全文获取类型
收费全文 | 293篇 |
免费 | 45篇 |
国内免费 | 2篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 15篇 |
妇产科学 | 3篇 |
基础医学 | 26篇 |
口腔科学 | 10篇 |
临床医学 | 37篇 |
内科学 | 64篇 |
皮肤病学 | 10篇 |
神经病学 | 21篇 |
特种医学 | 65篇 |
外科学 | 39篇 |
综合类 | 3篇 |
预防医学 | 11篇 |
眼科学 | 5篇 |
药学 | 5篇 |
中国医学 | 1篇 |
肿瘤学 | 17篇 |
出版年
2024年 | 2篇 |
2023年 | 13篇 |
2022年 | 2篇 |
2021年 | 8篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 8篇 |
2017年 | 11篇 |
2016年 | 12篇 |
2015年 | 10篇 |
2014年 | 15篇 |
2013年 | 20篇 |
2012年 | 7篇 |
2011年 | 5篇 |
2010年 | 10篇 |
2009年 | 19篇 |
2008年 | 6篇 |
2007年 | 6篇 |
2006年 | 3篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 7篇 |
2002年 | 1篇 |
2001年 | 7篇 |
2000年 | 5篇 |
1999年 | 6篇 |
1998年 | 16篇 |
1997年 | 12篇 |
1996年 | 14篇 |
1995年 | 5篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 7篇 |
1989年 | 11篇 |
1988年 | 8篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 5篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1975年 | 1篇 |
排序方式: 共有340条查询结果,搜索用时 0 毫秒
41.
42.
The identification of small numbers of leukemic cells in the cerebrospinal fluid (CSF) presents a diagnostic problem in the treatment of children with acute lymphoblastic leukemia (ALL). We adapted a latex sphere rosetting technique to allow us to identify simultaneously cell surface markers and cell morphology in 199 CSF samples from 34 patients and 14 control subjects. In patients without leukemic meningitis, the majority of CSF lymphocytes (69%) were found to be mature T cells positive for OKT11. A much smaller number of cells (8%) were found to be B cells positive for la. In these children, only 3% of CSF lymphoid cells expressed the common acute lymphoblastic leukemia antigen (CALLA). Similar results were found in the control subjects. By contrast, 28 CSF samples from nine children with varying numbers of CSF lymphoblasts had much greater proportions of CALLA- and la-positive CSF cells (24% to 96%). Leukemic meningitis was present in one of these patients and later developed in four others. However, three patients with small numbers of lymphoblasts present but with low proportions of CALLA-positive CSF cells (less than 5%) subsequently had normal CSF examinations. We found the use of this rosetting technique valuable in providing information complementary to that obtained from cell morphology alone about the possible malignant nature of small numbers of lymphoblast-like CSF cells seen on cytocentrifuge preparations in children with ALL. 相似文献
43.
Optical imaging and electrophysiology of rat barrel cortex. I. Responses to small single-vibrissa deflections 总被引:2,自引:2,他引:0
A study was undertaken to investigate the response of the rodent
somatosensory barrel cortex to single-whisker, near-threshold vibrissal
stimuli. Cortical responses to controlled whisker deflections were recorded
by (i) conventional multi-unit extracellular recording within the
cytochrome oxidase rich barrels centers and the interbarrel septa, and (ii)
intrinsic signal optical imaging, a technique that provides a spatial view
of cortical activation thought to be related to the deoxygenation of
hemoglobin in activated areas. Barrel cortex neurons responded weakly to
whisker deflections of 0.04 degrees. Their response to a series of small
stimuli of increasing amplitude was well-fitted by a logarithmic function.
Responses to larger stimuli declined monotonically with distance from the
center of the barrel column, and were characterized by greater onset and
offset firing rates, by greater post-excitatory reduction of firing to
below spontaneous levels, and by shorter response latency. In comparison to
measurements taken previously from primary vibrissal afferent fibers, we
conclude that cortical cells can respond to activity in a very small
fraction of first-order sensory neurons.
相似文献
44.
Maturo VG; Zusmer NR; Gilson AJ; Smoak WM; Janowitz WR; Bear BE; Goddard J; Dick DE 《Radiology》1980,137(2):457-463
Innovations in design of a dedicated breast scanner resulted in automation of the scanning process, the production of high resolution images of the whole breast and an efficient mode of image review. The results of clinical evaluation of the prototype of this breast scanner investigating normal breasts as well as benign and malignant breast lesions are presented. 相似文献
45.
Rajasekaran S Thapar V Dave H Huang CH 《Journal of clinical monitoring and computing》2005,19(4-5):351-359
Multiple sequence alignment (MSA) is a vital problem in biology. Optimal alignment of multiple sequences becomes impractical
even for a modest number of sequences [1] since the general version of the problem is NP-hard. Because of the high time complexity
of traditional MSA algorithms, even today's fast computers are not able to solve the problem for large number of sequences.
In this paper we present a randomized algorithm to calculate distance matrices, which is a major step in many multiple sequence
alignment algorithms. The basic idea employed is sampling (along the lines of [2]). We also illustrate how to parallelize
this algorithm.
In Section 1 we introduce the problem of multiple sequence alignments. In Section 2 we provide a discussion on various methods
that have been employed in the literature for Multiple Sequence Alignment. In this section we also introduce our new sampling
approach. We extend our randomized algorithm to the case of non-uniform length sequences as well. We show that our algorithms
are amenable to parallelism in Section 3. In Section 4 we back up our claim of speedup and accuracy with empirical data and
examples. In Section 5 we provide some concluding remarks. 相似文献
46.
47.
Burn depth assessment by dual-wavelength light emitting diodes-excited photoacoustic imaging in rats
Yasuyuki Tsunoi PhD Naoto Sato BE Izumi Nishidate PhD Fumiyuki Ichihashi PhD Daizoh Saitoh MD PhD Shunichi Sato PhD 《Wound repair and regeneration》2023,31(1):69-76
Accurate burn depth assessment is crucial to determine treatment plans for burn patients. We have previously proposed a method for performing burn depth assessments based on photoacoustic (PA) imaging, and we have demonstrated the validity of this method, which allows the successful detection of PA signals originating from the blood under the bloodless burned tissue, using rat burn models. Based on these findings, we started a clinical study in which we faced two technical issues: (1) When the burn depth was shallow, PA signals due to skin contamination and/or melanin in the epidermis (surface signals) could not be distinguished from PA signals originating from the blood in the dermis; (2) the size of the system was too large. To solve these issues, we propose a burn depth diagnosis based on dual-wavelength light emitting diodes (LEDs)-excited PA imaging. The use of LEDs rendered the system compact compared to the previous one that used a conventional solid-state laser. We replicated human burned skin by applying a titrated synthetic melanin solution onto the wound surface in albino rat burn models and measured their burn depths by PA excitation at 690 and 850 nm, where melanin and haemoglobin show greatly different absorption coefficients. As a result, the surface signals were eliminated by subtracting the PA signals at 690 nm from those at 850 nm. The resultant estimated burn depths were strongly correlated with the histological assessment results. The validity of the proposed method was also examined using a burn model of rats with real melanin. 相似文献
48.
Wei Lv PhD Tao Chen ME Yifan Zeng BE Weihong Liu BE Chuying Huang BE 《Journal of Cosmetic Dermatology》2023,22(9):2565-2578
Background
Deep-learning object detection has been applied in various industries, including healthcare, to address hair loss.Methods
In this paper, YOLOv5 object detection algorithm was used to detect hair follicles in a small and specific image dataset collected using a specialized camera on the scalp of individuals with different ages, regions, and genders. The performance of YOLOv5 was compared with other popular object detection models.Results
YOLOv5 performed well in the detection of hair follicles, and the follicles were classified into five classes based on the number of hairs and the type of hair contained. In single-class object detection experiments, a smaller batch size and the smallest YOLOv5s model achieved the best results, with an map of 0.8151. In multiclass object detection experiments, the larger YOLOv5l model was able to achieve the best results, and batch size affected the result of model training.Conclusion
YOLOv5 is a promising algorithm for detecting hair follicles in a small and specific image dataset, and its performance is comparable to other popular object detection models. However, the challenges of small-scale data and sample imbalance need to be addressed to improve the performance of target detection algorithms. 相似文献49.
Yongheon Kim BE Hyunseon Yu MS Sunghwan An MD Donghoon Ha BE Byungjo Jung PhD 《Journal of Cosmetic Dermatology》2023,22(11):2982-2988
Objective
Although focused ultrasound modalities have achieved positive clinical results in noninvasive skin rejuvenation, they presented various side effects and particularly severe pain during treatment. This study introduces a microfocused ultrasound (MFU) device, ULTIGHT, to overcome the severe pain issue, providing quasi-facial lifting.Materials and Methods
Transducer surface was imaged with a scanning electron microscope. The energies of four treatment cartridges were measured using an ultrasound power meter. In vitro experiments were performed to quantitatively evaluate the MFU thermal zones (MFUTZs) and treatment line (TL) of 10 MFUTZs. Ex vivo experiments were performed to evaluate the MFUTZs and temperature rise in tissue. Clinical trials using eight volunteers were performed to qualitatively evaluate facial lifting.Results
The MFU transducer clearly showed a smooth and no air gap surface. ULTIGHT produced 10 discrete MFUTZs in a TL of length 10 mm. In ex vivo tissue, discrete linear MFUTZs were clearly observed at lower number of TLs; however, they started to aggregate at higher number of TLs. The temperature rise was linearly increased as a function of the number of treatments. A single MFUTZ resulted in a temperature rise of 3°C–10°C that could cause hyperthermia for body temperature. In the clinical trials, the volunteers showed quasi-facial lifting right after treatment on the lower facial region.Conclusions
ULTIGHT provides relatively low energy, which may be advantageous or disadvantageous depending on clinical applications. Additionally, it has the advantage of being pain-free even without anesthetic during treatment, providing quasi-facial lifting right after treatment. 相似文献50.