全文获取类型
收费全文 | 14258篇 |
免费 | 1171篇 |
国内免费 | 28篇 |
专业分类
耳鼻咽喉 | 214篇 |
儿科学 | 597篇 |
妇产科学 | 152篇 |
基础医学 | 1981篇 |
口腔科学 | 378篇 |
临床医学 | 1306篇 |
内科学 | 2642篇 |
皮肤病学 | 297篇 |
神经病学 | 1397篇 |
特种医学 | 700篇 |
外国民族医学 | 1篇 |
外科学 | 1884篇 |
综合类 | 214篇 |
一般理论 | 21篇 |
预防医学 | 1229篇 |
眼科学 | 312篇 |
药学 | 1093篇 |
中国医学 | 11篇 |
肿瘤学 | 1028篇 |
出版年
2022年 | 98篇 |
2021年 | 212篇 |
2020年 | 126篇 |
2019年 | 216篇 |
2018年 | 215篇 |
2017年 | 178篇 |
2016年 | 167篇 |
2015年 | 227篇 |
2014年 | 297篇 |
2013年 | 530篇 |
2012年 | 751篇 |
2011年 | 793篇 |
2010年 | 436篇 |
2009年 | 397篇 |
2008年 | 678篇 |
2007年 | 726篇 |
2006年 | 731篇 |
2005年 | 768篇 |
2004年 | 718篇 |
2003年 | 711篇 |
2002年 | 712篇 |
2001年 | 268篇 |
2000年 | 261篇 |
1999年 | 264篇 |
1998年 | 213篇 |
1997年 | 190篇 |
1996年 | 180篇 |
1995年 | 172篇 |
1994年 | 117篇 |
1993年 | 138篇 |
1992年 | 190篇 |
1991年 | 174篇 |
1990年 | 169篇 |
1989年 | 179篇 |
1988年 | 154篇 |
1987年 | 140篇 |
1986年 | 164篇 |
1985年 | 150篇 |
1984年 | 140篇 |
1983年 | 161篇 |
1982年 | 176篇 |
1981年 | 144篇 |
1980年 | 152篇 |
1979年 | 115篇 |
1978年 | 122篇 |
1977年 | 103篇 |
1976年 | 104篇 |
1974年 | 103篇 |
1973年 | 110篇 |
1972年 | 97篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
The H-reflex is an indirect measure of the excitability levels of alpha motoneurons. The authors have developed an adaptation of H-reflex testing which allows the continuous monitoring of human alpha motoneuron activity during movement. The technique differs from previously used H-reflex testing techniques in that it utilizes a 5 Hz stimulation to elicit the H-reflex. This allows for continuous and concomitant H- and M-wave recordings during a movement. This is an improvement over past single stimulus techniques in that the time and discomfort associated with this type of experimentation is greatly decreased. The repetitive stimulation technique enables H-reflex testing to be used clinically with neurologically impaired patient populations. Thus far, the authors have used the repetitive H-reflex testing procedures to assess alpha motoneuron activation and reciprocal inhibition of antagonist musculature during voluntary movement and anticipatory postural control responses of non-disabled individuals and of individuals with cerebral palsy. This paper describes the methodology involved in this technique and reports the results obtained. 相似文献
42.
43.
44.
Raymer P. Grant Cliff Morgan Michael S. Page David N. Malm Victor Huckel Leonard C. Jenkins 《Journal canadien d'anesthésie》1990,37(4):409-415
Dipyridamole thallium scanning (DTS) is an imaging technique with good sensitivity for coronary artery disease (CAD). The purpose of this study was to compare the haemodynamic courses and the correlation between pulmonary capillary wedge pressure (PCWP) and central venous pressure (CVP) in patients with normal DTS (Group 1: n = 12) with those whose scans demonstrated CAD (Group2: n = 11). Haemodynamic profiles were obtained prior to anaesthesia and at several times during surgery. The haemodynamic courses in both groups were similar with significant decreases in cardiac index, stroke index, and left ventricular stroke work index during aortic cross-clamping compared with values prior to anaesthesia. There were no significant changes in PCWP and CVP throughout the study. The correlations between PCWP and CVP were significant in both groups as were the correlations between the changes in PCWP and the changes in CVP observed at the time of cross-clamping. These correlations all had large standard errors of the estimate, however, making it impossible to predict the PCWP from the CVP with precision. It is concluded that, in a limited study population, an abnormal DTS did not identify patients in whom the PCWP and CVP correlated poorly during abdominal aortic aneurysmectomy. 相似文献
45.
John S March Martin E Franklin Henrietta Leonard Abbe Garcia Phoebe Moore Jennifer Freeman Edna Foa 《Neuropsychopharmacology》2007,61(3):344-347
BACKGROUND: The presence of a comorbid tic disorder may predict a poorer outcome in the acute treatment of pediatric obsessive-compulsive disorder (OCD). METHODS: Using data from the National Institute of Mental Health (NIMH)-funded Pediatric OCD Treatment Study (POTS) that compared cognitive-behavior therapy (CBT), medical management with sertraline (SER), and the combination of CBT and SER (COMB), to pill placebo (PBO) in children and adolescents with OCD, we asked whether the presence of a comorbid tic disorder influenced symptom reduction on the Children's Yale-Brown Obsessive Compulsive Scale (CY-BOCS) after 12 weeks of treatment. RESULTS: Fifteen percent (17 of 112) of patients exhibited a comorbid tic disorder. In patients without tics, results replicated previously published intent-to-treat outcomes: COMB > CBT > SER > PBO. In patients with a comorbid tic disorder, SER did not differ from PBO, while COMB remained superior to CBT and CBT remained superior to PBO. CONCLUSIONS: In contrast to CBT outcomes, which are not differentially impacted, tic disorders appear to adversely impact the outcome of medication management of pediatric OCD. Children and adolescents with obsessive-compulsive disorder and a comorbid tic disorder should begin treatment with cognitive-behavior therapy alone or the combination of cognitive-behavior therapy plus a serotonin reuptake inhibitor. 相似文献
46.
47.
J E Fildes A H Walker C G Densem A K Deiraniya I V Hutchinson C T Leonard N Yonan 《The Journal of heart and lung transplantation》2005,24(4):406-410
BACKGROUND: The angiotensin converting enzyme insertion deletion polymorphism (ACE I/D) has been associated with much cardiovascular pathology, including posttransplantation hypertension. Hypertension is a significant cause of morbidity and mortality after cardiac transplantation. We investigated the influence of the ACE I/D polymorphism on posttransplantation hypertension. METHODS: A total of 211 heart transplant recipients and 154 corresponding donors were genotyped for the ACE I/D polymorphism by polymerase chain reaction. ACE enzymatic activity was measured by spectrophotometric kinetic analysis. Sitting systolic and diastolic blood pressures were recorded at 3 consecutive visits, and the mean was calculated. Clinical data, including demographics and medication, were collected for all recipients. Results were analyzed by the chi-square test and analysis of variance, taking a p value of <0.05 to be significant. RESULTS: A total of 41.7% of the subjects were hypertensive (diastolic blood pressure >90 mm Hg) at the time of the study, with 79.6% taking at least one antihypertensive agent. We found no difference between the number of antihypertensive agents, cyclosporin dose and level, renal function, or systolic blood pressure for the different recipient or donor genotypes. We also found no significant correlation between ACE enzymatic activity and systolic or diastolic blood pressure. CONCLUSIONS: Our study of 211 recipients and 154 corresponding donors is the largest investigation of this polymorphism in a cardiac transplantation population. We found no apparent relationship between the ACE genotype (of either donor or recipient) and systemic hypertension (absolute measurements and the number or dose of antihypertensive agents used). 相似文献
48.
Jennifer B Freeman Molly L Choate-Summers Phoebe S Moore Abbe M Garcia Jeffrey J Sapyta Henrietta L Leonard Martin E Franklin 《Neuropsychopharmacology》2007,61(3):337-343
Obsessive-compulsive disorder (OCD) is a distressing and functionally impairing disorder that can emerge as early as age 4. Cognitive behavior therapy (CBT) for OCD in youth shows great promise for amelioration of symptoms and associated functional impairment. However, the empirical evidence base for the efficacy of CBT in youth has some significant limitations, particularly as related to treating the very young child with OCD. This report includes a quantitative review of existing child CBT studies to evaluate evidence for the efficacy of CBT for OCD. It identifies gaps in the literature that, when addressed, would enhance the understanding of effective treatment in pediatric OCD. Finally, it presents a proposed research agenda for addressing the unique concerns of the young child with OCD. 相似文献
49.
Heart failure is the number one reason for hospital admissionin patients above 65 years of age. It is predicted that thenumber of heart failure patients will almost double in the next20 years. Ischaemic and hypertensive heart disease are the majorcauses of this disabling disease. Approximately 22% of womenand 46% of men who have had a myocardial infarction will developheart failure within 6 years.1 Still, hypertension is a chiefcause of cardiac failure: diastolic dysfunction accounts for>50% of all heart failure patients.2 In the world we livein, an increasing number of people become at risk of developinghypertension heart 相似文献
50.
Michael Leonard Uthman Alao Aaron Glynn Mark Dolan 《European journal of orthopaedic surgery & traumatology : orthopedie traumatologie》2009,19(8):553-558
Between 1999 and 2005, we treated 41 patients with a total hip arthroplasty for failed fixation of a hip fracture. This study
had three purposes: (1) to determine the reason/s for fixation failure (2) to record difficulties/complications encountered
in converting to a salvage arthroplasty and (3) to compare the outcome of these patients (Group 1) with a matched group of
patients who underwent a primary hip arthroplasty (Group 2). Failure to achieve a good reduction and optimal screw placement
was evident in 80% of cases of failed fixation. A high incidence of complications was recorded in the perioperative period
during conversion to a salvage arthroplasty. Functional outcome was statistically inferior in Group1; this group also had
a higher incidence of complications. Radiographs at 2 years postoperatively showed evidence of femoral stem loosening in 16%
of the salvage group compared with 3% in the primary hip arthroplasty group. 相似文献