全文获取类型
收费全文 | 1678篇 |
免费 | 221篇 |
出版年
2021年 | 20篇 |
2020年 | 17篇 |
2019年 | 15篇 |
2018年 | 20篇 |
2017年 | 20篇 |
2016年 | 37篇 |
2015年 | 45篇 |
2014年 | 64篇 |
2013年 | 63篇 |
2012年 | 96篇 |
2011年 | 103篇 |
2010年 | 62篇 |
2009年 | 57篇 |
2008年 | 81篇 |
2007年 | 67篇 |
2006年 | 74篇 |
2005年 | 48篇 |
2004年 | 61篇 |
2003年 | 57篇 |
2002年 | 61篇 |
2001年 | 59篇 |
2000年 | 55篇 |
1999年 | 49篇 |
1998年 | 21篇 |
1997年 | 29篇 |
1996年 | 13篇 |
1995年 | 30篇 |
1994年 | 18篇 |
1993年 | 19篇 |
1992年 | 39篇 |
1991年 | 28篇 |
1990年 | 46篇 |
1989年 | 43篇 |
1988年 | 41篇 |
1987年 | 36篇 |
1986年 | 17篇 |
1985年 | 19篇 |
1984年 | 11篇 |
1982年 | 9篇 |
1980年 | 14篇 |
1979年 | 15篇 |
1978年 | 22篇 |
1977年 | 10篇 |
1976年 | 9篇 |
1975年 | 9篇 |
1974年 | 9篇 |
1973年 | 14篇 |
1972年 | 13篇 |
1971年 | 15篇 |
1968年 | 12篇 |
排序方式: 共有1899条查询结果,搜索用时 0 毫秒
81.
Edward B. Blanchard Maria L. Peters Christiane Hermann Shannon M. Turner Todd C. Buckley Kristine Barton Mark P. Dentinger 《Applied psychophysiology and biofeedback》1997,22(4):227-245
In order to test for the specific therapeutic effects of thermal biofeedback (TBF) for hand warming on vascular headache (HA),
70 patients with chronic vascular HA were randomly assigned to TBF for hand warming, TBF for hand cooling, TBF for stabilization
of hand temperature, or biofeedback to suppress alpha in the EEG. Patients in each condition initially had high levels of
expectation of therapeutic benefit and found the treatment rationales highly credible. Participants in each condition received
12 treatment sessions on a twice-per-week basis. Based on daily HA diary data gathered for 4 weeks prior to treatment and
4 weeks after treatment, HA Index was significantly (p=.003) reduced as was HA medication consumption. There were no differential
reducations in HA Index or Medication Index among the four conditions. Global self-reports of improvement gathered at the
end of the post-treatment monitoring period also did not differ among the four conditions. We were unable to demonstrate a
specific effect of TBF for hand warming on vascular HA activity. 相似文献
82.
83.
Samuel Barton James Jenkins Angus Buckling C.-Elisa Schaum Nicholas Smirnoff John A. Raven Gabriel Yvon‐Durocher 《Ecology letters》2020,23(4):722-733
The efficiency of carbon sequestration by the biological pump could decline in the coming decades because respiration tends to increase more with temperature than photosynthesis. Despite these differences in the short‐term temperature sensitivities of photosynthesis and respiration, it remains unknown whether the long‐term impacts of global warming on metabolic rates of phytoplankton can be modulated by evolutionary adaptation. We found that respiration was consistently more temperature dependent than photosynthesis across 18 diverse marine phytoplankton, resulting in universal declines in the rate of carbon fixation with short‐term increases in temperature. Long‐term experimental evolution under high temperature reversed the short‐term stimulation of metabolic rates, resulting in increased rates of carbon fixation. Our findings suggest that thermal adaptation may therefore have an ameliorating impact on the efficiency of phytoplankton as primary mediators of the biological carbon pump. 相似文献
84.
85.
Hui Li Shuyi Wang Fang-Hua Lee Ryan S. Roark Alex I. Murphy Jessica Smith Chengyan Zhao Juliette Rando Neha Chohan Yu Ding Eunlim Kim Emily Lindemuth Katharine J. Bar Ivona Pandrea Cristian Apetrei Brandon F. Keele Jeffrey D. Lifson Mark G. Lewis Thomas N. Denny Barton F. Haynes Beatrice H. Hahn George M. Shaw 《Journal of virology》2021,95(11)
86.
Microengineered systems with iPSC-derived cardiac and hepatic cells to evaluate drug adverse effects
Hepatic and cardiac drug adverse effects are among the leading causes of attrition in drug development programs, in part due to predictive failures of current animal or in vitro models. Hepatocytes and cardiomyocytes differentiated from human induced pluripotent stem cells (iPSCs) hold promise for predicting clinical drug effects, given their human-specific properties and their ability to harbor genetically determined characteristics that underlie inter-individual variations in drug response. Currently, the fetal-like properties and heterogeneity of hepatocytes and cardiomyocytes differentiated from iPSCs make them physiologically different from their counterparts isolated from primary tissues and limit their use for predicting clinical drug effects. To address this hurdle, there have been ongoing advances in differentiation and maturation protocols to improve the quality and use of iPSC-differentiated lineages. Among these are in vitro hepatic and cardiac cellular microsystems that can further enhance the physiology of cultured cells, can be used to better predict drug adverse effects, and investigate drug metabolism, pharmacokinetics, and pharmacodynamics to facilitate successful drug development. In this article, we discuss how cellular microsystems can establish microenvironments for these applications and propose how they could be used for potentially controlling the differentiation of hepatocytes or cardiomyocytes. The physiological relevance of cells is enhanced in cellular microsystems by simulating properties of tissue microenvironments, such as structural dimensionality, media flow, microfluidic control of media composition, and co-cultures with interacting cell types. Recent studies demonstrated that these properties also affect iPSC differentiations and we further elaborate on how they could control differentiation efficiency in microengineered devices. In summary, we describe recent advances in the field of cellular microsystems that can control the differentiation and maturation of hepatocytes and cardiomyocytes for drug evaluation. We also propose how future research with iPSCs within engineered microenvironments could enable their differentiation for scalable evaluations of drug effects. 相似文献
87.
Gabor J. Barton Malcolm B. Hawken Gill Holmes Michael H. Schwartz 《Computer methods in biomechanics and biomedical engineering》2013,16(1):57-63
The ability of the Movement Deviation Profile (MDP) and Gait Deviation Index (GDI) to detect gait changes was compared in a child with cerebral palsy who underwent game training. Conventional gait analysis showed that sagittal plane angles became mirrored about normality after training. Despite considerable gait changes, the GDI showed minimal change, while the MDP detected a difference equal to a shift between 10-9 on the Functional Assessment Questionnaire scale. Responses of the GDI and MDP were examined during a synthetic transition of the patient's curves from before intervention to a state mirrored about normality. The GDI showed a symmetric response on the two opposite sides of normality but the neural network based MDP gave an asymmetric response reflecting faithfully the unequal biomechanical consequences of joint angle changes. In conclusion, the MDP can detect altered gait even if the changes are missed by the GDI. 相似文献
88.
89.
90.
Jennifer L Barton Gabriela Schmajuk Laura Trupin Jonathan Graf John Imboden Edward H Yelin Dean Schillinger 《Arthritis research & therapy》2013,15(5):R157