全文获取类型
收费全文 | 2023篇 |
免费 | 94篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 15篇 |
儿科学 | 141篇 |
妇产科学 | 83篇 |
基础医学 | 258篇 |
口腔科学 | 27篇 |
临床医学 | 159篇 |
内科学 | 402篇 |
皮肤病学 | 29篇 |
神经病学 | 105篇 |
特种医学 | 67篇 |
外科学 | 168篇 |
综合类 | 30篇 |
预防医学 | 204篇 |
眼科学 | 177篇 |
药学 | 124篇 |
中国医学 | 8篇 |
肿瘤学 | 127篇 |
出版年
2023年 | 5篇 |
2022年 | 32篇 |
2021年 | 54篇 |
2020年 | 30篇 |
2019年 | 39篇 |
2018年 | 48篇 |
2017年 | 37篇 |
2016年 | 55篇 |
2015年 | 53篇 |
2014年 | 74篇 |
2013年 | 91篇 |
2012年 | 166篇 |
2011年 | 192篇 |
2010年 | 111篇 |
2009年 | 88篇 |
2008年 | 136篇 |
2007年 | 136篇 |
2006年 | 115篇 |
2005年 | 115篇 |
2004年 | 124篇 |
2003年 | 89篇 |
2002年 | 106篇 |
2001年 | 11篇 |
2000年 | 17篇 |
1999年 | 13篇 |
1998年 | 19篇 |
1997年 | 12篇 |
1996年 | 12篇 |
1995年 | 4篇 |
1994年 | 8篇 |
1993年 | 9篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 9篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 6篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1979年 | 8篇 |
1978年 | 5篇 |
1976年 | 5篇 |
1974年 | 6篇 |
1971年 | 2篇 |
1962年 | 2篇 |
排序方式: 共有2124条查询结果,搜索用时 31 毫秒
1.
Usha Patel Manish Pandey Sadhana Kannan Tanuja A. Samant Poonam Gera Neha Mittal Swapnil Rane Asawari Patil Vanita Noronha Amit Joshi Vijay M. Patil Kumar Prabhash Manoj B. Mahimkar 《British journal of cancer》2020,123(12):1757
Background Anti-EGFR-based therapies have limited success in HNSCC patients. Predictive biomarkers are greatly needed to identify the patients likely to be benefited from these targeted therapies. Here, we present the prognostic and predictive association of biomarkers in HPV-negative locally advanced (LA) HNSCC patients.Methods Treatment-naive tumour tissue samples of 404 patients, a subset of randomised Phase 3 trial comparing cisplatin radiation (CRT) versus nimotuzumab plus cisplatin radiation (NCRT) were analysed to evaluate the expression of HIF1α, EGFR and pEGFR by immunohistochemistry and EGFR gene copy change by FISH. Progression-free survival (PFS), locoregional control (LRC) and overall survival (OS) were estimated by Kaplan–Meier method. Hazard ratios were estimated by Cox proportional hazard models.Results Baseline characteristics of the patients were balanced between two treatment groups (CRT vs NCRT) and were representative of the trial cohort. The median follow-up was of 39.13 months. Low HIF1α was associated with better PFS [HR (95% CI) = 0.62 (0.42–0.93)], LRC [HR (95% CI) = 0.56 (0.37–0.86)] and OS [HR (95% CI) = 0.63 (0.43–0.93)] in the CRT group. Multivariable analysis revealed HIF1α as an independent negative prognostic biomarker. For patients with high HIF1α, NCRT significantly improved the outcomes [PFS:HR (95% CI) = 0.55 (0.37–0.82), LRC:HR (95% CI) = 0.55 (0.36–0.85) and OS:HR (95% CI) = 0.54 (0.36–0.81)] compared to CRT. While in patients with low HIF1α, no difference in the clinical outcomes was observed between treatments. Interaction test suggested a predictive value of HIF1α for OS (P = 0.008).Conclusions High HIF1α expression is a predictor of poor clinical response to CRT in HPV-negative LA-HNSCC patients. These patients with high HIF1α significantly benefited with the addition of nimotuzumab to CRT.Clinical trial registration Registered with the Clinical Trial Registry of India (Trial registration identifier—CTRI/2014/09/004980).Subject terms: Tumour biomarkers, Head and neck cancer, Tumour biomarkers, Head and neck cancer, Predictive markers 相似文献
2.
3.
Usha Chinappen-Horsley Glen M Blake Ignac Fogelman Tim D Spector 《BMC musculoskeletal disorders》2007,8(1):113
Background
Skeletal ratios and bone lengths are widely used in anthropology and forensic pathology and hip axis length is a useful predictor of fracture. The aim of this study was to show that skeletal ratios, such as length of femur to height, could be accurately measured from a DXA (dual energy X-ray absorptiometry) image. 相似文献4.
Prevalence of silent myocardial ischemia in asymptomatic individuals with subclinical atherosclerosis detected by electron beam tomography 总被引:3,自引:0,他引:3
Anand D. Vijay Lim Eric Raval Usha Lipkin David Lahiri Avijit 《Journal of nuclear cardiology》2004,11(4):450-457
BACKGROUND: Electron beam tomography coronary calcium imaging is an evolving technique for the early detection of coronary atherosclerosis, and recent studies have established its prognostic value in asymptomatic individuals. The relationship of coronary artery calcium scores (CAC) to obstructive coronary artery disease (CAD) has been poorly studied but is clinically relevant because it determines which individuals are likely to benefit from revascularization procedures. Hence, we prospectively evaluated the prevalence of myocardial ischemia in asymptomatic patients with cardiovascular risk factors and subclinical atherosclerosis. METHODS AND RESULTS: We studied 864 asymptomatic patients with no previous CAD but with cardiovascular risk factors, referred for electron beam tomography coronary calcium imaging to our institution over an 18-month period. From this group, 220 consecutive patients (85% men; mean age, 61 +/- 9 years; age range, 31-84 years) with moderate to severe atherosclerotic disease (coronary calcium score > or =100 Agatston units) were prospectively evaluated by technetium 99m sestamibi single photon emission computed tomography (SPECT). Patients were followed up (mean follow-up, 14 months) and data regarding their subsequent clinical management recorded. Of the 220 patients, 119 had moderate atherosclerosis (CAC score of 100-400 Agatston units) and 101 had severe atherosclerosis (CAC score > or =400 Agatston units). Abnormal SPECT findings were seen in 18% of patients with moderate atherosclerosis (n = 21) and 45% of patients with severe atherosclerosis (n = 45). Increasing severity of atherosclerosis was related to increasing ischemic burden (summed difference score = 1 +/- 0.2 for CAC score of 100-400 Agatston units and 3.2 +/- 0.5 for CAC score > or =400 Agatston units). In a multivariate linear regression model incorporating risk factors, CAC was the only predictor of silent ischemia. CONCLUSION: In comparison to previously published data, we detected a higher prevalence of silent ischemia even in patients with moderate coronary atherosclerosis (18%). This may reflect the differing risk factor profile of our patient population. When coronary calcium screening is used to preselect asymptomatic patients with cardiovascular risk factors for myocardial perfusion imaging, the optimum coronary calcium score threshold will depend on the population prevalence of risk factors and asymptomatic obstructive CAD. 相似文献
5.
Dorit Naot Usha Bava Brya Matthews Karen E Callon Gregory D Gamble Michael Black Sarah Song Rocco P Pitto Tim Cundy Jill Cornish Ian R Reid 《Journal of bone and mineral research》2007,22(2):298-309
Paget's disease is a focal condition of bone. To study changes in cells within pagetic lesions, we cultured osteoblasts and stromal cells from 22 patients and compared gene expression in these cells to cells from healthy bone. We identified several differentially regulated genes, and we suggest that these changes could lead to the formation of the lesions. INTRODUCTION: Paget's disease is a focal condition of bone of unknown cause. Although it is regarded as primarily an osteoclast disorder, the tight coupling of the activity of osteoclasts and osteoblasts suggests that the osteoblast could play a key role in its pathogenesis. The aim of the study was to identify possible changes in pagetic osteoblasts and stromal cells that might contribute to the development of pagetic lesions. MATERIALS AND METHODS: Candidate genes were identified based on known bone cell regulators, supplemented with microarray analysis. Gene expression was determined by real-time PCR in primary cultures of osteoblasts and bone marrow stromal cells from pagetic patients and control subjects. Concentrations of secreted proteins were determined by ELISA. RESULTS: Dickkopf1 mRNA and protein levels were increased in both pagetic osteoblast and stromal cell cultures, and interleukin (IL)-1 and IL-6 were overexpressed in pagetic osteoblasts. These changes parallel recent findings in myeloma bone disease, which shares some clinical similarities with Paget's disease. Alkaline phosphatase was overexpressed, and bone sialoprotein and osteocalcin were underexpressed in pagetic osteoblasts, consistent with their circulating levels in pagetic patients. It is hypothesized that overexpression of Dickkopf1, IL-1, and IL-6 would result in stimulation of osteoclast proliferation and inhibition of osteoblast growth, leading to the development of the characteristic lytic bone lesions. By stimulating osteoblast differentiation, Dickkopf1 and IL-6 may also promote mineralization, leading to the conversion of lytic lesions to sclerotic. CONCLUSIONS: These findings suggest that dysregulated gene expression in pagetic osteoblasts could cause the changes in bone cell number and function characteristic of Paget's disease. 相似文献
6.
7.
Listeria--review of epidemiology and pathogenesis. 总被引:2,自引:0,他引:2
Vidhya Ramaswamy Vincent Mary Cresence Jayan S Rejitha Mohandas Usha Lekshmi K S Dharsana Suryaprasad Priya Prasad Helan Mary Vijila 《Journal of microbiology, immunology, and infection》2007,40(1):4-13
Listeria monocytogenes (commonly called Listeria) is a Gram-positive facultatively intracellular foodborne pathogen often found in food and elsewhere in nature. It can cause a rare but serious disease called listeriosis, especially among pregnant women, the elderly or individuals with a weakened immune system. In serious cases, it can lead to brain infection and even death. Listeria is more likely to cause death than other bacteria that cause food poisoning. In fact, 20 to 30% of food borne listeriosis infections in high-risk individuals may be fatal. Recent technological developments have increased the ability of scientists to identify the cause of foodborne illnesses. L. monocytogenes has been used as a model organism for the study of intracellular parasitism. Whilst the basic mechanisms of cellular pathogenesis have been elucidated by a series of elegant studies, recent research has begun to focus upon the gastrointestinal phase of L. monocytogenes infection. Epidemiological studies of outbreaks of human disease now demonstrate that the pathogen can cause gastroenteritis in the absence of invasive disease and associated mortality. Elucidation of whole genome sequences and virulence determinants have greatly contributed to understanding of the organism and its infection pathways. 相似文献
8.
9.
Tuberculosis (TB) is a common infection affecting patients with human immunodeficiency virus (HIV) and diabetes mellitus (DM). With the increasing incidence of HIV infection and DM in a developing country like India, TB is definitely on the rise. In a given population, one expects to see these three diseases in varying combinations, such as HIV and TB, DM and TB, HIV and DM with TB. In such combinations TB may lack the characteristic clinical and histological picture due to the associated depressed cell-mediated immunity seen in both diseases and TB may have an unusual clinical presentation and cytology picture. In this retrospective study of 36 months, from January 1997 to December 1999, 109 cases diagnosed cytologically as tuberculous lymphadenitis and tested for HIV infection and investigated as well for DM were selected. Forty-six (42%) were nondiabetic HIV patients, 13 (12%) were non-HIV DM patients, and 50 (46%) had TB without HIV infection or DM. The coexistence of both HIV and DM was not noted. The cytomorphological characteristics supplemented by culture studies of each of these three groups were compared in detail and based on these four cytological patterns, Pattern 1, Pattern 2, Pattern 3, and Pattern 4 emerged and were characterized. This study highlights the usefulness of cytomorphology of the lymph nodes to characterize the cytopathological profile of TB in both HIV and DM, which have many clinical and immunological similarities, and indirectly postulate the extent of immune suppression and evolve effective strategies in the management of coexisting diseases. Such a comparative study has not been carried out in the past. 相似文献
10.
Panda S Kumar MS Lokabiraman S Jayashree K Satagopan MC Solomon S Rao UA Rangaiyan G Flessenkaemper S Grosskurth H Gupte MD 《Journal of acquired immune deficiency syndromes (1999)》2005,39(1):9-15
OBJECTIVES: Determining HIV prevalence in injection drug users (IDUs) and their regular sex partners in Chennai, India. METHODS: A total of 226 IDUs and their regular sex partners were enrolled during April-July 2003. After informed consent was obtained, a semistructured questionnaire was administered and serum was tested for HIV antibody. RESULTS: The HIV seroprevalence was 30% (68/226) in IDUs and 5% in their regular sex partners (11/226). While in 25% of couples only the male partner was HIV positive, 5% of the couples were concordant for HIV infection and 70% were HIV negative. Fifty-seven percent of the HIV-positive IDUs and 45% of the HIV-infected women thought that they had "no chance" or "very little chance" of getting HIV, reflecting low HIV risk perception. More than 20% IDUs reported borrowing or lending of injection equipment. In univariate analyses "sex" and "condom use" with sex workers had no bearing but "more than twice a day injecting frequency," "history of incarceration," "tattoos," "recruitment from northern part of the city," and ever-injecting drugs in drug-selling places had significant association with HIV infection in IDUs. In an adjusted model, the odds of HIV infection were 2 times higher among IDUs who had ever injected drugs in drug-selling places and 6 times higher in those who were recruited from the northern part of central Chennai. CONCLUSION: Reducing sharing of injection equipment and unsafe tattooing through targeted and environmental interventions, increasing HIV risk perception, and promoting safer sex practices among IDUs and their sex partners are urgent program needs. 相似文献