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   15561篇
  免费   1011篇
  国内免费   191篇
耳鼻咽喉   219篇
儿科学   352篇
妇产科学   744篇
基础医学   1957篇
口腔科学   267篇
临床医学   1611篇
内科学   3275篇
皮肤病学   380篇
神经病学   950篇
特种医学   554篇
外科学   2398篇
综合类   461篇
现状与发展   2篇
一般理论   3篇
预防医学   777篇
眼科学   292篇
药学   1103篇
中国医学   102篇
肿瘤学   1316篇
  2023年   79篇
  2022年   236篇
  2021年   438篇
  2020年   223篇
  2019年   331篇
  2018年   430篇
  2017年   294篇
  2016年   295篇
  2015年   464篇
  2014年   593篇
  2013年   751篇
  2012年   1112篇
  2011年   1102篇
  2010年   727篇
  2009年   595篇
  2008年   882篇
  2007年   899篇
  2006年   832篇
  2005年   836篇
  2004年   738篇
  2003年   594篇
  2002年   549篇
  2001年   476篇
  2000年   418篇
  1999年   352篇
  1998年   153篇
  1997年   124篇
  1996年   105篇
  1995年   96篇
  1994年   81篇
  1993年   51篇
  1992年   183篇
  1991年   171篇
  1990年   149篇
  1989年   133篇
  1988年   117篇
  1987年   129篇
  1986年   109篇
  1985年   85篇
  1984年   80篇
  1983年   65篇
  1981年   37篇
  1980年   44篇
  1979年   57篇
  1978年   53篇
  1977年   46篇
  1976年   39篇
  1975年   38篇
  1974年   47篇
  1972年   59篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
BACKGROUND: Many publications recommend nonoperative treatment for stable blunt hepatic injury patients. Unstable hemodynamic status is the only indication for surgery. When operation is indicated, controversies exist regarding which operative procedure will be more beneficial to the patients. The purposes of this study are to compare the results of operative and nonoperative management of patients with blunt hepatic injuries and to identify the optimal surgical approach when surgery is indicated. METHODS: Different prospective protocols of treating adult blunt hepatic injuries were conducted. From 1992 to 1993 (group I), urgent surgery would be performed in the presence of hemoperitoneum. The policy shifted to aggressive nonoperative approach between 1996 and 1997 (group II). The patients from each period were divided into three subgroups. Group A included the patients who received nonoperative treatment in either period. Group B consisted of the patients who received surgery in the first period and nonoperative management in the second period. Group C included the patients who were operated on in either group. Comparisons were made between matched groups. RESULTS: Groups IA and IIA patients had minor injuries and could be successfully treated nonoperatively. The results of groups IB and IIB were similar concerning hospital stay, morbidity, and mortality. Transfusion requirements of group IIB patients were significantly higher (2.2 vs. 1.1 units,p = 0.01) than those of group IB. However, 25 (58%) celiotomies of group IB patients were nontherapeutic. When surgery was indicated, group IC patients had significantly higher liver-related mortality (14 of 49 vs. 3 of 55, p = 0.002). Anatomic resection was performed more frequently in that period. CONCLUSION: Nonoperative treatment significantly decreased the rate of nontherapeutic laparotomy but carried the risks of higher transfusion requirements and delaying operation. When surgery was indicated, the policy of minimal intervention positively affected the patients' outcomes. The goal of surgery should be hemorrhage control rather than resection of the injured liver tissues.  相似文献   
82.
BACKGROUND AND PURPOSE: Although chronic inflammatory bowel disease (IBD) is rare in Asian children, increasing numbers of pediatric patients with chronic IBD worldwide have been noted in recent years. This study was conducted to delineate the trend in incidence and clinical patterns of childhood IBD in Taiwan. METHODS: All children admitted to National Taiwan University Hospital (NTUH) between 1979 and 2000 who met the criteria for IBD, Crohn's disease (CD), ulcerative colitis (UC), probable CD (PCD), or indeterminate colitis were included. The clinical features and outcomes were analyzed retrospectively. Incidence was calculated using cases of chronic diarrhea during the same period of time as the risk population. RESULTS: IBD was diagnosed in 17 children (9 females and 8 males, aged 2 months to 18 years) during the study period. Six (35%) of these children had UC, 9 (53%) had CD, and 2 (12%) had PCD. The cumulative incidence of CD during 1979-1995 was 0.85%, and increased to 2.6% during 1996-2000 (p < 0.001), while the incidence of UC did not change significantly between these periods (from 0.85% to 0.99%, p = 0.16). The median interval from onset to diagnosis was 7.7 months. Eighty percent of patients had moderate to severe disease activity at diagnosis. The follow-up duration ranged from less than 1 year to 20 years, with a mean of 4.3 years. Two patients were lost to follow-up. Eighty six percent of patients responded to treatment, and 80% of patients had inactive to mild disease activity when re-evaluated at the end of 2000. CONCLUSION: There has been a marked recent increase in the incidence of childhood CD in Taiwan but the rate of childhood UC has remained unchanged. Eighty percent of cases of childhood IBD responded well to treatment.  相似文献   
83.
Hepatocellular carcinoma (HCC) is one of the most common cancers and is the leading cause of cancer death in Taiwan. Curative surgery is feasible for only about 30% of patients. Transarterial embolization or chemoembolization (TAE/TACE) has been demonstrated to provide a survival benefit compared with supportive care for HCC patients with adequate liver reserves, tumors confined to the liver, and no evidence of portal vein thrombosis. Percutaneous ethanol injection (PEI) may provide long-term disease control if the extent of liver tumors is limited (3 or less in number and less than 3 cm in diameter). The relative efficacy of TAE/TACE, PEI, and other locoregional treatment modalities, such as radiofrequency ablation or cryosurgery, remains unclear. Radiotherapy has been used mostly as a salvage therapy in combination with other locoregional modalities. Despite the incorporation of 3-dimensional conformal technology, radiation-induced liver injury remains an important problem, especially for patients with hepatitis B-related cirrhosis. Systemic therapy is difficult for HCC because of the underlying cirrhosis and accompanying hypersplenism and peripheral cytopenia. HCC is typically resistant to most cytotoxic agents. Biochemical modulation with high-dose tamoxifen may sensitize HCC cells to doxorubicin-induced apoptosis and improve the clinical response to doxorubicin in patients with advanced HCC. Thalidomide, which inhibits angiogenesis induced by vascular endothelial growth factor and basic fibroblast growth factor, can produce a response in some HCC patients. Future research on drug therapy for HCC will focus on identification of tumor-specific targets.  相似文献   
84.
85.
When all conventional treatments for respiratory failure in patients with acute respiratory distress syndrome (ARDS) have failed, extracorporeal membrane oxygenation (ECMO) can provide a chance of survival in these desperately ill patients. A 49-year-old male patient developed septic shock and progressive ARDS after liver abscess drainage. Venovenous ECMO was given due to refractory respiratory failure on postoperative day 6. Initially, two heparin-binding hollow-fiber microporous membrane oxygenators in parallel were used in the ECMO circuit. Twenty-two oxygenators were changed in the first 22 days of ECMO support because of plasma leak in the oxygenators. Each oxygenator had an average life of 48 hours. Thereafter, a single silicone membrane oxygenator was used in the ECMO circuit, which did not require change during the remaining 596 hours of ECMO. The patient's tidal volume was only 90 mL in the nadir and less than 300 mL for 26 days during the ECMO course. The patient required ECMO support for 48 days and survived despite complications, including septic shock, ARDS, acute renal failure, drug-induced leukopenia, and multiple internal bleeding. This patient received an unusually long duration of ECMO support. However, he survived, recovered well, and was in New York Heart Association functional class I-II, with a forced expiratory volume in 1 second of 81% of the predicted level 18 months later. In conclusion, ECMO can provide a chance of survival for patients with refractory ARDS. The reversibility of lung function is possible in ARDS patients regardless of the severity of lung dysfunction at the time of treatment.  相似文献   
86.
BACKGROUND: High tibial osteotomy (HTO) is a well-established treatment for unicompartmental gonarthrosis of the knee, but its durability and complications remain controversial. We previously introduced a novel dome-shaped HTO, and the long-term follow-up results using this technique are analyzed in this study. METHODS: We treated 25 varus knees in 22 patients with medial gonarthrosis, using a specially designed calibrated cutting jig along with rigid external fixation and early joint motion postoperatively. A total of 16 patients (19 knees) completed the study protocol and were followed up for 13-16 years (mean, 15 years). RESULTS: The surgery attempted to obtain 8 degrees valgus; the actual postoperative alignment averaged 12.4 degrees valgus, which decreased significantly to 7.8 degrees valgus after 5 years. The outcome as assessed by the Hospital for Special Surgery knee score was excellent or good in 18 knees at 5 years postoperatively, and in 13 knees at the final follow-up, showing a significant deterioration with time. Loss of correction with time was not correlated with the postoperative alignment achieved: at 5 years, loss greater than 2 degrees was found in 12 knees, but their mean corrected angle (11.8 degrees valgus) was not significantly different from that of the others (13.3 degrees valgus). Nor was the loss of correction correlated with the knee scores. The mean amount of joint motion after surgery did not change significantly with time: 124 degrees preoperatively and 114 degrees at the final follow-up. The patellar position also did not change from preoperative values during postoperative follow-up: mean Insall-Salvati index was 0.88 before and 0.90 5 years after surgery, neither showing patella baja. CONCLUSION: Dome-shaped HTO is a durable time-buying procedure for patients with unicompartmental medial gonarthrosis, and can avoid subsequent development of patella baja that may complicate further prosthetic arthroplasty.  相似文献   
87.
BACKGROUND/PURPOSE: Conventional training in bronchoscopy may increase patient's discomfort and procedure-related morbidity. Computer-based bronchoscopy simulator (CBBS) permits the acquisition and evaluation of the necessary skills through a realistic bronchoscopic experience. This study was conducted to validate the use of a CBBS system developed in Taiwan as a learning and assessment tool. METHODS: Twenty novice bronchoscopists and 10 expert bronchoscopists were enrolled as subjects in this prospective study. The 20 novice bronchoscopists were randomized into two groups, which received conventional bronchoscopic training or CBBS training and then completed a satisfaction survey. Subsequently, the novices who received CBBS training underwent an observational performance trial and the results were compared with those of expert bronchoscopists. All 10 expert bronchoscopists completed a realism survey and observational trial after CBBS performance. RESULTS: The satisfaction survey showed that the CBBS training program significantly increased participants' satisfaction (p = 0.002) and interest in learning (p < 0.001). The realism survey by the 10 expert bronchoscopists indicated that CBBS provides a favorable degree of realism with regard to the mechanical and visual parameters examined. Analysis of the performance results showed that the following parameters were capable of differentiating the participants by level of expertise: total procedure time (p = 0.002), percentage of bronchial segments entered (p = 0.012), percentage of bronchial segments identified (p < 0.001), percentage of repeated bronchial segments entered (p = 0.004), percentage of pathologies identified (p < 0.001), number of times that the bronchoscope tip collided with airway walls (p = 0.013), and number of times oral instruction was needed (p = 0.01). CONCLUSION: CBBS is a valid training method that increases interest in learning and provides a favorable degree of virtual realism. It can also distinguish various levels of competence at actual bronchoscopy and may have a useful role in the bronchoscopic training curriculum.  相似文献   
88.
Discovertebral erosion with pseudoarthrosis is a well-known complication in ankylosing spondylitis but it is seldom mentioned in psoriatic arthritis. We report a 53-year-old woman with an 8-year history of psoriatic arthritis who developed severe low back pain followed by sudden onset of numbness in the lower limbs, weakness and dysesthesia. Abnormal contour of L1 and L2 vertebrae and intervertebral disc space was noted during radiologic examination. Pseudoarthrosis was suspected based on extensive osseous resorption and reactive sclerosis about the discovertebral junction on magnetic resonance imaging study. She underwent emergency operation due to spinal instability with neurologic deficit. Pseudoarthrosis was confirmed intraoperatively. No evidence of infection or neoplasms was found. This case shows that pseudoarthrosis can be complicated in patients with psoriatic arthritis, and this possibility should be considered in patients with previously quiescent disease.  相似文献   
89.
PURPOSE AND EXPERIMENTAL DESIGN: The etiologic association and prognostic significance of mismatch repair gene/protein alterations have never been examined in nonsmoking lung cancer. Therefore, we investigated protein expression and promoter hypermethylation of hMLH1 and hMSH2 genes in the tumor specimens from 105 nonsmoking female non-small cell lung cancer (NSCLC) patients. Immunohistochemistry and restriction enzyme-based multiplex PCR were used to examine the protein expression and promoter hypermethylation, respectively. The occurrence of gene/protein alteration for each gene was compared with the patients' clinicopathologic variables as well as the overall survival and cancer-specific survival rates. RESULTS: Protein expression alteration and promoter hypermethylation were observed in 66% to 67% and 30% to 34% of tumor specimens for hMLH1 and hMSH2 genes, respectively. Loss of hMLH1 and hMSH2 protein expression was significantly associated with their promoter hypermethylation (P < 0.0001 and P = 0.049). The overall survival and cancer-specific survival rates were significantly lower in patients with promoter hypermethylation of hMSH2 gene than in those without hypermethylation (P = 0.038 and P = 0.004). The poor prognosis was still especially significant in adenocarcinoma (P = 0.035 and P = 0.061) and early-stage NSCLC patients (P = 0.067 and P = 0.041). CONCLUSION: Our data suggest that hMLH1 is the major altered mismatch repair gene involved in nonsmoking NSCLC tumorigenesis and that promoter methylation is the predominant mechanism in hMLH1 and hMSH2 deregulation. In addition, promoter methylation of the hMSH2 gene may be a potential prognostic factor in nonsmoking female lung cancer.  相似文献   
90.
The activation of the PI3K signaling pathway resulting from genetic alterations induces carcinogenesis and resistance to anticancer therapies. Breast cancer is a major malignancy that is associated with dysregulation of the PI3K signaling pathway. PIK3CA mutations and PTEN loss occur in every subtype of breast cancer. PI3K inhibitors are being evaluated in breast cancer after the success of an alpha isoform-specific PI3K inhibitor in estrogen receptor (ER)-positive/HER2-negative metastatic breast cancer. Some preclinical data indicate the potential for PI3K/mTOR targeting in combination with trastuzumab for HER2-positive breast cancer with or without expression of the estrogen receptor. However, the role of this therapy in HER2-positive breast cancer with PIK3CA mutations and/or PTEN loss remains unclear. We examined three HER2-positive, ER-negative breast cancer cell lines to determine the efficacy of a novel alpha isoform-specific PI3K inhibitor in combination with trastuzumab. The results indicated that this combination was effective in PIK3CA-mutant or PTEN-deficient breast cancer cells by inducing apoptosis and inhibiting the expression of downstream proteins. PTEN loss by siRNA modulation in parental HER2-positive cancer cells with PI3K signaling pathway alterations could not confer resistance to alpelisib or GDC-0077 plus trastuzumab. We selected the CK-MB-1 cell line without alterations in the PI3K pathway to demonstrate that PI3K inhibitors plus trastuzumab represented a biomarker-specific treatment. In vivo effects of alpelisib plus trastuzumab were tested and confirmed in a mouse model, showing the combination strategy offered the best opportunity to achieve tumor volume reduction. With known safety profiles, this cytotoxic chemotherapy-free regimen warrants further attention as a biomarker-driven strategy for treating HER2-positive breast cancer.  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