全文获取类型
收费全文 | 13931篇 |
免费 | 1173篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 338篇 |
儿科学 | 546篇 |
妇产科学 | 269篇 |
基础医学 | 2026篇 |
口腔科学 | 187篇 |
临床医学 | 1626篇 |
内科学 | 3007篇 |
皮肤病学 | 244篇 |
神经病学 | 1510篇 |
特种医学 | 478篇 |
外国民族医学 | 1篇 |
外科学 | 1672篇 |
综合类 | 239篇 |
现状与发展 | 1篇 |
一般理论 | 12篇 |
预防医学 | 965篇 |
眼科学 | 280篇 |
药学 | 800篇 |
中国医学 | 38篇 |
肿瘤学 | 883篇 |
出版年
2022年 | 88篇 |
2021年 | 192篇 |
2020年 | 135篇 |
2019年 | 192篇 |
2018年 | 203篇 |
2017年 | 152篇 |
2016年 | 212篇 |
2015年 | 221篇 |
2014年 | 325篇 |
2013年 | 531篇 |
2012年 | 674篇 |
2011年 | 746篇 |
2010年 | 459篇 |
2009年 | 364篇 |
2008年 | 680篇 |
2007年 | 699篇 |
2006年 | 687篇 |
2005年 | 794篇 |
2004年 | 652篇 |
2003年 | 628篇 |
2002年 | 579篇 |
2001年 | 335篇 |
2000年 | 321篇 |
1999年 | 275篇 |
1998年 | 200篇 |
1997年 | 159篇 |
1996年 | 141篇 |
1995年 | 125篇 |
1994年 | 128篇 |
1993年 | 122篇 |
1992年 | 187篇 |
1991年 | 193篇 |
1990年 | 195篇 |
1989年 | 175篇 |
1988年 | 159篇 |
1987年 | 162篇 |
1986年 | 157篇 |
1985年 | 127篇 |
1984年 | 124篇 |
1983年 | 135篇 |
1982年 | 136篇 |
1981年 | 153篇 |
1980年 | 138篇 |
1979年 | 142篇 |
1978年 | 114篇 |
1977年 | 126篇 |
1976年 | 111篇 |
1975年 | 85篇 |
1974年 | 131篇 |
1973年 | 96篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Psychogenic excoriation (also called neurotic excoriation, acne excoriée, pathological or compulsive skin picking, and dermatotillomania) is characterised by excessive scratching or picking of normal skin or skin with minor surface irregularities. It is estimated to occur in 2% of dermatology clinic patients and is associated with functional impairment, medical complications (e.g. infection) or substantial distress. Psychogenic excoriation is not yet recognised in the DSM. We propose preliminary operational criteria for its diagnosis that take into account the heterogeneity of behaviour associated with psychogenic excoriation and allow for subtyping along a compulsivity-impulsivity spectrum. Psychiatric comorbidity in patients with psychogenic excoriation, particularly mood and anxiety disorders, is common. Patients with psychogenic excoriation frequently have comorbid disorders in the compulsivity-impulsivity spectrum, including obsessive-compulsive disorder, body dysmorphic disorder, substance use disorders, eating disorders, trichotillomania, kleptomania, compulsive buying, obsessive-compulsive personality disorder, and borderline personality disorder. There are few studies of the pharmacological treatment of patients with psychogenic excoriation. Case studies, open trials and small double-blind studies have demonstrated the efficacy of selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors in psychogenic excoriation. Other pharmacological treatments that have been successful in case reports include doxepin, clomipramine, naltrexone, pimozide and olanzapine. There are no controlled trials of behavioural or psychotherapeutic treatment for psychogenic excoriation. Treatments found to be effective in case reports include a behavioural technique called 'habit reversal'; a multicomponent programme consisting of self-monitoring, recording of episodes of scratching, and procedures that produce alternative responses to scratching; and an 'eclectic' psychotherapy programme with insight-oriented and behavioural components. 相似文献
992.
Arnold RW Barnett M Limstrom SA Swanson D 《Binocular vision & strabismus quarterly》2001,16(3):181-186
An exotropic 60 year old suffered a scleral-choroidal penetration and vitreous hemorrhage during and after strabismus surgery on a highly myopic eye when her anesthetic airway management was complicated by her previously asymptomatic and unrecognized rigid cervical spine which placed both the surgeon and the anesthetist in disadvantaged positions both physically and medically. Restoration of vision and binocularity ultimately required vitrectomy and intraocular lens implantation. 相似文献
993.
Neurodevelopmental theories of the pathoetiology of schizophrenia have been at the forefront of schizophrenia research in recent years. Support for these theories is substantial and growing. Epidemiological, phenomenological, and clinical neurobiological research have provided compelling though still circumstantial evidence. Neuropathological investigations also have provided some evidence; however, these have yet to actualize their potential for revealing the cellular and molecular nature of developmental aberrancies in this disease. This article summarizes the clinical evidence suggesting abnormal neurodevelopment in schizophrenia, outlines some of the important anatomic, cellular, and molecular mechanisms of normal central nervous system development, reviews current neuropathological findings relevant to neurodevelopment in schizophrenia, and suggests some new directions and opportunities for discovering the molecular neurodevelopmental basis of the disorder. 相似文献
994.
Language regression in childhood 总被引:8,自引:0,他引:8
Shinnar S Rapin I Arnold S Tuchman RF Shulman L Ballaban-Gil K Maw M Deuel RK Volkmar FR 《Pediatric neurology》2001,24(3):183-189
Language regression is observed both in autistic regression and as part of acquired epileptic aphasia (Landau-Kleffner Syndrome). We prospectively identified 177 children with language regression at four major medical centers, and their clinical characteristics were recorded. Their mean age at regression was 22.8 months. The mean time-to-specialist referral was 38 months of age. Most children (88%) met criteria for autism or manifested autistic features. Males (P = 0.02) and children less than 3 years of age who regressed (P = 0.016) had a higher probability of developing autistic behaviors. Seizures were more common in children who regressed after they reached 3 years of age (P < 0.001), and children with seizures were less likely to have associated autistic regression (P < 0.001). Electroencephalogram abnormalities were reported in 37% of patients and were more common in children with seizures (P < 0.001). At last follow-up, language function was impaired in 88% of the children, although some improvement was noted in 57%. We conclude that the loss of previously acquired language at any age, even if that language only includes a few words or communicative gestures, is often associated with a more global regression in cognition and/or behavior and has serious implications for future function. Early identification and referral of these children is necessary to allow for diagnosis and intervention. 相似文献
995.
Methylphenidate dosage for children with ADHD over time under controlled conditions: lessons from the MTA 总被引:2,自引:0,他引:2
Vitiello B Severe JB Greenhill LL Arnold LE Abikoff HB Bukstein OG Elliott GR Hechtman L Jensen PS Hinshaw SP March JS Newcorn JH Swanson JM Cantwell DP 《Journal of the American Academy of Child and Adolescent Psychiatry》2001,40(2):188-196
OBJECTIVES: To examine the trajectory of methylphenidate (MPH) dosage over time, following a controlled titration, and to ascertain how accurately the titration was able to predict effective long-term treatment in children with attention-deficit/hyperactivity disorder (ADHD). METHOD: Using the 14-month-treatment database of the NIMH Collaborative Multisite Multimodal Treatment Study of Children With Attention-Deficit/Hyperactivity Disorder (MTA), the outcome of the initial placebo-controlled, double-blind, randomized daily switch titration of MPH was compared with the subsequent maintenance pharmacotherapy. Children received monthly monitoring visits and, when needed, medication adjustments. RESULTS: Of the 198 children for whom MPH was the optimal treatment at titration (mean +/- SD dose: 30.5 +/- 14.2 mg/day), 88% were still taking MPH at the end of maintenance (mean dose 34.4 +/- 13.3 mg/day). Titration-determined dose and end-of-maintenance dose were significantly correlated (r = 0.52-0.68). Children receiving combined pharmacotherapy and behavioral treatment ended maintenance on a lower dose (31.1 +/- 11.7 mg/day) than did children receiving pharmacotherapy only (38.1 +/- 14.2 mg/day). Of the 230 children for whom titration identified an optimal treatment, 17% continued both the assigned medication and dosage throughout maintenance. The mean number of pharmacological changes per child was 2.8 +/- 1.8 (SD), and time to first change was 4.7 months +/- 0.3 (SE). CONCLUSIONS: For most children, initial titration found a dose of MPH in the general range of the effective maintenance dose, but did not prevent the need for subsequent maintenance adjustments. For optimal pharmacological treatment of ADHD, both careful initial titration and ongoing medication management are needed. 相似文献
996.
997.
Arnold SE 《Harvard Review of Psychiatry》2001,9(2):69-76
The neurobiological basis of cognitive and functional deterioration commonly observed in elderly persons with schizophrenia is unclear. Despite superficial similarities in the clinical and neuropsychological profiles of schizophrenia in late life with neurodegenerative dementias, extensive neuropathological investigations have failed to find any evidence of neurodegeneration or neural injury beyond what is typically observed in brains of individuals without neuropsychiatric illness. In contrast, growing neuropathological data indicate aberrant brain development and connectivity in schizophrenia (including abnormalities in cytoarchitecture, innervation, and synaptic integrity) and abnormal molecular signaling pathways important in the formation of the nervous system and ongoing plasticity in maturity. These developmental abnormalities may represent a state of decreased cerebral reserve that causes persons with schizophrenia to be more vulnerable to the toxic effects of even "normal" accumulations of age-related neurodegenerative lesions. 相似文献
998.
999.
BACKGROUND: The purpose of this study was to determine the role of fluorodeoxyglucose positron emission tomography (PET) in localizing disease in patients with colorectal cancer with radiologically occult symptomatology or increases in carcinoembryonic antigen (CEA) level. METHODS: Two hundred seventy-seven patients with colorectal cancer underwent PET scanning between November 1998 and September 2000 prompted by (1) increasing CEA level and nondiagnostic imaging or (2) symptoms with normal CEA level and nondiagnostic imaging. PET results were correlated with operative findings/histology, clinical follow-up data, and CEA level to determine PET's accuracy in determining the source of symptoms or CEA. RESULTS: Fifteen patients had increasing CEA levels, and 14 had abnormal PET. Two of these 14 were denied exploration because PET suggested widely metastatic disease. Nine patients underwent exploration with curative intent. In 1 patient, recurrence was not pathologically confirmed (false-positive rate, 8%). Two had disease beyond that predicted by PET, and 6 underwent complete resection and normalized their CEA levels. Four symptomatic patients with normal CEA levels and negative x-rays had abnormal PET; at exploration, 3 had no evidence of recurrence. CONCLUSIONS: PET imaging can often accurately localize the source of radiologically occult increases in CEA level and select that subset of patients eligible for therapeutic laparotomy. Symptomatic, PET-positive patients with normal CEA levels frequently undergo nontherapeutic laparotomy, and PET findings should be interpreted with caution in these patients. 相似文献
1000.
Comparison of gastrointestinal tolerance to two enteral feeding protocols in critically ill patients: a prospective, randomized controlled trial 总被引:4,自引:0,他引:4
Pinilla JC Samphire J Arnold C Liu L Thiessen B 《JPEN. Journal of parenteral and enteral nutrition》2001,25(2):81-86
BACKGROUND: The purpose of this study was to compare gastrointestinal tolerance to two enteral feeding protocols in critically ill patients. METHODS: A prospective, randomized controlled trial, that involved 96 consecutive patients expected to stay in the intensive care unit for > or =3 days and who had no contraindications to enteral feeding. The patients were randomized to either the current protocol (group I; gastric residual volume threshold, 150 mL, optional prokinetic) or proposed feeding protocol (group II; gastric residual volume threshold 250 mL, mandatory prokinetic). Gastrointestinal intolerance was recorded as episodes of high gastric residual volume, emesis, or diarrhea. The time to reach the goal rate of feeding and the percentage of nutritional requirements received during the study period were also recorded. RESULTS: Nineteen of 36 patients (19/36 = 0.53) in group I had one or more episodes of high gastric residual volume, compared with 10 of 44 patients (10/44 = 0.23) in group II (p < .005). There was no statistical difference between the two protocols with regards to emesis, diarrhea, or the total episodes of intolerance. The patients in group II reached their goal rates on average in 15 hours and received 76% of their nutritional requirements, compared with 22 hours and 70% in group I; however, these differences were not statistically significant. CONCLUSIONS: The incidence of enteral feeding intolerance was reduced by using a gastric residual volume of 250 mL along with the mandatory use of prokinetics. The study showed a trend of improved enteral nutrition provision and reduced the time to reach the goal rate in group II. These improvements support the adoption of the proposed feeding protocol for critically ill patients. 相似文献