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   1792篇
  免费   104篇
  国内免费   7篇
耳鼻咽喉   24篇
儿科学   40篇
妇产科学   25篇
基础医学   240篇
口腔科学   88篇
临床医学   129篇
内科学   477篇
皮肤病学   50篇
神经病学   126篇
特种医学   93篇
外科学   161篇
综合类   7篇
预防医学   57篇
眼科学   54篇
药学   178篇
中国医学   3篇
肿瘤学   151篇
  2023年   20篇
  2022年   45篇
  2021年   74篇
  2020年   35篇
  2019年   63篇
  2018年   74篇
  2017年   45篇
  2016年   43篇
  2015年   40篇
  2014年   74篇
  2013年   76篇
  2012年   113篇
  2011年   139篇
  2010年   73篇
  2009年   65篇
  2008年   106篇
  2007年   124篇
  2006年   96篇
  2005年   83篇
  2004年   100篇
  2003年   85篇
  2002年   80篇
  2001年   30篇
  2000年   22篇
  1999年   26篇
  1998年   18篇
  1997年   9篇
  1996年   10篇
  1995年   6篇
  1994年   4篇
  1993年   6篇
  1992年   12篇
  1991年   13篇
  1990年   6篇
  1989年   7篇
  1988年   4篇
  1987年   10篇
  1986年   8篇
  1984年   5篇
  1982年   3篇
  1981年   3篇
  1979年   3篇
  1978年   5篇
  1975年   4篇
  1974年   6篇
  1972年   4篇
  1971年   5篇
  1970年   4篇
  1967年   3篇
  1966年   3篇
排序方式: 共有1903条查询结果,搜索用时 31 毫秒
1.
International Journal of Clinical Oncology - The practice of cancer diagnosis disclosure to children has been changed with the times. The regulations of clinical trials in the 2000s might change...  相似文献   
2.
3.
Platinum (Pt) levels were determined in various tissues and body fluids obtained from a patient who died 181 days after cisplatin overdosing. The symptoms of cisplatin overdose, however, might have almost disappeared by day 40, and the patient’s death was ascribed to the recurrence of malignant lymphoma. Determination of Pt derived from cisplatin was performed by electrospray ionization mass spectrometry (ESI-MS) using silver (Ag) as internal standard. Pt and Ag complexed with diethyldithiocarbamate (DDC) in wetashed blood, and tissue solutions were extracted into isoamyl alcohol, and then acidified with oxalic acid. By injecting an aliquot of the isoamyl alcohol layer into a mass spectrometer in the direct flow injection mode, the quantitation was performed using the signals of Pt(DDC)3 + and Ag(DDC)2 + at m/z 639 and 403, respectively. The Pt levels ranged from 25ng/ml in blood to 2050ng/g wet weight in the liver of the patient, indicating that Pt remained at high levels in tissues, even after a period as long as 181 days after cisplatin overdosing.  相似文献   
4.
Objective.To identify the clinicopathological and chemoresistant factors predicting the response to neoadjuvant chemotherapy and the patient prognosis in high-risk cervical carcinomas.Methods.We retrospectively reviewed 47 patients with locally advanced or bulky cervical carcinoma treated with two courses of intraarterial infusion of cisplatin, doxorubicin, mitomycin C, and 5-fluorouracil (5-FU), followed by radical hysterectomy at our hospital between 1988 and 1995. Expressions of the chemoresistance-related proteins, such as P-glycoprotein, glutathioneS-transferase π (GST-π), and proliferating cell nuclear antigen (PCNA) in the tumor cells, were examined by immunohistochemistry using pretreatment biopsy specimens. These results were compared with the chemotherapeutic response, which was evaluated by magnetic resonance imaging (MRI) and histopathology. Outcome of the patients was also studied.Results.Chemotherapeutic effect of either complete (CR) or partial (PR) response on MRI was obtained in 36 of the 47 (86%) patients. Poor response to chemotherapy was significantly correlated with P-glycoprotein expression (P< 0.005) and low PCNA labeling (P< 0.05), but not GST-π expression in the tumor cells. Independent prognostic factors for patient survival were parametrial involvement and lymph node metastasis. Neither the expression of GST-π nor PCNA was correlated with the patient survival.Conclusion.Assessment of the expression of P-glycoprotein and PCNA is potentially useful for the prediction of tumor response to neoadjuvant chemotherapy for cervical carcinomas.  相似文献   
5.
BACKGROUND AND PURPOSE.: Heme-proteins, besides causing renal tubular obstruction, maycontribute to rhabdomyolysis-induced renal injury through aheme-iron-mediated lipid peroxidation process. In the presentstudy, we compared the combined therapy of a lipid peroxidationinhibitor, 21-aminosteroid (21-AS) and fluid-alkaline-mannitol(FAM) diuresis with either of them alone to determine the efficacyof the combination therapy and to delineate the roles of lipidperoxidation and cast formation. METHODS AND RESULTS.: Employing Raman spectroscopy, we confirmed in vitro the abilityof 21-AS to inhibit iron-induced fatty acid peroxidation. 21-ASwas then administered to rats developing renal failure fromglycerol-induced rhabdomyolysis. Although 21-AS inhibited rhabdomyolysis-inducedplasma and renal lipid peroxidation, renal protection was incomplete.Administration of FAM to inhibit cast formation afforded a betterrenal protection. However, when these therapies were combinedto inhibit both lipid peroxidation and cast formation, therewas a synergistic renal functional protection. This was accompaniedby a maximum inhibition of renal and plasma lipid peroxidation,as well as, renal tubular necrosis and cast formation. Comparedto combination therapy, FAM therapy alone, despite identicalvolume, was accompanied by a higher tubular necrosis and castformation. CONCLUSIONS.: That combining a lipid peroxidation inhibitor with fluid-alkalinediuresis in rhabdomyolysis further lowers renal lipid peroxidation,tubular necrosis and cast formation and synergistically limitsrenal dysfunction (i) supports a role for lipid peroxidationin the pathophysiology of rhabdomyolysis ARF, (ii) underscoresthe role of intratubular heme retention, a cause for tubularobstruction as well a source for prodigious amount of iron,likely involved in the lipid peroxidation, and (iii) raisesthe possibility of interactions between non-oxidant and oxidantmechanisms.  相似文献   
6.
A case of small round and spindle cell sarcoma with neuronal differentiation and oncocyte-like features is presented. The tumor was encountered in a 32 year old Japanese woman with an initial presentation of palpable tumor in the left lateral region of the thorax. The resected tumor was a partially well encapsulated whitish medullary one and consisted of small round and spindle tumor cells, together with so-called rhabdoid cells in the small round cell area. Although pseudorosettes were often observed, true rosette formation could not be detected anywhere. Ultrastructurally, despite a histologic variety of tumor cells, most tumor cells possessed numerous mitochondria, some of which occasionally contained abnormal filamentous or crystalloid structures. Various amounts of microfilaments were present in most tumor cells and microtubules were present in a few. A minority of small round cells possessed a small number of neurosecretory granules, especially in short cytoplasmic processes. A positive immunoreaction for neuron specific enolase was found by immunohistochemical examination in several small round tumor cells and for neurofilaments in lesser numbers. Despite the lack of S-100 protein, MB2 was detected in both small round and spindle cells. On the basis of these findings, the tumor of the present case corresponds to malignant peripheral nerve sheath tumor with neuronal differentiation and oncocytic features.  相似文献   
7.
A goal of systems biology is to build a concrete biochemical network map, which provides an important instruction to trace the pathways of interest or to understand the mechanism of a biological system. In the postgenomic era, not only the concrete biochemical maps, but also postgenomic maps (mRNA coexpression and protein-protein interaction networks) have been extensively produced. In the biochemical map, the individual reactions are reliable, but the number of the reactions is limited, because molecular biology requires extensive experiments to verify them. By contrast, postgenomic data provide much information regarding interactions, but are coarse-grained. To expand the biochemical network, an intuitional approach, which superposes postgenomic data on the map one by one, has been carried out, but it is not effective when a large amount of the coarse-grained data is handled. In order to effectively integrate such postgenomic interactions into a biochemical map, a statistical approach would be suitable rather than intuition. In this article, we proposed a novel statistical approach that integrates postgenomic interaction networks into the biochemical network, predicting novel pathways. A statistical correlation for such different types of networks identifies functional modules; subsequently the superposition of the different networks on the functional modules predicts inter-modular relations, which are the key pathways to construct a large-scale biochemical network.  相似文献   
8.
Extraskeletal myxoid chondrosarcoma arising from the retroperitoneum   总被引:1,自引:0,他引:1  
A case of extraskeletal myxoid chondrosarcoma is presented. The tumor occurred in the retroperitoneum and systemic metastases were found at autopsy. The primary and metastatic tumors were soft and strikingly myxoid on gross appearance. Microscopic observation revealed undifferentiated malignant tumor having large amounts of myxoid substance and a small amount of well-differentiated chondrosarcoma element in the primary lesions. The authors obtained an immunohistochemical result that the tumor cells showed positivity for alpha-1-antitrypsin and alpha-1-antichymotrypsin. Regarding S-100 protein, the well-differentiated chondrosarcoma element revealed intense positivity, whereas the poorly differentiated myxoid areas were not positive except for a few tumor cells. This is the first case, to our knowledge, of extraskeletal myxoid chondrosarcoma arising from the retroperitoneum, and immunohistologic findings suggest that alpha-1-antitrypsin and alpha-1-antichymotrypsin may be available markers in poorly differentiated chondrosarcomas showing a negative reaction for S-100 protein.  相似文献   
9.
A case of the clear cell variant of hepatocellular carcinoma with an abundant myxoid stroma is presented. The tumor occurred in a 55-year-old Japanese man, and swelling of the scrotum was the initial symptom. The patient underwent high-level orchiectomy, and the pathologic diagnosis was a metastatic tumor on the surface of the processus vaginalis and intact testis. Extensive examination failed to show a primary site. Subsequent autopsy revealed a large hepatic tumor and metastatic nodules with a prominent myxoid appearance in multiple organs. Histologically, each tumor consisted of uniform small tumor cells with clear cytoplasm attributed to abundant accumulation of glycogen particles, and an abundant myxoid stroma was also present. The tumor cells were positive for keratin, alpha 1-antitrypsin, alpha 1-antichymotrypsin, liver ferritin, prealbumin, and fibrinogen, but lacked alpha-fetoprotein. These findings indicated that this case was hepatocellular carcinoma of the clear cell type with a prominent myxoid stroma.  相似文献   
10.
We report six cases of carcinoma showing sarcomatous change in the urinary tract examined by conventional histochemistry and immunohistochemistry. All of the cases were transitional cell carcinoma with or without focal squamous cell carcinoma. Sarcomatous components resembling spindle cell sarcoma with a marked myxoid stroma or chondrosarcomatous element were also observed in all cases. The sarcomatous elements were closely associated with the areas of squamous cell carcinoma in three cases. Various histochemical staining procedures demonstrated mesenchymal features in the stroma of sarcomatous areas. By immunohistochemical examination, the epithelial components showed positive reactions for keratin, epithelial membrane antigen and, focally, carcinoembryonic antigen. The sarcomatous components revealed a positive immunoreaction for keratin but lacked other epithelial markers in all cases. Chondrosarcomatous elements in two cases were positive for both keratin and S-100 protein. These findings indicate that sarcomatous elements in carcinoma may represent mesenchymal metaplasia with partial or complete loss of epithelial features. However, further study will be necessary in order to determine whether heterogeneous elements, such as chondrosarcomatous areas, are epithelial or truly mesenchymal in origin.  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