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31.
Heterogeneous oxygen tension and access to metabolites in solid tumors may produce variability in response to adjuvant therapy. To better understand these microenvironmental features, we examined survival and proliferation of neuroblastoma (NB) cells in an in vitro model of hypoxia and metabolite deprivation. Human NB cells (SH-SY5Y) were subjected to a "self-generated" diffusion gradient of nutrient and oxygen deprivation in a modified in vitro "sandwich model." In this model, the extent of both hypoxia and metabolite deprivation were individually altered, and the effects of each were studied. Cellular proliferation was confirmed by proliferating cell nuclear antigen (PCNA) immunocytochemistry and morphology and hypoxia by vascular endothelial growth factor (VEGF) and pimonidazole immunocytochemistry. We examined apoptotic cell death using TUNEL analysis, assaying for plasma membrane transfer of phosphotidylserine and the presence of the anti-apoptotic protein Bcl-2 using immunocytochemistry. As predicted, cellular survival diminished with increasing duration and severity of hypoxia and metabolite deprivation; oxygen deprivation was determined to be the more important contributory factor to early survival and proliferation. PCNA immunocytochemistry confirmed decreasing fractions of proliferating cells as a function of distance from oxygen and metabolites. VEGF and Bcl-2 immunoreactivity increased with prolonged exposure and increased extent of oxygen/metabolite deprivation. TUNEL analysis and phosphotidylserine transfer demonstrated cellular death of hypoxic and metabolite-deprived NB cells in a manner consistent with a mitochondrial apoptotic pathway. This in vitro model demonstrates that increasing the severity of hypoxia and metabolite deprivation results in diminished proliferation and greater apoptotic death, observations analogous to that of clinical NB tumors. 相似文献
32.
K. Mani, A. W. Ashton and R. N. Kitsis. Taking the BAD out of Adrenergic Stimulation. Journal of Molecular and Cell Cardiology (2002) 34, 709-712. 相似文献
33.
Incidence of malignancy in complex cystic renal masses (Bosniak category III): should imaging-guided biopsy precede surgery? 总被引:2,自引:0,他引:2
Harisinghani MG Maher MM Gervais DA McGovern F Hahn P Jhaveri K Varghese J Mueller PR 《AJR. American journal of roentgenology》2003,180(3):755-758
OBJECTIVE: Complex indeterminate renal cystic masses (Bosniak type III) can have benign and malignant causes and have been traditionally considered surgical lesions. We sought to determine the incidence of malignancy and to assess a possible role for imaging-guided biopsy for this category of renal masses. MATERIALS AND METHODS: Three hundred ninety-seven renal biopsies were performed at our institution between 1991 and 2000. Between January 1997 and August 2000, 28 Bosniak category III lesions, based on established CT imaging criteria on helical CT scans, were identified for analysis. The incidence of malignancy, based on surgical pathology or imaging follow-up and percentage of lesions proceeding to surgery, among these 28 lesions, was determined. The surgical results were correlated with the biopsy findings. RESULTS: Of the 28 biopsied category III lesions, 17 (60.7%) were malignant (16 renal cell carcinomas and one lymphoma), and 11 (39.3%) were benign (six hemorrhagic cysts, three inflammatory cysts, one metanephric adenoma, and one cystic oncocytoma). Seventeen of the 28 lesions (16 renal cell carcinomas and one inflammatory cyst) had surgical resection after the biopsy. All resected lesions had pathologic diagnoses identical to the percutaneous imaging-guided biopsy results. The remaining 11 patients who had undergone nonsurgical biopsies had radiologic follow-up for a minimum of 1 year, with benign lesions showing no interval change. CONCLUSION: Renal biopsy and radiologic follow-up were useful in identifying nonmalignant lesions in complex cystic renal masses and avoided unnecessary surgery in 39% of patients. 相似文献
34.
Vaidya VS Shankar K Lock EA Bucci TJ Mehendale HM 《Toxicology and applied pharmacology》2003,188(2):110-121
S-(1,2-dichlorovinyl)-L-cysteine (DCVC), a metabolite of a common environmental contaminant, trichloroethylene, is a selective proximal tubular nephrotoxicant. The objective of our study was to examine the dose-response relationship of renal injury and repair following DCVC administration. Male Swiss-Webster mice were injected with DCVC [15, 30, or 75 mg/kg ip in distilled water (10 ml/kg)] and the extent of nephrotoxicity and tissue repair was assessed over a 14-day period. The renal injury due to the low and medium doses of DCVC peaked at 36 and 72 h after dosing, respectively, and then regressed over time due to a timely and adequate tissue repair response. At the highest dose tissue repair was inhibited, thereby causing progression of renal injury, which led to acute renal failure and death of the mice. The possibility that compromised tissue repair was a result of the extensive nephrotoxic injury attendant to the high dose of DCVC was investigated via an equinephrotoxicity study in which separate groups of mice received 40 (LD40) and 75 (LD90) mg DCVC/kg, respectively. Bioactivation-based renal proximal tubular injury measured in these two groups over a time course was identical but there was a marked difference in mortality due to an early and robust tissue repair in the first group relative to the second group. These results support the concept that quantitative evaluation of renal tissue repair in parallel with injury is useful in the assessment of the likely toxic outcome associated with exposure to nephrotoxic drugs and toxicants. 相似文献
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38.
Venkatesh KK Lurie MN Triche EW De Bruyn G Harwell JI McGarvey ST Gray GE 《Tropical medicine & international health : TM & IH》2010,15(11):1364-1374
Objective To evaluate growth parameters assessed by weight and length in HIV‐infected and HIV‐uninfected infants born to HIV‐infected mothers in South Africa from birth to 6 months of age. Methods We calculated z‐scores for weight‐for‐age (WAZ), length‐for‐age (LAZ) and weight‐for‐length (WLZ) among a cohort of 840 mother–infant dyads. Multivariable Cox proportional hazards models with time‐varying covariates were used to estimate the risk of falling 2 z‐scores for WAZ, LAZ, and WLZ as a function of infant and maternal characteristics. Results By 6 months after birth, a fifth of infants had WAZ 2, 19% had an LAZ 2, and 29% had a WLZ 2. WLZ and WAZ were significantly lower in HIV‐infected infants than in uninfected infants by 3 months of age and LAZ by 6 months of age (P < 0.001). The risk of WAZ falling 2 was associated with decreasing maternal CD4 cell count (adj. HR for CD4 cell count <200 cells/μl: 1.64; 95% CI: 1.10–2.43), premature birth (adj. HR: 2.82; 95% CI: 2.06–3.86) and formula feeding (adj. HR: 3.35; 95% CI: 1.64–6.85). The risk of LAZ falling 2 was associated with increasingly lower maternal age (adj. HR for<20 years: 0.54; 95% CI: 0.31–0.96), lower maternal CD4 cell count (adj. HR for CD4 cell count <200 cells/μl: 1.72; 95% CI: 1.14–2.59), premature birth (adj. HR: 2.37; 95% CI: 1.70–3.30) and formula feeding (adj. HR: 4.22; 95% CI: 1.85–9.62). The risk of WLZ falling 2 was significantly associated with infant HIV infection (adj. HR: 1.64; 95% CI: 1.16–2.32) and formula feeding (adj. HR: 1.78; 95% CI: 1.11–2.83). The risk of WAZ and LAZ falling 2 was more than two times greater for HIV‐infected infants than for uninfected infants with gastrointestinal infections. Conclusions HIV‐infected infants were more likely to be stunted and wasted than uninfected infants, which often occurred within 3 months after birth. Infants who were born to mothers with advanced HIV disease, formula‐fed and co‐infected with HIV and gastrointestinal infections were at greater risk for growth disturbances. Further interventions are needed to promptly initiate both HIV‐infected mothers and infants on appropriate antiretroviral therapy and nutritional supplementation. 相似文献
39.
Selective attention has been shown to bias sensory processing in favor of relevant stimuli and against irrelevant or distracting stimuli in perceptual tasks. Increasing evidence suggests that selective attention plays an important role during working memory maintenance, possibly by biasing sensory processing in favor of to-be-remembered items. In the current study, we investigated whether selective attention may also support working memory by biasing processing against irrelevant and potentially distracting information. Event-related potentials (ERPs) were recorded while subjects (n = 22) performed a delayed-recognition task for faces and shoes. The delay period was filled with face or shoe distractors. Behavioral performance was impaired when distractors were congruent with the working memory domain (e.g., face distractor during working memory for faces) relative to when distractors were incongruent with the working memory domain (e.g., face distractor during shoe working memory). If attentional biasing against distractor processing is indeed functionally relevant in supporting working memory maintenance, perceptual processing of distractors is predicted to be attenuated when distractors are more behaviorally intrusive relative to when they are nonintrusive. As such, we predicted that perceptual processing of distracting faces, as measured by the face-sensitive N170 ERP component, would be reduced in the context of congruent (face) working memory relative to incongruent (shoe) working memory. The N170 elicited by distracting faces demonstrated reduced amplitude during congruent versus incongruent working memory. These results suggest that perceptual processing of distracting faces may be attenuated due to attentional biasing against sensory processing of distractors that are most behaviorally intrusive during working memory maintenance. 相似文献
40.
Alexander Ploss Salman R. Khetani Christopher T. Jones Andrew J. Syder Kartik Trehan Valeriya A. Gaysinskaya Kathy Mu Kimberly Ritola Charles M. Rice Sangeeta N. Bhatia 《Proceedings of the National Academy of Sciences of the United States of America》2010,107(7):3141-3145
Hepatitis C virus (HCV) remains a major public health problem, affecting approximately 130 million people worldwide. HCV infection can lead to cirrhosis, hepatocellular carcinoma, and end-stage liver disease, as well as extrahepatic complications such as cryoglobulinemia and lymphoma. Preventative and therapeutic options are severely limited; there is no HCV vaccine available, and nonspecific, IFN-based treatments are frequently ineffective. Development of targeted antivirals has been hampered by the lack of robust HCV cell culture systems that reliably predict human responses. Here, we show the entire HCV life cycle recapitulated in micropatterned cocultures (MPCCs) of primary human hepatocytes and supportive stroma in a multiwell format. MPCCs form polarized cell layers expressing all known HCV entry factors and sustain viral replication for several weeks. When coupled with highly sensitive fluorescence- and luminescence-based reporter systems, MPCCs have potential as a high-throughput platform for simultaneous assessment of in vitro efficacy and toxicity profiles of anti-HCV therapeutics. 相似文献