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   165篇
  免费   9篇
  国内免费   2篇
儿科学   1篇
基础医学   20篇
临床医学   13篇
内科学   28篇
皮肤病学   1篇
神经病学   7篇
特种医学   27篇
外科学   21篇
综合类   2篇
预防医学   5篇
眼科学   17篇
药学   12篇
中国医学   1篇
肿瘤学   21篇
  2023年   1篇
  2022年   3篇
  2021年   1篇
  2020年   1篇
  2019年   2篇
  2017年   2篇
  2016年   3篇
  2015年   3篇
  2014年   5篇
  2013年   8篇
  2012年   6篇
  2011年   17篇
  2010年   6篇
  2009年   2篇
  2007年   8篇
  2006年   6篇
  2005年   3篇
  2004年   8篇
  2003年   5篇
  2002年   4篇
  2001年   8篇
  2000年   5篇
  1999年   5篇
  1998年   5篇
  1997年   7篇
  1996年   5篇
  1995年   2篇
  1994年   5篇
  1993年   3篇
  1992年   5篇
  1991年   1篇
  1990年   1篇
  1989年   3篇
  1988年   3篇
  1987年   5篇
  1986年   3篇
  1985年   3篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1981年   2篇
  1980年   1篇
  1979年   1篇
  1978年   1篇
  1977年   2篇
  1975年   3篇
排序方式: 共有176条查询结果,搜索用时 15 毫秒
31.
32.
8名男性健康志愿者po阿米替林100 mg后,以阿米替林及其3种代谢物的血浓度曲线下面积(AUC0)计算阿米替林的脱甲基化代谢及羟基化代谢能力。结果提示个体间阿米替林及其3种代谢物的AUC差异很大。其中7名志愿者测定异喹呱羟化代谢表型,6例为异喹呱强代谢者,1例为弱代谢者。尿中异喹呱的羟化代谢率与阿米替林的羟基化代谢率、阿米替林和10-羟基阿米替林的AUC0呈显著相关。阿米替林总血浆清除率与异喹呱羟化代谢率呈弱相关。此结果表明阿米替林和异喹呱的羟化代谢可能由同一酶控制,阿米替林的羟基化代谢和脱甲基化代谢可能为两个独立的代谢途径。  相似文献   
33.
BACKGROUND: There is now much data that suggest a relationship between angiogenesis and breast cancer prognosis. Angiogenesis is a multistep process resulting from an ordered set of events and regulated by positive and negative modulators of microvessels growth and by the expression of various proteolytic enzymes. MATERIALS AND METHODS: We prospectively evaluated VEGF and microvessels density on tumor specimen and cytosolic levels of uPA and PAI-1. RESULTS: We enrolled 81 primary breast cancer patients. The median follow-up was 38 months. Using the median value as cutoff for the statistical analysis, we found significant correlation between cytosolic levels of uPA and PAI-1 (r = 0.61; p < .0001), between VEGF and steroid hormone receptor status (p = .01), between PAI-1 and tumor grading (p = .009), and between uPA and tumor size greater than 1 cm (p = .04). With respect to the prognosis, we observed a significant correlation between low uPA levels and RFS and an unforeseen, direct correlation between high VEGF values and better RFS. CONCLUSIONS: Our preliminary results indicate that the cytosolic level of uPA at diagnosis may be predictive of early relapse in primary breast cancer.  相似文献   
34.
Langerhans cell histiocytosis (LCH) is a myeloid neoplasm characterized by a clonal proliferation of CD1a+/CD207+ dendritic cells. Although individuals of any age can be affected, the disease is most common in infants younger than 5 years of age, especially males. A wide range of manifestations, from asymptomatic to aggressive, have been described, along with multiorgan involvement. Even though the majority of bone lesions are observed, skin, lymph nodes, brain and lungs can also be involved. The involvement of hematopoietic system, including bone marrow, liver and spleen, is less frequent yet associated with worse prognosis, due to a worse treatment response. Diagnosis of LCH is based on the integration of clinical, laboratory, and radiological data; however, only histopathological examination might confirm it. As far as the spleen involvement is concerned, according to literature, it has been reported in about 15% patients with multisystem involvement, nonetheless only a few cases show parenchymal lesions. The present study reports the case of an infant with LCH with multisystem involvement, including bone, skin, liver, and spleen, with evidence of parenchymal lesions.  相似文献   
35.
Solitary bronchioloalveolar carcinoma: CT criteria   总被引:14,自引:0,他引:14  
The computed tomographic (CT) scans of 30 patients with solitary bronchioloalveolar carcinoma were reviewed. Common features at CT included the peripheral or subpleural location of a pulmonary mass (25 cases), pseudocavitation (18 cases), heterogeneous attenuation (17 cases), irregular margins forming a star pattern (22 cases), and pleural tags (21 cases). Using these CT criteria, four independent observers attempted to identify cases of bronchioloalveolar carcinoma from a larger sample of lung cancers and benign lesions by categorizing a series of test cases into four probability categories. Although the bronchioloalveolar carcinomas were correctly ranked in the two highest probability categories 75% of the time (in 45 of 60 cases), there was considerable overlap with other lung lesions, particularly with adenocarcinoma and large cell undifferentiated carcinoma. However, even though the typical features of bronchioloalveolar carcinoma are not invariable or highly specific, they are characteristic enough to suggest the diagnosis.  相似文献   
36.
37.
A new class of radio frequency (RF) coils for magnetic resonance (MR) imaging and spectroscopy is introduced. The coils consist of two loop-gap resonators of equal diameters positioned along a common axis. They are tuned to the mode in which the current in the two loops flows in opposite directions. These coils are "decoupled" from a uniform excitation field of arbitrary orientation (including circularly polarized fields) by intrinsic decoupling and by means of back-to-back fast recovery diodes. Measurements made with the coils and a phantom saline tank indicate that the signal-to-noise ratio obtainable with these coils is almost identical to that obtained with single loops. Imaging of several anatomic areas, including knee, wrist, and shoulder, has been performed with a 1.5-T MR system that uses circularly polarized RF. A small series of patients with torn rotator cuffs underwent imaging. Difficulties in establishing the diagnosis with MR imaging because of anatomic complexity are illustrated. The value of pulse sequences with long repetition times to increase the signal intensity of fluid in the joint is shown.  相似文献   
38.

Introduction and hypothesis

We present a simple approach to the marsupialization of a Skene’s gland cyst.

Methods

Our technique facilitates suture placement to exteriorize the cyst wall to efficiently treat a distal Skene’s gland cyst and reduce the risk of recurrence.

Conclusion

Marsupialization is an accepted option for the surgical management of Skene’s gland cyst. This technique is an effective and streamlined approach to Skene’s gland marsupialization.
  相似文献   
39.

Background

There is increased reliance on traditional herbal medicines by several millions of people worldwide, especially in West Africa and Nigeria in particular. This is due to escalating cost of good quality drugs and consequent proliferation of faked cheaper drugs. However, non standardization of production and handling methods have resulted in herbal medicines with varying quality and safety indices, thus resulting in possible public health concerns. This work investigated the microbial load and aflatoxin levels in herbal medicines from selected states in Nigeria.

Materials and Methods

A total of 210 samples obtained from various renowned herbal medicine practitioners from some selected states in Nigeria, based on their medicinal uses, were analyzed to determine the microbial load by the plate count method and aflatoxin contamination levels using thin layer chromatography with aflatoxin standards.

Results

At least six bacterial genera (Bacillus, Pseudomonas, Salmonella, EPEC, EHEC, Streptococcus and other coliforms) and 6 fungal genera (Aspergillus, Penicillium, Rhizopus, Cladosporium, Geotricum and Candida) were isolated. Aflatoxin B1, B2 and G1 were detected in varying concentrations in the samples analyzed, with an average occurrence of 18.6%. Some of these herbal concoctions were found to contain unacceptably high bioload, according to WHO standards.

Conclusion

Microbial contamination and the presence of aflatoxins in herbal medicines appear to be an endemic problem in Nigeria, as observed in this work, probably due to poor observation of basic hygiene during preparations and poor storage conditions. The findings in this work may serve in developing and instituting public health standards for the production and safety of herbal remedies in Nigeria.  相似文献   
40.
The performance of two computer programs, DEREK and TOPKAT, was examined with regard to predicting the outcome of the Ames bacterial mutagenicity assay. The results of over 400 Ames tests conducted at Glaxo Wellcome (now GlaxoSmithKline) during the last 15 years on a wide variety of chemical classes were compared with the mutagenicity predictions of both computer programs. DEREK was considered concordant with the Ames assay if (i) the Ames assay was negative (not mutagenic) and no structural alerts for mutagenicity were identified or (ii) the Ames assay was positive (mutagenic) and at least one structural alert was identified. Conversely, the DEREK output was considered discordant if (i) the Ames assay was negative and any structural alert was identified or (ii) the Ames assay was positive and no structural alert was identified. The overall concordance of the DEREK program with the Ames results was 65% and the overall discordance was 35%, based on over 400 compounds. About 23% of the test molecules were outside the permissible limits of the optimum prediction space of TOPKAT. Another 4% of the compounds were either not processable or had indeterminate mutagenicity predictions; these molecules were excluded from the TOPKAT analysis. If the TOPKAT probability was (i) > or =0.7 the molecule was predicted to be mutagenic, (ii) < or =0.3 the compound was predicted to be non-mutagenic and (iii) between 0.3 and 0.7 the prediction was considered indeterminate. From over 300 acceptable predictions, the overall TOPKAT concordance was 73% and the overall discordance was 27%. While the overall concordance of the TOPKAT program was higher than DEREK, TOPKAT fared more poorly than DEREK in the critical Ames-positive category, where 60% of the compounds were incorrectly predicted by TOPKAT as negative but were mutagenic in the Ames test. For DEREK, 54% of the Ames-positive molecules had no structural alerts and were predicted to be non-mutagenic. Alternative methods of analyzing the output of the programs to increase the accuracy with Ames-positive compounds are discussed.  相似文献   
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