全文获取类型
收费全文 | 5636篇 |
免费 | 368篇 |
国内免费 | 32篇 |
专业分类
耳鼻咽喉 | 37篇 |
儿科学 | 124篇 |
妇产科学 | 182篇 |
基础医学 | 787篇 |
口腔科学 | 142篇 |
临床医学 | 768篇 |
内科学 | 1197篇 |
皮肤病学 | 84篇 |
神经病学 | 537篇 |
特种医学 | 109篇 |
外科学 | 479篇 |
综合类 | 29篇 |
一般理论 | 3篇 |
预防医学 | 658篇 |
眼科学 | 45篇 |
药学 | 329篇 |
中国医学 | 25篇 |
肿瘤学 | 501篇 |
出版年
2023年 | 42篇 |
2022年 | 62篇 |
2021年 | 174篇 |
2020年 | 97篇 |
2019年 | 148篇 |
2018年 | 140篇 |
2017年 | 120篇 |
2016年 | 128篇 |
2015年 | 158篇 |
2014年 | 198篇 |
2013年 | 301篇 |
2012年 | 430篇 |
2011年 | 500篇 |
2010年 | 240篇 |
2009年 | 227篇 |
2008年 | 386篇 |
2007年 | 371篇 |
2006年 | 370篇 |
2005年 | 338篇 |
2004年 | 351篇 |
2003年 | 324篇 |
2002年 | 282篇 |
2001年 | 33篇 |
2000年 | 31篇 |
1999年 | 47篇 |
1998年 | 53篇 |
1997年 | 49篇 |
1996年 | 27篇 |
1995年 | 30篇 |
1994年 | 28篇 |
1993年 | 28篇 |
1992年 | 18篇 |
1991年 | 24篇 |
1990年 | 15篇 |
1989年 | 14篇 |
1988年 | 20篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 9篇 |
1984年 | 27篇 |
1983年 | 18篇 |
1982年 | 19篇 |
1981年 | 18篇 |
1980年 | 17篇 |
1979年 | 7篇 |
1978年 | 10篇 |
1977年 | 9篇 |
1976年 | 7篇 |
1973年 | 13篇 |
1969年 | 5篇 |
排序方式: 共有6036条查询结果,搜索用时 234 毫秒
101.
Pepi M Tamborini G Maltagliati A Guazzi M Berna G Susini F Muratori M Celeste F 《Clinical cardiology》2003,26(9):424-430
BACKGROUND: The normal and dilated heart behaves as a single functional unit during preload reduction: volume unloading in the setting of diastolic ventricular interaction allows for increased left ventricular (LV) filling. HYPOTHESIS: We hypothesized that reduction of venous return induced by a physiologic stimulus (tilting) or by acute angiotensin-converting enzyme (ACE) inhibitors in dilated heart is likely to have a marked and similar effect on ventricular chamber geometry and filling. This study was designed to assess how the normal and dilated heart adapts to preload reduction. METHODS: Twenty normal subjects and 20 patients with moderate heart failure due to dilated cardiomyopathy were studied with two-dimensional and Doppler echocardiography in supine position (B) and after 40 degrees of head-up tilting (T). The following day, patients repeated supine (C) and tilting test (TC) after administration of captopril (25 mg s.l.). Right ventricular (RV) and LV dimensions, LV geometry, and tricuspid, mitral, and pulmonary venous flow patterns were recorded at each step of the study. RESULTS: In the two groups, T was associated with reduction of RV area and LV volumes; C and TC produced a similar effect on RV and LV. Changes in LV septal-lateral diameter and anterior-posterior diameter were different at each step of the study: during T (both groups) and after C and TC, the septallateral diameter increased slightly while the anterior-posterior diameter decreased. During T, mitral and tricuspid peak flow velocities decreased, peak late velocities were unchanged, and the deceleration time of mitral flow increased; the systolic forward flow of pulmonary venous flow decreased, the diastolic forward flow did not change, and the difference in duration between reverse pulmonary flow and mitral peak late flow decreased: C and CT induced similar changes. CONCLUSION: Preload reduction induced by tilting or by ACE inhibitors induces profound and similar effects on LV and RV dimensions, LV geometry, and biventricular filling. Reduction of RV dimension is associated with adaptation of LV geometry and decrease of LV diastolic pressure, which facilitates LV filling and pulmonary venous drainage: ACE inhibition associated with tilting exerts an additional effect on these changes. These data confirm the role of ventricular interaction in modulating LV filling in heart failure. 相似文献
102.
Espinosa G Santos E Cervera R Piette JC de la Red G Gil V Font J Couch R Ingelmo M Asherson RA 《Medicine》2003,82(2):106-118
To describe the clinical and immunologic characteristics of patients with adrenal involvement and antiphospholipid syndrome (APS), we conducted a computer-assisted (PubMed) search of the literature to identify all cases of primary adrenal insufficiency associated with antiphospholipid antibodies published in English, French, and Spanish from 1983 (when APS was first defined) through March 2002. We reviewed 86 patients (80 from the literature plus 6 from our cohort); 55% were male, and the mean age at presentation was 43 +/- 16 years. Sixty-one (71%) patients had primary APS, and 14 (16%) had systemic lupus erythematosus. In 31 (36%) patients, adrenal insufficiency was the first clinical manifestation of APS. Abdominal pain was present in 55% of patients, followed by hypotension (54%), fever (40%), nausea or vomiting (31%), weakness or fatigue (31%), and lethargy or altered mental status (19%). The main finding in imaging techniques was compatible with adrenal hemorrhage (59%) and in histopathologic study was a hemorrhagic infarction with vessel thrombosis (55%). Lupus anticoagulant was detected in 97% of patients and the anticardiolipin antibodies titer was positive in 93% of patients. Most patients (95%) were positive for the IgG isotype of anticardiolipin antibodies, whereas 40% were positive for the IgM isotype. Baseline cortisol levels were decreased in 98% of patients, ACTH hormone levels were increased in 96% of patients, and the cosyntropin stimulation test was positive in 100% of patients tested. Steroid replacement therapy was the most frequent treatment (84%), followed by anticoagulation (52%) and aspirin (6%). Thirty-two of 35 (91%) patients with prolonged anticoagulant therapy were in good health with a mean follow-up of 25 months, whereas 25 of the 69 (36%) patients with outcome data available had died. The results of the present review stress the clinical importance of systematic screening for lupus anticoagulant and anticardiolipin antibodies in all cases of adrenal hemorrhage or infarction. An initial screening for hypoadrenalism is mandatory in any antiphospholipid antibody-positive patient who complains of abdominal pain and undue weakness or asthenia. 相似文献
103.
104.
Harry Gibbs Ben Freedman Mårten Rosenqvist Saverio Virdone Wael Al Mahmeed Giuseppe Ambrosio A. John Camm Barry Jacobson Carlos Jerjes-Sanchez Gloria Kayani Ali Oto Elizaveta Panchenko Hany Ragy Ajay K. Kakkar 《The American journal of medicine》2021,134(7):893-901.e11
BackgroundAsymptomatic atrial fibrillation is often detected incidentally. Prognosis and optimal therapy for asymptomatic compared with symptomatic atrial fibrillation is uncertain. This study compares clinical characteristics, treatment, and 2-year outcomes of asymptomatic and symptomatic atrial fibrillation presentations.MethodsGlobal Anticoagulant Registry in the Field-Atrial Fibrillation (GARFIELD-AF) is a global, prospective, observational study of newly diagnosed atrial fibrillation with ≥1 stroke risk factors (http://www.clinicaltrials.gov, unique identifier: NCT01090362). Patients were characterized by atrial fibrillation-related symptoms at presentation and the CHA2DS2-VASc score. Two-year follow-up recorded anticoagulation patterns (vitamin K antagonist, direct oral anticoagulants, parenteral therapy) and outcomes (stroke/systemic embolism, all-cause mortality, and bleeding).ResultsAt presentation, of 52,032 eligible patients, 25.4% were asymptomatic and 74.6% symptomatic. Asymptomatic patients were slightly older (72 vs 70 years), more often male (64.2% vs 52.9%), and more frequently initiated on anticoagulation ± antiplatelets (69.4% vs 66.0%). No difference in events (adjusted hazard ratios, 95% confidence interval) for nonhemorrhagic stroke/systemic embolism (1.19, 0.97-1.45), all-cause mortality (1.06, 0.94-1.20), or bleeding (1.02, 0.87-1.19) was observed. Anticoagulation was associated with comparable reduction in nonhemorrhagic stroke/systemic embolism (0.59, 0.43–0.82 vs 0.78, 0.65–0.93) and all-cause mortality (0.69, 0.59-0.81 vs 0.77, 0.71-0.85) in asymptomatic versus symptomatic, respectively.ConclusionsMajor outcomes do not differ between asymptomatic and symptomatic atrial fibrillation presentations and are comparably reduced by anticoagulation. Opportunistic screening-detected asymptomatic atrial fibrillation likely has the same prognosis as asymptomatic atrial fibrillation at presentation and likely responds similarly to anticoagulation thromboprophylaxis. 相似文献
105.
106.
Margarida Corominas-Roso Gloria Palomar Roser Ferrer Alberto Real Mariana Nogueira Montserrat Corrales Miguel Casas Josep Antoni Ramos-Quiroga 《The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP)》2015,18(9)
Background:
Differences in the cortisol response have been reported between children exhibiting the inattentive and hyperactive/impulsive subtypes of attention deficit hyperactivity disorder. However, there is no such information about adults. The aim of the present study was to determine the possible differences between the combined and inattentive subtypes in the cortisol response to stress.Methods:
Ninety-six adults with attention deficit hyperactivity disorder, 38 inattentive and 58 combined, without any medical or psychiatric comorbidities and 25 healthy controls were included. The Trier Social Stress Test was used to assess physiological stress responses. Clinical data and subjective stress levels, including the Perceived Stress Scale, were also recorded.Results:
No significant differences in the cortisol response to the Trier Social Stress Test were found between patients and controls. However, albeit there were no basal differences, lower cortisol levels at 15 (P=.015), 30 (P=.015), and 45 minutes (P=.045) were observed in the combined compared with the inattentive subtype after the stress induction; these differences disappeared 60 minutes after the stress. In contrast, the subjective stress responses showed significant differences between attention deficit hyperactivity disorder patients and controls (P<.001), but no differences were seen between attention deficit hyperactivity disorder subtypes. In turn, subjective stress measures, such as the Perceived Stress Scale, positively correlated with the whole cortisol stress response (P<.027).Conclusions:
Both the combined and inattentive attention deficit hyperactivity disorder adults exhibited a normal cortisol response to stress when challenged. Nevertheless, the inattentive patients displayed a higher level of cortisol after stress compared with the combined patients. Despite the differences in the cortisol response, adults with attention deficit hyperactivity disorder reported high levels of subjective stress in their every-day life. 相似文献107.
Gemma Bullich Daniel Trujillano Sheila Santín Stephan Ossowski Santiago Mendizábal Gloria Fraga álvaro Madrid Gema Ariceta José Ballarín Roser Torra Xavier Estivill Elisabet Ars 《European journal of human genetics : EJHG》2015,23(9):1192-1199
Genetic diagnosis of steroid-resistant nephrotic syndrome (SRNS) using Sanger sequencing is complicated by the high genetic heterogeneity and phenotypic variability of this disease. We aimed to improve the genetic diagnosis of SRNS by simultaneously sequencing 26 glomerular genes using massive parallel sequencing and to study whether mutations in multiple genes increase disease severity. High-throughput mutation analysis was performed in 50 SRNS and/or focal segmental glomerulosclerosis (FSGS) patients, a validation cohort of 25 patients with known pathogenic mutations, and a discovery cohort of 25 uncharacterized patients with probable genetic etiology. In the validation cohort, we identified the 42 previously known pathogenic mutations across NPHS1, NPHS2, WT1, TRPC6, and INF2 genes. In the discovery cohort, disease-causing mutations in SRNS/FSGS genes were found in nine patients. We detected three patients with mutations in an SRNS/FSGS gene and COL4A3. Two of them were familial cases and presented a more severe phenotype than family members with mutation in only one gene. In conclusion, our results show that massive parallel sequencing is feasible and robust for genetic diagnosis of SRNS/FSGS. Our results indicate that patients carrying mutations in an SRNS/FSGS gene and also in COL4A3 gene have increased disease severity. 相似文献
108.
109.
Daniel Zúiga-Núez Pablo Barrias Gloria Crdenas-Jirn M. Soledad Ureta-Zaartu Camilo Lopez-Alarcn F. Eduardo Morn Vieyra Claudio D. Borsarelli Emilio I. Alarcon Alexis Aspe 《RSC advances》2018,8(4):1927
Coumarin compounds have been described as anti-inflammatories, and chemotherapeutic agents as well as antioxidants. However, the origin of the antioxidant activity of non phenolic coumarins remains obscure. In the present report, we demonstrate that non-phenolic 7-dialkyl-aminocoumarins may also have significant antioxidant properties against free radicals derived from 2,2′-azobis(2-amidinopropane) dihydrochloride under aerobic conditions. This atypical behaviour is due to the presence of traces of very reactive hydroxycinnamic acid-type compounds. Changing functional groups at the C-3 and C-4 positions shifts the reactivity of the compounds from peroxyl to alkoxyl free radicals. Kinetic and theoretical studies based on Density Functional Theory support the formation of reactive hydroxycinnamic acid and directly link the antioxidant behaviour of the compounds to hydrogen atom transfer.Relevant antioxidant properties of non-phenolic 7-dialkyl-aminocoumarins against free radicals derived from 2,2′-azobis(2-amidinopropane) dihydrochloride under aerobic conditions have been experimentally and theoretically demonstrated. 相似文献
110.
Blanca Gregoria Melo Melo Yamile Vargas Hernández Gloria Mabel Carrillo Diana Katherine Alarcón Trujillo 《Enfermería clínica》2018,28(1):36-43