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   8554篇
  免费   510篇
  国内免费   106篇
耳鼻咽喉   101篇
儿科学   130篇
妇产科学   152篇
基础医学   892篇
口腔科学   292篇
临床医学   696篇
内科学   2560篇
皮肤病学   115篇
神经病学   757篇
特种医学   295篇
外国民族医学   1篇
外科学   1542篇
综合类   23篇
一般理论   1篇
预防医学   375篇
眼科学   113篇
药学   411篇
中国医学   8篇
肿瘤学   706篇
  2024年   14篇
  2023年   149篇
  2022年   275篇
  2021年   503篇
  2020年   291篇
  2019年   340篇
  2018年   391篇
  2017年   276篇
  2016年   317篇
  2015年   328篇
  2014年   435篇
  2013年   496篇
  2012年   693篇
  2011年   630篇
  2010年   342篇
  2009年   329篇
  2008年   456篇
  2007年   425篇
  2006年   412篇
  2005年   347篇
  2004年   262篇
  2003年   240篇
  2002年   168篇
  2001年   86篇
  2000年   88篇
  1999年   85篇
  1998年   46篇
  1997年   35篇
  1996年   33篇
  1995年   35篇
  1994年   27篇
  1992年   56篇
  1991年   36篇
  1990年   32篇
  1989年   51篇
  1988年   37篇
  1987年   41篇
  1986年   40篇
  1985年   28篇
  1984年   20篇
  1983年   17篇
  1979年   29篇
  1978年   19篇
  1976年   13篇
  1974年   21篇
  1973年   20篇
  1972年   16篇
  1969年   21篇
  1967年   14篇
  1966年   12篇
排序方式: 共有9170条查询结果,搜索用时 15 毫秒
991.
The objective of the present study was to prospectively evaluate relationships linking age, respiratory function and locomotor function in 29 outpatients with late-onset Pompe's disease and to retrospectively determine clinical outcomes. Using univariate regression analysis, vital capacity (VC) was weakly, but significantly, correlated to shoulder motility, Walton score and lower-limb Modified Medical Research Council score. Six patients were able to walk without a walking aid and with only the help of a handrail on the stairs (Walton score=3), although VC was <50%. No parameters were significantly correlated with age. As assessed retrospectively, VC and locomotion deteriorated over time in most patients. In contrast, among the 16 patients started on invasive or noninvasive ventilation with VC monitoring, eight had a VC increase at the first measurement time-point. The absence of correlation with age and the presence, in some patients, of severe respiratory insufficiency without severe limb girdle muscle weakness indicate that respiratory function should be monitored independently from the degree of peripheral muscle weakness. Mechanical ventilation and tracheostomy may improve vital capacity and should, therefore, be taken into account when evaluating treatments for the adult form of Pompe's disease.  相似文献   
992.
993.
994.
OBJECTIVES: This observational study evaluated the clinical and angiographic outcomes of patients with aorto-ostial coronary artery disease treated with sirolimus-eluting stents (SESs) or with bare metal stents (BMSs). BACKGROUND: The safety and effectiveness of SESs for the treatment of aorto-ostial lesions have not been demonstrated. METHODS: We identified 82 consecutive patients who underwent percutaneous coronary interventions in 82 aorto-ostial lesions using the SES (32 patients) or BMS (50 patients) and compared the two groups of patients. The incidence of major adverse cardiac events (MACE), including death or Q-wave myocardial infarction (MI), target lesion revascularization (TLR), and target vessel revascularization (TVR), were recorded in-hospital and at a 10-month follow-up. RESULTS: All stents were implanted successfully. There were no statistically significant differences regarding major in-hospital complications between the two groups. At 10-month follow-up, two (6.3%) patients in the SES group and 14 (28%) patients in the BMS group underwent TLR (p = 0.01); MACE were less frequent in the SES group compared to the BMS group (19% vs. 44%, p = 0.02). Angiographic follow-up showed lower binary restenosis rates (11% vs. 51%, p = 0.001) and smaller late loss (0.21 +/- 0.31 mm vs. 2.06 +/- 1.37 mm, p < 0.0001) in the SES group. CONCLUSIONS: The main finding of our study is that, compared to the BMS, implantation of the SES in aorto-ostial lesions appears safe and effective, with no increase in major in-hospital complications and a significant improvement in restenosis and late event rates at 10-month follow-up.  相似文献   
995.
OBJECTIVES: The aim of this study was to assess the feasibility of using electrode temperature, impedance, and power to predict and thereby potentially prevent steam pops during cooled radiofrequency (RF) ablation. BACKGROUND: When myocardial temperature reaches 100 degrees C during RF catheter ablation, steam explosions are seen. Saline-cooled RF ablation reduces temperatures at the electrode-tissue interface, but excessive intramyocardial heating still may occur. METHODS: In anesthetized swine, 26 cooled RF applications were made in the right and left atria while observing with intracardiac echocardiography (ICE). Power delivery was increased gradually until a steam explosion was seen or a maximum output of 50 W was reached. RESULTS: ICE identified steam explosions in 21 RF applications. Steam explosions were associated with a large impedance increase, >25 Omega in only three cases, whereas small increases <10 Omega (mean 5.3 +/- 2.6 Omega) occurred in 18 cases. Mean electrode temperature at the time of steam explosion was 43.6 degrees C +/- 5.3; 18 of 21 explosions occurred when temperature reached >/=40 degrees C. Mean power and impedance drop were similar for applications with and without steam explosions. Five steam explosions were associated with a sudden drop in electrode temperature. CONCLUSIONS: Steam explosions are common when cooled electrode temperature exceeds 40 degrees C and are not predictable from power or impedance drop. Small impedance rises and sudden drops in measured electrode temperature indicate possible steam formation. Maintaining cooled electrode temperature <40 degrees C during RF likely will reduce the risk of steam explosions.  相似文献   
996.
997.
998.
999.

Purpose

Invasive aspergillosis (IA) represents a major cause of morbidity and mortality in immunocompromised patients. Involvement of the gastrointestinal tract by Aspergillus is mostly reported as part of a disseminated infection from a primary pulmonary site and only rarely as an isolated organ infection.

Methods

We report a case of small bowel perforation due to IA in a patient with acute leukemia under chemotherapy and pulmonary aspergillosis. We performed a systematic review of the literature as well.

Results

A 43-year-old man with acute myeloid leukemia under chemotherapy developed severe neutropenia and pulmonary aspergillosis due to Aspergillus flavus. He developed melena and hemodynamic failure and a contrast-enhanced ultrasound scan suggested active intestinal bleeding. During emergency laparotomy we found multiple intestinal abscesses, several perforations of intestinal loop and Aspergillus flavus was isolated from the abscesses. Resection of the jejunum was performed. The patient received voriconazole and finally recovered. The patient is now alive and in complete disease remission. From literature review we found 35 intestinal IA previously published in single case reports or small case series as well.

Conclusion

Clinical manifestations of gastrointestinal aspergillosis are nonspecific, such as abdominal pain, and only occasionally it presents as an acute abdomen. Antemortem detection of bowel involvement is rarely achieved and, only in cases of complicated gastrointestinal aspergillosis, the diagnosis is achieved thanks to the findings during surgery. Gastrointestinal aspergillosis should be suspected in patients with severe and prolonged neutropenia with or without pulmonary involvement in order to consider the right therapy and prompt surgery.
  相似文献   
1000.
BACKGROUND/AIMS: Surgery has appeared to induce lymphocytopenia and this decrease in host defenses during postoperative period could promote both the proliferation of possible micrometastases and the implantation of surgically disseminated tumor cells. The aim of this study is to evaluate if the preoperative subcutaneous injection of IL-2 (interleukin-2) may be able to abrogate surgery-induced immunosuppression in radically operable gastric cancer and to assess its toxicity. METHODOLOGY: This phase II study included 39 consecutive patients with histologically proven gastric adenocarcinoma (M/F 26/13; mean age 68; range 48-82) who underwent radical surgery from October 1999 to December 2000. Patients were randomized to be treated with surgery alone as controls (20 patients) or surgery plus preoperative treatment with recombinant human IL-2 (19 patients). IL-2 was administered subcutaneously, at a dose of 9,000,000 IU, for three consecutive days, followed by surgery within 36 hours from IL-2 withdrawal. We considered the total lymphocyte count and lymphocyte subset (CD4, CD4/CD8) during the preoperative period, before IL-2 administration, and on the 14th and 50th day. RESULTS: Two groups were well matched for type of surgery and extent of disease. All the patients underwent radical surgery plus D2 lymphadenectomy. At baseline, there were no significant differences in total lymphocyte and lymphocyte subsets between groups. The control group showed a significant decrease of total lymphocytes, CD4 cells, and CD4/CD8 ratio at the 14th postoperative day relative to the baseline value. Among the 22 patients evaluated in the control group 13 had a decreased of CD4 under 500 cells/mm3 (65%). Instead in the IL-2 group a significant increase was observed over the control group values of total lymphocytes and CD4 cells (14th ly total and CD4: IL-2 vs. control p<0.05). Moreover in this group only 3 patients had CD4 under 500 cells/mm3 (15%). This difference in CD4 count, is significant at the 50th postoperative day too (p=0.006). No anesthesiologic or surgical complication was seen in IL-2 treated group, with low grade of toxicity (WHO grade:1): the main effect was fever (14/19) easily manageable, with no cardiovascular complications. Furthermore, IL-2 group showed lower postoperative complications (p<0.05) and higher lymphocyte/eosinophil infiltration into the tumor (p<0.002). CONCLUSIONS: This phase II study would suggest that a preoperative immunotherapy with IL-2 is a well tolerated treatment able to prevent surgery induced lymphocytopenia. IL-2 seems to neutralize the immunosuppression induced by operation and so to stimulate the host reaction against tumor tissue (lymphocytes/eosinophils infiltration). Next randomized clinical trials could investigate the prognostic impact of IL-2 on the clinical course.  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