全文获取类型
收费全文 | 4382篇 |
免费 | 287篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 80篇 |
儿科学 | 92篇 |
妇产科学 | 88篇 |
基础医学 | 801篇 |
口腔科学 | 218篇 |
临床医学 | 383篇 |
内科学 | 975篇 |
皮肤病学 | 98篇 |
神经病学 | 436篇 |
特种医学 | 67篇 |
外科学 | 332篇 |
综合类 | 12篇 |
一般理论 | 2篇 |
预防医学 | 333篇 |
眼科学 | 86篇 |
药学 | 372篇 |
中国医学 | 14篇 |
肿瘤学 | 302篇 |
出版年
2024年 | 4篇 |
2023年 | 40篇 |
2022年 | 131篇 |
2021年 | 175篇 |
2020年 | 88篇 |
2019年 | 151篇 |
2018年 | 144篇 |
2017年 | 112篇 |
2016年 | 128篇 |
2015年 | 171篇 |
2014年 | 217篇 |
2013年 | 243篇 |
2012年 | 360篇 |
2011年 | 402篇 |
2010年 | 212篇 |
2009年 | 189篇 |
2008年 | 299篇 |
2007年 | 293篇 |
2006年 | 298篇 |
2005年 | 282篇 |
2004年 | 219篇 |
2003年 | 189篇 |
2002年 | 162篇 |
2001年 | 16篇 |
2000年 | 14篇 |
1999年 | 13篇 |
1998年 | 23篇 |
1997年 | 26篇 |
1996年 | 10篇 |
1995年 | 13篇 |
1994年 | 13篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1990年 | 2篇 |
1989年 | 4篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1970年 | 2篇 |
1968年 | 1篇 |
1962年 | 1篇 |
1929年 | 1篇 |
1900年 | 1篇 |
排序方式: 共有4691条查询结果,搜索用时 15 毫秒
31.
Cai Grau Jai Prakash Agarwal Kaukab Jabeen Abdul Rab Khan Sarath Abeyakoon Tatiana Hadjieva Ibrahim Wahid Sedat Turkan Hideo Tatsuzaki Ketayun A Dinshaw Jens Overgaard 《Radiotherapy and oncology》2003,67(1):17-26
BACKGROUND AND PURPOSE: Single agent mitomycin c (MMC) has been shown to improve the outcome of radiotherapy in single institution trials. In order to confirm these findings in a broader worldwide setting, the International Atomic Energy Agency (IAEA) initiated a multicentre trial randomising between radiotherapy alone versus radiotherapy plus MMC. MATERIAL AND METHODS: Patients with advanced head and neck cancer were treated with primary curative radiotherapy (66 Gy in 33 fractions with five fractions per week) +/-a single injection (15 mg/m(2)) of MMC at the end of the first week of radiotherapy. Stratification parameters were tumour localization, T-stage, N-stage, and institution. A total of 558 patients were recruited in the trial from February 1996 to December 1999. Insufficient accrual and reporting led to the exclusion of three centres. The final study population consisted of 478 patients from seven centres. Patients had stage III (n=223) or stage IV (n=255) squamous cell carcinoma of the oral cavity (n=230), oropharynx (n=140), hypopharynx (n=65) or larynx (n=43). Prognostic factors like age, gender, site, size, differentiation and stage were well balanced between the two arms. RESULTS: The haematological side effects of MMC were very modest (<5% grade 3-4) and did not require any specific interventions. Furthermore, MMC did not enhance the incidence or severity of acute and late radiation side effects. Confluent mucositis and dry skin desquamation was common, occurring in 56% and 62% of patients, respectively. The overall 3-year primary locoregional tumour control, disease-specific and overall survival rates were 19, 36 and 30%, respectively. Gender, haemoglobin drop, tumour site, tumour and nodal stage were significant parameters for loco-regional tumour control. There was no significant effect of MMC on locoregional control or survival, except for the 161 N0 patients, where MMC resulted in a better loco-regional control (3-year estimate 16% vs. 29%, P=0.01). CONCLUSIONS: The study did not show any major influence of MMC on loco-regional tumour control, survival or morbidity after primary radiotherapy in stage III-IV head and neck cancer except in N0 patients where loco-regional control was significantly improved. 相似文献
32.
Mutations in the tyrosine kinase domain of the epidermal growth factor receptor in non-small cell lung cancer. 总被引:4,自引:0,他引:4
Sei Hoon Yang Leah E Mechanic Ping Yang Maria Teresa Landi Elise D Bowman Jason Wampfler Daoud Meerzaman Kyeong Man Hong Felicia Mann Tatiana Dracheva Junya Fukuoka William Travis Neil E Caporaso Curtis C Harris Jin Jen 《Clinical cancer research》2005,11(6):2106-2110
We evaluated somatic genetic alterations in the kinase domain of the EGFR gene in the tumors of 219 non-small cell lung cancer patients of primarily Caucasian and African American origins. We identified 26 patients (12%) whose tumors had a mutation in the EGFR gene, and 11 (5%) patients carried novel genomic variations consistent with germ-line polymorphisms. All but one mutation were identified in Caucasian patients affected with adenocarcinoma. EGFR mutations were more frequent in women and in nonsmokers, but a significant portion of the affected patients were men (12 of 26) and current or past smokers accounted for half of the patients affected (13 of 26). Screening subjects with EGFR mutations may identify patients whose tumors could respond to targeted therapy using tyrosine kinase inhibitors. 相似文献
33.
This paper presents the use of hydrophobic silica aerogel (HSA) and hydrophilic fly ash cenosphere (FCS) aggregates for improvements in the thermal insulating and mechanical properties of 100- and 250 °C-autoclaved calcium aluminate phosphate (CaP) cement composites reinforced with micro-glass (MGF) and micro-carbon (MCF) fibers for deployment in medium- (100 °C) and high-temperature (250 °C) reservoir thermal energy storage systems. The following six factors were assessed: (1) Hydrothermal stability of HSA; (2) Pozzolanic activity of the two aggregates and MGF in an alkali cement environment; (3) CaP cement slurry heat release during hydration and chemical reactions; (4) Composite phase compositions and phase transitions; (5) Mechanical behavior; (6) Thermal shock (TS) resistance at temperature gradients of 150 and 225 °C. The results showed that hydrophobic trimethylsilyl groups in trimethylsiloxy-linked silica aerogel structure were susceptible to hydrothermal degradation at 250 °C. This degradation was followed by pozzolanic reactions (PR) of HSA, its dissolution, and the formation of a porous microstructure that caused a major loss in the compressive strength of the composites at 250 °C. The pozzolanic activities of FCS and MGF were moderate, and they offered improved interfacial bonding at cement-FCS and cement-MGF joints through a bridging effect by PR products. Despite the PR of MGF, both MGF and MCF played an essential role in minimizing the considerable losses in compressive strength, particularly in toughness, engendered by incorporating weak HSA. As a result, a FCS/HSA ratio of 90/10 in the CaP composite system was identified as the most effective hybrid insulating aggregate composition, with a persistent compressive strength of more than 7 MPa after three TS tests at a 150 °C temperature gradient. This composite displayed thermal conductivity of 0.28 and 0.35 W/mK after TS with 225 and 150 °C thermal gradients, respectively. These values, below the TC of water (TC water = 0.6 W/mK), were measured under water-saturated conditions for applications in underground reservoirs. However, considering the hydrothermal disintegration of HSA at 250 °C, these CaP composites have potential applications for use in thermally insulating, thermal shock-resistant well cement in a mid-temperature range (100 to 175 °C) reservoir thermal energy storage system. 相似文献
34.
Rosalinda Posadas-Snchez Jos Manuel Fragoso Fausto Snchez-Muoz Gustavo Rojas-Velasco Julian Ramírez-Bello Alberto Lpez-Reyes Laura E. Martínez-Gmez Carlos Sierra-Fernndez Tatiana Rodríguez-Reyna Nora Elemi Regino-Zamarripa Gustavo Ramírez-Martínez Joaquín Zuiga-Ramos Gilberto Vargas-Alarcn 《Viruses》2022,14(9)
SARS-CoV-2 uses the ACE2 receptor and the cellular protease TMPRSS2 for entry into target cells. The present study aimed to establish if the TMPRSS2 polymorphisms are associated with COVID-19 disease. The study included 609 patients with COVID-19 confirmed by RT-PCR test and 291 individuals negative for the SARS-CoV-2 infection confirmed by RT-PCR test and without antibodies anti-SARS-CoV-2. Four TMPRSS2 polymorphisms (rs12329760, rs2298659, rs456298, and rs462574) were determined using the 5′exonuclease TaqMan assays. Under different inheritance models, the rs2298659 (pcodominant2 = 0.018, precessive = 0.006, padditive = 0.019), rs456298 (pcodominant1 = 0.014, pcodominant2 = 0.004; pdominant = 0.009, precessive = 0.004, padditive = 0.0009), and rs462574 (pcodominant1 = 0.017, pcodominant2 = 0.004, pdominant = 0.041, precessive = 0.002, padditive = 0.003) polymorphisms were associated with high risk of developing COVID-19. Two risks (ATGC and GAAC) and two protectives (GAGC and GAGT) haplotypes were detected. High levels of lactic acid dehydrogenase (LDH) were observed in patients with the rs462574AA and rs456298TT genotypes (p = 0.005 and p = 0.020, respectively), whereas, high heart rate was present in patients with the rs462574AA genotype (p = 0.028). Our data suggest that the rs2298659, rs456298, and rs462574 polymorphisms independently and as haplotypes are associated with the risk of COVID-19. The rs456298 and rs462574 genotypes are related to high levels of LDH and heart rate. 相似文献
35.
Karel Petrzik Jaroslava Pibylov Josef pak Tatiana Sarkisova Jana Frnov Jan Holub Jan Skalík Igor Koloniuk 《Viruses》2022,14(11)
A virome screen was performed on a new breeding line, KB1, of blackcurrant. Rhabdovirus-like particles were observed by electron microscopy in ultrathin sections of flower stalks, and the complete genome sequence of a novel virus, provisionally named blackcurrant rhabdovirus 2 (BCRV2), was determined and verified using high-throughput sequencing. The genomic organization of BCRV2 was characteristic of cytorhabdoviruses (family Rhabdoviridae) and included seven genes: 3′-N-P′-P-P3-M-G-L-5′. BLASTP analysis revealed that the putative L protein had the highest amino acid sequence identity (75%) with strawberry virus 2. BCRV2 was detected in Cryptomyzus galeopsidis, but efficient transmission by this aphid was not confirmed. Of note, we observed coinfection of the KB1 line with blackcurrant-associated rhabdovirus (BCaRV) by RT-PCR. This is likely the first evidence of the presence of a cyto- and a nucleorhabdovirus in a single host. 相似文献
36.
Luisa Carbognin Cristina Accetta Danilo Di Giorgio Paola Fuso Margherita Muratore Giordana Tiberi Francesco Pavese Tatiana DAngelo Alessandra Fabi Diana Giannarelli Alba Di Leone Stefano Magno Giorgia Garganese Alejandro Martin Sanchez Daniela Andreina Terribile Gianluca Franceschini Riccardo Masetti Giovanni Scambia Ida Paris 《Current oncology (Toronto, Ont.)》2022,29(10):7218
The prevention of chemotherapy-induced alopecia still represents an urgent need for every day clinical practice. In this regard, this prospective single-center study included breast cancer (BC) patients who underwent a scalp cooling device (Dignicap®) during (neo)adjuvant chemotherapy with the aim to evaluate the efficacy and safety of this device in preventing alopecia. One hundred and seventy-eight patients (median age 43 years) were enrolled. The chemotherapy regimen included anthracycline and taxane-based chemotherapy (68.1%), docetaxel and cyclophosphamide (25.8%), anthracycline and taxane-based plus carboplatin (3.9%), and paclitaxel alone (2.2%). In 25.3% of cases, a dose dense schedule was used. Overall, the success rate was 68.0%: 100% in paclitaxel alone, 87.0% in docetaxel-cyclophosphamide, 59.5% in anthracycline and taxane, and 71.4% in the sequential regimen plus carboplatin group (anthracycline and taxane-based chemotherapy versus taxane-based chemotherapy, p ≤ 001. No difference in terms of hair preservation between dose-dense or standard schedule was found (p = 0.557). Early discontinuation of the scalp cooling was observed in 50 patients (28.1%). Although 138 patients (77.5%) experienced adverse events, 70.2% of patients were satisfied with this device. In conclusion, this large prospective study confirmed the helpful effect of the scalp cooling system in preventing alopecia in BC patients also undergoing sequential anthracyclines and taxane-based chemotherapy. 相似文献
37.
With diet-related chronic diseases being the largest contributors to U.S. morbidity and mortality, identifying population-level strategies to promote healthier diets is essential. Intervention during early childhood may be particularly important. The Child and Adult Care Food Program (CACFP), a federal nutrition assistance program in the U.S. that supports serving meals and snacks in child care settings, reaches millions of U.S. children. Recent 2017 updates to CACFP’s meal patterns were meant to improve the nutritional quality of food served through CACFP by providing more whole grains, fruit, and vegetables. In this study, we used a natural experimental, longitudinal study of child care centers participating in CACFP compared to nonparticipating centers to assess whether the quality of food and beverages served (per menu analysis) improved following the CACFP meal pattern changes. While we found that CACFP centers were more likely to meet several key nutrition standards in comparison to non-CACFP centers overall, there were no differences in menu quality from before to after the 2017 standards change between CACFP and non-CACFP centers. Nutrition standards for CACFP may need to be further strengthened with adequate financial and technical support given to child care programs for effective implementation. 相似文献
38.
39.
Alexandre de Matos Soeiro Bruno Biselli Tatiana C.A.T. Leal Aline Siqueira Bossa Maria Cristina Csar Srgio Jallad Priscila Gherardi Goldstein Patrícia Oliveira Guimares Carlos Vicente Serrano Jr Cesar Higa Nomura Dbora Nakamura Carlos Eduardo Rochitte Paulo Rogrio Soares Múcio Tavares de Oliveira Jr. 《Arquivos brasileiros de cardiologia》2022,118(5):894
BackgroundCoronary tomography angiography (CTA) has been mainly used for chest pain evaluation in low-risk patients, and few data exist regarding patients at intermediate risk.ObjectiveTo evaluate the performance of serial measures of sensitive troponin and CTA in intermediate-risk patients.MethodsA total of 100 patients with chest pain, TIMI risk scores of 3 or 4, and negative troponin were prospectively included. All patients underwent CTA and those with coronary stenosis ≥ 50% were referred to invasive coronary angiography. Patients with coronary lesions <50% were discharged and contacted 30 days later by a telephone call to assess clinical outcomes. Outcomes were hospitalization, death, and myocardial infarction at 30 days. The comparison between methods was performed by Kappa agreement test. The performance of troponin measures and CTA for detecting significant coronary lesions and clinical outcomes was calculated. Results were considered statistically significant when p < 0.05.ResultsCoronary stenosis ≥ 50% on CTA was found in 38% of patients and significant coronary lesions on coronary angiography were found in 31 patients. Two clinical events were observed. Kappa agreement analysis showed low agreement between troponin measures and CTA in the detection of significant coronary lesions (kappa = 0.022, p = 0.78). The performance of CTA for detecting significant coronary lesions on coronary angiography or for predicting clinical events at 30 days was better than sensitive troponin measures (accuracy of 91% versus 60%).ConclusionCTA performed better than sensitive troponin measures in the detection of significant coronary disease in patients with chest pain and intermediate risk for cardiovascular events. 相似文献
40.
Fedor M. Zurabov Ekaterina A. Chernevskaya Natalia V. Beloborodova Alexander Yu. Zurabov Marina V. Petrova Mikhail Ya. Yadgarov Valentina M. Popova Oleg E. Fatuev Vladislav E. Zakharchenko Marina M. Gurkova Ekaterina A. Sorokina Egor A. Glazunov Tatiana A. Kochetova Victoria V. Uskevich Artem N. Kuzovlev Andrey V. Grechko 《Viruses》2022,14(12)
Increasing evidence suggests that gut dysbiosis is associated with coronavirus disease 2019 (COVID-19) infection and may persist long after disease resolution. The excessive use of antimicrobials in patients with COVID-19 can lead to additional destruction of the microbiota, as well as to the growth and spread of antimicrobial resistance. The problem of bacterial resistance to antibiotics encourages the search for alternative methods of limiting bacterial growth and restoring the normal balance of the microbiota in the human body. Bacteriophages are promising candidates as potential regulators of the microbiota. In the present study, two complex phage cocktails targeting multiple bacterial species were used in the rehabilitation of thirty patients after COVID-19, and the effectiveness of the bacteriophages against the clinical strain of Klebsiella pneumoniae was evaluated for the first time using real-time visualization on a 3D Cell Explorer microscope. Application of phage cocktails for two weeks showed safety and the absence of adverse effects. An almost threefold statistically significant decrease in the anaerobic imbalance ratio, together with an erythrocyte sedimentation rate (ESR), was detected. This work will serve as a starting point for a broader and more detailed study of the use of phages and their effects on the microbiome. 相似文献