全文获取类型
收费全文 | 1521篇 |
免费 | 117篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 7篇 |
儿科学 | 34篇 |
妇产科学 | 70篇 |
基础医学 | 194篇 |
口腔科学 | 8篇 |
临床医学 | 270篇 |
内科学 | 166篇 |
皮肤病学 | 55篇 |
神经病学 | 200篇 |
特种医学 | 33篇 |
外科学 | 216篇 |
综合类 | 27篇 |
一般理论 | 2篇 |
预防医学 | 147篇 |
眼科学 | 7篇 |
药学 | 125篇 |
肿瘤学 | 89篇 |
出版年
2023年 | 9篇 |
2022年 | 10篇 |
2021年 | 23篇 |
2020年 | 19篇 |
2019年 | 19篇 |
2018年 | 28篇 |
2017年 | 26篇 |
2016年 | 27篇 |
2015年 | 20篇 |
2014年 | 31篇 |
2013年 | 59篇 |
2012年 | 79篇 |
2011年 | 96篇 |
2010年 | 55篇 |
2009年 | 51篇 |
2008年 | 71篇 |
2007年 | 81篇 |
2006年 | 79篇 |
2005年 | 82篇 |
2004年 | 64篇 |
2003年 | 68篇 |
2002年 | 75篇 |
2001年 | 54篇 |
2000年 | 50篇 |
1999年 | 48篇 |
1998年 | 29篇 |
1997年 | 16篇 |
1996年 | 17篇 |
1995年 | 13篇 |
1994年 | 11篇 |
1993年 | 9篇 |
1992年 | 40篇 |
1991年 | 28篇 |
1990年 | 18篇 |
1989年 | 22篇 |
1988年 | 19篇 |
1987年 | 19篇 |
1986年 | 13篇 |
1985年 | 14篇 |
1984年 | 7篇 |
1983年 | 11篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1977年 | 7篇 |
1973年 | 7篇 |
1972年 | 6篇 |
1971年 | 11篇 |
1970年 | 8篇 |
1969年 | 12篇 |
排序方式: 共有1650条查询结果,搜索用时 31 毫秒
31.
Margaret L. Crivello MD Karen Ruth MS Elin R. Sigurdson MD PhD Brian L. Egleston PhD Kathryn Evers MD Yu-Ning Wong MD Marcia Boraas MD Richard J. Bleicher MD 《Annals of surgical oncology》2013,20(1):102-110
Background
Guidelines for breast cancer staging exist, but adherence remains unknown. This study evaluates patterns of imaging in early stage breast cancer usually reserved for advanced disease.Methods
Surveillance Epidemiology, and End Results data linked to Medicare claims from 1992–2005 were reviewed for stage I/II breast cancer patients. Claims were searched for preoperative performance of computed tomography (CT), positron emission tomography (PET), bone scans, and brain magnetic resonance imaging (MRI) (“advanced imaging”).Results
There were 67,874 stage I/II breast cancer patients; 18.8 % (n = 12,740) had preoperative advanced imaging. The proportion of patients having CT scans, PET scans, and brain MRI increased from 5.7 % to 12.4 % (P < 0.0001), 0.8 % to 3.4 % (P < 0.0001) and 0.2 % to 1.1 % (P = 0.008), respectively, from 1992 to 2005. Bone scans declined from 20.1 % to 10.7 % (P < 0.0001). “Breast cancer” (174.x) was the only diagnosis code associated with 62.1 % of PET scans, 37.7 % of bone scans, 24.2 % of CT, and 5.1 % of brain MRI. One or more symptoms or metastatic site was suggested for 19.6 % of bone scans, 13.0 % of CT, 13.0 % of PET, and 6.2 % of brain MRI. Factors associated (P < 0.05) with use of all modalities were urban setting, breast MRI and ultrasound. Breast MRI was the strongest predictor (P < 0.0001) of bone scan (odds ratio [OR] 1.63, 95 % confidence interval [CI] 1.44–1.86), Brain MRI (OR 1.74, 95 % CI 1.15–2.63), CT (OR 2.42, 95 % CI 2.12–2.76), and PET (OR 5.71, 95 % CI 4.52–7.22).Conclusions
Aside from bone scans, performance of advanced imaging is increasing in early stage Medicare breast cancer patients, with limited rationale provided by coded diagnoses. In light of existing guidelines and increasing scrutiny about health care costs, greater reinforcement of current indications is warranted. 相似文献32.
33.
Sir, The recent mini-review on the treatment of repeated implantationfailure (RIF) by Margalioth et al. (2006) has caught our attention.It is timely, concise and to the point. Margalioth et al. mentionpossible etiologies and suggest methods for treatment of RIFafter IVF. There is no doubt in our mind that some of thesemethods will have been followed by a successful pregnancy inan isolated case, or even in a small number of cases. 相似文献
34.
Bordet T Buisson B Michaud M Drouot C Galéa P Delaage P Akentieva NP Evers AS Covey DF Ostuni MA Lacapère JJ Massaad C Schumacher M Steidl EM Maux D Delaage M Henderson CE Pruss RM 《The Journal of pharmacology and experimental therapeutics》2007,322(2):709-720
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive death of cortical and spinal motor neurons, for which there is no effective treatment. Using a cell-based assay for compounds capable of preventing motor neuron cell death in vitro, a collection of approximately 40,000 low-molecular-weight compounds was screened to identify potential small-molecule therapeutics. We report the identification of cholest-4-en-3-one, oxime (TRO19622) as a potential drug candidate for the treatment of ALS. In vitro, TRO19622 promoted motor neuron survival in the absence of trophic support in a dose-dependent manner. In vivo, TRO19622 rescued motor neurons from axotomy-induced cell death in neonatal rats and promoted nerve regeneration following sciatic nerve crush in mice. In SOD1(G93A) transgenic mice, a model of familial ALS, TRO19622 treatment improved motor performance, delayed the onset of the clinical disease, and extended survival. TRO19622 bound directly to two components of the mitochondrial permeability transition pore: the voltage-dependent anion channel and the translocator protein 18 kDa (or peripheral benzodiazepine receptor), suggesting a potential mechanism for its neuroprotective activity. TRO19622 may have therapeutic potential for ALS and other motor neuron and neurodegenerative diseases. 相似文献
35.
People with eating disorders (ED) have difficulties regulating their emotions adaptively. Little is known about differences and similarities between different types of ED and how these regulation difficulties relate to other emotional problems. The present study examines maladaptive (suppression) and adaptive (cognitive reappraisal) emotion regulation strategies in women with different ED and relationships with anxiety and depression levels. In 32 women with AN restrictive subtype (ANR), 32 with AN binge-purge subtype (ANBP), 30 with bulimia nervosa (BN), 29 with binge eating disorder (BED), and 64 healthy women, the ERQ (emotion regulation) as well as STAI-T (anxiety), BDI-SF (depression), and EDDS (eating pathology) were administered. Women across different ED subtypes were inclined to suppress emotions and lacked the capacity to reappraise emotions (except women with ANBP). Correlational relations of suppression and reappraisal with anxiety and depression levels differed across ED groups. Emotion regulation problems were found across ED subtypes. However, the types of emotion regulation problems, and the effect of coexisting other emotional problems such as anxiety and depression may differ across ED subtypes. These findings illustrate the importance to of considering ED subtypes in emotion regulation research rather than consider ED as a whole. 相似文献
36.
Daniela N Schulz Eline S Smit Nicola E Stanczyk Stef PJ Kremers Hein de Vries Silvia MAA Evers 《Journal of medical Internet research》2014,16(3)
Background
Different studies have reported the effectiveness of Web-based computer-tailored lifestyle interventions, but economic evaluations of these interventions are scarce.Objective
The objective was to assess the cost-effectiveness and cost-utility of a sequential and a simultaneous Web-based computer-tailored lifestyle intervention for adults compared to a control group.Methods
The economic evaluation, conducted from a societal perspective, was part of a 2-year randomized controlled trial including 3 study groups. All groups received personalized health risk appraisals based on the guidelines for physical activity, fruit intake, vegetable intake, alcohol consumption, and smoking. Additionally, respondents in the sequential condition received personal advice about one lifestyle behavior in the first year and a second behavior in the second year; respondents in the simultaneous condition received personal advice about all unhealthy behaviors in both years. During a period of 24 months, health care use, medication use, absenteeism from work, and quality of life (EQ-5D-3L) were assessed every 3 months using Web-based questionnaires. Demographics were assessed at baseline, and lifestyle behaviors were assessed at both baseline and after 24 months. Cost-effectiveness and cost-utility analyses were performed based on the outcome measures lifestyle factor (the number of guidelines respondents adhered to) and quality of life, respectively. We accounted for uncertainty by using bootstrapping techniques and sensitivity analyses.Results
A total of 1733 respondents were included in the analyses. From a willingness to pay of €4594 per additional guideline met, the sequential intervention (n=552) was likely to be the most cost-effective, whereas from a willingness to pay of €10,850, the simultaneous intervention (n=517) was likely to be most cost-effective. The control condition (n=664) appeared to be preferred with regard to quality of life.Conclusions
Both the sequential and the simultaneous lifestyle interventions were likely to be cost-effective when it concerned the lifestyle factor, whereas the control condition was when it concerned quality of life. However, there is no accepted cutoff point for the willingness to pay per gain in lifestyle behaviors, making it impossible to draw firm conclusions. Further economic evaluations of lifestyle interventions are needed.Trial Registration
Dutch Trial Register NTR2168; http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=2168 (Archived by WebCite at http://www.webcitation.org/6MbUqttYB). 相似文献37.
Jesse Mez MD MS Daniel H. Daneshvar MD PhD Bobak Abdolmohammadi BA Alicia S. Chua MS Michael L. Alosco PhD Patrick T. Kiernan BA Laney Evers BA Laura Marshall BA Brett M. Martin MS Joseph N. Palmisano MS Christopher J. Nowinski PhD Ian Mahar PhD Jonathan D. Cherry PhD Victor E. Alvarez MD Brigid Dwyer MD Bertrand R. Huber MD PhD Thor D. Stein MD PhD Lee E. Goldstein MD PhD Douglas I. Katz MD Robert C. Cantu MD Rhoda Au PhD Neil W. Kowall MD Robert A. Stern PhD Michael D. McClean MS ScD Jennifer Weuve MPH ScD Yorghos Tripodis PhD Ann C. McKee MD 《Annals of neurology》2020,87(1):116-131
38.
Andreas Tzschach Ute Grasshoff Stefanie Beck-Woedl Claudia Dufke Claudia Bauer Martin Kehrer Christina Evers Ute Moog Barbara Oehl-Jaschkowitz Nataliya Di Donato Robert Maiwald Christine Jung Alma Kuechler Solveig Schulz Peter Meinecke Stephanie Spranger Jürgen Kohlhase J?rg Seidel Silke Reif Manuela Rieger Angelika Riess Marc Sturm Julia Bickmann Christopher Schroeder Andreas Dufke Olaf Riess Peter Bauer 《European journal of human genetics : EJHG》2015,23(11):1513-1518
X-linked intellectual disability (XLID) is a genetically heterogeneous disorder with more than 100 genes known to date. Most genes are responsible for a small proportion of patients only, which has hitherto hampered the systematic screening of large patient cohorts. We performed targeted enrichment and next-generation sequencing of 107 XLID genes in a cohort of 150 male patients. Hundred patients had sporadic intellectual disability, and 50 patients had a family history suggestive of XLID. We also analysed a sporadic female patient with severe ID and epilepsy because she had strongly skewed X-inactivation. Target enrichment and high parallel sequencing allowed a diagnostic coverage of >10 reads for ~96% of all coding bases of the XLID genes at a mean coverage of 124 reads. We found 18 pathogenic variants in 13 XLID genes (AP1S2, ATRX, CUL4B, DLG3, IQSEC2, KDM5C, MED12, OPHN1, SLC9A6, SMC1A, UBE2A, UPF3B and ZDHHC9) among the 150 male patients. Thirteen pathogenic variants were present in the group of 50 familial patients (26%), and 5 pathogenic variants among the 100 sporadic patients (5%). Systematic gene dosage analysis for low coverage exons detected one pathogenic hemizygous deletion. An IQSEC2 nonsense variant was detected in the female ID patient, providing further evidence for a role of this gene in encephalopathy in females. Skewed X-inactivation was more frequently observed in mothers with pathogenic variants compared with those without known X-linked defects. The mutation rate in the cohort of sporadic patients corroborates previous estimates of 5–10% for X-chromosomal defects in male ID patients. 相似文献
39.
The purpose of this qualitative study was to describe the psychosocial impact and coping processes of normal (negative) results from predictive testing for an inherited neurodegenerative disease. Ten adults with normal results of predictive testing for the Huntington disease (HD) or the Pallido-Ponto-Nigral Degeneration (PPND) gene mutation participated in semi-structured interviews 1 month after receiving results, and seven of these participants were interviewed 6 months later. The major theme of Redefinition was derived using Knafl and Webster's analysis method (1988). People who received normal gene results experienced loss of former beliefs about themselves and developed new self definitions, relationships with family, and roles in society. This coping process evolved from a personal focus at 1 month to a broader future perspective at 6 months after testing. Identifying components of the redefinition process may be an important consideration in planning interventions to promote coping with normal gene results in persons within at-risk families. 相似文献
40.
Ornithine decarboxylase (ODC) is a growth-associated enzyme which is critical for cell growth and transformation. ODC activity follows a specific ontogenetic pattern of activity in distinct brain regions according to their developmental stage. Perturbations in the pattern of ODC activity have been associated with brain damage including arrested cerebral growth. Modulations in the pattern of ODC activity were examined in the hippocampus, neocortex and cerebellum of neonatal rats (PND 3, 6, 9, 15) exposed via the dam to 0.2% lead-acetate (Pb2+ prenatally (gestational day 13 to birth), postnatally (PND 1–15) or perinatally (gestational day 13 to PND 15). Prenatal exposure to Pb2+ perturbed the profile of ODC activity in all three brain regions examined, while postnatal exposure to Pb2+ resulted in prolonged stimulations of ODC activity in the cerebellum. Following prenatal exposure, these effects were manifested as a stimulation of ODC activity in the hippocampus, a repression of activity in the neocortex and a combination of these effects in the cerebellum. Perinatal exposure to Pb2+ transiently modulated the pattern of ODC activity similarly in all three brain regions, in a characteristic manner irrespective of their developmental stage. These Pb2+-induced modulations of ODC activity suggest that polyamine-dependent processes may play a significant role in the manifestation of Pb2+-induced neurotoxicity dependent upon developmental factors at specific exposure periods. 相似文献