽喉   218篇
儿科学   384篇
妇产科学   496篇
基础医学   3363篇
口腔科学   439篇
临床医学   1938篇
内科学   3707篇
皮肤病学   367篇
神经病学   1948篇
特种医学   958篇
外科学   2972篇
综合类   143篇
一般理论   3篇
预防医学   1051篇
眼科学   586篇
药学   1338篇
中国医学   57篇
肿瘤学   1073篇
  2023年   78篇
  2022年   144篇
  2021年   309篇
  2020年   181篇
  2019年   323篇
  2018年   370篇
  2017年   311篇
  2016年   383篇
  2015年   407篇
  2014年   548篇
  2013年   801篇
  2012年   1130篇
  2011年   1088篇
  2010年   751篇
  2009年   688篇
  2008年   1097篇
  2007年   1133篇
  2006年   1158篇
  2005年   1174篇
  2004年   974篇
  2003年   965篇
  2002年   926篇
  2001年   258篇
  2000年   210篇
  1999年   230篇
  1998年   213篇
  1997年   162篇
  1996年   157篇
  1995年   171篇
  1994年   126篇
  1993年   129篇
  1992年   126篇
  1991年   116篇
  1990年   126篇
  1989年   89篇
  1988年   100篇
  1987年   100篇
  1986年   86篇
  1985年   99篇
  1984年   110篇
  1983年   90篇
  1982年   94篇
  1981年   94篇
  1933年   97篇
  1932年   93篇
  1931年   81篇
  1930年   83篇
  1928年   79篇
  1926年   80篇
  1924年   77篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
Zusammenfassung Kaninchen zeigen bei kalorischer Reizung eines Labyrinths Unterschiede im Tonus der Vorderbeine.Bei ampullopetaler Strömung im horizontalen Bogengange wird die gleichseitige Extremität gestreckt und abduziert, die gegenseitige gebeugt und adduziert, bei ampullofugaler Strömung tritt das umgekehrte Verhalten ein.Diese Reaktionsbewegungen fallen nach Labyrinthexstirpation fort.Sie sind unverändert erhalten nach Exstirpation des Großhirns, nach Zerstörung der Mittelohrschleimhaut und nach einseitiger Exstirpation des Ganglion Gasseri.Bei rotatorischer Reizung treten unsichere und bisher nicht einheitlich zu deutende Reaktionsbewegungen auf.  相似文献   
94.
95.
BACKGROUND: Cannabinoids present neurotoxic and neuroprotective properties in in vitro studies, inconsistent alterations in human neuroimaging studies, neuropsychological deficits, and an increased risk for psychotic episodes. METHODS: Proton magnetic resonance spectroscopy ((1)H-MRS), neuropsychological testing, and hair analysis for cannabinoids was performed in 13 male nontreatment-seeking recreational cannabis users and 13 male control subjects. RESULTS: A significantly diminished N-acetylaspartate/total creatine (NAA/tCr) ratio in the dorsolateral prefrontal cortex (DLPFC) was observed in cannabis users (p = .0003). The NAA/tCr in the putamen/globus pallidum region correlated significantly with cannabidiol (R(2) = .66, p = .004). Results of the Wisconsin Card Sorting test, Trail making Test, and D2 test for attention were influenced by cannabinoids. CONCLUSIONS: Chronic recreational cannabis use is associated with an indication of diminished neuronal and axonal integrity in the DLPFC in this study. As chronic cannabis use is a risk factor for psychosis, these results are interesting because diminished NAA/tCr ratios in the DLPFC and neuropsychological deficits were also reported in schizophrenia. The strong positive correlation of NAA/tCr and cannabidiol in the putamen/globus pallidum is in line with neuroprotective properties of cannabidiol, which were also observed in in vitro model studies of Parkinson's disease.  相似文献   
96.
BACKGROUND: Partial response, no response, or residual symptoms following antidepressant therapy is common in clinical psychiatry. This study evaluated modafinil in patients with major depressive disorder (MDD) who were partial responders to adequate selective serotonin reuptake inhibitor (SSRI) therapy and excessive sleepiness and fatigue. METHODS: This retrospective analysis pooled the data of patients (18-65 yrs) who participated in two randomized, double-blind, placebo-controlled studies of modafinil (6-week, flexible-dose study of 100-400 mg/day or 8-week, fixed-dose study of 200 mg/day) plus SSRI therapy. Patients (n=348) met criteria for several residual symptoms (Epworth Sleepiness Scale [ESS] score>or=10; 17-item Hamilton Depression Scale [HAM-D] score between 4 and 25; and Fatigue Severity Scale [FSS] score>or=4). RESULTS: Compared to placebo, modafinil augmentation rapidly (within 1 week) and significantly improved overall clinical condition (Clinical Global Impression-Improvement), wakefulness (ESS), depressive symptoms (17-item HAM-D), and fatigue (FSS) (p<.01 for all). At final visit, patients receiving modafinil augmentation experienced statistically significant improvements in overall clinical condition, wakefulness, and depressive symptoms. Modafinil was well tolerated in combination with SSRI. CONCLUSIONS: Results of this pooled analysis provide further evidence suggesting that modafinil is an effective and well-tolerated augmentation therapy for partial responders to SSRI therapy, particularly when patients continue to experience fatigue and excessive sleepiness.  相似文献   
97.
Zusammenfassung Bei normal ernährten und Vitamin A-frei ernährten Ratten wird bei Sesamölzugabe keine Erhöhung der Thrombocyten beobachtet. Auch bei Gesunden und Kranken mit einer relativen Thrombopenie gelang es nicht, durch Verabreichung von Sesamöl die Thrombocyten zur Norm zu steigern. Die Anwesenheit des Faktors T im Sesamöl wird abgelehnt.  相似文献   
98.
Tibiotalocalcaneal arthrodesis with retrograde intramedullary nailing   总被引:1,自引:0,他引:1  
Nineteen patients (20 feet) with severe hindfoot and ankle deformity underwent tibiotalocalcaneal fusion with a retrograde locked intramedullary nail as a limb-salvage procedure. The purpose of this study was to compare the complication rates of this procedure in diabetic versus nondiabetic patients. There were 8 men and 11 women with preoperative diagnoses including Charcot neuroarthropathy, primary osteoarthritis, rheumatoid arthritis, equinocavovarus, posttraumatic osteoarthritis, gouty arthritis, and ankle malunion. Ten of 20 procedures were performed in patients with diabetes. The average patient age was 56 years, and the average postoperative follow-up was 19.8 months. Nineteen of 20 ankles (95%) achieved successful fusion with an average time of 4.1 months. Four patients (21%) required either a fracture brace or an ankle foot orthosis at final follow-up. Five patients (25%) had major complications and 11 patients had minor complications. Major complications included osteomyelitis (n = 2), Charcot arthropathy (n = 2), failure of fixation (n =1), soft-tissue necrosis (n = 1), cardiac arrest (n = 1), cerebral vascular accident (n = 1), and fatal pulmonary embolus (n = 1). All patients with major complications were diabetic, and 14 of 20 combined major and minor complications occurred in patients with diabetes. The complication rate was found to be high in diabetic patients with end-stage deformity undergoing a limb salvage  相似文献   
99.
This study examines the correlation between development of expressed emotion (EE) in relatives and course of illness of 99 DSM-III schizophrenic patients. Patients whose relatives were high EE at baseline and at the 2nd CFI approximately 20 months later had a poor prognosis at the very outset of the study and an unfavourable course of illness. They had a higher rehospitalisation rate, more symptoms, lower psychosocial assessment, and a poorer 2-year and even 8-year outcome. Patients from families with a fluctuating EE or a consistently low EE had better courses. Expessed emotion is therefore a valid predictor not only of symptomatic relapses, but also of other important aspects of schizophrenia. The connection between EE index and course of illness seerns not to be simply reactive or causal, but complex and non-uniform.  相似文献   
100.
There is controversy whether the short-term and long-term results of coronary artery bypass grafting in elderly patients justify performing the procedure. Between January 1977 and December 1986, 4580 patients underwent coronary artery bypass grafting, of whom 222 (4.9%) were 75 years old or older (mean 77 years). There were 143 men and 79 women and 139 (63%) were in New York Heart Association class IV. One hundred forty-six patients (66%) had had at least one preoperative myocardial infarction. Myocardial revascularization was performed under emergency conditions in 17 patients (18%). The mammary artery was used in 43%, 96% of the patients received two or more grafts. The mean number of bypass grafts was 3.1 per patient. The overall hospital mortality rate was 10.8% (24/222), 3.6% for elective procedures, 14.9% in urgent cases, and 35% in emergencies. In contrast, the overall early mortality rate was 3.1% in 4358 patients less than 75 years old. Complications occurred in 83 patients (37%). Of the patients discharged from the hospital, 198 were followed up for a mean of 48 months (1 to 130). Actuarial probability of survival was 75% at 48 months. Postoperatively 70% were in New York Heart Association class I or II and only 21% were rehospitalized for cardiac problems. During the follow-up period 77% of the patients were free from angina, and of those experiencing angina the mean time from operation to the first episode was 75 months. Although elderly patients have a somewhat increased operative mortality rate, particularly if operated on urgently or emergently, long-term survival and freedom from angina are excellent and justify continued performance of coronary bypass grafting in selected patients over 75 years of age.  相似文献   
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