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   1713篇
  免费   88篇
  国内免费   29篇
耳鼻咽喉   8篇
儿科学   86篇
妇产科学   26篇
基础医学   248篇
口腔科学   50篇
临床医学   103篇
内科学   424篇
皮肤病学   26篇
神经病学   66篇
特种医学   91篇
外科学   299篇
综合类   15篇
预防医学   68篇
眼科学   12篇
药学   84篇
中国医学   8篇
肿瘤学   216篇
  2023年   9篇
  2022年   12篇
  2021年   25篇
  2020年   19篇
  2019年   26篇
  2018年   22篇
  2017年   17篇
  2016年   30篇
  2015年   31篇
  2014年   50篇
  2013年   46篇
  2012年   95篇
  2011年   97篇
  2010年   69篇
  2009年   52篇
  2008年   113篇
  2007年   138篇
  2006年   108篇
  2005年   140篇
  2004年   134篇
  2003年   134篇
  2002年   146篇
  2001年   23篇
  2000年   20篇
  1999年   27篇
  1998年   44篇
  1997年   34篇
  1996年   23篇
  1995年   24篇
  1994年   15篇
  1993年   26篇
  1992年   22篇
  1991年   9篇
  1990年   11篇
  1989年   11篇
  1988年   7篇
  1987年   3篇
  1986年   2篇
  1985年   1篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
  1978年   2篇
  1976年   1篇
  1969年   3篇
  1967年   2篇
  1966年   1篇
  1964年   1篇
排序方式: 共有1830条查询结果,搜索用时 31 毫秒
101.
A 61-year-old male patient had esophageal carcinoma with multiple mediastinal and right supraclavicular lymph node metastases. Chemotherapy consisting of infusion of nedaplatin and continuous infusion of 5-fluorouracil was performed. After three courses of the chemotherapy, the patient was treated with a combination of cisplatin and 5-FU and radiotherapy. However, only radiotherapy was performed after 18 Gy because of grade 3 leukocytonenia during the chemoradiotherapy. The patient achieved a partial response (nearly complete response) for 9 months after the initiation of the treatment. In conclusion, chemotherapy with NDP and 5-FU followed by chemoradiotherapy is effective and safe for patients with esophageal carcinoma with multiple lymph node metastases.  相似文献   
102.
We report a case in which weekly paclitaxel (TXL) administration was effective for gastric cancer with malignant ascites. TXL (80 mg/m2) was infused over 1 hour after short premedication on an outpatient basis. Administration was continued for 3 weeks followed by 1 week rest. The patient was a 49-year-old woman who suffered from non-resectable gastric cancer, staged intraoperatively as having severe lymph node metastasis and malignant ascites. As an outpatient treatment, she was first treated with 5-fluorouracil combined with high-dose Leucovorin for 4 cycles. However, she complained of abdominal fullness and ascites, and received weekly TXL administration as the second line treatment. The ascites had completely disappeared 3 months after administration. The toxic events were anemia (grade 1) and alopecia (grade 2). No major adverse effects such as hypersensitivity reaction, leukopenia or peripheral neuropathy were observed.  相似文献   
103.
BACKGROUND AND PURPOSE: Although digital subtraction angiography (DSA) is considered the criterion standard for depiction of intracranial aneurysms, it is often difficult to determine the relationship of overlapping vessels to aneurysms when using 2D DSA. We compared 2D and 3D DSA in evaluation of intracranial aneurysms. METHODS: Thirty-six consecutive patients with cerebral aneurysms underwent 2D and 3D DSA. After standard 2D DSA, rotational DSA was performed. Maximum intensity projection (MIP) and shaded surface display (SSD) images were created from the rotational DSA data sets. All images were assessed randomly for overall image quality, presence of aneurysm, presence of aneurysmal lobulation, visualization of aneurysmal neck, and relationship to adjacent vessels. Data analysis was conducted for 40 aneurysms treated by clip placement. RESULTS: One aneurysm that was not detected at 2D DSA was classified as uncertain on the basis of rotational DSA. All aneurysms were classified as probably or definitively present on the basis of MIP and SSD findings. Overall image quality of rotational DSA, MIP, and SSD was statistically inferior to that of the standard 2D DSA for visualization of distal arteries. However, MIP and SSD images were significantly superior to those of standard 2D DSA for all other evaluations. For detection of lobulation, SSD images were significantly superior to other images, and for visualization of aneurysmal neck and relationship to neighboring arteries, SSD images were significantly superior to those of rotational DSA. For evaluation of the relationship to neighboring arteries, MIP images were significantly superior to those of rotational DSA. CONCLUSION: Three-dimensional DSA, especially SSD, provided more detailed information for evaluating cerebral aneurysms than did standard 2D and rotational DSA.  相似文献   
104.
PURPOSE: Primary non-Hodgkin's lymphoma (LY) and anaplastic carcinoma (AC) of the thyroid gland are rare malignant tumors, and the initial symptoms of these diseases are very similar. The aim of our study was to compare the characteristics of the two diseases using computed tomographic (CT) scans in order to make an accurate differential diagnosis. MATERIALS AND METHODS: Ten patients with LY and 10 with AC were analyzed. Differences in the CT findings of the two diseases were evaluated before treatment and statistically tested with either Student's t-test or the chi-square test. RESULTS: In the analysis of characteristics of CT imaging, the existence of calcification and necrosis, and heterogeneous tumor were dominant findings in AC, and there was a statistically significant difference in frequency between the two diseases (p < 0.01). Calcification detected in AC was usually multiple and/or gross (mean size: phi8.2 mm). All lymphadenopathies were delineated as having the same homogeneous attenuation as the tumors in the thyroid gland in LY, but were shown as irregular rim enhancement in AC. CONCLUSION: The CT features of the two diseases are characteristic in terms of calcification, necrosis, and tumor composition. Evaluation by means of CT imaging is useful in distinguishing between LY and AC.  相似文献   
105.
PURPOSE: The authors retrospectively reviewed CT findings of unilateral proximal interruption of the pulmonary artery in eight adults. METHODS: Patient age ranged from 23 to 65 years (mean, 44 years), and three men and five women (six left-side affected and two right-side affected) comprised the study group. High resolution CT was obtained in five patients. Associated anomalies of great vessels included five cases of right aortic arch and one tetralogy of Fallot. RESULTS: On the affected side, complete defects of pulmonary arteries were seen in all patients. CT revealed serrated pleural thickening in six patients (75%), subpleural parenchymal bands in five (63%), and mosaic attenuation in three (38%) on the affected lung. Dilatation of bronchial arteries in five patients (71%), internal thoracic arteries in four (57%), and intercostal arteries in three (43%) were also seen. As for other parenchymal changes, cystic bronchiectasis and honeycombing were seen in two (25%) respective cases. On the unaffected lung, mosaic attenuation was seen in four (50%) patients. CONCLUSIONS: The main manifestations of unilateral proximal interruption of the pulmonary artery were complete defects of pulmonary arteries, enlarged bronchial arteries, and formed pleural thickening or some parenchymal changes of the lung.  相似文献   
106.
A service information system using the Internet, which connected the various people who are related to medical treatment and nursing welfare, was constructed. An intractable neurological disease patient who lives in the Onga district, Fukuoka, Japan, and the people who are related to the service were chosen as test users in an experimental model. The communicated service information was divided into open-use data (electronic bulletin board, welfare service, medical care service, and link to private company service home page) and closed-use data (the individual patient's hysterics). The open data server was installed in an Internet service provider The open data could be accessed not only by the patient, but also by the family, information center, companies, hospitals, and nursing commodity store related to patient's nursing and medical treatment. Closed data server was installed in an information center (public health center). Only patient and information center staff can access the closed data. Patients should search and collect the service information of various medical and welfare services by themselves. Therefore, services prepared for the patient are difficult to know, and they cannot be sufficiently utilized. With the use of this information system, all usable service information became accessible, and patients could easily use it. The electronic bulletin board system (BBS) was used by patients for knowing each other or each others' family, and was used as a device for exchange of wisdom. Also, the questions for the specialist, such as doctor, dentist, teacher, physical therapist, care manager, welfare office staff member, and public health nurse, and the answers were shown on the BBS. By arranging data file, a reference of various patients in question and answer, which appeared in this BBS, was made as "advisory hints" and was added to the open data. The advisory hints became the new service information for the patients and their family. This BBS discovered the possibility of becoming an important information source for companies, hospital and, administration to know the requirements of patients and their families and the kind of services to be served. Although suppliers provide medical and welfare services for the patient, there is a tendency that the service information is sent by the suppliers at their own convenience. The information system in which various people participated was constructed in order to collect information for the patient, taking a patient-oriented approach. The result of the model test showed that this information system using Internet technology is a good system for both the service supplier and its receiver.  相似文献   
107.
Involvement of prostaglandin E receptor subtype EP(4) in colon carcinogenesis.   总被引:16,自引:0,他引:16  
Accumulating evidence indicates that overproduction of prostanoids attributable to overexpression of cyclooxygenase-2 (COX-2) plays an important role in colon carcinogenesis. We have shown recently that the prostaglandin (PG) E receptor, EP(1), but not EP(3), is involved in mouse colon carcinogenesis. In line with our previous study, here we examined the role of prostanoid receptors in colon carcinogenesis using six additional lines of knockout mice deficient in prostanoid receptors EP(2), EP(4), DP, FP, IP, or TP. The animals were treated with the colon carcinogen, azoxymethane (AOM), and examined for the development of aberrant crypt foci (ACFs), putative preneoplastic lesions in the colon. Formation of ACFs was decreased only in the EP(4)-knockout mice, to 56% of the wild-type level. To confirm these results, we also examined the inhibitory effects of an EP(4)-selective antagonist, ONO-AE2-227, in the diet on the formation of AOM-induced colon ACFs in C57BL/6Cr mice and on the development of intestinal polyps in Min mice. ONO-AE2-227 at a dose of 400 ppm reduced the formation of ACFs to 67% of the control level, and intestinal polyp numbers in Min mice receiving 300 ppm were decreased to 69% of the control level. Plating efficiency assays showed that addition of 1.0 microM ONO-AE1-329, an EP(4)-selective agonist, resulted in a 1.8-fold increase in the colony number of the human colon cancer cell line, HCA-7, similar to the effect of PGE(2). Moreover, EP(4) mRNA expression was clearly observed in normal colon mucosa and colon tumors in mice. Our previous and present results indicate that PGE(2) contributes to colon carcinogenesis through its actions mediated through EP(1) and EP(4) receptors; therefore, antagonists for these two receptors may be good candidates as chemopreventive agents against colon cancer.  相似文献   
108.
Background: In the pathology of autoimmune hepatitis the immunity mechanism of T-helper 1 (Th1) and Th2 cells was recently evaluated. The purpose of the present study was to measure the mRNA levels in peripheral mononuclear cells and serum cytokines obtained from children with autoimmune hepatitis for a better understanding of the mechanism.
Methods: Twenty-five patients with autoimmune hepatitis and seven controls were enrolled. mRNA levels in peripheral mononuclear cells and serum cytokines were measured using real-time polymerase chain reaction and immunoassay.
Results: Serum interferon-γ (IFN-γ) and interleukin-4 (IL-4) were rarely detected. In contrast the IFN-γ/β-actin mRNA levels were high.
Conclusion: Autoimmune hepatitis is a Th1-predominant state, therefore immune modulation therapies that target the control of Th1 cytokines should be used.  相似文献   
109.
Loss of heterozygosity (LOH) on chromosomes 1p, 4q, 5q, 8p, 13q, 16q, 17p, and 22q, and mutation of the p53 gene were simultaneously analyzed in 63 hepatocellular carcinomas (HCCs) with distinct histopathological grades, 80% of the tumors being from patients who had been exposed to hepatitis B virus (HBV) or hepatitis C virus (HCV). The frequencies of LOH on 8 chromosomes were 0–25% in 10 well differentiated HCCs, LOH being observed on 4q, 5q and 17p, 21–53% in 26 moderately differentiated HCCs, LOH on 8p and 17p being high, and 29–75% in 27 poorly differentiated HCCs, LOH on 17p, 4q and 8p heing the most frequent. p53 gene mutation was detected in moderately and poorly differentiated HCCs at 15% and 52%, respectively, but not at all in well differentiated HCCs. Of the mutations detected, 42% were transition mutation and only 5% were CpG transition, in contrast to the high frequencies of these types of mutations in colon tumors (78% and 54%, respectively). LOH on every chromosome and p53 mutation were more frequent in more advanced tumors, and accumulation of genetic changes increased with increase of the histopathological grade. Frequency of genetic changes in HCCs from HBV-positive patients was comparable to that from HCV-positive patients. The present results suggest that accumulation of genetic changes in multiple tumor suppressor genes, especially LOH on 17p, 4q and 8p, and mutation in p53 gene, are involved in the progression of liver cancer, and LOH on 17p and 4q precedes other genetic changes. Differences in the direction of p53 mutation between HCC and colon carcinoma suggest that liver carcinogens are distinct from colon carcinogens. Furthermore, mechanisms affecting the frequency of LOH in HCCs in HBV-infected patients may be similar to those in HCV-infected patients.  相似文献   
110.
In contrast-enhanced 1.5 harmonic imaging sonography, images are obtained in a band intermediate between the fundamental and the 2nd harmonic components. In the present study, we investigated the usefulness of 1.5 harmonic imaging sonography with the use of the contrast agent Levovist for the diagnosis of hepatocellular carcinoma (HCC), metastatic hepatic tumor, and hepatic hemangioma. The subjects in this study were 64 patients with 70 nodules of hepatic tumors (42 nodules in 36 cases of hepatocellular carcinoma, 20 nodules in 20 cases of metastatic hepatic tumor, and 8 nodules in 8 cases of hepatic hemangioma). Contrast enhancement of tumors acquired in the early, portal, and late phases with 1.5 harmonic imaging sonography were compared to classify the tumors. 1.5 harmonic imaging sonography of HCC showed contrast enhancement of 36 nodules (85.7%). Hypervascular enhancement in the early phase, which was maintained in the portal phase, changed to images with no contrast enhancement with partial persistence of contrast enhancement in the late phase. 1.5 harmonic imaging sonography of metastatic hepatic tumor showed hypervascular enhancement of the margin of 20 nodules (100%) in the early and portal phases, which changed to images with no contrast enhancement in the late phase. 1.5 harmonic imaging sonography of hepatic hemangiomas maintained hypervascular enhancement on the tumor margin of 5 nodules (62.5%) in the early and portal phases. When early phase 1.5 harmonic imaging sonography did not show hypervascular enhancement in 3 nodules (37.5%), and late-phase images confirmed that these 3 nodules were hypervascular enhancement on the tumor margin. 1.5 harmonic imaging sonography of hepatic tumors (hepatocellular carcinoma, metastatic hepatic tumor and hepatic hemangioma) provided characteristic findings of contrast enhancement in the early, portal, and late phases, and will contribute to differential diagnosis.  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