全文获取类型
收费全文 | 681篇 |
免费 | 42篇 |
国内免费 | 1篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 19篇 |
妇产科学 | 47篇 |
基础医学 | 73篇 |
口腔科学 | 23篇 |
临床医学 | 109篇 |
内科学 | 127篇 |
皮肤病学 | 23篇 |
神经病学 | 39篇 |
特种医学 | 31篇 |
外科学 | 89篇 |
综合类 | 9篇 |
预防医学 | 48篇 |
眼科学 | 5篇 |
药学 | 54篇 |
中国医学 | 1篇 |
肿瘤学 | 19篇 |
出版年
2023年 | 3篇 |
2022年 | 6篇 |
2021年 | 16篇 |
2019年 | 20篇 |
2018年 | 17篇 |
2017年 | 18篇 |
2016年 | 21篇 |
2015年 | 17篇 |
2014年 | 31篇 |
2013年 | 39篇 |
2012年 | 65篇 |
2011年 | 41篇 |
2010年 | 25篇 |
2009年 | 18篇 |
2008年 | 38篇 |
2007年 | 45篇 |
2006年 | 38篇 |
2005年 | 32篇 |
2004年 | 24篇 |
2003年 | 28篇 |
2002年 | 13篇 |
2001年 | 18篇 |
2000年 | 18篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1992年 | 13篇 |
1991年 | 10篇 |
1990年 | 9篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 8篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1982年 | 4篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1976年 | 4篇 |
1975年 | 2篇 |
1974年 | 6篇 |
1972年 | 3篇 |
1971年 | 3篇 |
1967年 | 3篇 |
1963年 | 2篇 |
1954年 | 2篇 |
1942年 | 2篇 |
排序方式: 共有724条查询结果,搜索用时 15 毫秒
1.
2.
Rian M. Hasson Kayla A. Fay Joseph D. Phillips Timothy M. Millington David J. Finley 《American journal of surgery》2021,221(4):725-730
BackgroundRural populations face many health disadvantages compared to urban areas. There is a critical need to better understand the current lung cancer screening landscape in these communities to identify targeted areas to improve the impact of this proven tool.MethodsData from the County Health Rankings of New Hampshire and Vermont was reviewed for population density, distribution of adult smokers, and level of education compared to the distribution of Lung Cancer Screening Facilities throughout these two states.ResultsScreening programs in southern counties of Vermont with lower levels of education have decreased access. In New Hampshire, there are no programs within 30 miles of the areas with the largest distribution of smokers, and decreased access in some areas with the lowest levels of education.ConclusionsImproving equitable access to high-quality screening services in rural regions and the creation of targeted interventions to address decreased access in areas of high tobacco use and low education is vital to decreasing the incidence of latestage presentations of lung cancer within these populations. 相似文献
3.
4.
Quantitative diagnostic performance of myocardial perfusion SPECT with attenuation correction in women. 总被引:1,自引:0,他引:1
Arik Wolak Piotr J Slomka Mathews B Fish Santiago Lorenzo Daniel S Berman Guido Germano 《Journal of nuclear medicine》2008,49(6):915-922
Attenuation correction (AC) for myocardial perfusion SPECT (MPS) had not been evaluated separately in women despite specific considerations in this group because of breast photon attenuation. We aimed to evaluate the performance of AC in women by using automated quantitative analysis of MPS to avoid any bias. METHODS: Consecutive female patients--134 with a low likelihood (LLk) of coronary artery disease (CAD) and 114 with coronary angiography performed within less than 3 mo of MPS--who were referred for rest-stress electrocardiography-gated 99mTc-sestamibi MPS with AC were considered. Imaging data were evaluated for contour quality control. An additional 50 LLk studies in women were used to create equivalent normal limits for studies with AC and with no correction (NC). An experienced technologist unaware of the angiography and other results performed the contour quality control. All other processing was performed in a fully automated manner. Quantitative analysis was performed with the Cedars-Sinai myocardial perfusion analysis package. All automated segmental analyses were performed with the 17-segment, 5-point American Heart Association model. Summed stress scores (SSS) of > or =3 were considered abnormal. RESULTS: CAD (> or =70% stenosis) was present in 69 of 114 patients (60%). The normalcy rates were 93% for both NC and AC studies. The SSS for patients with CAD and without CAD for NC versus AC were 10.0 +/- 9.0 (mean +/- SD) versus 10.2 +/- 8.5 and 1.6 +/- 2.3 versus 1.8 +/- 2.5, respectively; P was not significant (NS) for all comparisons of NC versus AC. The SSS for LLk patients for NC versus AC were 0.51 +/- 1.0 versus 0.6 +/- 1.1, respectively; P was NS. The specificity for both NC and AC was 73%. The sensitivities for NC and AC were 80% and 81%, respectively, and the accuracies for NC and AC were 77% and 78%, respectively; P was NS for both comparisons. CONCLUSION: There are no significant diagnostic differences between automated quantitative MPS analyses performed in studies processed with and without AC in women. 相似文献
5.
Arik Hasson Michael Fainzilber Eliahu Zlotkin Micha Spira 《The European journal of neuroscience》1995,7(4):815-818
A novel peptide toxin, PnIVB, isolated from the venom of Conus pennaceus blocks voltage-gated sodium current in Aplysia neurons. Complete blockade is obtained at a PnIVB concentration of 80±2.2 nM and 50% blockade at 16±0.86 nM. The potency of PnIVB in blocking Aplysia sodium current is four orders of magnitude larger than that of tetrodotoxin. The toxin has no paralytic activity when injected into fish. The rapid blockade of sodium current by PnIVB is not associated with a change in the activation or inactivation kinetics of the current, or with the reversal potential. Sodium current blockade is reversible after a 30 min wash with 50 times the bath volume. The novel conotoxin PnlVB can be used as a powerful tool for mollusc neurobiological research and as a molecular probe to explore the structure-function relations of voltage-gated sodium channel subtypes. 相似文献
6.
The evolution of morphologic and biomechanical changes in reversed and in-situ vein grafts.
下载免费PDF全文
![点击此处可从《Annals of surgery》网站下载免费的PDF全文](/ch/ext_images/free.gif)
R P Cambria J Megerman D C Brewster D F Warnock J Hasson W M Abbott 《Annals of surgery》1987,205(2):167-174
A comparative study of experimental reversed (RV) and in-situ (INS) vein grafts with respect to the evolution of morphologic and compliance characteristics was done in a canine model. In addition, the compliance characteristics in a series of human INS vein grafts were recorded as a function of time after operation. At 6 months after implantation, all experimental grafts displayed well-developed intimal hyperplasia. There was no significant difference in either absolute intimal thickness (INS 0.133 +/- 0.09 mm vs. RV 0.085 +/- 0.06 mm; NS) nor in the percentage of the total wall thickness occupied by the intima when experimental INS grafts were compared with RV grafts after 6 months. Similarly, compliance values of INS and RV vein grafts were similar at all time intervals examined up to 6 months after operation. Thirty-three human INS vein grafts had a mean compliance value of 1.74 +/- 0.72 (percent radial changes per mmHg X 10(-2) at a median postoperative interval of 14 weeks. This value did not differ significantly from those measured in the INS vein grafts. Although all vein grafts examined retained their native viscoelastic properties, this study suggests that functioning human INS vein grafts are less compliant than previously suspected on the basis of prior ex-vivo and clinical studies of RV saphenous vein grafts. The purported clinical superiority of the INS vein graft cannot be explained on the basis of superior biomechanical performance or failure to develop intimal hyperplasia. 相似文献
7.
Magnetic field tomography of coherent thalamocortical 40-Hz oscillations in humans. 总被引:20,自引:6,他引:14
下载免费PDF全文
![点击此处可从《Proceedings of the National Academy of Sciences of the United States of America》网站下载免费的PDF全文](/ch/ext_images/free.gif)
U Ribary A A Ioannides K D Singh R Hasson J P Bolton F Lado A Mogilner R Llinás 《Proceedings of the National Academy of Sciences of the United States of America》1991,88(24):11037-11041
This paper introduces the use of magnetic field tomography (MFT), a noninvasive technique based on distributed source analysis of magnetoencephalography data, which makes possible the three-dimensional reconstruction of dynamic brain activity in humans. MFT has a temporal resolution better than 1 msec and a spatial accuracy of 2-5 mm at the cortical level, which deteriorates to 1-3 cm at depths of 6 cm or more. MFT is used here to visualize the origin of a spatiotemporally organized pattern of coherent 40-Hz electrical activity. This coherence, initially observed during auditory input, was proposed to be generated by recurrent corticothalamic oscillation. In support of this hypothesis, we illustrate well-defined 40-Hz coherence between cortical-subcortical sites with a time shift that is consistent with thalamocortical conduction times. Studies on Alzheimer patients indicate that, while a similar activity pattern is present, the cortical component is reduced in these subjects. 相似文献
8.
Zahava Sololmon Shimon E. Spiro Arik Shalev Avi Bleich Samuel Cooper 《Journal of traumatic stress》1992,5(2):217-223
Nine months after the residential stage of Koach, participants were asked to evaluate the program's effectiveness. Most of the veterans reported improvement in the areas queried, and especially in social relations, and nearly all of them stated that they would recommend the program to other veterans. The commander-therapists became the major source of help for these veterans following the Koach project, and about half reported that they participated regularly in self-help groups. Most of the participants acquired coping techniques that continued to serve them 9 months after the end of the residential stage of Koach. One of the more important measures of Koach was thought to be the veterans' own evaluations of the project, their assessment of the project's success in achieving its aims, and their satisfaction with it. In this article we will present the subjects' evaluations of treatment effectiveness as expressed in behavioral and emotional changes that they attributed to the treatment. 相似文献
9.
Identification and overlapping expression of multiple unconventional myosin genes in vertebrate cell types. 总被引:1,自引:1,他引:0
W M Bement T Hasson J A Wirth R E Cheney M S Mooseker 《Proceedings of the National Academy of Sciences of the United States of America》1994,91(14):6549-6553
Myosin diversity in the human epithelial cell line Caco-2BBe, the porcine epithelial cell line LLC-PK1 (CL-4), human peripheral blood leukocytes, and human liver was analyzed. PCR amplification yielded 8-11 putative myosins (depending on the cDNA source) representing six distinct myosin classes. Analysis of clones obtained by hybridization screening demonstrated that the original PCR products correspond to bona fide myosins, based on the presence of sequences highly conserved in other myosins. RNase protection analysis confirmed mRNA expression of 11 myosins in Caco-2BBe cells. Immunoblot analysis showed that at least 6 myosin immunogens are expressed in Caco-2BBe cells. The results reveal the existence of at least 11 unconventional human myosin genes, most of which are expressed in an overlapping fashion in different cell types. The abundance of myosins suggests that the myosin I vs. myosin II paradigm is inadequate to explain actin-based cellular motility. 相似文献
10.
Subclinical adrenocortical insufficiency in renal amyloidosis 总被引:1,自引:0,他引:1
In order to investigate the functional significance of possible adrenal amyloid infiltration in patients with renal amyloidosis, we performed corticotrophin stimulation tests in 15 patients having renal amyloidosis with no clinical evidence of adrenocortical insufficiency and 12 controls. In 7 of the patients, the cortisol increments obtained during the test were found to be consistent with primary adrenal insufficiency due to possible amyloid infiltration of the adrenal cortex; in contrast, in all control subjects, adrenal responses to the test were regarded as sufficient for proper adrenal function. 相似文献