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101.
102.
A mixed-flow blood pump for long-term applications has been developed at the Helmholtz-Institute in Aachen, Germany. Central features of this implantable pump are a centrally integrated motor, a blood-immersed mechanical bearing, magnetic coupling of the impeller, and a shrouded impeller, which allows a relatively wide clearance. The aim of the study was a numerical analysis of hydraulic and hemolytic properties of different impeller design configurations. In vitro testing and numerical simulation techniques (computational fluid dynamics [CFD]) were applied to achieve a comprehensive overview. Pressure-flow charts were experimentally measured in a mock loop in order to validate the CFD data. In vitro hemolysis tests were performed at the main operating point of each impeller design. General flow patterns, pressure-flow charts, secondary flow rates, torque, and axial forces on the impeller were calculated by means of CFD. Furthermore, based on streak line techniques, shear stress (stress loading), exposure times, and volume percentage with critical stress loading have been determined. Comparison of CFD data with pressure head measurements showed excel-lent agreement. Also, impressive trend conformity was observed between in-vitro hemolysis results and numerical data. Comparison of design variations yielded clear trends and results. Design C revealed the best hydraulic and hemolytic properties and was chosen as the final design for the mixed-flow rotary blood pump. 相似文献
103.
104.
Nearly 80% of patients with systemic lupus erythematosus (SLE) are treated with NSAIDs for fever, arthritis, serositis and headaches. This article reviews currently available literature on non-selective and selective inhibitors of cyclooxygenases, with an emphasis on the efficacy and safety profile reported in SLE patients. All NSAIDs, regardless of their cyclooxygenase selectivity, induced renal side effects including sodium retention and reduction in glomerular filtration rate. In addition, lupus nephritis is a risk factor for NSAID-induced acute renal failure. NSAID-induced hepatotoxicity is increased in SLE patients in addition to cutaneous and allergic reactions. Finally, aseptic meningitis has been reported more frequently in NSAID-treated SLE patients. Nevertheless, NSAIDs can safely be prescribed to most lupus patients provided that their administration is re-evaluated on a regular basis and the patient is closely monitored. 相似文献
105.
Kheradvar A Tabassi AR Nikbin B Khosravi F Naroueynejad M Moradi B Amirzargar AA 《Multiple sclerosis (Houndmills, Basingstoke, England)》2004,10(5):526-531
BACKGROUND: Genetic predisposition in multiple sclerosis (MS) has always been a critical concern in aetiology and progress of the disease. The present study looks into the relations between human leukocyte antigen (HLA), optic neuritis (ON) and MS in the Iranian population. METHODS: Patients with potential diagnosis of acute ON underwent a standardized clinical examination for confirming the diagnosis. Selected patients were gathered for HLA typing and clinical follow up. RESULTS: Of the 55 patients, 46 (83.6%) were female. The mean age was 25(+/-7.3) with a range of 12-43. Twenty of the 55 (36%) were confirmed for the diagnosis of clinically definite MS (CDMS). Results show that A23, B21, A11 and B51 alleles were present in 4 (20%), 6 (30%), 2 (10%) and 1 (5%) of the CDMS patients, respectively. Ten (50%) and 17 (85%) CDMS patients were positive for HLA class II alleles, DR2 and DQ1, correspondingly. CONCLUSIONS: The study strongly suggests the association among DR2, A23 and B21 allele and the evolution of ON to MS. High prevalence of A23 and DR2 alleles in CDMS patients compared with the normal population may suggest an important role for these alleles in the development of MS. The study suggests B51 as a protective factor against development of ON in the normal population. In addition, results do not confirm previous studies considering A11 as a predisposing factor. The present study finally evokes that different classes of HLA have different roles in susceptibility to MS and confirms disease heterogeneity as an important emerging concept in MS. 相似文献
106.
107.
BACKGROUND: This study was designed to elucidate the possible correlation of cranial anthropometric measurements with the chiasm to limbus sphenoidale distance to facilitate preoperative estimation of this distance and to choose a better surgical approach. METHODS: Thirty-three fresh adult cadaver heads (22 males and 11 females) were evaluated for cranial anthropometric measurements. The precraniotomy anthropometric measurements included (A) inion to nasion distance and (B) the longest intermeatal meridian. Subsequently, with a standard craniotomy, the following intervals were measured: (C) optic chiasm to falciform ligament, (D) anterior aspect of optic chiasm to limbus sphenoidale, and (E) limbus sphenoidale to inner nasion. A combined ratio parameter, labeled as (F), was calculated from the following equation: F = B/E x 10. RESULTS: The mean values and standard errors of the mean of parameters A to F were 195.8 +/- 14.53 mm, 374.7 +/- 25.29 mm, 10.47 +/- 1.89 mm, 9.93 +/- 2.01 mm, 38.46 +/- 3.17 mm, and 9.81 +/- 1.11, respectively. The parameter D had significant correlation to the parameters B, C, E, and F. The most significant correlation was seen between parameters D and F (p < 0.001). According to linear regression assessment between parameters D and F, the following regression equation was obtained: D = 4.24 + 0.58F. CONCLUSIONS: Optic nerve topography and dimensions show inter-personal variations that may be anticipated to some extent with cranial anthropometric data. Calculating of F ratio gives us an acceptable estimation of the actual distance of chiasm to limbus sphenoidale, which in turn can help the surgeon to select the approach to tumors of intrasellar region. However, the role of meticulous imaging studies cannot be overemphasized to confirm the anticipated estimations. 相似文献
108.
109.
Arya A Piorkowski C Sommer P Bollmann A Hindricks G 《Herzschrittmachertherapie & Elektrophysiologie》2008,19(2):68-72
Atrial fibrillation (AF) is a common arrhythmia, affecting an estimated 2 million people in the United States and its prevalence increases with age, reaching 10% in those > or = 80 years. AF confers a four- to fivefold increased risk of stroke compared to the general population and has been associated with a doubling of all-cause mortality. During the past decade, limited success rates of drug treatment stimulated an exploration of interventional treatment options for AF. As our knowledge on initiating triggers and perpetuating substrate of AF expanded, different potentially curative catheter ablation techniques have been developed. In this article we review the current patient selection criteria, methods, and the results of the catheter ablation of atrial fibrillation. 相似文献
110.
Aghasadeghi MR Bahramali G Sadat SM Farahani A Mohraz M Davar Siadat S Mostafavi E Memarnejadian A Ardestani MS Vahabpour R Saraji AA Delbaz SA 《Current HIV research》2011,9(4):263-269
Chronic hepatitis B affects nearly 10% of HIV-infected patients. Hepatitis B virus (HBV) infection is a dynamic disease and coinfection with HIV impacts directly on the outcome of HBV infection, considerably complicating its natural history, diagnosis, and management. The aim of this study was to compare two cohorts of HBV monoinfected and HBV/HIV coinfected Iranian patients undergoing long-term lamivudine therapy from the clinical and virological aspects, as well as the frequency of detected mutations in HBV genome. To this end, HBV Pol/S regions from 72 patients were PCR-amplified and directly sequenced. Phylogenetic analysis indicated a 40-times higher risk of coinfection with ayw3 subtype of HBV genotype D rather than ayw2 subtype [P<0.001, odd: 40.66, CI: 95 % (4.69-352.23)]. While no resistance mutation was detected in HBV/HIV coinfected cohort, LAM-resistance mutations (rtM204I/V in YMDD and rtL180M in FLLA polymerase motifs) were identified in 30% (9 out of 30) and 16.66% (5 out of 30) of HBV monoinfected patients (P<0.05). Moreover, several mutations (sP105A, sI110S/L, sS136Y and sP127T/L) with significant differences in the frequency were identified in the S region of both cohorts. Finally, this study found strong correlation between the type of infection (mono or coinfection) and characteristics like patient gender, ALT levels, HBV-DNA levels and HBV subtypes. These results pointed to the importance of determination of HBV variants in the management of patients and suggested that in contrary to HBV monoinfections, LAM may be still an appropriate drug for the treatment of HBV in HBV/HIV coinfected patients; however, further studies to clarify the role of HIV in HBV LAM-resistance mutations are required. 相似文献