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   5690篇
  免费   321篇
  国内免费   32篇
耳鼻咽喉   52篇
儿科学   133篇
妇产科学   146篇
基础医学   764篇
口腔科学   123篇
临床医学   438篇
内科学   1253篇
皮肤病学   121篇
神经病学   638篇
特种医学   106篇
外科学   539篇
综合类   14篇
一般理论   1篇
预防医学   448篇
眼科学   67篇
药学   469篇
中国医学   17篇
肿瘤学   714篇
  2024年   11篇
  2023年   44篇
  2022年   122篇
  2021年   184篇
  2020年   120篇
  2019年   144篇
  2018年   156篇
  2017年   142篇
  2016年   150篇
  2015年   181篇
  2014年   217篇
  2013年   270篇
  2012年   483篇
  2011年   397篇
  2010年   227篇
  2009年   197篇
  2008年   349篇
  2007年   363篇
  2006年   369篇
  2005年   372篇
  2004年   341篇
  2003年   317篇
  2002年   272篇
  2001年   51篇
  2000年   54篇
  1999年   43篇
  1998年   54篇
  1997年   35篇
  1996年   44篇
  1995年   43篇
  1994年   31篇
  1993年   29篇
  1992年   21篇
  1991年   26篇
  1990年   10篇
  1989年   14篇
  1988年   15篇
  1987年   10篇
  1986年   15篇
  1985年   8篇
  1984年   17篇
  1983年   14篇
  1982年   6篇
  1981年   7篇
  1980年   6篇
  1979年   11篇
  1978年   10篇
  1976年   6篇
  1975年   5篇
  1974年   6篇
排序方式: 共有6043条查询结果,搜索用时 15 毫秒
1.
2.
3.
Aim and methods  Nutrition, unhealthy lifestyles and cancer appear to be strictly related, but few authors have analysed the interest in dietary information of cancer patients and their families. This survey was conducted in the Veneto area (Italy) to investigate the concern of cancer patients and their family members about diet as a health tool before and after diagnosis of cancer. Results  Seven hundred and four questionnaires were collected: 380 from cancer patients and 324 from family members of cancer subjects. Breast cancer (BC) was the most frequent disease for patients (61.8%) as well as families (26.5%). Generally, the importance of having precise diet information after diagnosis is recognised by 40.3% of patients, with significant differences between the various types of cancer: gastric and colon/rectum cancer (GCC) patients were more concerned than BC women about precise information concerning a diet to follow immediately after diagnosis (p = 0.000, ODs = 3.10, CI 1.68–5.71) or during treatments (p = 0.001, ODs = 2.67, CI 1.46–4.89). The nutritional information is supplied to patients in 34% of cases and to relatives in 30.3%, often from non-medical sources. In total healthcare workers (family doctor, oncologist, surgeon, dietician) represented the exclusive source of dietary information for 24.9% of patients and 22.9% of family members. Diet after diagnosis changes in 69.1% of GCC patients and in 39.2% of BC women. Relatives, particularly women, report difficulties preparing patients’ meals in 30.7% of cases, changes in the eating habits of the entire family in 29.9% and discontent connected with patients diet in 13.9%. The concern about proper nutrition after diagnosis increases more in GCC subjects (p < 0.025) when compared to BC subjects and in patients with more recent diagnosis (p < 0.041) when compared with patients with diagnosis >5 years ago, while in family members the interest in diet after diagnosis increases more in women than in men (p < 0.030) without other differences regarding the degree of relationship, type of cancer or diagnosis time. Relatives (92.7%) have more interest in nutritional education than patients (74.9%). Cancer patients <65 years were more interested in educational initiatives concerning nutrition (p = 0.000, ODs = 4.46, CI 2.6–7.4) than older patients (>65 years) and female subjects were more concerned than male patients (p = 0.008, ODs = 2.11, CI 1.2–3.6). Conclusions  The interest in the dietary knowledge and in educational initiatives concerning nutrition is high in cancer patients and their relatives, although it decreases with the age. The poor attention paid to nutrition of cancer patients by various healthcare workers deserves consideration, since the psychophysical wellbeing and perhaps also survival of cancer patients can be improved by correct dietary management, as well as, naturally, by the principal treatments themselves.  相似文献   
4.
5.
Ten protein coding loci (6‐PGD, A1‐AT, ACP1, CaII, ESD, GC, GPX1, Hbβ, PGM1, and TF) were analyzed in the Mbenzele Pygmies from the Central African Republic. The frequency data were used to calculate the genetic distances between Mbenzele Pygmies and other African groups. In the principal coordinate plot of FST genetic distances, the Mbenzele cluster together with other Pygmies of the western cluster, the Biaka from C.A.R., Gielli from Cameroon, and Babinga from Congo. By contrast, they are considerably distanced from other Pygmy groups of the eastern cluster (Twa from Rwanda, Mbuti from Zaire). Genetic distances obtained using protein loci were compared with those based on microsatellite loci. The two distance matrices are insignificantly correlated (r = 0.268; one tail probability = 0.332), and the main difference is in the higher genetic affinity between the Mbenzele and Biaka Pygmies observed at the protein level. Although reasons underlying the discrepancy between inter‐populational variation at protein and DNA loci are not established with certainty, the comparison suggests that the genetic distance between the Mbenzele and Biaka Pygmies at microsatellite loci could have been shaped by genetic drift. Am. J. Hum. Biol. 14:9–14, 2002.© 2002 Wiley‐Liss, Inc.  相似文献   
6.
7.
BACKGROUND. The incidence of primary gastric non-Hodgkin's lymphoma (NHL) appears to have increased worldwide in recent years, and this seems to be confirmed by large-sample population studies. METHODS AND RESULTS. We derived our data from the Lombardy Cancer Registry, which provides the incidence of cancer in the province of Varese, Northern Italy. From 1978 to 1987 we identified 3261 cases of gastric neoplasms, 119 of which were gastric NHL: 32 (1.87%) from 1978 to 1982, and 87 (5.32%) from 1983 to 1987. The difference in the age and sex standardized incidence trend between these two time periods was statistically significant (p < 0.001). The overall survival rate of the 112 evaluable patients was 54% at 5 years and 45% at 10 years. A multivariate analysis was performed. Age (p < 0.0005), clinical stage (p < 0.04) and therapy (p < 0.0005) were found to be significant prognostic factors for survival. CONCLUSIONS. This study stresses the utility of prospective randomized clinical trials that could indicate the optimal management of patients with primary gastric lymphoma.  相似文献   
8.
Objective: Severe atherosclerosis of the ascending aorta and arch frequently causes difficulties during heart operations, hindering surgical manoeuvres and potentially leading to systemic embolism. The aim of our study was to assess the safety and effectiveness of replacing the atherosclerotic ascending aorta in this setting. Methods: Aortic atherosclerosis was characterized by epiaortic ultrasonographic scanning in 90.1% of 1927 consecutive adult patients undergoing cardiac operations, and by computed tomographic chest scanning in selected cases. Thirty-six of the 152 patients requiring major derangements from our standard practice due to aortic atherosclerosis underwent replacement of the ascending aorta and constitute the study group. Replacement of the aorta was extended to the arch in 13 cases (36.1%). It was associated with single or multiple valve surgery in 34 patients (94.4%) and with coronary revascularization in 30 (83.3%). Two patients (5.6%) underwent coronary bypass grafting without valve surgery. A cryoablation procedure was associated in three patients with permanent atrial fibrillation. Deep hypothermic circulatory arrest was employed in 34 patients (94.4%), while proximal aortic disease allowed conventional distal crossclamping in 2 cases. The risk of operative mortality was estimated by the logistic EuroSCORE both with and withholding the variable ‘surgery of the thoracic aorta’. All survivors were followed-up for 1–41 months (16 ± 12). Results: Two patients died in the hospital (5.6%) and two during follow-up, for a cumulative survival of 91.3% and 85.6% at 1 and 3 years, respectively (hospital deaths included). The hospital death rate compared favourably with the expected estimates of 25.5% (p < 0.05) and 10.3% (p = 0.67) obtained by the EuroSCORE full model and without ‘aortic surgery’, respectively. In-hospital adverse neurologic events occurred in six patients (16.7%), including stroke in one patient (2.8%) and neurocognitive disturbances in five (13.9%), although they were all transient and cleared before discharge. Excess bleeding required re-exploration in four patients (11.1%), and one more patient underwent emergency grafting for acute postoperative coronary occlusion. Ten patients (38.5%) were intubated for longer than 24 h. Conclusion: Despite significant perioperative morbidity, replacement of the severely atherosclerotic aorta is worth consideration to avert expectedly higher death and stroke rates.  相似文献   
9.
10.
OBJECTIVE: Our purpose was to investigate immunosuppressive acidic protein in the prognostic characterization of advanced ovarian cancer. STUDY DESIGN: Serum levels of immunosuppressive protein were prospectively measured in 80 patients with untreated ovarian carcinoma. To evaluate the prognostic significance of immunosuppressive acidic protein levels, cutoff points were studied every 50 μg/ml between 450 and 1350 μg/ml. RESULTS: Pretreatment immunosuppressive acidic protein levels were not significantly associated with stage, histotype, grade of differentiation, postoperative residual tumor, and response to chemotherapy. The most significant association with survival was observed at a cutoff value of 1100 μg/ml (p = 0.0089). In the univariate analysis for overall survival, International Federation of Gynecology and Obstetrics stage and immunosuppressive acidic protein status were found to have a role in predicting ovarian cancer prognosis. In the multivariate analysis only immunosuppressive acidic protein status was significantly associated with survival. A statistical correlation was found between serum levels and overall survival (p = 0.0104, χ2 6.56), including immunosuppressive acidic protein as a continuous variable. CONCLUSION: Our data suggest that immunosuppressive acidic protein assay is a potentially useful tool in the prognostic characterization of advanced ovarian cancer. (Am J Obstet Gynecol 1996;175:1606-10.)  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