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排序方式: 共有8563条查询结果,搜索用时 15 毫秒
51.
Leonardo Furi Maria Laura Ciusa Daniel Knight Valeria Di Lorenzo Nadia Tocci Daniela Cirasola Lluis Aragones Joana Rosado Coelho Ana Teresa Freitas Emmanuela Marchi Laura Moce Pilar Visa John Blackman Northwood Carlo Viti Elisa Borghi Graziella Orefici the BIOHYPO Consortium Ian Morrissey Marco Rinaldo Oggioni 《Antimicrobial agents and chemotherapy》2013,57(8):3488-3497
The MICs and minimum bactericidal concentrations (MBCs) for the biocides benzalkonium chloride and chlorhexidine were determined against 1,602 clinical isolates of Staphylococcus aureus. Both compounds showed unimodal MIC and MBC distributions (2 and 4 or 8 mg/liter, respectively) with no apparent subpopulation with reduced susceptibility. To investigate further, all isolates were screened for qac genes, and 39 of these also had the promoter region of the NorA multidrug-resistant (MDR) efflux pump sequenced. The presence of qacA, qacB, qacC, and qacG genes increased the mode MIC, but not MBC, to benzalkonium chloride, while only qacA and qacB increased the chlorhexidine mode MIC. Isolates with a wild-type norA promoter or mutations in the norA promoter had similar biocide MIC distributions; notably, not all clinical isolates with norA mutations were resistant to fluoroquinolones. In vitro efflux mutants could be readily selected with ethidium bromide and acriflavine. Multiple passages were necessary to select mutants with biocides, but these mutants showed phenotypes comparable to those of mutants selected by dyes. All mutants showed changes in the promoter region of norA, but these were distinct from this region of the clinical isolates. Still, none of the in vitro mutants displayed fitness defects in a killing assay in Galleria mellonella larvae. In conclusion, our data provide an in-depth comparative overview on efflux in S. aureus mutants and clinical isolates, showing also that plasmid-encoded efflux pumps did not affect bactericidal activity of biocides. In addition, current in vitro tests appear not to be suitable for predicting levels of resistance that are clinically relevant. 相似文献
52.
Natália Pereira de Almeida Nogueira José Andrés Morgado-Díaz Rubem Figueiredo Sadok Menna-Barreto Marcia Cristina Paes Raquel Elisa da Silva-López 《Acta tropica》2013
It has been reported that serine peptidase activities of Trypanosoma cruzi play crucial roles in parasite dissemination and host cell invasion and therefore their inhibition could affect the progress of Chagas disease. The present study investigates the interference of the Stichodactyla helianthus Kunitz-type serine protease inhibitor (ShPI-I), a 55-amino acid peptide, in T. cruzi serine peptidase activities, parasite viability, and parasite morphology. The effect of this peptide was also studied in Leishmania amazonensis promastigotes and it was proved to be a powerful inhibitor of serine proteases activities and the parasite viability. The ultrastructural alterations caused by ShPI-I included vesiculation of the flagellar pocket membrane and the appearance of a cytoplasmic vesicle that resembles an autophagic vacuole. ShPI-I, which showed itself to be an important T. cruzi serine peptidase inhibitor, reduced the parasite viability, in a dose and time dependent manner. The maximum effect of peptide on T. cruzi viability was observed when ShPI-I at 1 × 10−5 M was incubated for 24 and 48 h which killed completely both metacyclic trypomastigote and epimastigote forms. At 1 × 10−6 M ShPI-I, in the same periods of time, reduced parasite viability about 91–95% respectively. Ultrastructural analysis demonstrated the formation of concentric membranar structures especially in the cytosol, involving organelles and small vesicles. Profiles of endoplasmic reticulum were also detected, surrounding cytosolic vesicles that resembled autophagic vacuoles. These results suggest that serine peptidases are important in T. cruzi physiology since the inhibition of their activity killed parasites in vitro as well as inducing important morphological alterations. Protease inhibitors thus appear to have a potential role as anti-trypanosomatidal agents. 相似文献
53.
54.
Francesco Scolari Elisa Delbarba Domenico Santoro Loreto Gesualdo Antonello Pani Nadia Dallera Laila-Yasmin Mani Marisa Santostefano Sandro Feriozzi Marco Quaglia Giuliano Boscutti Angelo Ferrantelli Carmelita Marcantoni Patrizia Passerini Riccardo Magistroni Federico Alberici Gian Marco Ghiggeri Claudio Ponticelli Pietro Ravani for the RI-CYCLO Investigators 《Journal of the American Society of Nephrology : JASN》2021,32(4):972
55.
Romina F. Aromando Elisa M. Heber Verónica A. Trivillin David W. Nigg Amanda E. Schwint María E. Itoiz 《Journal of oral pathology & medicine》2009,38(5):448-454
Objective: The therapeutic success of different boron neutron capture therapy (BNCT) protocols employing the hamster cheek pouch oral cancer model has been previously reported by our laboratory. The aim of this study was to explore potential mechanisms of BNCT‐induced damage to tumor in terms of potential inhibition in DNA synthesis and induction of apoptosis in the tumors that underwent partial remission following application of the different BNCT protocols in this model. Materials and methods: We evaluated DNA synthesis employing incorporation of 5‐bromo‐2′‐deoxyuridine as an end‐point. Apoptosis was evaluated by immunohistochemistry employing the deoxynucleotidyl transferase‐mediated deoxyuridine triphosphate‐biotin nick end‐labeling technique and Bax and Bcl‐2 labeling. These studies were performed in tumors that underwent partial remission 1–30 days post‐BNCT mediated by boronophenylalanine (BPA), GB‐10 (Na210B10H10) or (BPA + GB‐10). Results: BNCT exerted a marked inhibitory effect on DNA synthesis in tumors for all the protocols under study. The inhibitory effect of BPA‐BNCT occurred as soon as 1 day post‐treatment (P < 0.001). Conversely, the effect of GB‐10‐BNCT became apparent 7–14 days after therapy (P < 0.001) and was sustained until killed at 30 days post‐treatment (P < 0.001). (GB‐10 + BPA)‐BNCT exerted a rapid and persistent effect, conceivably because of the combined effect of BNCT mediated by both boron compounds. The apoptosis studies did not show differences between the pre‐treatment group and any of the BNCT groups. Conclusions: One of the mechanisms involved in BNCT‐induced tumor control in our model would be an inhibitory effect on DNA synthesis. Apoptosis does not seem to have a significant role in BNCT‐induced tumor control in our model. 相似文献
56.
Infantile hemangioma is a vascular tumor that occurs in 5–10% of infants of European descent. A defining feature of infantile
hemangioma is the dramatic growth and development into a disorganized mass of blood vessels. Subsequently, a slow spontaneous
involution begins around 1 year of age and continues for 4–6 years. The growth and involution of infantile hemangioma is very
different from other vascular tumors and vascular malformations, which do not regress and can occur at any time during childhood
or adult life. Much has been learned from careful study of the tissue morphology and gene expression patterns during the life-cycle
of hemangioma. Tissue explants and tumor-derived cell populations have provided further insight to unravel the cellular and
molecular basis of infantile hemangioma. A multipotent progenitor cell capable of de novo blood vessel formation has been
isolated from infantile hemangioma, which suggests that this common tumor of infancy, long considered to be a model for pathologic
angiogenesis, may also represent pathologic vasculogenesis. Whether viewed as angiogenesis or vasculogenesis, infantile hemangioma
represents a vascular perturbation during a critical period of post-natal growth, and as such provides a unique opportunity
to decipher mechanisms of human vascular development. 相似文献
57.
Claudio Pratola Elisa Baldo Pasquale Notarstefano Toselli Tiziano Roberto Ferrari 《Journal of interventional cardiac electrophysiology》2006,16(2):111-116
Background Radiofrequency ablation of fast and unstable left ventricular tachycardia (VT) usually requires non-contact mapping. The procedure is usually performed by a retrograde-transaortic route, requiring a double femoral artery puncture, for the 9F multielectrode catheter and the 7F ablation catheter which are advanced through the aorta and aortic valve into the left ventricle (LV). Reported limitations of the procedure are due to the stiffness of the balloon catheter, particularly in patients with tortuous peripheral arteries, atherosclerotic aorta, or with aortic stenosis. The aim of our study was to test the feasibility and assess the safety of a transseptal approach for left VT non-contact mapping and ablation.Materials and methods Ten patients with multiple cardiac defibrillator shocks because of fast and unstable VT were selected for non-contact mapping and ablation. After a double transseptal puncture the multielectrode catheter (Ensite Array™, St. Jude Medical) was advanced through a standard 10F introducer to a stable position in the LV apex over a 260 cm length 0.035 J-tip guidewire. The ablation catheter (Celsius™ Thermo-cool, Biosense Webster) was then inserted through the second 8F introducer. Twenty-five monomorphic sustained ventricular tachycardia were induced and ablated at the level of the diastolic pathway or exit point revealed by unipolar isopotential mapping. The total procedural and fluoroscopy times were 209 ± 32 min and 28.5 ± 9.27 min, respectively, which were comparable to those described with the traditional retrograde-transaortic approach. No major complication related with the transseptal approach were reported.Conclusion A transseptal approach can be a feasible and effective alternative approach for mapping and ablation of fast and unstable left VT with a non-contact mapping system. 相似文献
58.
Kushwaha RS Hayne D Vaizey CJ Wrightham E Payne H Boulos PB 《Diseases of the colon and rectum》2003,46(9):1182-1188
INTRODUCTION: The effect of pelvic radiotherapy on anorectal function is not clearly documented and is investigated in this prospective study. METHODS: Thirty-one males (median age, 70 years) with carcinoma of the prostate (n = 28) and bladder (n = 3) completed proctitis/incontinence symptom score questionnaires and anorectal physiology studies before and six weeks after pelvic radiotherapy. At six months after completion of radiotherapy, 25 of these patients were studied again. The results were expressed as medians and ranges and compared by the Mann-Whitney U test (2-tailed). RESULTS: Six weeks and six months after treatment, respectively, the proctitis symptom scores (0 (0-4) vs. 2 (0-7) (P < 0.001) vs. 2 (0-5) (P < 0.001)) and the incontinence symptom scores (0 (0-5) vs. 4 (0-11) (P < 0.001) vs. 3 (0-14) (P < 0.001)) increased. Urgency, frequency of defecation, anorectal pain, incontinence to liquid stool and to flatus, and alteration in lifestyle were significant symptoms after treatment. The following measurements decreased: anal canal resting pressure (83 (35-137) vs. 79 (26-152) (P = NS) vs. 71 (29-97) (P < 0.01) cm H2O), the squeeze increment (152 (51-135) vs. 162 (63-321) (P = NS) vs. 108 (45-296) (P < 0.042) cm H2O), and the maximum tolerated rectal volume (245 (115-450) vs. 194 (112-344) (P < 0.05) vs. 200 (109-350) (P < 0.138) ml). The rectal electrosensory threshold increased (20 (5.4-44) vs. 22 (9-50.5) (P < 0.134) vs. 31.5 (13.6-76) (P < 0.001) mA). CONCLUSIONS: Anorectal symptoms at six weeks after pelvic radiotherapy are related to reduced rectal capacity and compounded at six months by diminished internal and external sphincter function and rectal mucosal sensitivity. 相似文献
59.
Alpha-myosin heavy chain: a sarcomeric gene associated with dilated and hypertrophic phenotypes of cardiomyopathy 总被引:1,自引:0,他引:1
60.
Martínez E Milinkovic A de Lazzari E Ravasi G Blanco JL Larrousse M Mallolas J García F Miró JM Gatell JM 《Lancet》2004,364(9428):65-67
The rise in didanosine concentrations in plasma when given with tenofovir raises concern for a high risk of toxic effects. Recommendations to reduce didanosine dose have been issued, but only for adults weighing more than 60 kg. We reviewed cases of pancreatitis in patients receiving didanosine plus tenofovir, didanosine alone, and tenofovir alone to assess the incidence of and risk factors for pancreatitis. Between Aug 1, 2001, and Nov 30, 2003, five of 185 (2.7%) patients receiving didanosine plus tenofovir, one of 182 (0.5%) on didanosine without tenofovir, and none of 208 on tenofovir without didanosine developed pancreatitis (p=0.016). Co-administration of both drugs versus each of them individually was an independent risk factor for pancreatitis (crude hazard ratio 10.666, 95% CI 1.246-91.294, p=0.031). These results suggest that the risk of pancreatitis is heightened when didanosine and tenofovir are given together. 相似文献