首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   18785篇
  免费   1563篇
  国内免费   39篇
耳鼻咽喉   132篇
儿科学   708篇
妇产科学   544篇
基础医学   2410篇
口腔科学   230篇
临床医学   2098篇
内科学   3594篇
皮肤病学   371篇
神经病学   2026篇
特种医学   315篇
外国民族医学   5篇
外科学   2000篇
综合类   171篇
一般理论   67篇
预防医学   2840篇
眼科学   266篇
药学   1184篇
  1篇
中国医学   38篇
肿瘤学   1387篇
  2024年   43篇
  2023年   284篇
  2022年   491篇
  2021年   926篇
  2020年   568篇
  2019年   773篇
  2018年   873篇
  2017年   631篇
  2016年   635篇
  2015年   705篇
  2014年   919篇
  2013年   1175篇
  2012年   1628篇
  2011年   1660篇
  2010年   847篇
  2009年   676篇
  2008年   1169篇
  2007年   1227篇
  2006年   995篇
  2005年   921篇
  2004年   833篇
  2003年   751篇
  2002年   552篇
  2001年   92篇
  2000年   81篇
  1999年   75篇
  1998年   119篇
  1997年   82篇
  1996年   46篇
  1995年   52篇
  1994年   43篇
  1993年   43篇
  1992年   46篇
  1991年   32篇
  1990年   27篇
  1989年   31篇
  1988年   14篇
  1987年   24篇
  1986年   22篇
  1985年   27篇
  1984年   21篇
  1983年   9篇
  1982年   17篇
  1981年   15篇
  1980年   15篇
  1978年   8篇
  1977年   18篇
  1975年   10篇
  1974年   13篇
  1961年   7篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Objectives.The objective was to evaluate the sensitivity and specificity of cervical cytology in women infected with the human immunodeficiency virus (HIV), risk factors for abnormal cytology in HIV-infected and uninfected women, and risk factors for histologic diagnosis of cervical intraepithelial neoplasia (CIN) in HIV-infected women.Methods.Methods included a cross-sectional analysis of cervical cytology, colposcopic impression, and histology in 248 HIV-infected women and multivariate analyses of risk factors for abnormal cytology in 253 HIV-infected and 220 uninfected women and risk factors for CIN in 186 HIV-infected women.Results.The sensitivity and specificity of cytology for all CIN grades were 0.60 and 0.80 and, for high-grade CIN, 0.83 and 0.74. The prevalence of abnormal cytology was 32.9% in HIV-infected and 7.6% in HIV-negative women. Independent risk factors for abnormal cytology were immunodeficiency [odds ratio (OR) 8–17,P< 0.001] and human papillomavirus (HPV) infection (OR = 5,P< 0.001). The prevalence of CIN on histology was 32% in HIV-infected women, and the only independent risk factor for CIN was oncogenic HPV type (OR = 5,P= 0.005).Conclusion.Given the high prevalence of abnormal cytology and CIN in HIV-infected women, cytologic screening has significant limitations. Both immunodeficiency and type of HPV infection are important risk factors.  相似文献   
102.
流动人口结核病知识需求和健康教育现况分析   总被引:3,自引:0,他引:3  
目的:了解流动人口结核病健康教育的现状,探索存在的问题和解决措施。方法:流动人口小组讨论、流动人口中慢性咳嗽患者和结核病病人的个人深入访谈,结核病控制相关人员的关键人物访谈。结果:流动人口结核病知识贫乏和防范意识差,流动人口健康教育可及性较差,健康教育中存在一些问题。结论:流动人口是结核病健康教育的目标人群,健康教育开展要不断广泛、深入。  相似文献   
103.
目的:估计男性和女性糖尿病患者致死性冠心病的相对危险。设计:前瞻性队列研究的汇总分析。数据来源:自1966年至2005年3月间Embase和Medline确认并发表的研究,加上源自亚太队列研究协作组的研究,采用正文词组与MeSH主题词相结合的策略进行检索。综述方法:对入选研究的要求为报告有或无糖尿病的男性与女性致死性冠心病的相对危险比较的估计值。如果对估计值仅做年龄调整(而其它因素来经调整——泽者注),则将该研究排除在外。结果:总共纳入37项2型糖尿病和致死性冠心病的研究,涉及447064例患者。糖尿病患者的致死性冠心病发生率显著高于非糖尿病患者(5.4%比1.6%)。与无糖尿病者相比,糖尿病患者发生致死性冠心病的总的相对危险,女性为3.50,95%可信区间为2.70~4.53,显著高于男性患者(2.06,95%可信区间1.81~2.34)。在除外8项仅根据年龄调整的研究后,两性之间危险的差异大大减小,但仍然具有极显著统计学意义。汇集29项经多因素调整估计值的研究,总的相对危险比(女性比男性)为1.46(1.14~1.88)。结论:糖尿病相关的致死性冠心病相对危险,女性比男性高出50%。这种额外的冠心病危险可以通过女性糖尿病患者具有更多不利的心血管危险因素特点以及倾向于对男性患者更注重治疗的可能偏差来解释。  相似文献   
104.
PURPOSE: Obese women and women who gain weight after a breast cancer diagnosis are at a greater risk for breast cancer recurrence and death compared with lean women and women who do not gain weight after diagnosis. In this population-based study, we assessed weight and body fat changes from during the first year of diagnosis to during the third year after diagnosis, and whether any changes in weight and body fat varied by demographic, prognostic, and lifestyle factors in 514 women with incident Stage 0-IIIA breast cancer. METHODS: Patients were participants in the Health, Eating, Activity, and Lifestyle (HEAL) study. Weight and body fat (via dual-energy x-ray absorptiometry scans) were measured during the baseline visit and 2 years later at a follow-up visit. Analysis of covariance methods were used to obtain mean weight and body fat changes adjusted for potential cofounders. RESULTS: Women increased their weight and percent body fat by 1.7 +/- 4.7 kg and 2.1% +/- 3.9%, respectively, from during their first year of diagnosis to during their third year of diagnosis. A total of 68% and 74% of patients gained weight and body fat, respectively. Greater increases in weight were observed among women diagnosed with a higher disease stage, younger age, being postmenopausal, and women who decreased their physical activity from diagnosis to up to 3 years after diagnosis (P for trend < .05). CONCLUSION: Weight and body fat increased in the postdiagnosis period. Future research should focus on the effect of physical activity on weight and fat loss and breast cancer prognosis.  相似文献   
105.
OBJECTIVE: Evidence suggests that the in utero environment may contribute to subsequent development of cancers in childhood and adulthood. Raised levels of estrogen during pregnancy may be the primary in utero etiologic factor. Mothers of twins have higher estrogen levels during pregnancy than mothers of singletons, therefore, assessment of cancer risk in twins may be informative.METHOD: We conducted a retrospective cohort study of cancer among twin and singleton newborns selected from the Utah Population Database, matched on birth year and sex. Cancer diagnoses were determined by linkage with the Utah state cancer register. Relative rates of all cancers in childhood and in adulthood in twins compared with singletons, and for specific cancers including testicular, breast and melanoma, were calculated using Poisson regression.RESULTS: Twin (35,271) and singleton (74,199) births were identified, among whom there were 336 and 691 cancer diagnoses, respectively. The relative risk (RR) of childhood cancer in twins compared with singletons was 0.82 [95% confidence interval (CI) 0.55-1.24] and of adult cancer was 1.06 (0.92-1.22). We found nonsignificant increases in risk among adult twins for cancers of the breast, prostate, testis, lymphatic system, thyroid, and large bowel. The largest departures from unity were for testicular cancer (RR 1.47; 95% CI, 0.73-2.95) and melanoma (RR 0.67; 95% CI, 0.42-1.06).CONCLUSIONS: These results are consistent with the body of evidence suggesting that twins have a reduced risk of cancer in childhood. Although there is no overall differential in adult cancer risk, these data support the hypothesis that the in utero environment may play an important role in specific cancers.  相似文献   
106.
Bevacizumab--current status and future directions.   总被引:13,自引:0,他引:13  
Angiogenesis is crucial to tumour initiation, survival and metastasis. Vascular endothelial growth factor (VEGF) is one of the most important pro-angiogenic factors in cancer development. Bevacizumab (a humanised monoclonal antibody against VEGF) has a reasonable safety profile and proven efficacy in a phase III trial in advanced colorectal cancer. Efficacy of Bevacizumab also looks promising in non small cell lung cancer, renal cancer and a variety of other solid tumours. Questions still surround optimal dosing and the appropriate selection of patients who are most likely to benefit. Future trials will address these questions and provide further translational insights.  相似文献   
107.
108.
Early survivors of pediatric cancer are at increased risk of experiencing chronic conditions; however, little is known about the morbidity burden in this population. In this observational cohort study of commercially insured pediatric cancer survivors in the United States (2009–2014), we find that 22.5% of survivors had one chronic condition, and 36.3% had multiple. Compared with survivors without chronic conditions, the presence of multiple conditions significantly increased the odds of an emergency department visit by 70% (odds ratios [OR], 1.7; 95% confidence interval [CI], 1.4–2.1) and of a hospitalization almost four‐fold (OR, 3.8; 95% CI], 2.5–5.5). Findings are important for informing pediatric survivorship care plans in the years following completion of therapy.  相似文献   
109.
PurposeThe aim of this study was to assess both retinal and cortical structure in a cohort of patients with long-term acquired central retinal disease in order to identify potential disease biomarkers and to explore the relationship between the anterior and posterior visual pathways.MethodsFourteen participants diagnosed with long-term central retinal disease underwent structural assessments of the retina using spectral-domain optical coherence tomography, including macular ganglion cell layer (GCL) and peripapillary retinal nerve fiber layer (pRNFL) thickness. Structural magnetic resonance imaging was used to measure visual cortex, including cortical volume of the entire occipital lobe and cortical thickness of the occipital pole and calcarine sulcus, representing the central and peripheral retina, respectively.ResultsMean thickness was significantly reduced in both the macular GCL and the inferior temporal pRNFL across patients. Cortical thickness was significantly reduced in both the occipital pole and calcarine sulcus, representing the central and peripheral retina, respectively. Disease duration significantly correlated with GCL thickness with a large effect size, whereas a medium effect size suggests the possibility that cortical thickness in the occipital pole may correlate with visual acuity.ConclusionsLong-term central retinal disease is associated with significant structural changes to both the retina and the brain. Exploratory analysis suggests that monitoring GCL thickness may be a sensitive biomarker of disease progression and reductions in visual cortical thickness may be associated with reduced visual acuity. Although this study is limited by its heterogeneous population, larger cohort studies would be needed to better establish some of the relationships detected between disease dependent structural properties of the anterior and posterior visual pathway given the effect sizes reported in our exploratory analysis.  相似文献   
110.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号