全文获取类型
收费全文 | 5616篇 |
免费 | 401篇 |
国内免费 | 13篇 |
专业分类
耳鼻咽喉 | 104篇 |
儿科学 | 280篇 |
妇产科学 | 79篇 |
基础医学 | 591篇 |
口腔科学 | 82篇 |
临床医学 | 446篇 |
内科学 | 1246篇 |
皮肤病学 | 103篇 |
神经病学 | 351篇 |
特种医学 | 125篇 |
外科学 | 1034篇 |
综合类 | 93篇 |
一般理论 | 3篇 |
预防医学 | 400篇 |
眼科学 | 213篇 |
药学 | 503篇 |
中国医学 | 19篇 |
肿瘤学 | 358篇 |
出版年
2023年 | 45篇 |
2022年 | 85篇 |
2021年 | 214篇 |
2020年 | 125篇 |
2019年 | 169篇 |
2018年 | 204篇 |
2017年 | 134篇 |
2016年 | 169篇 |
2015年 | 171篇 |
2014年 | 247篇 |
2013年 | 268篇 |
2012年 | 384篇 |
2011年 | 373篇 |
2010年 | 233篇 |
2009年 | 204篇 |
2008年 | 332篇 |
2007年 | 384篇 |
2006年 | 379篇 |
2005年 | 309篇 |
2004年 | 290篇 |
2003年 | 266篇 |
2002年 | 218篇 |
2001年 | 98篇 |
2000年 | 64篇 |
1999年 | 56篇 |
1998年 | 58篇 |
1997年 | 32篇 |
1996年 | 41篇 |
1995年 | 21篇 |
1994年 | 25篇 |
1993年 | 31篇 |
1992年 | 31篇 |
1991年 | 35篇 |
1990年 | 28篇 |
1989年 | 29篇 |
1988年 | 40篇 |
1987年 | 31篇 |
1986年 | 27篇 |
1985年 | 15篇 |
1984年 | 19篇 |
1983年 | 10篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 12篇 |
1977年 | 9篇 |
1975年 | 13篇 |
1973年 | 11篇 |
1972年 | 9篇 |
1971年 | 8篇 |
1970年 | 17篇 |
排序方式: 共有6030条查询结果,搜索用时 62 毫秒
51.
Abhishek Singh Kaushalendra Kumar Ajit Kumar Yadav K. S. James Lotus McDougal Yamini Atmavilas Anita Raj 《Studies in family planning》2021,52(1):41-58
Previous research on sex ratio at birth (SRB) in India has largely relied on macro‐analysis of census data that do not contain the breadth of factors needed to explain patterns in SRB. Additionally, no previous research has examined the differentiation of factors associated with SRB across birth orders, a key determinant in societies affected by son preference. This study aims to fill these gaps using micro‐data related to 553,461 births occurring between 2005 and 2016 collected as part of the 2015–2016 National Family Health Survey. Analyses used multivariable logistic regressions stratified by birth order to examine associations with SRB at the national level. The SRB at birth order 1 was outside the biological normal limit, and generally increased with birth order. First births in households with wealth in the middle and richest quintiles, with mothers who desired a higher ideal number of sons than daughters, and in lower fertility communities had a higher probability of being male. Most SRB correlates were visible at birth orders 3 or higher. Programs and policies designed to address India's male‐skewed SRB must consider the diverse factors that influence SRB, particularly for higher order births. 相似文献
52.
53.
Fulminant hepatic failure is a serious condition with very high mortality. Development of new therapies designed to bridge the patient through the acute period of their disease has been hampered by the lack of a large animal model that closely reproduces the changes in humans. We have established an improved model of fulminant hepatic failure in the pig by administration of an aminosugar d-galactosamine hydrochloride. Galactosamine in a dose of 1.0 g/kg was dissolved in 5% dextrose in water (D5W) and given intravenously to seven young pigs weighing 8 to 15 kg. Seven control pigs received an equal volume of D5W alone. Two days prior to injection, a baseline ultrasound-guided liver biopsy was done in each pig under general anesthesia using isofluorane. Clinical data were recorded and blood for laboratory determinations was drawn at 0 h (baseline), 24 h, 48 h, and 72 h after infusion of galactosamine or D5W alone, under general anesthesia. Neurological data were recorded at the same intervals before inducing anesthesia. Galactosamine-treated animals showed 100% mortality. All of them died by 86 h after injection of galactosamine, with death resulting from fulminant hepatic failure characterized by marked increases in total bilirubin, liver enzymes, ammonia, and lactate; associated coagulopathy; hypoglycemia; and coma. Liver histology showed massive hepatocellular necrosis in all seven galactosamine-treated animals. This large and highly reproducible animal model appears promising for future evaluation of bioartificial liver support systems designed to treat fulminant hepatic failure in humans. 相似文献
54.
55.
Nitric oxide accelerates interleukin-13 cytotoxin-mediated regression in head and neck cancer animal model. 总被引:1,自引:0,他引:1
Receptors for interleukin-13 (IL-13R) are overexpressed on several types of solid cancers including gliobastoma, renal cell carcinoma, AIDS Kaposi's sarcoma, and head and neck cancer. Recombinant fusion proteins IL-13 cytotoxin (IL13-PE38QQR or IL13-PE38) have been developed to directly target IL-13R-expressing cancer cells. Although it has been found that IL-13 cytotoxin has a direct potent antitumor activity in vivo in nude mice models of human cancers, the involvement of indirect antitumor effecter molecules such as nitric oxide (NO) is unknown. To address this issue, we assessed the effect of NO inhibiter N(omega)-monomethyl-l-arginine on IL-13 cytotoxin-mediated cytotoxicity and NO2/NO3 production in HN12 head and neck cancer cells. In addition, antitumor effects and NO levels in HN12 and KCCT873 head and neck tumors xenografted s.c. in nude mice when treated with IL-13 cytotoxin were evaluated by tumor measurement, Western blot, and immunohistochemistry analyses. Pretreatment of animals with N(omega)-monomethyl-l-arginine significantly decreased the NO levels and IL-13 cytotoxin-mediated antitumor effects. In addition, depletion of macrophages, known to produce NO, also decreased antitumor activity of IL-13 cytotoxin. Based on these studies, we concluded that NO accelerates antitumor effect of IL-13 cytotoxin on head and neck tumor cells. Because IL-13 cytotoxin is currently being tested in the clinic for the treatment of patients with recurrent glioblastoma maltiforme, our current findings suggest maintaining macrophage and NO-producing cellular function for optimal therapeutic effect of this targeted agent. 相似文献
56.
This case report describes a primary hepatic leiomyoma presenting as a mass lesion detected on ultrasonography of the abdomen in an asymptomatic hepatitis B carrier on routine surveillance. Primary leiomyomata of the liver are rare occurrences, with only 9 cases reported in the literature. The presenting features of primary hepatic leiomyomata and diagnostic approach towards such lesions are discussed. The significance of such tumours in the immunocompromised is also mentioned. 相似文献
57.
Sudhir Tauro Charles Craddock Karl Peggs Gulnaz Begum Premini Mahendra Gordon Cook Judith Marsh Donald Milligan Anthony Goldstone Ann Hunter Asim Khwaja Raj Chopra Timothy Littlewood Andrew Peniket Anne Parker Graham Jackson Geoff Hale Mark Cook Nigel Russell Stephen Mackinnon 《Journal of clinical oncology》2005,23(36):9387-9393
PURPOSE: The toxicity of allogeneic stem-cell transplantation can be substantially reduced using a reduced-intensity conditioning (RIC) regimen. This has increased the proportion of patients with myeloid malignancies eligible for allogeneic transplantation. However, the capacity of RIC allografts to produce durable remissions in patients with acute myeloid leukemia (AML) and myelodysplasia (MDS) has not yet been defined, and consequently, the role of RIC allografts in the management of these diseases remains conjectural. PATIENTS AND METHODS: Seventy-six patients with high-risk AML or MDS received an allograft using a fludarabine/melphalan RIC regimen incorporating alemtuzumab. The median age of the cohort was 52 years (range, 18 to 71 years). RESULTS: The 100-day transplantation-related mortality rate was 9%, and no patient developed greater than grade 2 graft-versus-host disease. With a median follow-up of 36 months (range, 13 to 70 months), 27 patients were alive and in remission, with 3-year actuarial overall survival (OS) and disease-free survival (DFS) rates of 41% and 37%, respectively. The 3-year OS and DFS rates of patients with AML in complete remission at the time of transplantation were 48% and 42%, respectively. Disease relapse was the most common cause of treatment failure and occurred at a median time of 6 months after transplantation. All but one patient destined to relapse did so within 24 months of transplantation. CONCLUSION: The extended follow-up in this series identifies a high risk of early disease relapse but provides evidence that RIC allografts can produce sustained DFS in a significant number of patients with AML who would be ineligible for allogeneic transplantation with myeloablative conditioning. 相似文献
58.
Shiloah Elizabeth Darmanayagam Khanna Nehemiah Harichandran Sunil Retmin Raj Cyril Kannan Arputharaj 《Journal of digital imaging》2013,26(3):496-509
Segmentation of lung parenchyma from the chest computed tomography is an important task in analysis of chest computed tomography for diagnosis of lung disorders. It is a challenging task especially in the presence of peripherally placed pathology bearing regions. In this work, we propose a segmentation approach to segment lung parenchyma from chest. The first step is to segment the lungs using iterative thresholding followed by morphological operations. If the two lungs are not separated, the lung junction and its neighborhood are identified and local thresholding is applied. The second step is to extract shape features of the two lungs. The third step is to use a multilayer feed forward neural network to determine if the segmented lung parenchyma is complete, based on the extracted features. The final step is to reconstruct the two lungs in case of incomplete segmentation, by exploiting the fact that in majority of the cases, at least one of the two lungs would have been segmented correctly by the first step. Hence, the complete lung is determined based on the shape and region properties and the incomplete lung is reconstructed by applying graphical methods, namely, reflection and translation. The proposed approach has been tested in a computer-aided diagnosis system for diagnosis of lung disorders, namely, bronchiectasis, tuberculosis, and pneumonia. An accuracy of 97.37 % has been achieved by the proposed approach whereas the conventional thresholding approach was unable to detect peripheral pathology-bearing regions. The results obtained prove to be better than that achieved using conventional thresholding and morphological operations. 相似文献
59.
60.