全文获取类型
收费全文 | 16664篇 |
免费 | 999篇 |
国内免费 | 78篇 |
专业分类
耳鼻咽喉 | 96篇 |
儿科学 | 455篇 |
妇产科学 | 418篇 |
基础医学 | 2473篇 |
口腔科学 | 554篇 |
临床医学 | 1321篇 |
内科学 | 4032篇 |
皮肤病学 | 345篇 |
神经病学 | 1550篇 |
特种医学 | 612篇 |
外国民族医学 | 2篇 |
外科学 | 1511篇 |
综合类 | 69篇 |
一般理论 | 6篇 |
预防医学 | 1553篇 |
眼科学 | 366篇 |
药学 | 1224篇 |
中国医学 | 93篇 |
肿瘤学 | 1061篇 |
出版年
2023年 | 110篇 |
2022年 | 287篇 |
2021年 | 467篇 |
2020年 | 274篇 |
2019年 | 416篇 |
2018年 | 567篇 |
2017年 | 321篇 |
2016年 | 438篇 |
2015年 | 477篇 |
2014年 | 655篇 |
2013年 | 800篇 |
2012年 | 1253篇 |
2011年 | 1306篇 |
2010年 | 676篇 |
2009年 | 636篇 |
2008年 | 1019篇 |
2007年 | 1071篇 |
2006年 | 967篇 |
2005年 | 861篇 |
2004年 | 727篇 |
2003年 | 758篇 |
2002年 | 677篇 |
2001年 | 253篇 |
2000年 | 217篇 |
1999年 | 206篇 |
1998年 | 181篇 |
1997年 | 174篇 |
1996年 | 148篇 |
1995年 | 115篇 |
1994年 | 117篇 |
1993年 | 129篇 |
1992年 | 127篇 |
1991年 | 100篇 |
1990年 | 93篇 |
1989年 | 128篇 |
1988年 | 112篇 |
1987年 | 93篇 |
1986年 | 101篇 |
1985年 | 84篇 |
1984年 | 66篇 |
1983年 | 59篇 |
1982年 | 46篇 |
1981年 | 53篇 |
1980年 | 50篇 |
1979年 | 34篇 |
1978年 | 30篇 |
1977年 | 25篇 |
1976年 | 24篇 |
1975年 | 34篇 |
1974年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Solitary bronchioloalveolar carcinoma: CT criteria 总被引:14,自引:0,他引:14
Kuhlman JE; Fishman EK; Kuhajda FP; Meziane MM; Khouri NF; Zerhouni EA; Siegelman SS 《Radiology》1988,167(2):379-382
The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis. 相似文献
52.
Carlos Calderón Rafael Rotaeche Arritxu Etxebarria Mercé Marzo Rosa Rico Marta Barandiaran 《BMC health services research》2006,6(1):138-11
Background
The GRADE method represents a new approach to grading the quality of evidence and strength of recommendations in the preparation of Clinical Practice Guidelines (CPG). In the context of a pilot study to assess the implementability of the system in Spain, we considered it relevant to gain an insight into the significance of the perceptions and attitudes expressed by the actual experts participating in the system try-out. 相似文献53.
54.
Lauro Cortigiani Riccardo Bigi Rosa Sicari Patrizia Landi Francesco Bovenzi Eugenio Picano 《Journal of the American College of Cardiology》2006,47(3):605-610
OBJECTIVES: We sought to compare the prognostic value of pharmacological stress echocardiography (SE) in diabetic and nondiabetic patients with known or suspected coronary artery disease. BACKGROUND: Although SE is a useful tool for risk stratification of patients with diabetes, it has not been established whether it retains the same prognostic information in diabetic patients compared with nondiabetic patients. METHODS: A total of 5,456 patients (749 diabetics) undergoing dipyridamole (n = 3,306) or dobutamine (n = 2,150) SE were prospectively followed up for the occurrence of hard events (death and/or nonfatal myocardial infarction). RESULTS: During a median time of 31 months, 411 deaths and 236 infarctions occurred. There were 132 events in diabetic patients and 515 in nondiabetic patients (18% vs. 11%, respectively; p < 0.0001). Moreover, 1,607 (29%) patients underwent coronary revascularization and were censored. Ischemia at SE, resting wall motion score index, and age were independent predictors of death and hard events in both diabetic and nondiabetic patients. Compared with a normal test, ischemia and scar test patterns were associated to significantly lower age-corrected five-year hard event-free survival in diabetic as well as nondiabetic patients. However, a normal test was associated with a greater than two-fold annual event rate in diabetic patients as compared with nondiabetics who were either younger (2.6% vs. 1.0%) or older (5.5% vs. 2.2%) than 65 years of age. CONCLUSIONS: Stress echocardiography is equally effective in risk stratifying diabetic and nondiabetic patients independently of age. However, the normal test result predicts a less favorable outcome in diabetic than in nondiabetic patients. 相似文献
55.
Marta Padilla Castillo Yaiza Machado RyderManuel Cazorla Betancor Rocío Acebes TostiMargarita Medina Castellano Rosa Rodríguez-Mano 《Progresos de Obstetricia y Ginecología》2006
Heterotopic pregnancy is the combination of intrauterine and ectopic pregnancy. This potentially fatal condition rarely occurs in spontaneous conception cycles and consequently its diagnosis requires a high index of suspicion. We report a case of heterotopic pregnancy in a 30-year old primipara with no known risk factors who presented with acute abdominal pain due to a spontaneous heterotopic pregnancy. The ectopic pregnancy was resected via laparoscopy. After surgery, the intrauterine pregnancy was uneventful. 相似文献
56.
Raffael Kalisch Mirjam Schubert Wolfgang Jacob Melanie S Kessler Rosa Hemauer Alexandra Wigger Rainer Landgraf Dorothee P Auer 《Neuropsychopharmacology》2006,31(5):925-932
In depressed patients as well as healthy controls, a positive relationship between hippocampal volume and trait anxiety has been reported. This study sought to explore the possible inter-relation between hippocampal volume and trait anxiety further. Magnetic resonance imaging at 7 T was used to measure hippocampal volumes in a rat model of extremes in trait anxiety (experiment 1) and in a Wistar population with normal anxiety-related behavior (experiment 2). In addition to anxiety-related behavior, potentially confounding factors (depression-like, exploratory, and locomotor behavior) were assessed. Experiment 1 globally supported the hypothesis of a positive relationship between hippocampus volume and trait anxiety but did not allow for ruling out possible confounds arising from cosegregation of other behavioral traits. Experiment 2 yielded strong evidence for a negative relationship which was specific for trait anxiety. Thus, the relationship between hippocampal volume and anxiety may be more complex than expected. Interestingly, anxiety-related behavior in experiment 2 had a stronger influence on hippocampal volume than depression-like behavior. In the light of hippocampal volume loss in anxiety disorder and frequent comorbidity of anxiety and depression, this finding suggests that further research into the relationship between anxiety and hippocampal volume may be critical for understanding hippocampal contributions to normal and pathological behavior. 相似文献
57.
58.
Francesca Lodato Maria Rosa Tamé Marco Montagnani Vittorio Sambri Giovanna Liguori Francesco Azzaroli Paolo Costigliola Gianluca Grazi Enrico Roda Giuseppe Mazzella 《Liver transplantation》2006,12(11):1711-1714
The incidence of invasive fungal infection is increasing especially in the field of transplantation, affecting as many as 50% of bone marrow transplant (BMT) patients with neutropenia and 5-20% of solid-organ transplant (SOT) recipients. Fusarium species are soil saprophytes and plant pathogens. They may cause superficial mycoses or important opportunistic infections in patients with bone marrow suppression and neutropenia, they have been rarely described in solid organ recipients, and up to now there have been no reports of such infection in isolated liver transplanted patients. We describe a case of disseminated Fusarium solani infection with hepatic localization in a liver transplanted patient that resolved with the administration of amphotericin B. Our observation confirms that Fusarium spp. are emerging pathogens that may most frequently affect not only BMT patients and patients with hematological malignancies, but also SOT patients. They may cause both localized and disseminated infection. In conclusion, Fusarium spp. etiology should be considered in the context of infectious diseases following liver transplantation. 相似文献
59.
Joaquim Ferreira MD João Maia Silva MD Rita Freire BS João Pignatelli MD Leonor Correia Guedes MD Alexandra Feijó MD Mário Miguel Rosa MD Miguel Coelho MD João Costa MD Ana Noronha BS Russell Hewett MD A. Marques Gomes PhD J.L. Cirne de Castro MD Olivier Rascol PhD Cristina Sampaio PhD 《Movement disorders》2007,22(10):1471-1475
Our objective was to evaluate the frequency of neoplastic and preneoplastic skin lesions in Parkinson's disease (PD) patients when compared with an aged-matched population. We performed a cross-sectional survey in PD patients and in an age-matched control group. Patients and controls were examined by a movement disorder specialist and a dermatologist. 150 PD patients and 146 controls were included. Thirty-five PD patients (23.3%) presented skin lesions that could be classified as neoplastic or preneoplastic vs. 20 subjects in the control group (13.7%) (OR 95%, CI 1.92 [1.05, 3.51]). However, this difference lost statistical significance when adjusted for gender (recruitment of controls was matched just for age with an over representation of males in the PD group). Twenty-nine PD patients (19%) presented actinic keratosis and basal cell carcinoma was diagnosed in 4 patients (3%). Although nonconclusive, our results are in agreement with previous studies suggesting an increased risk of skin cancer in PD patients. The frequency of actinic keratosis in PD patients and the associated risk to develop melanoma recommends its screening in future epidemiological studies. 相似文献
60.
Rosa van Mourik Jaap Oosterlaan Dirk J Heslenfeld Claudia E Konig Joseph A Sergeant 《Clinical neurophysiology》2007,118(8):1855-1865
OBJECTIVE: Although an increased distractibility is one of the behavioral criteria of Attention Deficit Hyperactivity Disorder (ADHD), there is little empirical evidence that children with ADHD are in fact more distractible than their normal peers. METHODS: We recorded event-related potentials (ERPs) to distracting novel sounds (novels) and standard sounds, (standards) while children performed a visual two-choice reaction time task. Twenty-five children with ADHD were compared with eighteen normal controls (aged 8-12 years). RESULTS: Children with ADHD showed a larger early P3a (150-250 ms), both in response to the standard and in response to the novel. The late phase of the P3a had a larger amplitude in the ADHD group in the 250-300 ms window compared to the control group, which was only present in response to the novel. Interestingly, the novel reduced the errors of omission in the ADHD group to a greater extent than in the normal control group. CONCLUSIONS: Although children with ADHD show an increased orienting response to novels, this distracting information can enhance their performance temporarily, possibly by increasing their arousal to an optimal level, as indicated by the reduced omission rate. SIGNIFICANCE: These data indicate that distraction is not always distracting in children with ADHD and that distraction can also have beneficial effects. 相似文献