全文获取类型
收费全文 | 4181篇 |
免费 | 334篇 |
国内免费 | 8篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 94篇 |
妇产科学 | 103篇 |
基础医学 | 611篇 |
口腔科学 | 129篇 |
临床医学 | 425篇 |
内科学 | 826篇 |
皮肤病学 | 65篇 |
神经病学 | 382篇 |
特种医学 | 91篇 |
外科学 | 493篇 |
综合类 | 37篇 |
一般理论 | 8篇 |
预防医学 | 539篇 |
眼科学 | 53篇 |
药学 | 310篇 |
中国医学 | 9篇 |
肿瘤学 | 306篇 |
出版年
2023年 | 45篇 |
2022年 | 86篇 |
2021年 | 180篇 |
2020年 | 107篇 |
2019年 | 164篇 |
2018年 | 193篇 |
2017年 | 122篇 |
2016年 | 134篇 |
2015年 | 127篇 |
2014年 | 180篇 |
2013年 | 190篇 |
2012年 | 280篇 |
2011年 | 306篇 |
2010年 | 157篇 |
2009年 | 137篇 |
2008年 | 241篇 |
2007年 | 212篇 |
2006年 | 205篇 |
2005年 | 179篇 |
2004年 | 139篇 |
2003年 | 131篇 |
2002年 | 104篇 |
2001年 | 58篇 |
2000年 | 62篇 |
1999年 | 66篇 |
1998年 | 49篇 |
1997年 | 23篇 |
1996年 | 26篇 |
1995年 | 30篇 |
1994年 | 29篇 |
1993年 | 19篇 |
1992年 | 43篇 |
1991年 | 32篇 |
1990年 | 29篇 |
1989年 | 38篇 |
1988年 | 30篇 |
1987年 | 33篇 |
1986年 | 37篇 |
1985年 | 29篇 |
1984年 | 18篇 |
1983年 | 18篇 |
1982年 | 23篇 |
1981年 | 15篇 |
1980年 | 12篇 |
1979年 | 13篇 |
1978年 | 14篇 |
1977年 | 15篇 |
1975年 | 11篇 |
1972年 | 12篇 |
1969年 | 11篇 |
排序方式: 共有4523条查询结果,搜索用时 15 毫秒
51.
Risk of Second Cancers in Patients with Colorectal Carcinoids 总被引:10,自引:0,他引:10
David S. Tichansky Burt Cagir Edward Borrazzo Allan Topham Juan Palazzo Eric J. Weaver Andrea Lange Robert D. Fry 《Diseases of the colon and rectum》2002,45(1):91-97
INTRODUCTION: It is often stated that patients with colorectal carcinoid tumors have an increased risk of developing other malignancies. However, this risk has not been conclusively documented. A comprehensive evaluation is needed to more thoroughly assess the risk of second cancers in patients with colorectal carcinoids. METHODS: A search of the National Cancer Institute Surveillance, Epidemiology, and End Result database from 1973 to 1996 revealed 2,086 patients with colorectal carcinoids. This subset of patients was examined for occurrence of second cancers. The observed incidence of cancer for each site was compared with the expected incidence based on the gender-adjusted and age-adjusted cancer rates in the remaining Surveillance, Epidemiology, and End Result file. A Poisson distribution probability was used to determine the significance of these comparisons. RESULTS: Patients with colorectal carcinoids had an increased rate of cancer in the colon and rectum (P < 0.001), small bowel (P < 0.001), esophagus/stomach (P = 0.02), lung/bronchus (P < 0.001), urinary tract (P = 0.005), and prostate (P < 0.001), when compared with a control population. Most of the gastrointestinal tract cancers were synchronous cancers, whereas lesions outside the gastrointestinal tract were most commonly metachronous tumors. CONCLUSIONS: A significantly increased risk of synchronous colorectal, small-bowel, gastric, and esophageal cancers and metachronous lung, prostate, and urinary tract neoplasms is clearly demonstrated. After the diagnosis of colorectal carcinoid tumors, patients should undergo appropriate screening and surveillance for cancer at these sites. 相似文献
52.
The substantial morbidity and mortality associated with rheumatoid arthritis (RA), while not widely appreciated, provide adequate justification for consideration of high-dose immunoablative therapy followed by hematopoietic stem cell transplantation. While some patients with RA follow a benign course, selected subsets of patients have been identified with 5-year survival rates of 40-70%. A number of factors that can be easily determined serve as useful prognostic indicators for poor outcome. These include the presence of many involved joints (total joint count), the degree of functional disability as measured by the health assessment questionnaire and the presence of rheumatoid factor. This article summarises the present status of hematopoietic stem cell transplantation for rheumatoid arthritis and proposes future directions for research. 相似文献
53.
M R Goldman T J Brady I L Pykett C T Burt F S Buonanno J P Kistler J H Newhouse W S Hinshaw G M Pohost 《Circulation》1982,66(5):1012-1016
Determination of myocardial infarct size is important for clinical management of patients with ischemic heart disease and for research on limiting infarct size. Nuclear magnetic resonance (NMR) imaging permits tomographic depiction of the distribution of mobile tissue protons. NMR images have demonstrated high spatial resolution and contrast. To evaluate the potential of this technique in measuring myocardial infarct size, NMR imaging was performed in six canine hearts excised 24 hours after circumflex coronary artery ligation. Before sacrifice, the dogs received i.v. manganous chloride (0.05 mmol/kg). After NMR imaging, the heart were sectioned and the myocardial slices were stained with triphenyl tetrazolium chloride. The pathologically determined infarct size was compared with the infarct size measured by NMR imaging. The correlation was good (regression line slope 1.06; r = 0.94). We conclude that NMR imaging with paramagnetic contrast agents can be used to determine infarct size in excised hearts. 相似文献
54.
Alexander Egbe Sorin V. Pislaru Mahmoud A. Ali Arooj R. Khan Amber N. Boler Hartzell V. Schaff Emmanuel Akintoye Heidi M. Connolly Vuyisile T. Nkomo Patricia A. Pellikka 《JACC: Cardiovascular Imaging》2018,11(7):951-958
Objectives
The purpose of this study was to review the institutional practice of surveillance transthoracic echocardiography (TTE) for diagnosing early prosthetic valve dysfunction (PVD).Background
Bioprosthetic valve thrombosis (BPVT) is an important cause of PVD, and guidelines do not recommend routine TTE during the first 5 years after valve implantation.Methods
The authors performed a retrospective case-control study of all suspected (imaging diagnosis) or confirmed (histopathological diagnosis) cases of BPVT from January 1997 through December 2016. Patients were matched 1:2 (age, sex, prosthesis position) to patients whose prostheses were explanted because of structural failure (SF). PVD was defined as a 50% increase above baseline gradient at valve implantation and classified as early (≤5 years) or late (>5 years) after implantation.Results
There were 94 BPVT (51 suspected, 43 confirmed) and 188 SF cases; patient age 61 ± 9 years; men 61 (65%). The prosthesis positions were aortic 56%; mitral 26%; tricuspid 15%; and pulmonary 3%. Early PVD was more common in the BPVT versus SF group: 83 of 94 (88%) versus 20 of 188 (11%) (p < 0.001). Time from implantation to PVD was shorter for BPVT than SF: 26 months (interquartile range [IQR]: 12 to 43 months) versus 74 months (IQR: 48 to 102 months) (p < 0.001). At the initial PVD diagnosis, 81% of BPVT and 90% of SF patients were asymptomatic. However, BPVT patients had rapid symptomatic deterioration, requiring intervention sooner after PVD diagnosis: 6 months (IQR: 4 to 7 months) versus 51 months (IQR: 22 to 55 months) (p < 0.001).Conclusions
Most patients with PVD due to BPVT were asymptomatic at initial diagnosis, which was made based on routine surveillance TTE, often performed before 5 years. BPVT, an acute disease process, requires timely diagnosis because patient conditions rapidly deteriorate. Further studies are needed to determine whether routine surveillance TTE should be considered for patients with bioprosthetic valves to identify pre-symptomatic features of BPVT in order to provide effective, appropriate therapy. 相似文献55.
56.
Peikert T Finkielman JD Hummel AM McKenney ME Gregorini G Trimarchi M Specks U 《Arthritis and rheumatism》2008,58(5):1546-1551
OBJECTIVE: Antineutrophil cytoplasmic antibodies (ANCA) binding to neutrophil elastase (NE) and proteinase 3 (PR3) are detectable in most patients with cocaine-induced midline destructive lesions (CIMDL), but the pathogenic role and antigen specificity of these antibodies are unknown. This study was undertaken to assess the effects of NE ANCA on the enzymatic activity of NE, to determine whether these antibodies interfere with the physiologic effect of secretory leukoprotease inhibitor (SLPI), and to investigate the antigen specificity of both NE and PR3 ANCA in patients with CIMDL. We also compared the binding of PR3 ANCA in patients with CIMDL with that in patients with Wegener's granulomatosis (WG). METHODS: PR3 ANCA and NE ANCA were detected by capture enzyme-linked immunosorbent assays (ELISAs) and by indirect immunofluorescence. IgG was purified from the patients' sera, and the influence of NE ANCA on the enzymatic activity of NE and on the inhibitory activity of SLPI was investigated by determining the hydrolysis of N-methoxysuccinyl-Ala-Ala-Pro-Val p-nitroanilide by NE. RESULTS: IgG from NE ANCA-positive sera of patients with CIMDL inhibited the enzymatic activity of NE and did not interfere with the activity of SLPI. In contrast to the findings in WG sera, measurement of PR3 ANCA in CIMDL sera showed only fair to moderate concordance between the 2 different capture ELISAs. Cross-inhibition experiments demonstrated that NE ANCA and PR3 ANCA represent distinct autoantibodies in patients with CIMDL. CONCLUSION: The functional effects of NE ANCA on the enzymatic activity of NE or on the activity of SLPI cannot be implicated in the pathogenesis of CIMDL. The autoimmune reaction that targets neutrophil serine proteases in patients with CIMDL is frequently directed against more than one antigen. The ANCA response, including the reactivity of PR3 ANCA, in patients with CIMDL differs from what has been described in patients with WG. 相似文献
57.
Hanchen Xu Kevin Van der Jeught Zhuolong Zhou Lu Zhang Tao Yu Yifan Sun Yujing Li Changlin Wan Ka Man So Degang Liu Michael Frieden Yuanzhang Fang Amber L. Mosley Xiaoming He Xinna Zhang George E. Sandusky Yunlong Liu Samy O. Meroueh Chi Zhang Aruna B. Wijeratne Cheng Huang Guang Ji Xiongbin Lu 《The Journal of clinical investigation》2021,131(10)
One of the primary mechanisms of tumor cell immune evasion is the loss of antigenicity, which arises due to lack of immunogenic tumor antigens as well as dysregulation of the antigen processing machinery. In a screen for small-molecule compounds from herbal medicine that potentiate T cell–mediated cytotoxicity, we identified atractylenolide I (ATT-I), which substantially promotes tumor antigen presentation of both human and mouse colorectal cancer (CRC) cells and thereby enhances the cytotoxic response of CD8+ T cells. Cellular thermal shift assay (CETSA) with multiplexed quantitative mass spectrometry identified the proteasome 26S subunit non–ATPase 4 (PSMD4), an essential component of the immunoproteasome complex, as a primary target protein of ATT-I. Binding of ATT-I with PSMD4 augments the antigen-processing activity of immunoproteasome, leading to enhanced MHC-I–mediated antigen presentation on cancer cells. In syngeneic mouse CRC models and human patient–derived CRC organoid models, ATT-I treatment promotes the cytotoxicity of CD8+ T cells and thus profoundly enhances the efficacy of immune checkpoint blockade therapy. Collectively, we show here that targeting the function of immunoproteasome with ATT-I promotes tumor antigen presentation and empowers T cell cytotoxicity, thus elevating the tumor response to immunotherapy. 相似文献
58.
59.
Jonathan Bryant-Genevier Carol Y. Rao Barbara Lopes-Cardozo Ahoua Kone Charles Rose Isabel Thomas Diana Orquiola Ruth Lynfield Dhara Shah Lori Freeman Scott Becker Amber Williams Deborah W. Gould Hope Tiesman Geremy Lloyd Laura Hill Ramona Byrkit 《MMWR. Morbidity and mortality weekly report》2021,70(26):947
60.
Chiaravalloti Nancy D. Amato Maria Pia Brichetto Giampaolo Chataway Jeremy Dalgas Ulrik DeLuca John Meza Cecilia Moore Nancy B. Feys Peter Filippi Massimo Freeman Jennifer Inglese Matilde Motl Rob Rocca Maria Assunta Sandroff Brian M. Salter Amber Cutter Gary Feinstein Anthony 《Journal of neurology》2021,268(5):1598-1607
Journal of Neurology - Individuals with pre-existing chronic illness have shown increased anxiety and depression due to COVID-19. Here, we examine the impact of the COVID-19 pandemic on emotional... 相似文献