全文获取类型
收费全文 | 572篇 |
免费 | 42篇 |
国内免费 | 4篇 |
专业分类
儿科学 | 36篇 |
妇产科学 | 19篇 |
基础医学 | 57篇 |
口腔科学 | 19篇 |
临床医学 | 42篇 |
内科学 | 128篇 |
皮肤病学 | 2篇 |
神经病学 | 39篇 |
特种医学 | 59篇 |
外科学 | 59篇 |
综合类 | 8篇 |
预防医学 | 60篇 |
眼科学 | 7篇 |
药学 | 44篇 |
中国医学 | 2篇 |
肿瘤学 | 37篇 |
出版年
2022年 | 10篇 |
2021年 | 18篇 |
2019年 | 9篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 10篇 |
2015年 | 14篇 |
2014年 | 11篇 |
2013年 | 22篇 |
2012年 | 27篇 |
2011年 | 23篇 |
2010年 | 15篇 |
2009年 | 15篇 |
2008年 | 21篇 |
2007年 | 18篇 |
2006年 | 17篇 |
2005年 | 17篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 15篇 |
2001年 | 11篇 |
2000年 | 8篇 |
1999年 | 12篇 |
1998年 | 11篇 |
1997年 | 12篇 |
1996年 | 21篇 |
1995年 | 17篇 |
1994年 | 11篇 |
1993年 | 7篇 |
1992年 | 9篇 |
1991年 | 12篇 |
1990年 | 11篇 |
1989年 | 15篇 |
1988年 | 12篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 9篇 |
1984年 | 7篇 |
1981年 | 10篇 |
1980年 | 6篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1976年 | 6篇 |
1975年 | 9篇 |
1974年 | 7篇 |
1973年 | 9篇 |
1971年 | 9篇 |
1970年 | 6篇 |
1969年 | 5篇 |
排序方式: 共有618条查询结果,搜索用时 15 毫秒
1.
2.
Physicians as gatekeepers. A complex challenge 总被引:1,自引:0,他引:1
M D Reagan 《The New England journal of medicine》1987,317(27):1731-1734
3.
Cain, an oncologist and chair of her medical center's ethics advisory committee, and Reagan, a clinical ethicist, debate the pros and cons of compensation for ethics committee members. Among the issues raised are the value of monetary compensation in our society, the assumption of virtue as its own reward, and the potential for conflict of interest if ethics committee members are paid. 相似文献
4.
5.
The effect of upper motor neuron regulation on skeletal muscle development was studied in the fetal pig. A region of the spinal cord at the level of the upper cervical vertebrae was destroyed by cauterization at 45 days of gestation in four pig fetuses. Five fetuses with intact spinal cords served as controls. Innervation and enzyme activities in the longissimus muscle, the ultrastructure and quantitation of satellite cells in the sartorius muscle, and plasma composition were evaluated at 110 days of gestation. The terminal innervation ratios were similar (P greater than 0.05) for muscles from control and cauterized fetuses. Endplate morphology was also similar. Therefore, innervation of newly formed primary fibers is not controlled by upper motor neurons after 45 days of gestation. Mean values for body weight, percentage of muscle dry weight, percentage of myofibers with myonuclei and plasma levels of protein, glucose, triglycerides, lactate, and creatine phosphokinase activity were similar (P greater than 0.05) between the two groups of fetuses. All but one muscle fiber examined was of the secondary fiber type. These observations suggest that the physiological maturity of the muscle was not appreciably altered even though glucose-6-phosphate dehydrogenase activity was higher (P greater than 0.05) and total phosphorylase activity was lower (P greater than 0.05) in the spinal cauterized fetuses than in the control group. The percentage of satellite cells was lower when based on the number of myofibers observed (P greater than 0.005) or on the number of nuclei contained within the basal lamina (P greater than 0.001) in the muscle of the spinal cauterized fetuses than in the control fetuses. The cytoplasm of satellite cells from the muscles of control fetuses was rich in organelles indicative of metabolic and mitotic activity whereas a paucity of such organelles was observed in the satellite cells of cauterized fetuses. Since the percentage of myofibers that had myonuclei was similar (P greater than 0.05) for the control and cauterized fetuses, it appeared that the myonuclear population was maintained by direct incorporation of the parent satellite cell. 相似文献
6.
Mariah Farrell Heather Fairfield Samantha Costa Anastasia D'Amico Carolyne Falank Daniel J Brooks Michaela R Reagan 《Journal of bone and mineral research》2021,36(1):158-169
Obesity, a growing pandemic, is a risk factor for many cancers and causes increased bone marrow adipose tissue (BMAT). in vitro studies and obese animal models suggest that BMAT contributes to cancer progression, but there is a lack of preclinical models to directly test BMAT's role in cancer. Overactivation of peroxisome-proliferator-activated receptor-γ (PPARγ) can skew bone formation and resorption rates, resulting in increased BMAT and trabecular bone loss. Thiazolidinediones (eg, rosiglitazone) are anti-diabetic therapies that promote adipogenesis through PPARγ activation. We investigated if rosiglitazone increases BMAT in an immunocompromised model, commonly used in cancer research, and if these effects could be reversed by co-administering a bone anabolic agent (sclerostin-neutralizing antibody [Scl-Ab]), which has been shown to inhibit adipogenesis, using DXA, μCT, OsO4 μCT, and dynamic histomorphometry. Four weeks of rosiglitazone in female SCID Beige mice (cohort 1) significantly decreased trabecular bone volume (BV/TV) by about one-half, through increased osteoclast and suppressed osteoblast activity, and significantly increased BMAT. In cohort 2, mice were administered rosiglitazone ± Scl-Ab for 4 weeks, and then rosiglitazone was discontinued and Scl-Ab or vehicle were continued for 6 weeks. Scl-Ab significantly increased bone parameters (eg, BV/TV, N.Ob/B.Pm, and MS/BS) in both groups. Scl-Ab also overcame many negative effects of rosiglitazone (eg, effects on trabecular bone parameters, increased mineralization lag time [MLT], and decreased bone formation rate [BFR]). Interestingly, Scl-Ab significantly decreased rosiglitazone-induced BMAT in the femur, mostly due to a reduction in adipocyte size, but had a much weaker effect on tibial BMAT. These data suggest targeting sclerostin can prevent rosiglitazone-induced bone loss and reduce BM adiposity, in some, but not all BMAT locations. Collectively, our data demonstrate that rosiglitazone increases BMAT in SCID Beige mice, but concomitant changes in bone may confound its use to specifically determine BMAT's role in tumor models. © 2020 American Society for Bone and Mineral Research (ASBMR). 相似文献
7.
Natalie A. Winings Brian J. Daley Reagan W. Bollig R. Frank Roberts Jennifer Radtke R. Eric Heidel Jessica E. Taylor James C. McMillen 《The surgeon》2021,19(3):129-134
Backgroundand Purpose: Currently, dexmedetomidine versus propofol has primarily been studied in medical and cardiac surgery patients with outcomes indicating safe and effective sedation. The purpose of this study was to assess the efficacy of dexmedetomidine versus propofol for prolonged sedation in trauma and surgical patients.MethodsThis was a single-center prospective study conducted in the Trauma/Surgical Intensive Care Unit (ICU) at a Level I academic trauma center. It included patients 18 years of age or older requiring mechanical ventilation who were randomly assigned based on unit bed location to receive either dexmedetomidine or propofol. The primary outcome was duration of mechanical ventilation. Secondary outcomes included mortality; proportion of time in target sedation; incidence of delirium, hypotension, and bradycardia; and ICU and hospital length of stay (LOS).ResultsA total of 57 patients were included. Baseline characteristics were similar between groups. There was no significant difference in duration of mechanical ventilation (median [IQR]) between the dexmedetomidine (78.5[125] hours) and propofol (105[130] hours; p = 0.15) groups. There was no difference between groups in ICU mortality, ICU and hospital LOS, or incidence of delirium. Safety outcomes were also similar. Patients in the dexmedetomidine group spent a significantly greater percentage of time in target sedation (98[8] %) compared to propofol group (92[10] %; p = 0.02).ConclusionsOur results suggest that, similar to medical and cardiac surgery patients, dexmedetomidine and propofol are safe and effective sedation agents in critically ill trauma and surgical patients; however, dexmedetomidine achieves target sedation better than propofol for this specific population. 相似文献
8.
The steady increase in immigrants to the United States has fueled a critical analysis of the process of allocation of health and social benefits to these newcomers. The myriad of interests and values surrounding this issue precipitated the formulation and adoption of the Personal Responsibility and Work Opportunity (Welfare Reform) Act of 1996. This dramatic welfare reform impacts federal, state, and local agencies that are required to determine the eligibility of benefits and manage the attendant consequences to the public as well as members of this vulnerable group. Especially challenging are the decisions confronting public health professionals who struggle to reconcile the resulting policy, programmatic mandates, and compliance imperatives with prevailing public health principles and practice norms. This paper proposes a framework for understanding the incongruence between the provisions of the law as it pertains to legal and illegal immigrants and public health values. The impact of policy incongruence and professionals' dissonance on public health practice norms is explored with an explicit focus on public health outcomes and legal implications. The examination of tuberculosis as a health example reveals the policy conflicts and public health dilemmas. Finally, the paper elicits a range of options available to public professionals for responding to these legal mandates. 相似文献
9.
This study was designed to compare the growth of Pakistani schoolchildren in the UK with the 1990 UK growth standards. Measurements of height, weight, and sitting height were performed on 785 Pakistani schoolchildren aged 5-14 years with the mean values for each age and sex being plotted on the UK growth standards. The results were expressed as SD scores relative to the 1990 reference data. The mean height for the boys was only 0.2 SD scores below the mean for the new growth standards with the mean height for the girls being 0.4 SD scores below the mean. The mean values for weight and body mass index were 0.3 and 0.5 SD scores less than the mean for boys and girls respectively. This study demonstrates that the growth of Pakistani schoolchildren in the UK is comparable to the 1990 UK growth standards with only minor differences. It is not safe to assume that short stature or low body weight in a Pakistani child is due to his or her ethnic background. 相似文献
10.
Determination of malondialdehyde-induced DNA damage in human tissues using an immunoslot blot assay 总被引:3,自引:4,他引:3
Leuratti C; Singh R; Lagneau C; Farmer PB; Plastaras JP; Marnett LJ; Shuker DE 《Carcinogenesis》1998,19(11):1919-1924
Malondialdehyde (MDA) is a product of lipid peroxidation and prostaglandin
biosynthesis. It is mutagenic and carcinogenic and the major adduct formed
by reaction with DNA, a highly fluorescent pyrimidopurinone (M1-dG), has
been detected in healthy human liver and leukocyte DNA. Analytical methods
used so far for the detection of M1- dG have not been applied to a large
number of individuals or variety of samples. Often, only a few microg of
DNA from human tissues are available for analysis and a very sensitive
assay is needed in order to detect background levels of M1-dG in very small
amounts of DNA. In this paper, the development of an immunoslot blot (ISB)
assay for the measurement of MI-dG in 1 microg of DNA is described. The
limit of detection of the assay is 2.5 adducts per 10(8) bases. A series of
human samples were analysed and levels of 5.6-9.5 (n = 8) and 3.1-64.3 (n =
42) of M1-dG per 10(8) normal bases were detected in white blood cell and
gastric biopsy DNA, respectively. Results on four human samples were
compared with those obtained using an HPLC/32P-post- labelling (HPLC/PPL)
method previously developed and indicated a high correlation between M1-dG
levels measured by the two assays. The advantages of ISB over other assays
including HPLC/PPL, such as the possibility of analysing 1 microg
DNA/sample and the fact that it is less time-consuming and laborious, means
that it can be more easily used for routine analysis of a large number of
samples in biomonitoring studies.
相似文献