全文获取类型
收费全文 | 797篇 |
免费 | 42篇 |
国内免费 | 10篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 33篇 |
妇产科学 | 6篇 |
基础医学 | 107篇 |
口腔科学 | 11篇 |
临床医学 | 67篇 |
内科学 | 150篇 |
皮肤病学 | 33篇 |
神经病学 | 37篇 |
特种医学 | 185篇 |
外科学 | 54篇 |
综合类 | 35篇 |
预防医学 | 20篇 |
眼科学 | 5篇 |
药学 | 62篇 |
中国医学 | 6篇 |
肿瘤学 | 36篇 |
出版年
2023年 | 7篇 |
2021年 | 7篇 |
2020年 | 6篇 |
2019年 | 9篇 |
2018年 | 8篇 |
2017年 | 4篇 |
2016年 | 27篇 |
2015年 | 51篇 |
2014年 | 18篇 |
2013年 | 24篇 |
2012年 | 25篇 |
2011年 | 24篇 |
2010年 | 34篇 |
2009年 | 33篇 |
2008年 | 24篇 |
2007年 | 13篇 |
2006年 | 19篇 |
2005年 | 29篇 |
2004年 | 19篇 |
2003年 | 18篇 |
2002年 | 17篇 |
2001年 | 21篇 |
2000年 | 21篇 |
1999年 | 25篇 |
1998年 | 25篇 |
1997年 | 46篇 |
1996年 | 34篇 |
1995年 | 30篇 |
1994年 | 22篇 |
1993年 | 19篇 |
1992年 | 4篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 22篇 |
1988年 | 16篇 |
1987年 | 11篇 |
1986年 | 13篇 |
1985年 | 8篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 9篇 |
1981年 | 7篇 |
1980年 | 8篇 |
1978年 | 5篇 |
1977年 | 5篇 |
1976年 | 7篇 |
1972年 | 7篇 |
1971年 | 7篇 |
1970年 | 5篇 |
1967年 | 6篇 |
排序方式: 共有849条查询结果,搜索用时 15 毫秒
1.
Izuhara K Umeshita-Suyama R Akaiwa M Shirakawa T Deichmann KA Arima K Hamasaki N Hopkin JM 《Archivum immunologiae et therapiae experimentalis》2000,48(6):505-512
The prevalence of allergic disease has dramatically increased in recent decades, especially in urban and industrialized areas. Allergic diseases are disorders of the immune system, the results of complex interactions among various genetic and environmental factors. Among them, the important role of interleukin 13 (IL-13), a Th2-type cytokine, has recently emerged in the pathogenesis of bronchial asthma. Based on studies using mice, great attention has been paid to the direct effects of IL-13 on bronchial tissues. In this review, we describe recent advances in understanding the signal transduction mechanism of IL-13, the involvement of IL-13 signal-related genes as genetic factors in the pathogenesis of bronchial asthma, and the expression of IL-13 receptor on bronchial tissues. We describe potential strategies for targeting IL-13 signals to improve allergic states. 相似文献
2.
CP Schaecher KA Groesch 《American journal of reproductive immunology (New York, N.Y. : 1989)》2006,55(6):405-405
Background: Control of mRNA stability is an essential regulatory process in eukaryotic gene expression. HuR, a 3'UTR mRNA binding protein, can protect AU-rich mRNA from degradation in response to stresses. PlGF, an angiogenic growth factor, contains two consensus AU-rich sites suggesting that under normal conditions HuR may protect PlGF mRNA from degradation. Trophoblast expression of PlGF is significantly decreased in preeclampsia and by hypoxia in vitro . We hypothesize that decreased levels of cytoplasmic HuR may contribute to decreased PlGF expression in hypoxic and preeclamptic trophoblast.
Methods: Western blots were used to determine relative effects of in vitro hypoxia on HuR protein expression and subcellular localization in trophoblast. Immunohistochemistry was used to compare HuR expression patterns in trophoblast of preeclamptic and normal placentae.
Results: Cytoplasmic expression of HuR was decreased 1.4 fold in the cytoplasm and 1.2 fold in the nucleus of JEG3 cells. A shift in HuR was more apparent in primary trophoblast with a greater than 2-fold decrease in the cytoplasm and a 1.4 fold decrease in the nucleus following 24 hr of hypoxia. Immunohistochemical analyses detected HuR expression in near term trophoblast in situ . However, this technical approach did not detect a significant change in HuR expression between normal and preeclamptic trophoblast.
Conclusions: HuR expression is decreased in hypoxic trophoblast, at least in vitro , which may provide a causal link to decreased PlGF mRNA expression. Down regulation of trophoblast PlGF expression is thought to contribute to the pathophysiology associated with preeclampsia including the relative lack of perfusion of the placenta and systemic renal effects. 相似文献
Methods: Western blots were used to determine relative effects of in vitro hypoxia on HuR protein expression and subcellular localization in trophoblast. Immunohistochemistry was used to compare HuR expression patterns in trophoblast of preeclamptic and normal placentae.
Results: Cytoplasmic expression of HuR was decreased 1.4 fold in the cytoplasm and 1.2 fold in the nucleus of JEG3 cells. A shift in HuR was more apparent in primary trophoblast with a greater than 2-fold decrease in the cytoplasm and a 1.4 fold decrease in the nucleus following 24 hr of hypoxia. Immunohistochemical analyses detected HuR expression in near term trophoblast in situ . However, this technical approach did not detect a significant change in HuR expression between normal and preeclamptic trophoblast.
Conclusions: HuR expression is decreased in hypoxic trophoblast, at least in vitro , which may provide a causal link to decreased PlGF mRNA expression. Down regulation of trophoblast PlGF expression is thought to contribute to the pathophysiology associated with preeclampsia including the relative lack of perfusion of the placenta and systemic renal effects. 相似文献
3.
4.
The authors investigated patients' perception of two aspects of physician behavior during patient-physician interaction, namely, explanation given to the patient and concern for the patient. The relationship between these factors and patient compliance with the therapeutic regimen was then determined. Results showed a statistically significant relationship between these two aspects of physician behavior and patient compliance: the more patients perceived the physician as giving explanations and showing concern, the better was patient compliance. 相似文献
5.
OBJECTIVES: To investigate maternal knowledge and attitudes about otitis media (OM) risk, to estimate the prevalence of risk factors in the first year of life, and to identify barriers to the reduction of risk factors (eg, formula feeding, day care attendance, and exposure to passive smoke). METHODS: Questionnaires mailed to a systematic sample of 504 Minnesota women >/=18 years old identified through 1994 birth certificates. RESULTS: Eighty percent returned a completed survey. According to maternal report, 29% of infants (age 8 to 13 months) had recurrent OM (>/=3 episodes) and 2% had tympanostomy tubes. Forty-six percent attended day care, 29% had >/=1 smoking parent, and 49% breastfed for =2 months. Women were more knowledgeable about OM signs and symptoms than about risk factors. Mean OM knowledge score (the sum of correct true-false responses) was 7.0 (standard deviation = 1.6). Using multiple linear regression, knowledge score was significantly related to marital status, education, age, area of residence, breastfeeding (months), and number of cigarettes smoked per day by the mother, but not to infant or sibling OM history or day care attendance (R = .23). Infant history of OM (odds ratio, 1.9; 95% confidence interval, 1.1 to 3.2) and white race (odds ratio, 0.3; 95% confidence interval, 0. 1 to 0.8), but not the presence of risk factors, were significantly related to having received clinicians' advice about OM prevention advice. CONCLUSION: OM education and prevention programs should target pregnant women and new mothers with OM risk factors, and those who are young, single, and less educated. 相似文献
6.
7.
8.
9.
10.
Amgad Droby Kenneth S. L. Yuen Muthuraman Muthuraman Sarah-Christina Reitz Vinzenz Fleischer Johannes Klein René-Maxime Gracien Ulf Ziemann Ralf Deichmann Frauke Zipp Sergiu Groppa 《Brain imaging and behavior》2016,10(4):1117-1126
Diffuse inflammation in multiple sclerosis (MS) extends beyond focal lesion sites, affecting interconnected regions; however, little is known about the impact of an individual lesion affecting major white matter (WM) pathways on brain functional connectivity (FC). Here, we longitudinally assessed the effects of acute and chronic lesions on FC in relapsing-remitting MS (RRMS) patients using resting-state fMRI. 45 MRI data sets from 9 RRMS patients were recorded using 3T MR scanner over 5 time points at 8 week intervals. Patients were divided into two groups based on the presence (n?=?5; MS+) and absence (n?=?4; MS-) of a lesion at a predilection site for MS. While FC levels were found not to fluctuate significantly in the overall patient group, the MS+ patient group showed increased FC in the contralateral cuneus and precuneus and in the ipsilateral precuneus (p?<?0.01, corrected). This can be interpreted as the recruitment of intact cortical regions to compensate for tissue damage. During the study, one patient developed an acute WM lesion in the left posterior periventricular space. A marked increase in FC in the right pre-, post-central gyrus, right superior frontal gyrus, the left cuneus, the vermis and the posterior and anterior lobes of the cerebellum was noted following the clinical relapse, which gradually decreased in subsequent follow-ups, suggesting short-term functional reorganization during the acute phase. This strongly suggests that the lesion-related network changes observed in patients with chronic lesions occur as a result of reorganization processes following the initial appearance of an acute lesion. 相似文献