全文获取类型
收费全文 | 5347篇 |
免费 | 302篇 |
国内免费 | 18篇 |
学科分类
医药卫生 | 5667篇 |
出版年
2021年 | 57篇 |
2020年 | 43篇 |
2019年 | 42篇 |
2018年 | 58篇 |
2017年 | 61篇 |
2016年 | 67篇 |
2015年 | 66篇 |
2014年 | 111篇 |
2013年 | 244篇 |
2012年 | 225篇 |
2011年 | 193篇 |
2010年 | 123篇 |
2009年 | 112篇 |
2008年 | 178篇 |
2007年 | 211篇 |
2006年 | 204篇 |
2005年 | 170篇 |
2004年 | 171篇 |
2003年 | 162篇 |
2002年 | 160篇 |
2001年 | 160篇 |
2000年 | 135篇 |
1999年 | 148篇 |
1998年 | 70篇 |
1997年 | 55篇 |
1996年 | 69篇 |
1995年 | 63篇 |
1994年 | 54篇 |
1993年 | 44篇 |
1992年 | 108篇 |
1991年 | 110篇 |
1990年 | 124篇 |
1989年 | 131篇 |
1988年 | 117篇 |
1987年 | 138篇 |
1986年 | 148篇 |
1985年 | 115篇 |
1984年 | 89篇 |
1983年 | 90篇 |
1982年 | 62篇 |
1981年 | 54篇 |
1980年 | 56篇 |
1979年 | 80篇 |
1978年 | 65篇 |
1977年 | 58篇 |
1976年 | 41篇 |
1975年 | 39篇 |
1974年 | 61篇 |
1973年 | 43篇 |
1969年 | 40篇 |
排序方式: 共有5667条查询结果,搜索用时 0 毫秒
1.
Trevor J. Durbin Casper G. Bendixsen Danielle Jensen-Ryan Abigaile Molzer Sarah Strauss 《Journal of agromedicine》2019,24(2):157-166
ABSTRACTForest workers, including loggers, foresters, and wildland firefighters, are regularly exposed to some of the most fatal occupational environments in the United States. These hazardous work environments may become even more complex and dynamic when subject to bark beetle outbreaks that have resulted in significant tree mortality. The impacts of tree death from bark beetles are significant, with the cumulative 17-year (2000–2016) footprint for bark beetle caused tree mortality estimated at 54 million acres. However, how workers think about and act in these environments is understudied. This study, therefore, approaches the issue of beetle kill and forest worker safety by examining the perspectives or workers themselves. Its contribution is to leverage ethnographic research to provide insights that can generate new research questions, better inform outreach, and ultimately improve worker safety outcomes. The resulting insights show that beetle kill was understood by workers as a hazard that increased the complexity and dynamism of the work environment, making situational awareness both more necessary and more difficult to maintain. While much research about situational awareness focuses on hazardous situations, it is suggested that building adequate situational awareness should also include broader considerations of organizational communication, as well as training and experience considered over the course of entire careers. 相似文献
2.
Amy Y. Zhang Christopher Burant Alex Z. Fu Gerald Strauss Donald R. Bodner Lee Ponsky 《Journal of psychosocial oncology》2020,38(2):210-227
AbstractPurpose: We examined underlying psychosocial processes of a behavioral treatment for urinary incontinence (UI) of prostate cancer survivors.Design: Secondary analysis of data collected from a clinical trial.Sample: Two hundred forty-four prostate cancer survivors who participated in a clinical trial of behavioral intervention to UI as intervention or control subjects.Methods: The participants had a 3-month behavioral intervention or usual care and were followed up for an additional 3?months. They were assessed at baseline, 3, and 6?months. Latent growth curve models were performed to examine trajectories of each study variable and relationships among the variables.Findings: Increasing self-efficacy and social support were significantly and independently associated with more reduction of urinary leakage frequency over time.Implications for psychosocial oncology: Providing problem-solving skills and social support, including peer support, are essential for empowering patients to reduce UI. 相似文献
3.
4.
5.
Kerstin Schmidt Johannes Hoffend Annette Altmann Ludwig G Strauss Antonia Dimitrakopoulou-Strauss Britta Engelhardt Dirk Koczan J?rg Peter Thomas J Dengler Walter Mier Michael Eisenhut Uwe Haberkorn Ralf Kinscherf 《Journal of nuclear medicine》2006,47(3):543-551
Growth of malignant tumors is dependent on sufficient blood supply. Thus, inhibition of tumor angiogenesis is emerging as a promising target in the treatment of malignancies. Human angiostatin (hANG) is one of the most potent inhibitors of endothelial cell proliferation, angiogenesis, and tumor growth in vivo. However, its mechanisms operating in vivo are not well understood. METHODS: To obtain more information about functional changes in the angiogenic process, we established Morris hepatoma (MH3924A) cell lines expressing hANG (hANG-MH3924A). The effects of hANG expression on proliferation and apoptosis of human umbilical vein endothelial cells (HUVECs) were measured in coculture experiments in vitro. To evaluate changes in tumor perfusion and blood volume, H2 15O and 68Ga-DOTA-albumin (DOTA is 1,4,7,10-tetraazacyclododecane-N,N',N',N'-tetraacetic acid) were used for PET studies in vivo. Additionally, immunohistologic quantification of vascularization, apoptosis, and proliferation as well as gene array analyses were performed. RESULTS: Our in vitro experiments demonstrate reduced proliferation and increased apoptosis in HUVECs when being cocultured with hANG-MH3924A. In support, tumor growth of hANG-MH3924A is diminished by 95% in vivo. However, tumor perfusion and blood volume are increased in hANG-MH3924A corresponding to an increased microvessel density. Furthermore, hANG-transfected tumors show changes in expression of genes related to apoptosis, stress, signal transduction, and metabolism. CONCLUSION: hANG expression leads to inhibition of tumor growth, increased apoptosis, and changes in the expression of multiple genes involved in stress reactions, signal transduction, and apoptosis, which indicates a multifactorial reaction of tumors. An enhanced microvessel density is seen as part of these reactions and is associated with increased perfusion as measured by PET. 相似文献
6.
L G Strauss 《Der Radiologe》1989,29(7):318-321
Positron emission tomography with metabolically active substances is a noninvasive imaging modality to determine tumor metabolism. Quantification of tumor metabolism provides valuable information, e.g., for the differential diagnosis of malignancies. Radiolabeled therapeutic substances can be traced with PET. Measurement of fluorouracil metabolite concentrations provides data about the accumulation pattern of the cytostatic agent and allows assessment of the therapeutic outcome. 相似文献
7.
Background
Traumatic perforation of the distal oesophagus due to blunt trauma is a very rare condition and is still associated with a significant morbidity and mortality. This is further exacerbated by delayed diagnosis and management as symptoms and signs are often masked by or ascribed to more common blunt thoracic injuries. 相似文献8.
9.
The prediction of outcome in schizophrenia. IV: Eleven-year follow-up of the Washington IPSS cohort 总被引:5,自引:0,他引:5
Two- and five-year follow-up observations of the International Pilot Study of Schizophrenia's Washington cohort provided data bearing on several controversial issues regarding the course of schizophrenia. Forty schizophrenic patients have now been observed 11 years after their index admission. Social, occupational, hospital utilization, and symptom areas of functioning continue to be only modestly correlated with one another and do not become increasingly uniform over time. Initial prognostic variables continue to be more predictive of long-term outcome than are cross-sectional symptom manifestations. Restricted affect at the initial evaluation had been a predictor of 5-year outcome, but it was not a significant predictor of outcome at 11 years. While serious long-term consequences of illness are observed, the follow-up data suggest that the illness tends to reach a plateau of psychopathology early in the course, with as many patients tending to improve in the long-term as those who tend to show further deterioration. 相似文献
10.