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   527篇
  免费   13篇
  国内免费   6篇
耳鼻咽喉   2篇
儿科学   3篇
妇产科学   1篇
基础医学   98篇
口腔科学   2篇
临床医学   20篇
内科学   138篇
皮肤病学   1篇
神经病学   113篇
特种医学   7篇
外科学   57篇
综合类   1篇
预防医学   15篇
药学   45篇
中国医学   1篇
肿瘤学   42篇
  2023年   2篇
  2022年   10篇
  2021年   8篇
  2020年   6篇
  2019年   7篇
  2018年   9篇
  2017年   4篇
  2016年   7篇
  2015年   9篇
  2014年   6篇
  2013年   8篇
  2012年   19篇
  2011年   31篇
  2010年   17篇
  2009年   18篇
  2008年   34篇
  2007年   37篇
  2006年   46篇
  2005年   37篇
  2004年   27篇
  2003年   33篇
  2002年   31篇
  2001年   6篇
  2000年   10篇
  1999年   10篇
  1998年   8篇
  1997年   5篇
  1996年   6篇
  1995年   4篇
  1994年   5篇
  1993年   6篇
  1992年   8篇
  1991年   4篇
  1990年   4篇
  1989年   4篇
  1988年   3篇
  1987年   2篇
  1986年   3篇
  1985年   5篇
  1984年   11篇
  1982年   5篇
  1981年   6篇
  1980年   8篇
  1979年   4篇
  1977年   2篇
  1976年   2篇
  1967年   1篇
  1963年   1篇
  1959年   1篇
  1956年   1篇
排序方式: 共有546条查询结果,搜索用时 15 毫秒
1.
Background: Gastrointestinal stromal tumors (GIST) are one of the most common mesenchymal tumors of the gastrointestinal tract. GIST are defined by positive immunohistochemical staining for KIT or CD34 and thus are generally diagnosed after surgery. Because small GIST are rarely diagnosed before surgery, the clinical course of these small tumors is not clear. The aim of the present study was to follow changes in size and configuration of small GIST that were pathologically confirmed using endoscopic ultrasonography‐guided fine‐needle aspiration biopsy (EUS‐FNAB). Methods: Between July 1997 and December 2003, 16 tumors in 16 patients (10 men and 6 women) with an immunohistochemical diagnosis of GIST were regularly followed in our hospital. The median patient age when EUS‐FNAB was performed was 62 years (range 26–82 years) and the median follow‐up period was 4.9 years (range 0.5–9.6 years). Results: Fourteen tumors showed no remarkable changes in size and shape during follow up compared with the initial diagnosis. Two tumors enlarged: one tumor approximately doubled its diameter in 8 years and the other tumor increased from 1.8 cm at diagnosis to up to 10 cm after only 2 years. Doubling time of the latter tumor was calculated as 3.1 months. Conclusions: We conclude that EUS‐FNAB might be a good modality for final diagnosis of GIST without surgery, and that GIST without rapid growth on follow up can be endoscopically followed.  相似文献   
2.
We describe a case of a large bronchial fistula and empyema after right upper lobectomy that was treated successfully with open window thoracostomy followed by a latissimus dorsi myocutaneous flap and limited thoracoplasty. A latissimus dorsi myocutaneous flap can provide immediate airtight closure of a large bronchial fistula, allowing lavage and curettage of the empyema cavity to reduce the chance of postoperative infection. An important aspect of this technique is that the deepithelialized skin side rather than muscle is sutured to an opening of the bronchus. As compared with other techniques, a latissimus dorsi myocutaneous flap is superior in that it requires a single incision and does not require an intraop-erative change of position. In addition, the technique causes little dysfunction of the chest and shoulder and preserves the vascular supply to ensure the viability of the flap even if it was divided in a previous operation.  相似文献   
3.
While there have been many reports of the significant role of cytoplasmic free calcium ion in myocardial injury, these have been carried out in multicellular preparations. Since cell injury may occur inhomogeneously, it is necessary to observe the 'history' of an individual myocyte in order to investigate the detailed role of the calcium ion in the process of myocardial injury. We have observed the natural history of individual myocytes isolated from the left ventricle of rats with respect to changes in shape and cytoplasmic free calcium concentration ([Ca2+]i) measured with fura-2. We can discriminate four phases in the time course of cell deterioration. In the first phase (phase O), the myocyte is rod shaped, quiescent and responsive to electrical stimulation. The [Ca2+]i is stable. In the next phase (Phase 1), once initiated, the myocyte exhibits an asynchronous wavy contraction and gradually decreases in length. The [Ca2+]i gradually increases with some fluctuation. Phase 2 is characterized by rapid development of contracture with a marked increase in [Ca2+]i. In the period following establishment of contracture (Phase 3), changes in [Ca2+]i vary from cell to cell, possibly because of leakage of the dye caused by loss of cell membrane integrity. Our results indicate that, during naturally occurring cell deterioration, loss of [Ca2+]i control at the membrane of the sarcoplasmic reticulum precedes contracture and catastrophic increase in [Ca2+]i.  相似文献   
4.
Abstract: Two autopsied female sibling cases of sudanophilic leukodystrophy are reported. Case A and case B were the second and third of seven siblings, and a sister and a brother died from severe progressive neurological disease with similar symptoms. Consanguineous marriages were noted in the family of both cases through the past three generations. Case A gradually developed intellectual deterioration and tetraplegia at the age of 29, progressed to akinetic mutism within one year and thereafter survived for 14 years. Neuropathologically, a severe atrophy and degeneration were noted in the white matter of the whole cerebrum, sparing the subcortical U-fibers. Myelin and axons were severely damaged with peripheral astrocytic gliosis. Case B developed similar clinical symptoms at the age of 20 and survived for 7 years in the state of akinetic mutism. Similar postmortem findings as those of case A were found in the white matter of the cerebrum with formation of sudanophilic breakdown products and with thick fibrillary gliosis. The pyramidal tract was completely degenerated. There was no accumulation of abnormal lipid in the brains of both cases.  相似文献   
5.
Summary Physicochemical properties of two types of adriamycin preparation, suspensions and emulsions prepared for i.a. chemotherapy of hepatocellular cacinoma, were investigated. A suspension was prepared by dispersing adriamycin directly into the lipid contrast medium, Lipiodol, whereas an emulsion was obtained by emulsifying an aqueous solution of adriamycin into Lipiodol. The dispersibility of the drug in each preparation was examined microscopically. The chemical stability of and drug release from the preparation were determined by high-performance liquid chromatography and spectrophotometry, respectively. The suspension was then given to ten patients with primary hepatocellular carcinoma. The suspension maintained good dispersibility without coagulation of drug particles, whereas coalescence of aqueous droplets and the resultant phase separation occurred 4 h after preparation of the emulsion. Both preparations maintained the initial drug content for at least 1 week at room temperature. The release of adriamycin was more prolonged in the suspension than in the emulsion. After i.a. administration of the suspension, a selective accumulation of Lipiodol in the tumor and decrease in serum -fetoprotein (AFP) levels were found in most patients. A significant amount of adriamycin was still detected in hepatic speciments resected from two patients 1 and 2 months after treatment. These findings suggest that the adriamycin-Lipiodol suspension may be a useful preparation for targeting chemotherapy to hepatocellular carcinoma.  相似文献   
6.
Summary In this investigation, 83 human mammary carcinomas were examined for the expression of oestrogen receptor (ER), epidermal growth factor receptor (EGF-R), epidermal growth factor (EGF), transforming growth factor alpha (TGF-), c-erbB-2, histological grade, mitotic index and nodal status, all of which are reportedly prognostically significant factors (Bloom and Richardson 1957; Baak et al. 1985; Wright et al. 1989). ER expression was biochemically recognized in 43.4% of mammary carcinomas, and EGF-R, EGF, TGF- and c-erbB-2 were histochemically recognized in 25.3, 14.5, 27.7 and 18.0% of mammary carcinomas examined respectively, using conventional sections of buffered formalin-fixed, paraffin-embedded tissue and monoclonal or polyclonal antibodies. There were significant relationships between negative ER and positive EGF-R or TGF-; positive EGF-R and TGF-; positive EGF-R and c-erbB-2; and positive c-erbB-2 and TGF-. The single changes which were the negative ER and the positive c-erbB-2 correlated with histological grade and mitotic index. Co-expression of EGF-R and TGF- correlated with positive nodal status. Therefore, the present investigation indicates that the negative ER, single expression of c-erbB-2 and co-expression of EGF-R and TGF- are important markers which contribute indirectly to prognosis, which reconfirms previous findings on the former two while adding the new finding that immuno-histochemical demonstration of expression of EGF-R and TGF- may provide useful information for selecting the appropriate treatment.  相似文献   
7.
New thermotropic, liquid-crystalline polyesters ( 5a, b, 6a, b ) with mesogenic bipyridinediyl units were synthesized. They form complexes with Fe(II) and Cu(II) salts. Homopolyesters 5a, b , containing no metal or less than a certain amount of metal, are smectic. A nematic mesophase was observed in the case of copolyester 6a, b . The structural properties of a polyester complex 5a with Cu, as crystal, liquid-crystal and isotropic liquid, were examined by ESR.  相似文献   
8.
A number of studies have observed associations between the serotonin 2A (5-HT2A) receptor and mental disorders. Here, we investigated correlations between polymorphisms (-1438G/A and 102T/C) of the 5-HT2A gene and personality traits in healthy Japanese volunteers (n = 239). The personality traits were evaluated using the Revised NEO Personality Inventory (NEO PI-R). The -1438G/A and 102T/C were in complete linkage disequilibrium. There was a tendency for associations between the genotype and the scores for Agreeableness, Conscientiousness and Neuroticism of the NEO PI-R (P = 0.028, 0.039 and 0.062, respectively; analysis of variance, uncorrected for multiple testing). Subjects with the A/A of -1438G/A (or T/T of 102T/C) appeared to be lower in Neuroticism and higher in Conscientiousness than the rest of the subjects. However, the results were statistically non-significant after Bonferroni's correction for multiple testing of the five scales of the NEO PI-R. Thus, the present study provided no evidence for statistically significant associations between the 5-HT2A polymorphisms and the personality traits.  相似文献   
9.
BackgroundIntraoperative identification of small pulmonary nodules has been an important technical issue. We aimed to develop a new localization method which is much safer and simple procedure compared with conventional methods.MethodsThis was a retrospective study including patients with resected peripheral pulmonary nodules between November 2017 and April 2021 at Teikyo University School of Medicine, and Saitama Cardiovascular and Respiratory Center. All surgical procedure was wedge resection, and the tumor size was equal to or less than 20 mm which were detected by cone-beam computed tomography (CBCT; Philips Allura Xper FD 20, Philips). Some metal clips were put on several places of visceral pleura, where the target lesion was sandwiched by marking clips (sandwich marking technique). CBCT detected both the target lesion and metal clips, and video-assisted thoracoscopic surgery (VATS) was performed. Radiological and pathological findings were analyzed, and the correlation coefficient of tumor size was examined among pre-, intra-, and post-operative tumor sizes.ResultsThe average age of 90 patients was 65.2 years, and 47 were male (52.2%). All procedure was wedge resection including twelve bi-wedge resections, and one hundred nine peripheral pulmonary lesions were obtained by sandwich marking technique. The detection rate was 100%, and there was no marking-related complication.ConclusionsAll small peripheral pulmonary lesions were successfully detected and resected by using CBCT with no marking-related complication. Sandwich marking technique was demonstrated to provide safe, reliable, and simple localization procedure for small peripheral pulmonary lesions.  相似文献   
10.
The color reaction between partially saponified poly(vinyl acetate), (P-PVAc), which is dissolvable in water and iodine-iodide was investigated in the presence of amylose. As the concentration of amylose increases, the absorbance at λmax = 488 nm of the red-violet complex between P-PVAc and iodine-iodide decreases and, on the other hand, the absorbance at λmax = 625 nm of the blue complex between amylose and iodine-iodide increases. The equation for the relationship between the decrease in the red-violet complex and the increase in the blue complex was derived. On the basis of this equation, the molar absorption coefficient per iodine molecule at λmax = 625 nm for the blue complex of amylose with iodine-iodide was found to be 3,68·104 l mol?1 cm?1 at 15°C.  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