全文获取类型
收费全文 | 5619篇 |
免费 | 262篇 |
国内免费 | 53篇 |
专业分类
耳鼻咽喉 | 56篇 |
儿科学 | 86篇 |
妇产科学 | 78篇 |
基础医学 | 617篇 |
口腔科学 | 67篇 |
临床医学 | 377篇 |
内科学 | 1620篇 |
皮肤病学 | 44篇 |
神经病学 | 413篇 |
特种医学 | 204篇 |
外科学 | 1073篇 |
综合类 | 18篇 |
一般理论 | 2篇 |
预防医学 | 123篇 |
眼科学 | 66篇 |
药学 | 513篇 |
中国医学 | 12篇 |
肿瘤学 | 565篇 |
出版年
2023年 | 31篇 |
2022年 | 72篇 |
2021年 | 81篇 |
2020年 | 50篇 |
2019年 | 78篇 |
2018年 | 84篇 |
2017年 | 60篇 |
2016年 | 105篇 |
2015年 | 100篇 |
2014年 | 149篇 |
2013年 | 145篇 |
2012年 | 230篇 |
2011年 | 271篇 |
2010年 | 149篇 |
2009年 | 143篇 |
2008年 | 269篇 |
2007年 | 263篇 |
2006年 | 252篇 |
2005年 | 248篇 |
2004年 | 229篇 |
2003年 | 244篇 |
2002年 | 237篇 |
2001年 | 219篇 |
2000年 | 223篇 |
1999年 | 211篇 |
1998年 | 58篇 |
1997年 | 38篇 |
1996年 | 36篇 |
1995年 | 33篇 |
1994年 | 41篇 |
1993年 | 21篇 |
1992年 | 143篇 |
1991年 | 147篇 |
1990年 | 155篇 |
1989年 | 176篇 |
1988年 | 126篇 |
1987年 | 134篇 |
1986年 | 110篇 |
1985年 | 112篇 |
1984年 | 68篇 |
1983年 | 47篇 |
1982年 | 22篇 |
1979年 | 38篇 |
1978年 | 27篇 |
1977年 | 19篇 |
1975年 | 18篇 |
1974年 | 24篇 |
1972年 | 28篇 |
1971年 | 23篇 |
1969年 | 20篇 |
排序方式: 共有5934条查询结果,搜索用时 31 毫秒
951.
Computer-aided diagnosis for the classification of focal liver lesions by use of contrast-enhanced ultrasonography 总被引:1,自引:0,他引:1
The authors developed a computer-aided diagnostic (CAD) scheme for classifying focal liver lesions (FLLs) as liver metastasis, hemangioma, and three histologic differentiation types of hepatocellular carcinoma (HCC), by use of microflow imaging (MFI) of contrast-enhanced ultrasonography. One hundred and three FLLs obtained from 97 cases used in this study consisted of 26 metastases (15 hyper- and 11 hypovascularity types), 16 hemangiomas (five hyper- and 11 hypovascularity types) and 61 HCCs: 24 well differentiated (w-HCC), 28 moderately differentiated (m-HCC), and nine poorly differentiated (p-HCC). Pathologies of all cases were determined based on biopsy or surgical specimens. Locations and contours of FLLs on contrast-enhanced images were determined manually by an experienced physician. MFI was obtained with contrast-enhanced low-mechanical-index (MI) pulse subtraction imaging at a fixed plane which included a distinctive cross section of the FLL. In MFI, the inflow high signals in the plane, which were due to the vascular patterns and the contrast agent, were accumulated following flash scanning with a high-MI ultrasound exposure. In the initial step of our computerized scheme, a series of the MFI images was extracted from the original cine clip (AVI format). We applied a smoothing filter and time-sequential running average techniques in order to reduce signal noise on the single MFI image and cyclic noise on the sequential MFI images, respectively. A kidney, vessels, and a liver parenchyma region were segmented automatically by use of the last image of a series of MFI images. The authors estimated time-intensity curves for an FLL by use of a series of the temporally averaged MFI images in order to determine temporal features such as estimated replenishment times at early and delayed phases, flow rates, and peak times. In addition, they extracted morphologic and gray-level image features which were determined based on the physicians' knowledge of the diagnosis of the FLL, such as the size of lesion, vascular patterns, and the presence of hypoechoic regions. They employed a cascade of six independent artificial neural networks (ANNs) by use of extracted temporal and image features for classifying five types of liver diseases. A total of 16 temporal and image features, which were selected from 43 initially extracted features, were used for six different ANNs for making decisions at each decision in the cascade. The ANNs were trained and tested with a leave-one-lesion-out test method. The classification accuracies for the 103 FLLs were 88.5% for metastasis, 93.8% for hemangioma, and 86.9% for all HCCs. In addition, the classification accuracies for histologic differentiation types of HCCs were 79.2% for w-HCC, 50.0% for m-HCC, and 77.8% for p-HCC. The CAD scheme for classifying FLLs by use of the MFI on contrast-enhanced ultrasonography has the potential to improve the diagnostic accuracy in the histologic diagnosis of HCCs and the other liver diseases. 相似文献
952.
Algebraic method for the analysis of signaling crosstalk 总被引:1,自引:0,他引:1
953.
Matsuo S Yamane T Hioki M Tanigawa S Tokutake K Ito K Narui R Nakane T Tokuda M Yamashita S Inada K Date T Sugimoto K Yoshimura M 《Pacing and clinical electrophysiology : PACE》2012,35(3):e65-e68
Peri-mitral atrial flutter, which is a type of macroreentrant atrial tachycardia circulating around the mitral annulus, was terminated with the guidance of the high-density mapping catheter. A 72-year-old woman with atrial fibrillation and atrial tachycardia presented with symptoms of congestive heart failure. The recurrent peri-mitral atrial flutter following the initial catheter ablation for atrial tachycardia and atrial fibrillation was terminated by radiofrequency application on the gap that was identified using a novel high-density mapping catheter. 相似文献
954.
Niu CM Corcos DM Shapiro MB 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2012,216(2):191-201
Simple movements can be seen as building blocks for complex action sequences, and neural control of an action sequence can
be expected to preserve some control features of its constituent blocks. It was previously found that during single-joint
elbow movements to a single target, the proprioceptive feedback control is initially suppressed, and we tested this feedback
suppression in a two-segment sequence during which subjects momentarily slowed down at an intermediate target at a 30° distance
(first segment) and then immediately moved another 30° to the final target (second segment). Either the first or second segment
was unexpectedly perturbed; the latency of the earliest response to the perturbation in the muscle surface electromyogram
was analyzed. The perturbations were delivered either at the onset of each segment or about 0.1 s later. We found that in
both segments, the response latency to the late perturbation was shorter than the latency to the early perturbation, which
suggests that the proprioceptive feedback control is suppressed in the beginning of each segment. Next, we determined the
latency of the response to unexpected perturbations in 30° movements to a single target. We found that the response latency
was not significantly different in the movement to a single target and in each segment in the sequence. This result suggests
that the initial suppression of the proprioceptive feedback control in movements to single targets is preserved in movements
through intermediate targets and supports the idea of modular organization of neural control of movement sequences. 相似文献
955.
Spinal deformity is an important clinical manifestation after surgery for spinal cord tumors. One-third of patients who receive laminectomies and irradiation of the spinal column develop scoliosis, kyphosis, or kyphoscoliosis. Recent reports indicate good results after scoliosis surgery using segmental pedicle screws and a navigation system, but these reported studies have not included surgery for post-laminectomy kyphosis. Hooks and wires are ineffective in such patients who undergo laminectomy, and there are also high perioperative risks with insertion of pedicle screws because landmarks have been lost. Here, we report on the 5-year follow-up of a 13-year-old male patient with post-laminectomy and post-irradiation thoracic kyphoscoliosis after surgical treatment of spinal astrocytoma. Posterior segmental pedicle screw fixation was performed safely using a computer-assisted technique. The authors present the first case report for treatment of this condition using a navigation system. 相似文献
956.
A method for the measurement of temperature in the lateral ventricle using diffusion‐weighted imaging (DWI) has been proposed recently. This method uses predetermined arbitrary thresholds, but a more objective method of calculation would be useful. We therefore compared four different calculation methods, two of which were newly created and did not require predetermined thresholds. A rectangular polyethylene terephthalate bottle (8 × 10 × 28 cm3) was filled with heated water (35.0–38.8 °C) and used as a water phantom. The DWI data of 23 healthy subjects (aged 26–75 years; mean ± standard deviation, 50.13 ± 19.1 years) were used for this study. The temperature was calculated using the following equation: T(°C) = 2256.74/ln(4.39221/D) ? 273.15, where D is the diffusion coefficient. The mean ventricular temperature was calculated by four methods: two thresholding methods and two histogram curve‐fitting methods. As a reference, we used the temperature measured at the tympanic membrane, which is known to be approximately 1 °C lower than the brain temperature. The averaged differences in temperature between mercury thermometry and classical predetermined thresholding methods for the water phantom were 0.10 ± 0.42 and 0.05 ± 0.41 °C, respectively. The histogram curve‐fitting methods, however, yielded temperatures a little lower (averaged differences of ?0.24 ± 0.32 and ?0.14 ± 0.31 °C, respectively) than mercury thermometry. There was very little difference in temperature between tympanic thermometry and classical predetermined thresholding methods (+0.01 and ?0.07 °C, respectively). In humans, however, the histogram curve‐fitting methods yielded temperatures approximately 1 °C higher (+1.04 °C and +1.36 °C, respectively), suggesting that temperatures measured in this way more closely approximate the true brain temperature. The histogram curve‐fitting methods were more objective and better matched the estimated brain temperature than did classical predetermined thresholding methods, although the standard deviation was wider in the former methods. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
957.
Shimizu K Ogura H Hamasaki T Goto M Tasaki O Asahara T Nomoto K Morotomi M Matsushima A Kuwagata Y Sugimoto H 《Digestive diseases and sciences》2011,56(4):1171-1177
Background
Gut under severe insult is considered to have an important role in promoting infection and multiple organ dysfunction syndrome from the viewpoint of altered intestinal epithelium, immune system and commensal bacteria. There are few reports, however, about the relationship between gut flora and septic complications.Methods
We analyzed gut flora in patients with systemic inflammatory response syndrome (SIRS) and evaluated key bacteria and their cutoff values for infectious complications and mortality by using classification and regression trees (CART). Eighty-one SIRS patients with a serum C-reactive protein level higher than 10 mg/dL treated in the intensive care unit (ICU) for more than 2 days were included for the study. We quantitatively evaluated nine types of bacteria in fecal samples by plate or tube technique. Two hundred seventy-one samples were analyzed using CART and logistic regression.Results
The dominant factors for complication of enteritis were the minimum number of total obligate anaerobes and the maximum number of Staphylococcus and Enterococcus. The dominant factors for complication of bacteremia were the minimum numbers of total obligate anaerobes and total facultative anaerobes. The dominant factors for mortality were the numbers of total obligate anaerobes and total facultative anaerobes and age.Conclusions
A decrease in total obligate anaerobes and an increase in pathogenic bacteria in the gut are associated with septic complications and mortality in patients with SIRS. The altered gut flora may be a potential prognostic marker in SIRS patients. 相似文献958.
959.
Afable MG Shaik M Sugimoto Y Elson P Clemente M Makishima H Sekeres MA Lichtin A Advani A Kalaycio M Tiu RV O'Keefe CL Maciejewski JP 《Haematologica》2011,96(9):1269-1275
Background
A combination of horse anti-thymocyte globulin and cyclosporine produces responses in 60–70% of patients with severe aplastic anemia. We performed a phase II study of rabbit anti-thymocyte globulin and cyclosporine as first-line therapy for severe aplastic anemia.Design and Methods
Twenty patients with severe aplastic anemia treated with rabbit anti-thymocyte globulin were compared to 67 historical control cases with matched clinical characteristics treated with horse anti-thymocyte globulin.Results
Response rates at 3, 6 and 12 months were similar for patients treated with rabbit anti-thymocyte globulin or horse anti-thymocyte globulin: 40% versus 55% (P=0.43), 45% versus 58% (P=0.44) and 50% versus 58% (P=0.61), respectively. No differences in early mortality rates or overall survival were observed. We then performed multivariable analyses of response at 6 months and overall survival and identified the presence of a paroxysmal nocturnal hemoglobinuria clone (P=0.01) and a pretreatment absolute reticulocyte count greater than 30×109/L (P=0.007) as independent predictors of response and younger age (P=0.003), higher pretreatment absolute neutrophil (P=0.02) and absolute lymphocyte counts (P=0.03) as independent predictors of overall survival. None of the immunogenetic polymorphisms studied was predictive of response to immunosupressive therapy.Conclusions
Despite reports suggesting differences in biological activity of different anti-thymocyte globulin preparations, rabbit and horse anti-thymocyte globulin appear to have a similar efficacy for up-front treatment of severe aplastic anemia. Clinicaltrial.gov: ) NCT01231841相似文献960.
Matsuura T Yamade M Matsushita N Kawasaki S Terai T Uotani T Takayanagi Y Yamada T Kodaira C Sugimoto M Furuta T Sugimoto K Osawa S Ikuma M 《Nihon Shokakibyo Gakkai zasshi》2011,108(3):444-450
We encountered a very rare case of eosinophilic gastroenteritis accompanied with fasciitis of the extremities. The patient was a 28-year-old woman with epigastralgia, eosinophilia plus leukocytosis, massive pleural effusion and ascites, and thickening of the walls of the intestine. Increase of the eosinophilic fraction in her ascites led to a diagnosis of eosinophilic gastroenteritis. She soon developed resting pain in all limbs and MRI revealed fasciitis. Prednisolone was effective in treating both gastroenteritis and fasciitis. 相似文献