全文获取类型
收费全文 | 698篇 |
免费 | 143篇 |
出版年
2022年 | 7篇 |
2021年 | 13篇 |
2018年 | 11篇 |
2017年 | 16篇 |
2016年 | 14篇 |
2015年 | 23篇 |
2014年 | 16篇 |
2013年 | 20篇 |
2012年 | 24篇 |
2011年 | 27篇 |
2010年 | 17篇 |
2009年 | 19篇 |
2008年 | 22篇 |
2007年 | 30篇 |
2006年 | 29篇 |
2005年 | 24篇 |
2004年 | 20篇 |
2003年 | 22篇 |
2002年 | 19篇 |
2001年 | 22篇 |
2000年 | 25篇 |
1999年 | 16篇 |
1998年 | 14篇 |
1997年 | 8篇 |
1996年 | 12篇 |
1995年 | 8篇 |
1994年 | 10篇 |
1993年 | 9篇 |
1992年 | 22篇 |
1991年 | 23篇 |
1990年 | 13篇 |
1989年 | 21篇 |
1988年 | 19篇 |
1987年 | 9篇 |
1986年 | 23篇 |
1985年 | 14篇 |
1984年 | 14篇 |
1983年 | 11篇 |
1982年 | 15篇 |
1981年 | 12篇 |
1980年 | 11篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1976年 | 12篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1970年 | 7篇 |
1969年 | 6篇 |
1968年 | 9篇 |
排序方式: 共有841条查询结果,搜索用时 93 毫秒
51.
F H Wilcox 《The Journal of heredity》1975,66(1):19-22
Rate of electrophoretic migration of prealbumin-2 of mouse blood plasma was found to be controlled by three autosomal codominant alleles. Presence and absence of a component next to albumin (prealbumin-4) was shown to be controlled by autosomal dominant and recessive alleles, respectively, and to be affected by sex. Evidence was presented for close linkage of the Pre-2 and Pre-4 loci, and for the control of albumin conformation by a separate locus. 相似文献
52.
R G Wilcox 《BMJ (Clinical research ed.)》1978,1(6126):1513-1515
In 70 obese women no correlation was found between body weight and serum cholesterol or triglyceride concentrations, but there was a significant correlation between weight and blood pressure. Weight reduction by diet or jejunoileal shunt was not accompanied by any significant change in serum lipid concentrations other than the decrease in serum cholesterol expected after intestinal bypass. Twelve months after bypass surgery was carried out on 14 patients, however, both systolic and diastolic blood pressures were significantly reduced and at levels appropriate to the patients'' new weights. These results suggest that obesity in women cannot be taken to indicate the presence of hyperlipidaemia and that sustained weight loss may lower blood pressure. 相似文献
53.
Nitrosoguanidine induced mutants of Anabaena cylindrica have been obtained, which are altered in heterocyst spacing. In the wild type organism the pattern is composed of single intercalary heterocysts. The mutant patterns fall into several classes: those with only terminal heterocysts, with both terminal and intercalary heterocysts, with groups of heterocysts and those totally lacking heterocysts. The mutants are described in detail, and the various pattern modifications are interpreted in terms of a model we have proposed. 相似文献
54.
Wetlands Ecology and Management - Gas drilling into the Marcellus Shale play has been linked to environmental issues, including potential impacts on wildlife. In 2009, three separate accidents... 相似文献
55.
56.
Sarrawat Rehman Philippa E. Garner Jean E. Aaron Ruth K. Wilcox 《Computer methods in biomechanics and biomedical engineering》2013,16(11):1163-1169
The aim of this study was to investigate whether the predicted finite element (FE) stiffness of vertebral bone is altered when using images of preserved rather than fresh tissue to generate specimen-specific FE models. Fresh ovine vertebrae were used to represent embalmed (n = 3) and macerated dry-bone (n = 3) specimens and treated accordingly. Specimens were scanned pre- and post-treatment using micro-computed tomography. A constant threshold level derived from these images was used to calculate the respective bone volume fraction (BV/TV) from which the conversion factor validated for fresh tissue was used to determine material properties that were assigned to corresponding FE models. Results showed a definite change in the BV/TV between the fresh and the preserved bone. However, the changes in the predicted FE stiffness were not generally greater than the variations expected from assignment of loading and boundary conditions. In conclusion, images of preserved tissue can be used to generate FE models that are representative of fresh tissue with a tolerable level of error. 相似文献
57.
Alain Gagnon Matthew S. Miller Stacey A. Hallman Robert Bourbeau D. Ann Herring David JD. Earn Joaquín Madrenas 《PloS one》2013,8(8)
The worldwide spread of a novel influenza A (H1N1) virus in 2009 showed that influenza remains a significant health threat, even for individuals in the prime of life. This paper focuses on the unusually high young adult mortality observed during the Spanish flu pandemic of 1918. Using historical records from Canada and the U.S., we report a peak of mortality at the exact age of 28 during the pandemic and argue that this increased mortality resulted from an early life exposure to influenza during the previous Russian flu pandemic of 1889–90. We posit that in specific instances, development of immunological memory to an influenza virus strain in early life may lead to a dysregulated immune response to antigenically novel strains encountered in later life, thereby increasing the risk of death. Exposure during critical periods of development could also create holes in the T cell repertoire and impair fetal maturation in general, thereby increasing mortality from infectious diseases later in life. Knowledge of the age-pattern of susceptibility to mortality from influenza could improve crisis management during future influenza pandemics.
“The war is over – and I must go” Egon Schiele, 1890–1918.相似文献
58.
Carrie L. Wade Perry Krumenacher Kelley F. Kitto Cristina D. Peterson George L. Wilcox Carolyn A. Fairbanks 《PloS one》2013,8(11)
The development of opioid addiction in subjects with established chronic pain is an area that is poorly understood. It is critically important to clearly understand the neurobiology associated with propensity toward conversion to addiction under conditions of chronic pain. To pose the question whether the presence of chronic pain influences motivation to self-administer opioids for reward, we applied a combination of rodent models of chronic mechanical hyperalgesia and opioid self-administration. We studied fentanyl self-administration in mice under three conditions that induce chronic mechanical hyperalgesia: inflammation, peripheral nerve injury, and repeated chemotherapeutic injections. Responding for fentanyl was compared among these conditions and their respective standard controls (naïve condition, vehicle injection or sham surgery). Acquisition of fentanyl self-administration behavior was reduced or absent in all three conditions of chronic hyperalgesia relative to control mice with normal sensory thresholds. To control for potential impairment in ability to learn the lever-pressing behavior or perform the associated motor tasks, all three groups were evaluated for acquisition of food-maintained responding. In contrast to the opioid, chronic hyperalgesia did not interfere with the reinforcing effect of food. These studies indicate that the establishment of chronic hyperalgesia is associated with reduced or ablated motivation to seek opioid reward in mice. 相似文献
59.
Status epilepticus (SE) is a life threatening condition that often precedes the development of epilepsy. Traditional treatments for epilepsy have been focused on targeting neuronal mechanisms contributing to hyperexcitability, however, approximately 30% of patients with epilepsy do not respond to existing neurocentric pharmacotherapies. A growing body of evidence has demonstrated that profound changes in the morphology and function of astrocytes accompany SE and persist in epilepsy. Astrocytes are increasingly recognized for their diverse roles in modulating neuronal activity, and understanding the changes in astrocytes following SE could provide important clues about the mechanisms underlying seizure generation and termination. By understanding the contributions of astrocytes to the network changes underlying epileptogenesis and the development of epilepsy, we will gain a greater appreciation of the contributions of astrocytes to dynamic circuit changes, which will enable us to develop more successful therapies to prevent and treat epilepsy. This review summarizes changes in astrocytes following SE in animal models and human temporal lobe epilepsy and addresses the functional consequences of those changes that may provide clues to the process of epileptogenesis. 相似文献
60.
Wong T H Nicholas Dearlove Bethany L Hedge Jessica Giess Adam P Piazza Paolo Trebes Amy Paul John Smit Erasmus Smith E Grace Sutton Julian K Wilcox Mark H Dingle Kate E Peto Tim E A Crook Derrick W Wilson Daniel J Wyllie David H 《Virology journal》2013,10(1):1-10