全文获取类型
收费全文 | 8189篇 |
免费 | 464篇 |
国内免费 | 330篇 |
专业分类
耳鼻咽喉 | 164篇 |
儿科学 | 120篇 |
妇产科学 | 234篇 |
基础医学 | 468篇 |
口腔科学 | 161篇 |
临床医学 | 476篇 |
内科学 | 1381篇 |
皮肤病学 | 39篇 |
神经病学 | 276篇 |
特种医学 | 128篇 |
外科学 | 1530篇 |
综合类 | 638篇 |
预防医学 | 516篇 |
眼科学 | 24篇 |
药学 | 296篇 |
中国医学 | 62篇 |
肿瘤学 | 2470篇 |
出版年
2024年 | 7篇 |
2023年 | 150篇 |
2022年 | 379篇 |
2021年 | 499篇 |
2020年 | 397篇 |
2019年 | 411篇 |
2018年 | 432篇 |
2017年 | 315篇 |
2016年 | 296篇 |
2015年 | 344篇 |
2014年 | 668篇 |
2013年 | 546篇 |
2012年 | 415篇 |
2011年 | 515篇 |
2010年 | 332篇 |
2009年 | 445篇 |
2008年 | 482篇 |
2007年 | 420篇 |
2006年 | 300篇 |
2005年 | 238篇 |
2004年 | 212篇 |
2003年 | 149篇 |
2002年 | 114篇 |
2001年 | 124篇 |
2000年 | 107篇 |
1999年 | 117篇 |
1998年 | 67篇 |
1997年 | 65篇 |
1996年 | 47篇 |
1995年 | 46篇 |
1994年 | 41篇 |
1993年 | 31篇 |
1992年 | 35篇 |
1991年 | 23篇 |
1990年 | 24篇 |
1989年 | 33篇 |
1988年 | 22篇 |
1987年 | 21篇 |
1986年 | 16篇 |
1985年 | 21篇 |
1984年 | 14篇 |
1983年 | 16篇 |
1982年 | 13篇 |
1981年 | 10篇 |
1980年 | 11篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1973年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有8983条查询结果,搜索用时 0 毫秒
51.
Nonoperative Management of Primary Colorectal Cancer in Patients With Stage IV Disease 总被引:12,自引:0,他引:12
Scoggins CR Meszoely IM Blanke CD Beauchamp RD Leach SD 《Annals of surgical oncology》1999,6(7):651-657
Background: Traditional teaching maintains that patients with primary colorectal adenocarcinoma require timely resection to prevent bleeding, perforation, or obstruction. The true benefits of primary tumor resection remain undocumented for patients presenting with metastatic disease, however. We postulated that resection of primary colorectal tumors could be avoided safely in a select population of asymptomatic colorectal cancer patients presenting with incurable stage IV disease.Methods: A retrospective review of the Vanderbilt University Hospital tumor registry was performed for the years 1985 to 1997. During this period, 955 patients presented for management of primary colorectal cancer. From this group, all patients with stage IV disease at the time of diagnosis were identified. Patients who initially underwent resection of their primary lesion were included in the resection group; those who underwent initial nonoperative primary tumor management were included in the nonresection group. Data were obtained regarding age, extent of disease, nonsurgical therapy, tumor-specific complications, and palliative surgical procedures. Surgery-free survival and overall survival were analyzed using the Kaplan-Meier method. For patients with liver metastases, hepatic tumor burden was defined as either H1 (<25% parenchymal replacement), H2 (25% to 50%), or H3 (>50%) disease.Results: Sixty-six patients were included in the resection group, and 23 patients with intact asymptomatic primary colorectal lesions were included in the nonresection group. Among patients with hepatic metastases, most of the patients in both groups had H1 disease. Ten patients in the resection group and 3 patients in the nonresection group presented with exclusively extrahepatic metastases. In the nonresection group, primary therapy included chemotherapy in 13 patients, external beam radiation therapy in 1 patient, and combination chemoradiation in 9 patients. The median survival in the nonresection group was 16.6 months. The 2-year actuarial survival was 18%, and the surgery-free survival was 91.3%. Only 2 of 23 patients (8.7%) managed without resection eventually developed obstruction at the primary tumor site requiring emergent diversion. There were no episodes of tumor-related hemorrhage or perforation. For the resection group, the operative morbidity was 30.3%, and the perioperative mortality rate was 4.6%. The median survival in the resection group was 14.5 months (P = 0.59, log-rank test vs. nonresection group).Conclusions: Selected patients with asymptomatic primary colorectal tumors who present with incurable metastatic disease may safely avoid resection of their primary lesions, with an anticipated low rate of hemorrhage, perforation, or obstruction before death from systemic disease. No survival advantage is gained by resection of an asymptomatic primary lesion in the setting of incurable stage IV colorectal cancer. 相似文献
52.
S. Casari A. Donisi G. Paraninfo D. Tomasoni L. Palvarini P. Nasta A. Bergamasco G.P. Cadeo G. Carosi 《European journal of epidemiology》1999,15(8):691-698
The authors present the AIDS cases (CDC '93) observed in Brescia from 1983 to 1994. They observed 1189 subjects (M 84%, F 16%) with a mean age of 32.7 years (intra-venous drug users 75.1%, heterosexuals 14%, homosexuals 9.6%). The mean survival observed was 56.7 weeks from the diagnosis of AIDS (mortality per year 78%). The most frequent AIDS-defining events were Visceral Candidiasis, P.carinii Pneumonia (PCP) and Neurotoxoplasmosis, while the longest and shortest mean survival was for Kaposi's Sarcoma (89 weeks) and Wasting Syndrome (8.4). The mean value of CD4+ lymphocyte counts on AIDS diagnosis was 72.6/l (1166 cases) and the highest and lowest were in non-Hodgkin's Lymphoma (NHL; 147.6/l) and Cryptosporidiosis (18.8/l). Antiretroviral therapy had been given for at least a month in 41.4% subjects (mean treatment duration of 74.8 weeks). The Cox model has demonstrated the favourable effect on survival of high CD4+ lymphocyte counts on diagnosis, antiretroviral therapy, the diagnosis of Tuberculosis (TBC) and PCP as initial markers and the diagnosis of TBC, PCP or Cytomegalovirus infection (CMV) during the entire clinical evolution. Moreover, the unfavourable effect of high age, diagnosis of Progressive Multifocal Leucoencephalopathy (PML), Wasting Syndrome and NHL as initial markers and diagnosis of PML or NHL in any moment of the disease has been demonstrated. 相似文献
53.
Bitoh H 《Journal of anesthesia》1992,6(3):247-254
Oxygen free radicals (OFRs) have been reported to play pivotal roles in the pathogenesis of cell damage induced by ischemia and reperfusion. The efficacy of recombinant human superoxide dismutase (rh-SOD) in the treatment of circulatory disorders after reperfusion of the splanchnic area was investigated in rats. All rats died within 3 hours after release of 60-min superior mesenteric artery occlusion (SMAO) when no treatment was given. Animals which received rh-SOD, 2mg·100g–1BW, at reperfusion followed by a continuous infusion of rh-SOD 0.67mg·100g–1BW·hr–1, exhibited prolonged survival times compared with no treatment rats (231 ± 35min and 149 ± 43min, respectively). Mean blood pressure in rats treated with rh-SOD was higher than in controls after reperfusion, and was concomitant with improvement in splanchnic perfusion. The results suggest excessive activity of OFRs in reperfused organs and a possible scavenging effect of rh-SOD as a means of eliminating them.(Bitoh H: Recombinant human-type SOD attenuates circulatory disorders after reperfusion of splanchnic organs in rats. J Anesth 6: 247–254, 1992) 相似文献
54.
目的总结大量临床肾移植工作和提高移植肾存活率的经验。方法回顾5个年度中609例次异体肾移植临床资料,分析供、受者情况、组织配型、移植手术过程、免疫移植治疗、移植并发症等影响移植效果的因素,观察年度内人/肾存活率和术后转归。结果5个年度内共计发生术后并发症121例,以感染和外科并发症最常见。死亡患者28例,移植肾切除数34例,年度内人/肾成活率平均分别为95.40%和94.42%。结论高质量取肾、修肾、植肾手术及良好的组织配型和规范的术后处理,是提高临床移植肾存活率的关键。 相似文献
55.
Hemodialysis in elderly patients 总被引:1,自引:0,他引:1
Brown WW 《International urology and nephrology》2000,32(1):127-135
International Urology and Nephrology - 相似文献
56.
57.
K. Tada M. Yoshimoto S. Nishimura K. Takahashi M. Makita T. Iwase S. Takahashi Y. Ito K. Hatake M. Ueno K. Nakagawa F. Kasumi 《European journal of surgical oncology》2004,30(10):1077-1083
AIM: Large multicenter, randomized trials have revealed the advantages of using tamoxifen for 5 years vs 2 years in breast cancer patients. The aim of this report is to confirm the optimal duration of tamoxifen administration in a study of Japanese breast cancer patients. METHODS: Japanese post-menopausal estrogen receptor-positive breast cancer patients treated with mastectomy were randomly assigned to either a 5-year or 2-year course of tamoxifen. The primary endpoint was disease-free survival, with secondary endpoints of overall survival and a reduction in the development of metachronous contra-lateral breast cancer. RESULTS: A total of 256 breast cancer patients were randomized to a 5-year or 2-year tamoxifen administration group. After a median follow-up time of 81 months, there were no significant differences seen in terms of disease-free or overall survival (p=0.65 and 0.56, respectively). Furthermore, the impact of the 5-year use of tamoxifen on the development of contra-lateral breast cancer did not reach statistical significance (p=0.0511). However, 5-year tamoxifen use was closely associated with gynaecological complications (p=0.0081). CONCLUSION: We could not show a beneficial effect of using tamoxifen for 5 years over 2 years in Japanese estrogen receptor-positive patients. This is likely due to the small number of patients enrolled in our study; however, racial disparity may influence this result. A reevaluation is necessary to study the advantages of the 5-year use of tamoxifen in the Japanese racial subgroup. 相似文献
58.
59.
Ulrik N Lassen Fred R Hirsch Kell Østerlind Bengt Bergman Per Dombernowsky 《Lung cancer (Amsterdam, Netherlands)》1998,20(3):151-160
During the past two decades many different treatment regimens of combination chemotherapy have been applied in extensive stage small-cell lung cancer (SCLC). This study was carried out to identify whether these modifications have resulted in an improved overall survival for extensive stage during the past two decades. In total, 1111 patients with extensive stage SCLC were included in six consecutive randomised trials in our setting from 1973 until 1992. Of these, 526 patients treated in the early period (1973–1981) were compared with 585 patients treated in the late period (1981–1992) with respect to pretreatment prognostic factors, staging, treatment and outcome. No change in the distribution of prognostic factors was detected and the frequency of patients with extensive stage was equal in the two periods, and no difference in overall response rates and survival was observed (P=0.49). Median survival in the two periods was 208 days and 215 days, respectively. No stage migration or treatment-related improved outcome was observed in extensive disease. We suggest restricting aggressive treatment to patients with favorable prognosis and long-term survival as a realistic aim. 相似文献
60.
Anaya-Martínez V Montiel-Flores E Espinosa-Villanueva J García-Hernández F 《Archives of medical research》2000,31(6):311-557
BACKGROUND: Because of their lack of long-term viability, adrenal tissue transplants have shown limited success in alleviating the motor disturbances associated with experimental and pathologic striatal dopamine denervation. In this study, we examined how the graft placement site influences adrenal medulla transplant survival and its relation with the reduction of motor deficits in rats bearing unilateral 6-OHDA lesion. METHODS: One or 5 microL of fetal adrenal medullar tissue was grafted either inside the striatal parenchyma or into the lateral ventricle in contact with the dopamine-denervated striatum. Motor disturbances, as assessed by apomorphine-induced rotation, were correlated to the graft morphologic survival features. RESULTS: Apomorphine-induced rotation showed a marginal reduction of 11% in all groups independently of graft survival features or placement site. Intrastriatal transplants showed limited viability characterized by a substantial loss of graft initial volume as well as fewer and smaller chromaffin cells compared to ventricular grafts, which had a reduced loss of graft initial volume and more and larger chromaffin cells. CONCLUSIONS: Although the lateral ventricle may favor adrenal medulla transplant viability, their induced motor outcome is comparable to that induced by less viable intrastriatal grafts, suggesting that the implanted dopamine-producing cells may interact and influence striatal neurons better when placed in close proximity. 相似文献