首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   312篇
  免费   75篇
  国内免费   9篇
耳鼻咽喉   4篇
儿科学   10篇
妇产科学   2篇
基础医学   17篇
口腔科学   5篇
临床医学   71篇
内科学   71篇
皮肤病学   17篇
神经病学   11篇
特种医学   85篇
外科学   30篇
综合类   7篇
现状与发展   1篇
预防医学   20篇
眼科学   2篇
药学   9篇
肿瘤学   34篇
  2024年   4篇
  2023年   24篇
  2022年   5篇
  2021年   5篇
  2020年   16篇
  2019年   5篇
  2018年   15篇
  2017年   20篇
  2016年   20篇
  2015年   10篇
  2014年   18篇
  2013年   14篇
  2012年   5篇
  2011年   2篇
  2010年   12篇
  2009年   11篇
  2008年   4篇
  2007年   10篇
  2006年   2篇
  2005年   8篇
  2004年   5篇
  2003年   5篇
  2002年   3篇
  2001年   2篇
  2000年   3篇
  1999年   5篇
  1998年   16篇
  1997年   6篇
  1996年   4篇
  1995年   7篇
  1994年   19篇
  1993年   10篇
  1992年   7篇
  1991年   3篇
  1990年   3篇
  1989年   12篇
  1988年   9篇
  1987年   8篇
  1986年   5篇
  1985年   7篇
  1984年   11篇
  1983年   6篇
  1982年   5篇
  1981年   5篇
  1980年   7篇
  1979年   1篇
  1978年   3篇
  1977年   3篇
  1976年   2篇
  1975年   4篇
排序方式: 共有396条查询结果,搜索用时 29 毫秒
351.
Lewis  BD; Enzmann  DR; Guthaner  DF; Brody  WR 《Radiology》1984,151(3):789-790
Intravenous digital subtraction angiography was used to obtain a complete aortofemoral runoff examination of high diagnostic quality in a single patient session in eight patients. Using a 9-inch (22.9-cm) image intensifier, oblique and posteroanterior projections were obtained from the level of the aortic bifurcation to the tibial artery trifurcation. This technique is based upon the administration of one-half of the usual dose of contrast agent combined with a high frame-rate imaging technique and postacquisition integration to increase the signal-to-noise ratio. It is easily performed on an outpatient basis, lowers patient risk, and allows a significant savings of time, film, and cost compared with the conventional intra-arterial aortofemoral runoff examination.  相似文献   
352.
HIV-1 Gag、Tat、Rev和Nef蛋白特异性的免疫应答   总被引:1,自引:0,他引:1  
目的:探讨中国HIV/AIDS患者HIV—1 Gag、Tat、Rev和Nef蛋白特异性CTL应答的特征。方法:应用覆盖HIV-1 B、C亚型Gag、Tat、Rev和Nef蛋白的220个肽段作为抗原,通过ELISPOT方法俭测HIV/AIDS患者HIV特异性CTL应答。结果:无沦HIV—1 B亚型还是HIV-1C亚型所构建肽库的应答强度和频率,主要集中在Gag和Nef蛋白,Tat和Rev蛋白也有不同程度的应答。HIV—1 B、C亚型间应答比较,整体应答强度大致相同,但免疫优势区间存在着一定的差异,B亚型Gagp24亚蛋白的288~313氨基酸区应答最强,而C亚型Gagp24亚蛋白的155~181氨基酸区应答最强;两个亚型免疫优势区应答频率最高的都是Nef蛋白106~143氨基酸区(48.1%)。结论:中国人群CTL应答多集中在Gag和Nef蛋白,B、C业型间略有差异且存在交叉识别,这对设计针对中国人群的HIV疫苗是有重要的意义。  相似文献   
353.
三年来我室TDM室间质评结果回顾   总被引:1,自引:0,他引:1  
目的:对我室3年来TDM室间质评估结果的准确性作一个客观的评价,同时分析存在的问题及产生这些问题的原因。方法:对我室3年来参加室间质评的茶碱,苯妥英,地高辛3个监测品种的平均成绩进行纵向及横向对比,分析。结果;茶碱和苯妥英成绩较好,地高辛成绩呈逐年上升的趋势。结论;通过采取一系列有效措施后,我的治疗药物监测可成为临床用药较为可靠的参考。  相似文献   
354.
The enigma of arsenic carcinogenesis: role of metabolism   总被引:14,自引:4,他引:10  
Inorganic arsenic is considered a high-priority hazard, particularly because of its potential to be a human carcinogen. In exposed human populations, arsenic is associated with tumors of the lung, skin, bladder, and liver. While it is known to be a human carcinogen, carcinogenesis in laboratory animals by this metalloid has never been convincingly demonstrated. Therefore, no animal models exist for studying molecular mechanisms of arsenic carcinogenesis. The apparent human sensitivity, combined with our incomplete understanding about mechanisms of carcinogenic action, create important public health concerns and challenges in risk assessment, which could be met by understanding the role of metabolism in arsenic toxicity and carcinogenesis. This symposium summary covers three critical major areas involving arsenic metabolism: its biodiversity, the role of arsenic metabolism in molecular mechanisms of carcinogenesis, and the impact of arsenic metabolism on human risk assessment. In mammals, arsenic is metabolized to mono- and dimethylated species by methyltransferase enzymes in reactions that require S-adenosyl- methionine (SAM) as the methyl donating cofactor. A remarkable species diversity in arsenic methyltransferase activity may account for the wide variability in sensitivity of humans and animals to arsenic toxicity. Arsenic interferes with DNA methyltransferases, resulting in inactivation of tumor suppressor genes through DNA hypermethylation. Other studies suggest that arsenic-induced malignant transformation is linked to DNA hypomethylation subsequent to depletion of SAM, which results in aberrant gene activation, including oncogenes. Urinary profiles of arsenic metabolites may be a valuable tool for assessing human susceptibility to arsenic carcinogenesis. While controversial, the idea that unique arsenic metabolic properties may explain the apparent non-linear threshold response for arsenic carcinogenesis in humans. In order to address these outstanding issues, further efforts are required to identify an appropriate animal model to elucidate carcinogenic mechanisms of action, and to define dose-response relationships.   相似文献   
355.
356.
Lymphangiomas are benign tumors resulting from a congenital lymphatic malformation in infant and children. Most common sites are head, neck and axilla, and scrotal lymphangioma is very rare. Lymphangiomas are classified as capillary, cavernous, and cystic type and cystic type is most common. Complete surgical excision is definitive treatment and incomplete excision leads to local recurrence. We report a case of scrotal lymphangioma in 68‐year‐old male patient. Gray‐scale sonography revealed multiseptated, hypoechoic mass abutting the upper pole of the normal right testis. Color Doppler sonography showed no remarkable blood flow in the mass. MRI demonstrated multispetated extratesticular and extraepididymal mass in the right scrotum. Surgical excision was performed and the histopathologic diagnosis was a cystic lymphangioma. In conclusion when multiseptated cystic scrotal mass was discovered in an elderly patient, scrotal lymphangioma should be included in differential diagnosis. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound 2009  相似文献   
357.
Background: White‐to‐white corneal measurement is used frequently in cataract and refractive surgery as well as in diagnosing various corneal diseases and monitoring congenital glaucoma. In this article, we determine agreement in horizontal corneal diameter measurements in normal eyes among the Galilei V4.01, the EyeSys and the Orbscan IIz. Methods: In this prospective study, 37 consecutive volunteers were enrolled. All 74 eyes were measured with all three devices. Galilei, EyeSys and Orbscan II measurements were compared with one another. In addition, the data from the right and left eyes were compared for each device. Results: The mean horizontal corneal diameter measurements with the Galilei, the EyeSys and the Orbscan II were 12.01 ± 0.61 mm, 12.09 ± 0.87 mm and 11.67 ± 0.29 mm, respectively. The difference between the Galilei and EyeSys systems was not statistically significant (p = 0.76), however, the Orbscan II showed smaller measurements (p < 0.001). The best 95% limits of agreement between devices were for the Galilei and the Orbscan II (‐0.72, 1.48; r = 0.4, p < 0.01). The best 95% limits of agreement between two eyes for each device were found with the Orbscan II (‐0.15, 0.17; r = 0.996, p < 0.01). There was no correlation between measurements of right and left eyes for the Galilei or the EyeSys (r = 0.274, p = 0.176 and r = 0.31, p = 0.065, respectively). Conclusions: These results suggest that measurements made with the Orbscan II are smaller than those obtained with the EyeSys Corneal Analysis system and the Galilei. Among the three devices, the Galilei and the Orbscan II showed the best agreement, however, it is inadvisable to use the three devices interchangeably in every clinical situation.  相似文献   
358.
We performed an analysis of prospectively-acquired cross sectional data on 106 Parkinson disease (PD) patients who underwent comprehensive neuropsychological testing and the Unified Parkinson Disease Rating Scale (UPDRS) motor scale. A significant correlation between the UPDRS motor and neuropsychological tests in all cognitive domains except for general intelligence and visuo-spatial function was seen. In this study, cognitive decline within this PD cohort correlated with motor impairment but not disease duration. Our findings suggest that overall cognitive impairment (except visuospatial dysfunction) may track motor progression in PD more than duration of disease. Longitudinal studies are needed to confirm our results.  相似文献   
359.
Rabies is a communicable disease that is almost always fatal. In its classic form, rabies is well recognized, but cases presenting with a paralytic illness mimic Landre's Guillain–Barre syndrome and in such cases the diagnosis remains in doubt. This problem is further compounded when the history of dogbite is not forthcoming. At autopsy rabies can be diagnosed by subjecting fresh tissue to virologic investigations or examining formalin‐fixed paraffin‐embedded tissue sections for the presence of characteristic inclusions; that is, the Negri bodies. However, these inclusions are not present in all cases. Hence, the need arises for a better method for diagnosis. The present study utilized immunohistochemistry as a diagnostic tool using both monoclonal and polyclonal antirabies antibodies in 20 cases of rabies encephalomyelitis. The diagnosis of rabies could be confirmed in 17 cases (85%) based on neuropathologic findings alone. In contrast, immunohistochemistry yielded positive results in all cases. Moreover, the amount of rabies viral antigen was much more abundant than could be expected from the histopathologic findings. Thus immunohistochemistry is a rapid, safe, sensitive and specific technique for the diagnosis of rabies.  相似文献   
360.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号