全文获取类型
收费全文 | 3370篇 |
免费 | 276篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 21篇 |
儿科学 | 108篇 |
妇产科学 | 86篇 |
基础医学 | 555篇 |
口腔科学 | 75篇 |
临床医学 | 452篇 |
内科学 | 594篇 |
皮肤病学 | 36篇 |
神经病学 | 286篇 |
特种医学 | 150篇 |
外科学 | 424篇 |
综合类 | 40篇 |
预防医学 | 358篇 |
眼科学 | 83篇 |
药学 | 184篇 |
中国医学 | 11篇 |
肿瘤学 | 191篇 |
出版年
2022年 | 30篇 |
2021年 | 62篇 |
2020年 | 31篇 |
2019年 | 54篇 |
2018年 | 77篇 |
2017年 | 62篇 |
2016年 | 49篇 |
2015年 | 65篇 |
2014年 | 96篇 |
2013年 | 119篇 |
2012年 | 154篇 |
2011年 | 151篇 |
2010年 | 83篇 |
2009年 | 96篇 |
2008年 | 154篇 |
2007年 | 145篇 |
2006年 | 106篇 |
2005年 | 106篇 |
2004年 | 132篇 |
2003年 | 130篇 |
2002年 | 126篇 |
2001年 | 126篇 |
2000年 | 101篇 |
1999年 | 89篇 |
1998年 | 44篇 |
1997年 | 53篇 |
1996年 | 57篇 |
1995年 | 38篇 |
1994年 | 26篇 |
1993年 | 32篇 |
1992年 | 71篇 |
1991年 | 77篇 |
1990年 | 75篇 |
1989年 | 82篇 |
1988年 | 57篇 |
1987年 | 60篇 |
1986年 | 60篇 |
1985年 | 53篇 |
1984年 | 39篇 |
1983年 | 39篇 |
1982年 | 36篇 |
1981年 | 23篇 |
1980年 | 36篇 |
1979年 | 47篇 |
1978年 | 34篇 |
1977年 | 24篇 |
1976年 | 33篇 |
1974年 | 28篇 |
1973年 | 25篇 |
1972年 | 18篇 |
排序方式: 共有3654条查询结果,搜索用时 15 毫秒
151.
The mdx mouse has a mutated dystrophin gene and is used as a model for the study of Duchenne muscular dystrophy (DMD). We investigated whether regenerating mdx skeletal muscle contains the extracellular matrix protein tenascin-C (TN-C), which is expressed in wound healing and nerve regeneration. Prior to the initiation of muscle degeneration, both normal and mdx mice displayed similar weak staining for TN-C in skeletal muscle, but by 3 weeks of age the mice differed substantially. TN-C was undetectable in normal muscle except at the myotendinous junction, while in dystrophic muscle, TN-C was prominent in degenerating/regenerating areas but absent from undegenerated muscle. With increasing age, TN-C staining declined around stable regenerated mdx myofibers. TN-C was also observed in muscle from dogs with muscular dystrophy and in human boys with DMD. Therefore, in dystrophic muscle, TN-C expression may be stimulated by the degenerative process and remain upregulated unless the tissue undergoes successful regeneration. © 1996 John Wiley & Sons, Inc. 相似文献
152.
153.
Freeman ML DiSario JA Nelson DB Fennerty MB Lee JG Bjorkman DJ Overby CS Aas J Ryan ME Bochna GS Shaw MJ Snady HW Erickson RV Moore JP Roel JP 《Gastrointestinal endoscopy》2001,54(4):425-434
BACKGROUND: Post-ERCP pancreatitis is poorly understood. The goal of this study was to comprehensively evaluate potential procedure- and patient-related risk factors for post-ERCP pancreatitis over a wide spectrum of centers. METHODS: Consecutive ERCP procedures were prospectively studied at 11 centers (6 private, 5 university). Complications were assessed at 30 days by using established consensus criteria. RESULTS: Pancreatitis occurred after 131 (6.7%) of 1963 consecutive ERCP procedures (mild 70, moderate 55, severe 6). By univariate analysis, 23 of 32 investigated variables were significant. Multivariate risk factors with adjusted odds ratios (OR) were prior ERCP-induced pancreatitis (OR 5.4), suspected sphincter of Oddi dysfunction (OR 2.6), female gender (OR 2.5), normal serum bilirubin (OR 1.9), absence of chronic pancreatitis (OR 1.9), biliary sphincter balloon dilation (OR 4.5), difficult cannulation (OR 3.4), pancreatic sphincterotomy (OR 3.1), and 1 or more injections of contrast into the pancreatic duct (OR 2.7). Small bile duct diameter, sphincter of Oddi manometry, biliary sphincterotomy, and lower ERCP case volume were not multivariate risk factors for pancreatitis, although endoscopists performing on average more than 2 ERCPs per week had significantly greater success at bile duct cannulation (96.5% versus 91.5%, p = 0.0001). Combinations of patient characteristics including female gender, normal serum bilirubin, recurrent abdominal pain, and previous post-ERCP pancreatitis placed patients at increasingly higher risk of pancreatitis, regardless of whether ERCP was diagnostic, manometric, or therapeutic. CONCLUSIONS: Patient-related factors are as important as procedure-related factors in determining risk for post-ERCP pancreatitis. These data emphasize the importance of careful patient selection as well as choice of technique in the avoidance of post-ERCP pancreatitis. 相似文献
154.
Zeynettin Akkus Jason Cai Arunnit Boonrod Atefeh Zeinoddini Alexander D. Weston Kenneth A. Philbrick Bradley J. Erickson 《Journal of the American College of Radiology》2019,16(9):1318-1328
Ultrasound is the most commonly used imaging modality in clinical practice because it is a nonionizing, low-cost, and portable point-of-care imaging tool that provides real-time images. Artificial intelligence (AI)–powered ultrasound is becoming more mature and getting closer to routine clinical applications in recent times because of an increased need for efficient and objective acquisition and evaluation of ultrasound images. Because ultrasound images involve operator-, patient-, and scanner-dependent variations, the adaptation of classical machine learning methods to clinical applications becomes challenging. With their self-learning ability, deep-learning (DL) methods are able to harness exponentially growing graphics processing unit computing power to identify abstract and complex imaging features. This has given rise to tremendous opportunities such as providing robust and generalizable AI models for improving image acquisition, real-time assessment of image quality, objective diagnosis and detection of diseases, and optimizing ultrasound clinical workflow. In this report, the authors review current DL approaches and research directions in rapidly advancing ultrasound technology and present their outlook on future directions and trends for DL techniques to further improve diagnosis, reduce health care cost, and optimize ultrasound clinical workflow. 相似文献
155.
Judy A. Driskell Young-Nam Kim David W. Giraud Fayrene L. Hamouz Amilton S. de Mello Jr. Galen E. Erickson Chris R. Calkins 《Journal of food composition and analysis》2011,24(3):362-367
Selected vitamin (vitamin E, thiamin, riboflavin, niacin, vitamin B6, and vitamin B12) and mineral (calcium, phosphorus, magnesium, potassium, sulfur, iron, copper, zinc, manganese, and sodium) concentrations were determined for the value cuts—flat iron steaks (musculus infraspinatus) and petite tenders (musculus teres major) from cross-bred steers fed finishing rations containing 0% or 40% DM wet distiller's grains plus solubles (WDGS) with and without added daily supplemental vitamin E. The feeding treatment groups were: 0% WDGS with basal vitamin E (n = 6), 0% WDGS with supplemental vitamin E (500 IU/steer top-dressed daily) (n = 7), 40% WDGS with basal vitamin E (n = 8), and 40% WDGS with supplemental vitamin E (n = 8). Few differences in micronutrient concentrations were observed in either cut by treatment groups. Feeding steers diets containing 40% WDGS decreased vitamin B12 and increased sodium concentrations in flat iron steaks and increased thiamin and decreased manganese concentrations in petite tenders. Significant differences in α-tocopherol concentrations in both cuts were observed by vitamin E grouping. Several significant differences were observed by cut. Uncooked flat iron steaks and petite tenders from these steers are rich sources of vitamin B12, zinc, and sometimes phosphorus, good sources of riboflavin, niacin, vitamin B6, and iron, and low in sodium. 相似文献
156.
Erickson SJ Martinez SL Gonzalez J Caldera L Godavarty A 《Biomedical optics express》2010,1(1):126-134
Optical imaging is emerging as a non-invasive and non-ionizing method for breast cancer diagnosis. A hand-held optical imager has been developed with coregistration facilities towards flexible imaging of different tissue volumes and curvatures in near real-time. Herein, fluorescence-enhanced optical imaging experiments are performed to demonstrate deeper target detection under perfect and imperfect (100:1) uptake conditions in (liquid) tissue phantoms and in vitro. Upon summation of multiple scans (fluorescence intensity images), fluorescent targets are detected at greater depths than from single scan alone. 相似文献
157.
Yasuko O. Erickson Noelle I. Samia Bruce Bedell Kenneth D. Friedman Bonnie S. Atkinson Thomas J. Raife 《Journal of clinical apheresis》2009,24(4):150-154
Thrombotic microangiopathy (TMA) comprises a group of microvascular thrombosis syndromes associated with multiple pathogenic factors. Deficient activity of ADAMTS13 is a pathogenic factor in a subset of TMA patients that provides a strong rationale for plasma exchange treatment. However, the subset of TMA patients with normal ADAMTS13 activity remains a heterogeneous group of patients in which the appropriate treatment is not well understood. In addition to the common forms of TMA thrombotic thrombocytopenic purpura and the hemolytic uremic syndrome, the differential diagnosis of TMA may include sepsis, autoimmune disorders, and disseminated intravascular coagulation. Optimal treatment of TMA depends on timely recognition of treatable pathogenic factors. We hypothesized that sepsis is a rapidly identifiable pathogenic factor in a subset of TMA patients. To test this hypothesis, we retrospectively measured the rapid biomarkers of sepsis C‐reactive protein (CRP) and procalcitonin (PCT), in a repository of pretreatment plasma samples from 61 TMA patients treated with plasma exchange. Levels were analyzed in 31 severely ADAMTS13‐deficient and 30 ADAMTS13‐normal patients. None of the 31 patients with severe deficiency of ADAMTS13 had elevated PCT. However, 11 of 30 (37%) non‐ADAMTS13‐deficient patient samples were strongly positive for PCT. These patient samples also had a >10‐fold higher median CRP level than patients with normal PCT. We conclude that rapid assays may help identify sepsis in a subset of TMA patients. J. Clin. Apheresis, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
158.
159.
160.