全文获取类型
收费全文 | 1762篇 |
免费 | 78篇 |
国内免费 | 20篇 |
专业分类
耳鼻咽喉 | 12篇 |
儿科学 | 29篇 |
妇产科学 | 38篇 |
基础医学 | 229篇 |
口腔科学 | 28篇 |
临床医学 | 281篇 |
内科学 | 434篇 |
皮肤病学 | 9篇 |
神经病学 | 245篇 |
特种医学 | 100篇 |
外科学 | 178篇 |
综合类 | 5篇 |
预防医学 | 62篇 |
眼科学 | 13篇 |
药学 | 123篇 |
中国医学 | 6篇 |
肿瘤学 | 68篇 |
出版年
2023年 | 4篇 |
2022年 | 17篇 |
2021年 | 22篇 |
2020年 | 5篇 |
2019年 | 19篇 |
2018年 | 20篇 |
2017年 | 17篇 |
2016年 | 36篇 |
2015年 | 34篇 |
2014年 | 58篇 |
2013年 | 66篇 |
2012年 | 120篇 |
2011年 | 150篇 |
2010年 | 67篇 |
2009年 | 64篇 |
2008年 | 106篇 |
2007年 | 100篇 |
2006年 | 111篇 |
2005年 | 120篇 |
2004年 | 105篇 |
2003年 | 83篇 |
2002年 | 79篇 |
2001年 | 39篇 |
2000年 | 27篇 |
1999年 | 31篇 |
1998年 | 34篇 |
1997年 | 31篇 |
1996年 | 32篇 |
1995年 | 27篇 |
1994年 | 31篇 |
1993年 | 18篇 |
1992年 | 23篇 |
1991年 | 14篇 |
1990年 | 24篇 |
1989年 | 9篇 |
1988年 | 31篇 |
1987年 | 10篇 |
1986年 | 17篇 |
1985年 | 13篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1967年 | 2篇 |
1925年 | 2篇 |
排序方式: 共有1860条查询结果,搜索用时 15 毫秒
1.
2.
J Stolk M I M Versteegh L J Montenij M E Bakker E Grebski M Tutic S Wildermuth W Weder M el Bardiji J H C Reiber K F Rabe E W Russi B C Stoel 《The European respiratory journal》2007,29(6):1138-1143
To explore if change in the extent of emphysema correlated with change in lung function, the effect of resection of emphysematous tissue was studied by computed tomography (CT) densitometry. In addition, the current authors studied how surgery-induced change in emphysema related to lung density in control subjects. In total, 30 patients (14 females; mean+/-sd age 59+/-10 yrs) with severe emphysema before and 3 months after lung volume reduction surgery (LVRS), 48 patients with moderate emphysema and 76 control subjects were investigated. Lung density (15th percentile point) of both lungs and heterogeneity of lung density between 12 isovolumetric partitions in each lung were calculated from chest CT images. The 15th percentile point and its heterogeneity could distinguish controls from subjects with moderate emphysema with a sensitivity and specificity of >95%. LVRS significantly increased lung density by 5.0+/-10.9 g.L(-1) (n=30). Improvement in the diffusing capacity of the lung for carbon monoxide and in residual volume significantly correlated with an increase in lung density (n=20 and 28, respectively). Change in forced expiratory volume in one second did not correlate with change in lung density. In conclusion, lung density 15th percentile point is a valuable surrogate marker for detection of both the extent of and reduction in emphysema. 相似文献
3.
4.
5.
6.
Treatment of End-Stage Renal Disease in Central and Eastern Europe: Overview of Current Status and Future Needs 总被引:2,自引:0,他引:2
Bolesaw Rutkowski Aleksandru Ciocalteu Ljubica Djukanovic Istvan Kiss Aleksander Kovac Momir Polenakovic Zvonimir Puretic Rafail Rozental Maria Stanaityte Irina Tareyeva Vladimir Teplan Jeff Zavitz Krivoshiev Stefan & Kveder Rado 《Artificial organs》1998,22(3):187-191
The situation of end-stage renal disease (ESRD) patients in central and eastern Europe was very poor for many years during the so called socialistic era. Economical and political liberation resulted in the significant growth of renal replacement facilities in this region. The number of hemodialysis units increased significantly (56%) during the period 1990–1996, and the number of patients treated with this modality has risen by 75%. More dramatic progress was achieved in peritoneal dialysis. The number of units performing this method of renal replacement therapy (RTT) increased by 277% and the number of patients by more than 300%. Not only quantitative but also qualitative changes were observed. More modern hemodialysis machines installed in the vast majority of units allow for the performance of bicarbonate dialysis, controlled ultrafiltration, and sodium profile modeling. Also, a wider choice of biocompatible dialyzers has become available during the last few years. The number of centers performing renal transplantation has increased significantly, but the number of renal transplants has not followed this progress. Despite all the progress, further development of all RRT methods is necessary to achieve acceptance rates comparable to those observed in developed countries. 相似文献
7.
Neuropathogenesis of Chimeric Simian/Human Immunodeficiency Virus infection In Pig-tailed and Rhesus Macaques 总被引:2,自引:0,他引:2
Ravi Raghavan Edward B Stephens Sanjay V Joag Istvan Adany David M Pinson Zhuang Li Fenglan Jia Manisha Sahni Chunyang Wang Kevin Leung Larry Foresman Opendra Narayan 《Brain pathology (Zurich, Switzerland)》1997,7(3):851-861
We recently reported that a chimeric simian/human immunodeficiency virus (SHIVKU-1 ) developed in our laboratory caused progressive depletion of CD4+ T lymphocytes and AIDS within 6 months of inoculation into pig-tailed macaques (M.nemestrina). None of the pig-tailed macaques showed productive SHIV infection in the central nervous system (CNS). In this report, we show that by further passage of the pathogenic virus in rhesus macaques [M. mulatta], we have derived a new strain of SHIV (SHIVKU-2 ) that has caused AIDS and productive CNS infection in 3 of 5 rhesus macaques infected with the virus. Productive replication of SHIV in the CNS was clearly shown by high infectivity titers and p27 protein levels in brain homogenates, and in 2 of the 3 rhesus macaques this was associated with disseminated, nodular, demyelinating lesions, including focal multinucleated giant cell reaction, largely confined to the white matter. These findings were reminiscent of HIV-1 associated neurological disease, and our immunohistochemical and in situ hybridization data indicated that the neuropathological lesions were associated with the presence of SHIV-specific viral antigens and nucleic acid respectively. However, the concomitant reactivation of opportunistic infections in these macaques suggested that such pathogens may have influenced the replication of SHIV in the CNS, or modified the neuropathological sequelae of SHIV infection in the rhesus species, but not in pig-tailed macaques. Our findings in the two species of macaques highlight the complexities of lentiviral neuropathogenesis, the precise mechanisms of which are still elusive. 相似文献
8.
Role of endogenous cannabinoids in synaptic signaling 总被引:32,自引:0,他引:32
Research of cannabinoid actions was boosted in the 1990s by remarkable discoveries including identification of endogenous compounds with cannabimimetic activity (endocannabinoids) and the cloning of their molecular targets, the CB1 and CB2 receptors. Although the existence of an endogenous cannabinoid signaling system has been established for a decade, its physiological roles have just begun to unfold. In addition, the behavioral effects of exogenous cannabinoids such as delta-9-tetrahydrocannabinol, the major active compound of hashish and marijuana, await explanation at the cellular and network levels. Recent physiological, pharmacological, and high-resolution anatomical studies provided evidence that the major physiological effect of cannabinoids is the regulation of neurotransmitter release via activation of presynaptic CB1 receptors located on distinct types of axon terminals throughout the brain. Subsequent discoveries shed light on the functional consequences of this localization by demonstrating the involvement of endocannabinoids in retrograde signaling at GABAergic and glutamatergic synapses. In this review, we aim to synthesize recent progress in our understanding of the physiological roles of endocannabinoids in the brain. First, the synthetic pathways of endocannabinoids are discussed, along with the putative mechanisms of their release, uptake, and degradation. The fine-grain anatomical distribution of the neuronal cannabinoid receptor CB1 is described in most brain areas, emphasizing its general presynaptic localization and role in controlling neurotransmitter release. Finally, the possible functions of endocannabinoids as retrograde synaptic signal molecules are discussed in relation to synaptic plasticity and network activity patterns. 相似文献
9.
Attila Patocs Peter Gergics Katalin Balogh Miklos Toth Ferenc Fazakas Istvan Liko Karoly Racz 《BMC medical genetics》2008,9(1):29
Von Hippel-Lindau disease (VHL) is a rare autosomal dominant disease characterized by development of cystic and tumorous lesions
at multiple sites, including the brain, spinal cord, kidneys, adrenals, pancreas, epididymis and eyes. The clinical phenotype
results from molecular abnormalities of the VHL tumor suppressor gene, mapped to human chromosome 3p25-26. The VHL gene encodes two functionally active VHL proteins due to the presence of two translational initiation sites separated by
53 codons. The majority of disease-causing mutations have been detected downstream of the second translational initiation
site, but there are conflicting data as to whether few mutations located in the first 53 codons, such as the Pro25Leu could
have a pathogenic role. In this paper we report a large Hungarian VHL type 2 family consisting of 32 members in whom a disease-causing
AGT80AAT (Ser80Ile) c.239G>A, p.Ser80Ile mutation, but not the concurrent CCT25CTT (Pro25Leu) c.74C>T, p.Pro25Leu variant
co-segregated with the disease. To our knowledge, the Ser80Ile mutation has not been previously described in VHL type 2 patients
with high risk of pheochromocytoma and renal cell cancer. Therefore, this finding represents a novel genotype-phenotype association
and VHL kindreds with Ser80Ile mutation will require careful surveillance for pheochromocytoma. We concluded that the Pro25Leu
variant is a rare, neutral variant, but the presence such a rare gene variant may make genetic counseling difficult. 相似文献
10.
Follicle stimulating hormone measured in unextracted urine throughout the menstrual cycle correlates with age and ovarian reserve 总被引:3,自引:0,他引:3
Oosterhuis GJ Vermes I Michgelsen HW Schoemaker J Lambalk CB 《Human reproduction (Oxford, England)》2002,17(3):641-646
BACKGROUND: A method was previously described to measure FSH reliably in unextracted urine. The aim of the current study was to establish the course of FSH measured in urine throughout the cycle. METHOD: Daily urinary FSH (uFSH) concentrations were determined in 14 regularly menstruating volunteers aged 23-39 years during one complete menstrual cycle. RESULTS: In each subject, mean daily uFSH measured in urine, as gold standard for FSH tone, correlated significantly with FSH in early follicular phase fixed to menstruation on cycle day 3 (r = 0.75, P = 0.002), or fixed to ovulation 9 days before the pre-ovulatory FSH surge (r = 0.87, P = 0.0001), or when selected as being the highest follicular phase value (r = 0.91, P = 0.0001). Age correlated significantly with mean daily uFSH (r = 0.67, P = 0.009), highest follicular phase uFSH (r = 0.60, P = 0.024), uFSH on cycle day 3 (r = 0.80, P = 0.0006), and uFSH 9 days before FSH surge (r = 0.65, P = 0.0016). The uFSH was also measured on cycle day 3 in 104 IVF patients in a cycle prior to pituitary down-regulation. The uFSH correlated significantly with numbers of follicles (P = 0.02) and oocytes (P = 0.024). CONCLUSION: It is concluded that cycle day 3 uFSH is a good reflection of the mean uFSH of the complete cycle, and there is a highly significant correlation between uFSH and age and ovarian reserve. Measurement of FSH in urine on cycle day 3 seems to be a reliable and non-invasive tool for determining ovarian reserve in IVF. 相似文献