全文获取类型
收费全文 | 8677篇 |
免费 | 774篇 |
国内免费 | 46篇 |
专业分类
耳鼻咽喉 | 88篇 |
儿科学 | 376篇 |
妇产科学 | 143篇 |
基础医学 | 1128篇 |
口腔科学 | 245篇 |
临床医学 | 909篇 |
内科学 | 1975篇 |
皮肤病学 | 160篇 |
神经病学 | 729篇 |
特种医学 | 651篇 |
外国民族医学 | 2篇 |
外科学 | 1100篇 |
综合类 | 97篇 |
一般理论 | 1篇 |
预防医学 | 688篇 |
眼科学 | 144篇 |
药学 | 430篇 |
中国医学 | 16篇 |
肿瘤学 | 615篇 |
出版年
2023年 | 39篇 |
2022年 | 70篇 |
2021年 | 201篇 |
2020年 | 95篇 |
2019年 | 252篇 |
2018年 | 284篇 |
2017年 | 202篇 |
2016年 | 203篇 |
2015年 | 236篇 |
2014年 | 269篇 |
2013年 | 394篇 |
2012年 | 421篇 |
2011年 | 407篇 |
2010年 | 326篇 |
2009年 | 264篇 |
2008年 | 351篇 |
2007年 | 376篇 |
2006年 | 371篇 |
2005年 | 324篇 |
2004年 | 262篇 |
2003年 | 257篇 |
2002年 | 279篇 |
2001年 | 186篇 |
2000年 | 220篇 |
1999年 | 199篇 |
1998年 | 199篇 |
1997年 | 188篇 |
1996年 | 177篇 |
1995年 | 143篇 |
1994年 | 123篇 |
1993年 | 120篇 |
1992年 | 164篇 |
1991年 | 177篇 |
1990年 | 143篇 |
1989年 | 190篇 |
1988年 | 162篇 |
1987年 | 147篇 |
1986年 | 155篇 |
1985年 | 121篇 |
1984年 | 91篇 |
1983年 | 85篇 |
1982年 | 57篇 |
1981年 | 47篇 |
1980年 | 61篇 |
1979年 | 64篇 |
1978年 | 37篇 |
1977年 | 45篇 |
1976年 | 52篇 |
1975年 | 44篇 |
1973年 | 35篇 |
排序方式: 共有9497条查询结果,搜索用时 9 毫秒
21.
William Perry Arpi Minassian Brian Lopez Leeza Maron Alan Lincoln 《Neuropsychopharmacology》2007,61(4):482-486
BACKGROUND: Prepulse inhibition (PPI) is an operational measure of sensorimotor gating and is impaired in a family of neuropsychiatric disorders characterized by abnormalities of inhibitory function. Adults with autistic disorder (AD) exhibit clinical features of inhibitory deficits, such as restrictive and repetitive behaviors, that may be explained by deficits in sensorimotor gating. METHODS: Acoustic startle reactivity, habituation, and PPI (30-, 60-, 120-msec interstimulus intervals) were assessed in 14 adult men diagnosed with AD and 16 typically developing normal comparison (NC) participants. All participants were administered measures of intelligence and frontal-executive functioning. RESULTS: Adults with AD exhibited significantly less PPI in the 60-msec condition than NC participants, which was correlated with increased ratings of restricted and repetitive behaviors. The groups did not differ on measures of startle amplitude or overall habituation. There was, however, a significant group-by-block habituation effect. Furthermore, PPI was not related to intelligence but was moderately associated with performance on a measure of frontal-executive functioning. CONCLUSIONS: Adults with AD have sensorimotor gating deficits similar to other neurodevelopmental disorders, implicating a failure of normal inhibitory regulation of sensory, motor, and attentional mechanisms. Thus, PPI deficits may be indirectly linked to one of the hallmark features of AD. 相似文献
22.
Propofol versus traditional sedative agents for gastrointestinal endoscopy: a meta-analysis. 总被引:6,自引:0,他引:6
Mohammed A Qadeer John J Vargo Farah Khandwala Rocio Lopez Gregory Zuccaro 《Clinical gastroenterology and hepatology》2005,3(11):1049-1056
BACKGROUND & AIMS: Even though propofol has better recovery profile than traditional agents, its use is limited because of the perception of increased complication rates. Because an adequately powered trial comparing risk of propofol with traditional agents is lacking, we performed a meta-analysis of the current literature. METHODS: We searched Medline (1966-October 2004), EMBASE (1980-October 2004), and Cochrane controlled trials registry. The following 4 cardiopulmonary complications were assessed: hypoxia, hypotension, arrhythmias, and apnea. Procedures were divided into 3 groups: esophagogastroduodenoscopy group, colonoscopy group, and endoscopic retrograde cholangiopancreatography/endoscopic ultrasonography group. Pooled odds ratios for complications were calculated for all the procedures combined and then separately for the 3 groups. Random effects models were used for 2-proportion comparisons. RESULTS: Of the 90 citations identified, 12 original studies qualified for this meta-analysis and included 1161 patients. Of these, 634 received propofol, and 527 received midazolam, meperidine, and/or fentanyl. Most of the included studies were randomized trials of moderate quality and nonsignificant heterogeneity (Cochran Q = 4.81, P = .90). Compared with traditional sedative agents, the pooled odds ratio with the use of propofol for developing hypoxia or hypotension for all the procedures combined was 0.74 (95% confidence interval [CI], 0.44-1.24); for EGD, 0.85 (95% CI, 0.33-2.17); for colonoscopy, 0.4 (95% CI, 0.2-0.79); and for ERCP/EUS, 1.07 (95% CI, 0.38-3.01). CONCLUSIONS: Propofol sedation during colonoscopy appears to have lower odds of cardiopulmonary complications compared with traditional agents, but for other procedures, the risk of complications is similar. 相似文献
23.
E. M. Fredericks M. J. Lopez J. C. Magee V. Shieck L. Opipari-Arrigan 《American journal of transplantation》2007,7(8):1974-1983
The present study empirically assessed the relationships between adherence behaviors and HRQOL, parent and child psychological functioning and family functioning, and investigated the relationship between adherence behaviors and health outcomes in children who were within 5 years of their liver transplantation. Participants included 38 children (mean = 8.5 years, range 28 months to 16 years) and their parent/guardian(s). HRQOL and psychological functioning were examined using well-validated assessment measures. Measures of adherence included the rate of clinic attendance and standard deviations (SDs) of consecutive tacrolimus blood levels, which were collected and evaluated retrospectively. Measures of child health status included the frequency of hospital admissions, liver biopsies, episodes of rejection and graft function for the year prior to study participation. Results indicated that nonadherence was related to lower physical HRQOL, more limitations in social and school activities related to emotional and behavioral problems, parental emotional distress and decreased family cohesion. Nonadherence was also related to frequency and duration of hospitalizations, liver biopsies and rejection episodes. These results suggest that empirically based assessment of HRQOL, parenting stress and family functioning may help identify patients at risk for nonadherence, and may allow for the need-based delivery of appropriate clinical interventions. 相似文献
24.
A single VH family and long CDR3s are the targets for hypermutation in bovine immunoglobulin heavy chains 总被引:1,自引:0,他引:1
Summary: Bovine immunoglobulins are made from genes belonging to a small family of closely related Vh, genes. In this respect cattle resemble all species of domesticated mammals, which also use one VH family The family, named BoVH1, is homologous to the mouse Q52 family, and there are no more than 20 genes of this family in the bovine genome. Another feature of bovine heavy chains is the use of long CDR3s, which have an average of 21 codons. It seems that there are several families of long, closely related D genes rich in glycine and tyrosine responsible for this length. Sequences described as targets for mutations in other species can be found in CDR1, CDR2, and the putative D genes. The mutation mechanism starts at some point between late fetal stage and birth and seems to be antigen Independent. Diversity seems to be generated by hypermutation, although other mechanistns cannot be discomited at this time. Contrary to humans and mice, which have several Vh gene families comprising more than 100 genes, cattle use only a few genes and long CDR3s followed by somatic mutation to generate the necessary diversity to recognize the universe of antigens they will encounter during their life. 相似文献
25.
We report an adult female with a rare giant choledochal cyst. The patient presented following a normal pregnancy with the classical triad of an abdominal mass associated with jaundice and right upper quadrant abdominal pain. The cyst was excised using an intramural technique and biliary reconstruction achieved with a Roux-en-Y hepaticojejunostomy. Our patient has remained well with no evidence of malignancy over a 12 year review period. The aetiology and current management of this condition are discussed. 相似文献
26.
27.
Pathophysiology of HPA axis abnormalities in patients with major depression: an update 总被引:1,自引:0,他引:1
Four hypotheses have been proposed to explain why nonsuppression on the dexamethasone suppression test occurs in patients with major depression. These include 1) increased metabolism of dexamethasone, 2) decreased sensitivity of pituitary glucocorticoid receptors to dexamethasone, 3) hyperresponsivity of the adrenal gland to ACTH stimulation, and 4) increased central drive of the pituitary from hypothalamic/limbic structures that overrides the action of the dexamethasone. A critical review of the literature suggests that the last hypothesis is most closely supported by the data. Despite this conclusion, factors other than depression may be involved in hypothalamic-pituitary-adrenal axis dysfunction. 相似文献
28.
29.
J B Stewart S B Hardin S Weinrich S McGeorge J Lopez D Pesut 《Issues in mental health nursing》1992,13(2):105-119
Literature reports that cognitive understanding and social support can mitigate stress in both adults and adolescents. As a subcomponent of the Carolina Adolescent Health Project (CAHP), this research evaluated the efficacy of a Cognitive Social Support (CSS) group protocol designed to mitigate the disaster stress of adolescents who had been exposed seriously to Hurricane Hugo. A purposive sample of 259 students participated in and evaluated the CSS. This article reports the specific structure, content, process, rationale, and cost of the CSS. Evaluations indicated that 82% of the students evaluated the small-group component of the CSS as "very good" or "excellent," while 70% rated the large-group component as "very good" or "excellent." 相似文献
30.
Na+ dependence of in vitro pancreatic amylase release 总被引:1,自引:0,他引:1