全文获取类型
收费全文 | 35354篇 |
免费 | 2249篇 |
国内免费 | 164篇 |
专业分类
耳鼻咽喉 | 350篇 |
儿科学 | 897篇 |
妇产科学 | 889篇 |
基础医学 | 5281篇 |
口腔科学 | 2108篇 |
临床医学 | 3039篇 |
内科学 | 7879篇 |
皮肤病学 | 1028篇 |
神经病学 | 3100篇 |
特种医学 | 568篇 |
外科学 | 2835篇 |
综合类 | 147篇 |
一般理论 | 23篇 |
预防医学 | 4017篇 |
眼科学 | 588篇 |
药学 | 2759篇 |
中国医学 | 208篇 |
肿瘤学 | 2051篇 |
出版年
2024年 | 50篇 |
2023年 | 432篇 |
2022年 | 963篇 |
2021年 | 1708篇 |
2020年 | 979篇 |
2019年 | 1379篇 |
2018年 | 1641篇 |
2017年 | 1107篇 |
2016年 | 1082篇 |
2015年 | 1320篇 |
2014年 | 1723篇 |
2013年 | 2104篇 |
2012年 | 3257篇 |
2011年 | 3427篇 |
2010年 | 1718篇 |
2009年 | 1433篇 |
2008年 | 2361篇 |
2007年 | 2263篇 |
2006年 | 1994篇 |
2005年 | 1744篇 |
2004年 | 1473篇 |
2003年 | 1250篇 |
2002年 | 1090篇 |
2001年 | 142篇 |
2000年 | 80篇 |
1999年 | 117篇 |
1998年 | 145篇 |
1997年 | 133篇 |
1996年 | 92篇 |
1995年 | 71篇 |
1994年 | 73篇 |
1993年 | 57篇 |
1992年 | 54篇 |
1991年 | 37篇 |
1990年 | 26篇 |
1989年 | 30篇 |
1988年 | 20篇 |
1987年 | 17篇 |
1986年 | 18篇 |
1985年 | 13篇 |
1984年 | 15篇 |
1983年 | 14篇 |
1982年 | 18篇 |
1981年 | 9篇 |
1980年 | 14篇 |
1976年 | 8篇 |
1975年 | 9篇 |
1974年 | 7篇 |
1973年 | 11篇 |
1972年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
61.
A coupled chromogenic reaction (based on an agar overlay combining NADH, pyruvate kinase, lactate dehydrogenase, phosphoenolpyruvate, ATP, and kanamycin sulfate with thiazolyl blue-phenazine methosulfate for detection of NADH consumption) was optimized for the detection of aminoglycoside phosphotransferases (APHs). When used after analytical isoelectrofocusing of bacterial extracts from APH-producing strains, this method revealed one band in each of two strains with a genetically confirmed APH (3′) I and two bands in another strain with both APH (3′) I and APH (3′) VI, whereas no bands were detected in susceptible control strains or in aminoglycoside-resistant microorganisms without APH genes. 相似文献
62.
Ana Martín-Ancel María Luisa Casas Bartolomé Bonet 《Infection control and hospital epidemiology》2004,25(7):611-613
A neonate vaccinated against HBV was the source of an occupational exposure to blood. She was tested for hepatitis B surface antigen and found to be positive, leading to unnecessary treatment, retesting, and concern. Evaluation of the infectious status of HBV should rely on other means if vaccination has recently occurred. 相似文献
63.
64.
65.
António Travassos Susana Teixeira Pinto Ferreira Isaura Regadas Ana Sofia Travassos Florindo Esteves Esperancinha Isabel Prieto Grapa Pires Robert van Velze A Valido Maria do Céu Machado 《Ophthalmic surgery, lasers & imaging》2007,38(3):233-237
The anatomic response to intravitreal bevacizumab injection in three patients with aggressive, posterior retinopathy of prematurity is described. In all cases, the worse eye was treated with a single intravitreal injection of 0.75 mg of bevacizumab as monotherapy or complementary to laser therapy. In 24 hours, all injected eyes showed regression of the tunica vasculosa lentis and iris vessel engorgement and disappearance of iris rigidity. In addition, plus disease and retinal proliferation began to regress. None of the eyes required additional treatment. Follow-up of up to 10 months 相似文献
66.
67.
Mário Martins Oliveira Nogueira da Silva Ana Teresa Timóteo Joana Feliciano Lídia de Sousa Sofia Santos Fernando Marques Rui Ferreira 《Revista portuguesa de cardiologia》2007,26(7-8):691-702
Atrial electrical remodeling plays a part in recurrence of atrial fibrillation (AF). It has been related to an increase in heterogeneity of atrial refractoriness that facilitates the occurrence of multiple reentry wavelets and vulnerability to AF. AIM: To examine the relationship between dispersion of atrial refractoriness (Disp_A) and vulnerability to AF induction (A_Vuln) in patients with clinical paroxysmal AF (PAF). METHODS: Thirty-six patients (22 male; age 55+/-13 years) with > or =1 year of history of PAF (no underlying structural heart disease--n=20, systemic hypertension--n=14, mitral valve prolapse--n=1, surgically corrected pulmonary stenosis--n=1), underwent electrophysiological study (EPS) while off medication. The atrial effective refractory period (AERP) was assessed at five different sites--high (HRA) and low (LRA) lateral right atrium, high interatrial septum (IAS), proximal (pCS) and distal (dCS) coronary sinus--during a cycle length of 600 ms. AERP was taken as the longest S1-S2 interval that failed to initiate a propagation response. Disp_A was calculated as the difference between the longest and shortest AERP. A_Vuln was defined as the ability to induce AF with 1-2 extrastimuli or with incremental atrial pacing (600-300 ms) from the HRA or dCS. The EPS included analysis of focal electrical activity based on the presence of supraventricular ectopic beats (spontaneous or with provocative maneuvers). The patients were divided into group A--AF inducible (n=25) and group B--AF not inducible (n=11). Disp_A was analyzed to determine any association with A_Vuln. Disp_A and A_Vuln were also examined in those patients with documented repetitive focal activity. Logistic regression was used to determine any association of the following variables with A_Vuln: age, systemic hypertension, left ventricular hypertrophy, left atrial size, left ventricular function, duration of PAF, documented atrial flutter/tachycardia and Disp_A. RESULTS: There were no significant differences between the groups with regard to clinical characteristics and echocardiographic data. AF was inducible in 71% of the patients and noninducible in 29%. Group A had greater Disp_A compared to group B (105+/-78 ms vs. 49+/-20 ms; p=0.01). Disp_A was >40 ms in 50% of the patients without A_Vuln and in 91% of those with A_Vuln (p=0.05). Focal activity was demonstrated in 14 cases (39%), 57% of them with A_Vuln. Disp_A was 56+/-23 ms in this group and 92+/-78 ms in the others (p=0.07). Using logistic regression, the only predictor of A_Vuln was Disp_A (p=0.05). CONCLUSION: In patients with paroxysmal AF, Disp_A is a major determinant of A_Vuln. Nevertheless, the degree of nonuniformity of AERP appears to be less important as an electrophysiological substrate for AF due to focal activation. 相似文献
68.
69.
Ana Berta Sousa Ana Medeira Binita M Kamath Nancy B Spinner Isabel Cordeiro 《Revista portuguesa de cardiologia》2006,25(4):447-452
Although most congenital heart defects are isolated abnormalities of embryonic development, with little genetic contribution, a small number are components of syndromes. In such cases, an accurate diagnosis has important implications for individual prognosis and familial genetic counseling. Alagille syndrome (AGS) is a dominantly inherited multisystem developmental disorder, which primarily affects the liver, heart, eyes, skeleton, and face. In recent years, the identification of the AGS gene has drawn attention to the existence of subclinical carriers, and broadened the spectrum of phenotypical variation associated with this syndrome. The authors present a case of mother and son with benign stenosis of the pulmonary artery branches. Subtle facial aspects suggested the diagnosis of AGS, which was confirmed by molecular analysis. Relevant clinical investigations and diagnostic implications are discussed. 相似文献
70.
Andr ia Kist Fernandes Felipe Mallmann Ana Maria Pasquali Steinhorst Fernando Lopes Nogueira Eduardo Mü ller vila Dumitriu Zunino Saucedo Francisco Juchem Machado Marcelo Greg rio Raymundi S rgio Saldanha Menna Barreto Paulo de Tarso Roth Dalcin 《The Journal of asthma》2003,40(6):683-690
Asthma patients that depend on emergency department (ED) services are generally considered to have extremely poor disease control and prognosis. It is important to identify characteristics related to poor disease control and frequent visits to the ED to apply appropriate clinical management. This study comprised a cross-sectional survey of consecutive patients with asthma exacerbation (age ≥12 years) presenting at the adult ED of a large, tertiary care, university-affiliated hospital over a 2-month period. The frequent visitors (FV) were defined by ≥3 visits to the ED in the preceding year, and the occasional visitors (OV) by ≤2 visits. Eighty-six patients (61 females and 25 males) were included in the study (mean age 38 ± 18 years). Of these patients, 51.2% were FV and 48.8% were OV. Sixty-nine percent had annual income lower than A$3000 and 66.3% had ≤8 years of the formal education. Only 18.6% had used inhaled corticosteroids, 79.1% identified the asthma attack severity, 70.9% increased or initiated inhaled β-agonist, 20.9% increased or initiated steroid therapy, and 55.8% had an asthma action plan for attack. The number of hospital admissions in past year (OR 4.3, P = .02), use of home nebulizer (OR 3.6, P = .05) and the lack of a written asthma action plan (OR 3.3, P = .03) were independently associated with frequent visits to the ED. We conclude that a substantial proportion of the patients that visit the ED are FV. These patients are more likely to have hospital admission in the past year, to use a home nebulizer, and to lack a written asthma action plan. They should be considered the most important target for asthma education. 相似文献