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   8635篇
  免费   842篇
  国内免费   8篇
耳鼻咽喉   59篇
儿科学   294篇
妇产科学   252篇
基础医学   1357篇
口腔科学   328篇
临床医学   849篇
内科学   1652篇
皮肤病学   83篇
神经病学   932篇
特种医学   209篇
外科学   1131篇
综合类   169篇
一般理论   5篇
预防医学   934篇
眼科学   133篇
药学   625篇
肿瘤学   473篇
  2022年   60篇
  2021年   132篇
  2020年   99篇
  2019年   126篇
  2018年   161篇
  2017年   118篇
  2016年   119篇
  2015年   135篇
  2014年   234篇
  2013年   286篇
  2012年   470篇
  2011年   538篇
  2010年   266篇
  2009年   244篇
  2008年   408篇
  2007年   455篇
  2006年   401篇
  2005年   395篇
  2004年   368篇
  2003年   340篇
  2002年   364篇
  2001年   258篇
  2000年   242篇
  1999年   190篇
  1998年   89篇
  1997年   79篇
  1996年   67篇
  1995年   79篇
  1994年   74篇
  1993年   81篇
  1992年   170篇
  1991年   195篇
  1990年   134篇
  1989年   148篇
  1988年   150篇
  1987年   147篇
  1986年   145篇
  1985年   141篇
  1984年   122篇
  1983年   87篇
  1982年   70篇
  1981年   66篇
  1980年   56篇
  1979年   110篇
  1978年   76篇
  1977年   54篇
  1975年   59篇
  1974年   78篇
  1973年   64篇
  1972年   58篇
排序方式: 共有9485条查询结果,搜索用时 0 毫秒
71.
72.
73.
BACKGROUND: Squamous cell carcinoma (SCC) of the lower lip is a common malignancy in Australia. Surgical excision and/or radiotherapy are used in treatment, and are regarded as equally effective. METHODS: A retrospective review of 323 patients treated at the Peter MacCallum Cancer Institute with either surgical excision and/or radiotherapy, evaluated disease recurrence, cause-specific mortality, and the incidence of metachronous lesions. RESULTS: Recurrence-free survival at 10 years was estimated to be 92.5%, and cause-specific survival at 10 years was estimated to be 98.0%. Equivalent rates of local control were obtained with surgery and radiotherapy. Recurrence was related to tumour stage and differentiation. A high incidence of metachronous lesions was noted, 25 patients had a lesion prior to presentation and 33 patients developed second lip lesions during the study period. CONCLUSIONS: Squamous cell carcinoma of the lower lip is well treated with surgery or radiotherapy. The preferred treatment for most patients with SCC of the lower lip in the Australian population is surgical excision. This study has shown a significant incidence of metachronous lip neoplasia, except in those patients whose whole lip had been resurfaced.  相似文献   
74.
Supernatants from short-term cultures of murine decidual tissue (DS) were assessed for their regulatory effects on T cell lymphoproliferation and cytotoxic T lymphocyte (CTL) activity. DS non-specifically suppressed antigen- and mitogen-induced lymphoproliferation, spontaneous thymocyte proliferation, the mixed lymphocyte reaction (MLR) and CTL generation, but had no effect on CTL lytic activity. The immunosuppressive activity was lost after dialysis (14 kDa cut off). Supernatants from indomethacin-treated decidual tissue cultures (indomethacin-DS) lacked suppressive activity in the MLR, mitogen and thymocyte proliferation assays. Indomethacin-DS also showed markedly reduced or no suppressive effects on CTL generation. These findings suggest that prostaglandin production by the decidual component of the placenta could play a role in materno-fetal cellular interactions by regulating T cell lymphoproliferative responses and CTL generation.  相似文献   
75.
Macular halos describe a striking clinical finding of bilaterally elevated, doughnut-shaped, white rings around th fovea. This paper presents the third well-documented report of the association of macular halos with Niemann-Pick type B disease, demonstrated by color photographs and subtle fluorescein angiographic findings. The systemic association with Niemann-Pick type B disease was confirmed by bone marrow biopsy and enzyme assay. Of 13 family members examined, only the proposita had macular halos; 10 were found to be carriers by sphingomyelinase assay. Recognition of this pathognomonic eye finding warrants more widespread awareness as a presenting sign of Niemann-Pick type B disease.  相似文献   
76.
In order to stimulate antigen presentation and T cell activity against cancer, we treated three different tumor models in mice with the monoclonal antibodies anti-CD40 plus anti-CD137 (BiMab). In a subcutaneous transplantable MC38 colon cancer model, there was significant enhancement in the survival of mice following BiMab treatment. Anti-CD40 has shown considerable success against lymphoma in previous studies by other investigators, and we also showed in this study that, in a model of Eμ-Myc lymphoma, there was a statistically significant enhancement of survival of mice following BiMab treatment. Following the success of the BiMab treatment in the previous two models, we wished to determine if it would be successful in a mouse model of multiple myeloma. Firstly, we tested a transplantable model of disease in which multiple myeloma cells derived from Vk*MYC mice were injected intravenously. A minor proportion of anti-CD137 and BiMab treated mice experienced prolongation of life beyond 250 days. Then we tested the therapy in a spontaneously occurring multiple myeloma model, in Vk*MYC transgenic mice. The majority of mice treated survived longer than control mice, although statistical significance was not demonstrated.  相似文献   
77.
The major medical causes of maternal death and the effective interventions to prevent maternal death due to these causes are known. Yet, every year, an estimated 529,000 women die during and following pregnancy and childbirth. Most of these deaths occur in developing countries where other non-medical determinants of maternal health influence the accessibility to these interventions. Improvements in maternal health can be achieved through a health systems approach. Care should be provided as a continuum throughout the life cycle and across health facilities through the health system. Communities, professional organizations and academic institutions should work actively with the government to: provide a package of service, based on population health needs, that is close to home; ensure availability of essential medicines and commodities; address financial barriers to receiving care; strengthen the health workforce; and gather and use information to improve maternal health.  相似文献   
78.
The ultimate goal is to develop a safe vaginal ultrasound-directed myolysis needle to treat uterine myomas. The specific preclinical study objective was to determine the optimal power to coagulate myomas in hysterectomy specimens with a prototype needle in a prospective preclinical study with an echogenic insulated needle electrode. In phase I of the study, myolysis was performed with ultrasound guidance at various powers and times. In phase II, a 20-W coagulating current was applied at defined distances from the serosa and surface temperatures measured. Myolysis with 10 to 20 W applied 5 to 10 seconds was optimal, because tissue popping occurred at 30 W or more when the needle was 5 mm or less from the serosa. The serosal temperature was never elevated above physiological ranges at any distance at this setting. Ultrasound-directed transvaginal myolysis may provide another option for women with uterine myomas if it is proven safe and effective in future clinical studies. On the basis of the observations in these preclinical studies, myolysis with 20 W for 10 seconds should be a safe parameter for clinical research, because there is no increased serosal temperature at these settings.  相似文献   
79.
80.
Elevated office blood pressure (BP) has previously been associated with increased levels of circulating extracellular vesicles (EVs). The present study aimed to assess the relationship between levels of platelet derived EVs, ambulatory BP parameters, and pulse wave velocity as a marker of macrovascular organ damage. A total of 96 participants were included in the study. Platelet‐derived extracellular vesicles (pEVs) were evaluated by flow cytometry (CD41+/Annexin v+). BP evaluation included unobserved automated office BP and ambulatory BP monitoring. Carotid‐femoral pulse wave velocity (PWV) was measured as a marker of macrovascular damage. pEVs correlated with nocturnal systolic BP (r = 0.31; p = .003) and nocturnal dipping (r = ‐0.29; p = .01) in univariable analysis. Multivariable regression models confirmed robustness of the association of EVs and nocturnal blood pressure (p = .02). In contrast, systolic office, 24h‐ and daytime‐BP did not show significant associations with pEVs. No correlations were found with diastolic BP. Circulating pEVs correlated with pulse wave velocity (r = 0.25; p = .02). When comparing different hypertensive phenotypes, higher levels of EVs and PWV were evident in patients with sustained hypertension compared to patients with white coat HTN and healthy persons. Circulating platelet derived EVs were associated with nocturnal BP, dipping, and PWV. Given that average nocturnal BP is the strongest predictor of CV events, platelet derived EVs may serve as an integrative marker of vascular health, a proposition that requires testing in prospective clinical trials.  相似文献   
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