全文获取类型
收费全文 | 307篇 |
免费 | 21篇 |
国内免费 | 4篇 |
专业分类
儿科学 | 13篇 |
妇产科学 | 7篇 |
基础医学 | 35篇 |
口腔科学 | 19篇 |
临床医学 | 27篇 |
内科学 | 46篇 |
皮肤病学 | 2篇 |
神经病学 | 47篇 |
特种医学 | 52篇 |
外科学 | 12篇 |
综合类 | 7篇 |
预防医学 | 20篇 |
眼科学 | 3篇 |
药学 | 30篇 |
肿瘤学 | 12篇 |
出版年
2023年 | 2篇 |
2022年 | 3篇 |
2021年 | 13篇 |
2020年 | 7篇 |
2019年 | 8篇 |
2018年 | 14篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 10篇 |
2014年 | 20篇 |
2013年 | 10篇 |
2012年 | 17篇 |
2011年 | 8篇 |
2010年 | 8篇 |
2009年 | 5篇 |
2008年 | 5篇 |
2007年 | 7篇 |
2006年 | 6篇 |
2005年 | 10篇 |
2004年 | 7篇 |
2003年 | 8篇 |
2002年 | 4篇 |
2001年 | 2篇 |
1999年 | 4篇 |
1998年 | 15篇 |
1997年 | 13篇 |
1996年 | 16篇 |
1995年 | 9篇 |
1994年 | 9篇 |
1993年 | 15篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 9篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 3篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1969年 | 1篇 |
1967年 | 2篇 |
1965年 | 1篇 |
1963年 | 1篇 |
1962年 | 1篇 |
1949年 | 1篇 |
排序方式: 共有332条查询结果,搜索用时 859 毫秒
1.
2.
Image-directed percutaneous biopsies with a biopsy gun 总被引:3,自引:0,他引:3
Core tissue for histologic study is believed by many pathologists to be more diagnostic than material from needle aspiration. Recently, a biopsy "gun" has been introduced, which simplifies core biopsies. With this device, 182 biopsies of multiple anatomic sites were performed with ultrasonic, computed tomographic, and fluoroscopic guidance and 18-gauge needles. High-quality histopathologic specimens were obtained in 177 of the biopsies, and diagnostic target tissue was obtained in 167. Only three significant complications occurred: one bleeding complication that required transfusion and two cases of pneumothorax that necessitated placement of chest tubes. The biopsy gun eliminated the disjointed movements of conventional "skinny" needle biopsies, and none of the samples demonstrated significant "crush" artifact or obscuring blood, problems that are commonly associated with manual biopsy techniques. Patient discomfort was decreased with this system compared with that of manual biopsies, and the total procedure time was reduced. Because of these distinct advantages, the authors now use the biopsy gun exclusively for all percutaneous biopsies and recommend that other institutions consider the use of this biopsy method. 相似文献
3.
4.
5.
Osteosarcomatosis 总被引:10,自引:0,他引:10
Hopper KD; Moser RP Jr; Haseman DB; Sweet DE; Madewell JE; Kransdorf MJ 《Radiology》1990,175(1):233-239
A review of the 690 cases of osteosarcoma in the radiographic file of the Armed Forces Institute of Pathology revealed 29 cases of "osteosarcomatosis" (multiple skeletal sites of osteosarcoma). Fifteen of these patients were 18 years old and under and manifested rapidly appearing, usually symmetric, sclerotic metaphyseal lesions. The remaining 14 patients were more than 18 years old and had fewer, asymmetric sclerotic lesions. In most patients (28 of 29), a radiographically dominant skeletal tumor was seen. Pulmonary metastases occurred in the majority of patients and were detected at the same time as the bone lesions. These 29 patients were studied with regard to demographic data and skeletal distribution and radiographic appearance of their lesions. As a result of the findings, a metastatic origin from a primary dominant osteosarcoma is favored over a multifocal origin as the basis for osteosarcomatosis. Osteosarcomatosis is more commonly encountered in the mature skeleton than has been previously recognized. 相似文献
6.
Role of epidural medication through caudal route was studied in 109 patients having lumbago with or without sciatica to highlight the value of this mode of treatment which relieved symptoms in more than 70% of cases without hospitalisation and without being off work for long periods as in usual methods of conservative treatment.KEY WORDS: Epidural medication, Backache, Lumbago, Sciatica 相似文献
7.
H. David Humes Deborah Buffington Angela J. Westover Shuvo Roy William H. Fissell 《Pediatric nephrology (Berlin, Germany)》2014,29(3):343-351
The rapid understanding of the cellular and molecular bases of organ function and disease processes will be translated in the next decade into new therapeutic approaches to a wide range of clinical disorders, including acute and chronic renal failure. Central to these new therapies are the developing technologies of cell therapy and tissue engineering, which are based on the ability to expand stem or progenitor cells in tissue culture to perform differentiated tasks and to introduce these cells into the patient either via extracorporeal circuits or as implantable constructs. Cell therapy devices are currently being developed to replace the filtrative, metabolic, and endocrinologic functions of the kidney lost in both acute and chronic renal failure. This review summarizes the current state of development of a wearable or implantable bioartificial kidney. These devices have the promise to be combined to produce a wearable or implantable bioartificial kidney for full renal replacement therapy that may significantly diminish morbidity and mortality in patients with acute or chronic kidney disease. 相似文献
8.
Diffusion of nucleoside triphosphates and role of the entry site to the RNA polymerase II active center
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Batada NN Westover KD Bushnell DA Levitt M Kornberg RD 《Proceedings of the National Academy of Sciences of the United States of America》2004,101(50):17361-17364
Nucleoside triphosphates (NTPs) diffuse to the active center of RNA polymerase II through a funnel-shaped opening that narrows to a negatively charged pore. Computer simulation shows that the funnel and pore reduce the rate of diffusion by a factor of approximately 2 x 10(-7). The resulting limitation on the rate of RNA synthesis under conditions of low NTP concentration may be overcome by NTP binding to an entry site adjacent to the active center. Binding to the entry site greatly enhances the lifetime of an NTP in the active center region, and it prevents "backtracking" and the consequent occlusion of the active site. 相似文献
9.
Mouse bone marrow (BM) was separated into low-density, lineage- negative, wheat germ agglutinin-positive (WGA+), Rhodamine-123 bright (Rhbright) or dim (Rhdim) cells to obtain populations that were highly enriched for committed progenitors (Rhbright cells) or for more primitive stem cells (Rhdim). When 2,500 Rhbright or Rhdim cells were seeded onto 6-week-old irradiated (20 Gy) long-term BM cultures (LTBMC), the nonadherent cell production from Rhbright cells was transient and ended after 5 weeks. Production from Rhdim cells did not begin until week 3, peaked at week 5, and ended at week 8, when the irradiated stroma seemed to fail. Termination of cell production from Rhdim cells did not occur in nonirradiated LTBMC from W41/Wv mice. During peak nonadherent cell production, 25% to 30% of the cells in the nonirradiated LTBMC from W41/Wv mice had donor cell markers. Two approaches were tested to try to enhance the proportion or number of donor cells. Addition of Origen-HGF at the time of seeding Rhdim cells caused a nonspecific increase in both host and donor cell production, but a specific increase in production of donor cells was obtained by seeding the cultures at 2 weeks rather than 6 weeks. Limiting dilution of Rhdim cells gave the same frequency of wells producing cells on both irradiated +/+ and nonirradiated W41/Wv or W/Wv cultures. 相似文献
10.
Dennis J. Rebergen Sunil B. Nagaraj Eric S. Rosenthal Matt T. Bianchi Michel J. A. M. van Putten M. Brandon Westover 《Journal of clinical monitoring and computing》2018,32(1):53-61
We developed a simple and fully automated method for detecting artifacts in the R-R interval (RRI) time series of the ECG that is tailored to the intensive care unit (ICU) setting. From ECG recordings of 50 adult ICU-subjects we selected 60 epochs with valid R-peak detections and 60 epochs containing artifacts leading to missed or false positive R-peak detections. Next, we calculated the absolute value of the difference between two adjacent RRIs (adRRI), and obtained the empirical probability distributions of adRRI values for valid R-peaks and artifacts. From these, we calculated an optimal threshold for separating adRRI values arising from artifact versus non-artefactual data. We compared the performance of our method with the methods of Berntson and Clifford on the same data. We identified 257,458 R-peak detections, of which 235,644 (91.5%) were true detections and 21,814 (8.5%) arose from artifacts. Our method showed superior performance for detecting artifacts with sensitivity 100%, specificity 99%, precision 99%, positive likelihood ratio of 100 and negative likelihood ratio <0.001 compared to Berntson’s and Clifford’s method with a sensitivity, specificity, precision and positive and negative likelihood ratio of 99%, 78%, 82%, 4.5, 0.013 for Berntson’s method and 55%, 98%, 96%, 27.5, 0.460 for Clifford’s method, respectively. A novel algorithm using a patient-independent threshold derived from the distribution of adRRI values in ICU ECG data identifies artifacts accurately, and outperforms two other methods in common use. Furthermore, the threshold was calculated based on real data from critically ill patients and the algorithm is easy to implement. 相似文献