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   429篇
  免费   40篇
  国内免费   4篇
儿科学   7篇
妇产科学   6篇
基础医学   48篇
口腔科学   10篇
临床医学   34篇
内科学   115篇
皮肤病学   10篇
神经病学   60篇
特种医学   11篇
外科学   38篇
预防医学   39篇
眼科学   11篇
药学   19篇
肿瘤学   65篇
  2023年   4篇
  2022年   9篇
  2021年   24篇
  2020年   13篇
  2019年   19篇
  2018年   25篇
  2017年   19篇
  2016年   14篇
  2015年   12篇
  2014年   17篇
  2013年   25篇
  2012年   40篇
  2011年   31篇
  2010年   20篇
  2009年   25篇
  2008年   27篇
  2007年   35篇
  2006年   30篇
  2005年   34篇
  2004年   17篇
  2003年   14篇
  2002年   11篇
  2001年   1篇
  2000年   3篇
  1999年   1篇
  1998年   1篇
  1996年   1篇
  1994年   1篇
排序方式: 共有473条查询结果,搜索用时 15 毫秒
21.
22.
Purpose To evaluate the cosmetic outcome of breast conservative therapy and to examine the degree of agreement between the patients’ and oncologists’ ratings. We also analyze the influence of several factors on cosmesis. Methods and materials We retrospectively evaluated 145 patients with primary breast cancer treated by local excision and radiotherapy between January 2000 and May 2001. Cosmetic outcome was evaluated by doctors and patients and was scored as excellent, good, fair or poor. Results 73% of patients rated cosmesis as excellent or good while the percentage was 71% when rated by radiation oncologists. The degree of cosmesis concordance evaluated by oncologists and patients was low (kappa=0.3). In our study the variables which significantly influence on the cosmetic outcome were concomitant adjuvant chemotherapy (p=0.04) and radiation therapy boost, either by electron beam or brachytherapy (p=0.013). Conclusion The cosmetic outcome of breast conserving therapy was good. There was a similar rating by the patient and radiation oncologist, but the level of concordance between patients and doctors was low. Factors that significantly influence the cosmesis appear to be concomitant adjuvant chemotherapy and radiation therapy boost.  相似文献   
23.
Non-Hodgkin’s lymphoma (NHL) of the head and neck area is rare, and constitutes 0.4%–2% of all extranodal lymphomas and 6.4%–13% of extranodal lymphomas of the head and neck area1–6. The maxillary antrum, nasal cavity and ethmoid sinus are the most common sites for this tumor3. Prognosis of the NHL affecting the paranasal sinuses and nasal cavity is poor with 33% of survival at 5 years5–7. Failure of the treatment is local and with distant metastasis. Radiotherapy permits disease-free survival at 5 years in T1–T2 of 78% and in T3–T4 of 18%7. Only three cases in the literature have been described affecting the frontal sinus, in two cases there was infiltration of the other paranasal sinuses and in one case there was an isolated primary non-Hodgkin’s lymphoma of the frontal sinus3,4 (Medline from 1966 to 2001). We present the second case reported in the literature of NHL exclusively affecting the frontal sinus showing local control 5 years after diagnosis.  相似文献   
24.
Elbow tuberculosis: an unusual location and diagnostic problem   总被引:2,自引:1,他引:1  
Tuberculous arthritis of the elbow joint is not commonly seen by orthopaedic physicians. In the past 20 years, with the pandemic of the human immunodeficiency virus and the increase in immunocompromised people, we have observed a resurgence of tuberculosis. Osteoarticular involvement has increased, too. Spinal and monoarthritis of weight-bearing joints such as the hip or knee are most frequently involved. The elbow joint is an uncommon location of osteoarticular tuberculosis. The aim of this case report is to describe a case of tuberculous arthritis of the elbow and the diagnostic problems that may arise and lead to a delay in treatment.  相似文献   
25.
The existence of A2A-D2 heteromeric complexes is based on coimmunoprecipitation studies and on fluorescence resonance energy transfer and bioluminescence resonance energy transfer analyses. It has now become possible to show that A2A and D2 receptors also coimmunoprecipitate in striatal tissue, giving evidence for the existence of A2A-D2 heteromeric receptor complexes also in rat striatal tissue. The analysis gives evidence that these heteromers are constitutive, as they are observed in the absence of A2A and D2 agonists. The A2A-D2 heteromers could either be A2A-D2 heterodimers and/or higher-order A2A -D2 hetero-oligomers. In striatal neurons there are probably A2A-D2 heteromeric complexes, together with A2A-D2 homomeric complexes in the neuronal surface membrane. Their stoichiometry in various microdomains will have a major role in determining A2A and D2 signaling in the striatopallidal GABA neurons. Through the use of D2/D1 chimeras, evidence has been obtained that the fifth transmembrane (TM) domain and/or the I3 of the D2 receptor are part of the A2A-D2 receptor interface, where electrostatic epitope-epitope interactions involving the N-terminal part of I3 of the D2 receptor (arginine-rich epitope) play a major role, interacting with the carboxyl terminus of the A2A receptor. Computerized modeling of A2A-D2 heteromers are in line with these findings. It seems likely that A2A receptor-induced reduction of D2 receptor recognition, G protein coupling, and signaling, as well as the existence of A2A-D2 co-trafficking, are the consequence of the existence of an A2A-D2 receptor heteromer. The relevance of A2A-D2 heteromeric receptor complexes for Parkinson's disease and schizophrenia is emphasized as well as for the treatment of these diseases. Finally, recent evidence for the existence of antagonistic A2A-D3 heteromeric receptor complexes in cotransfected cell lines has been summarized.  相似文献   
26.
27.
The relationship between osteoporosis and primary hyperparathyroidism (pHPT) has not been definitely established because both diseases occur predominantly in postmenopausal women, and because PTH has a paradoxical effect on bone. We have investigated the prevalence of reduced bone mineral density (BMD) in women with pHPT, its relationship with metabolic parameters, and its course after parathyroidectomy. A prospective observational study was carried out on perimenopausal and postmenopausal women consecutively diagnosed and operated on for pHPT. Demographic data were recorded, as well as, PTH, Ca, calciuria/24h, P, vitamin D, adenoma weight. The BMD was measured at three sites: femoral neck (FN), proximal femur (PF), and lumbar spine (LS). Fifty-two patients were included with a mean age of 61 ± 12 years. The prevalence of reduced BMD ( 1SD, T-score) was 80%–100% depending on site. Parathyroid hormone was higher in patients with osteoporosis (319 ± 181 pg/ml) than in those with osteopenia (230 ± 83 pg/ml) or normal BMD (148 ± 81 pg/ml; p < 0,04). Twenty-eight patients were investigated 1 year after parathyroidectomy. The BMD improved significantly at all sites, particularly in patients with osteoporosis. Age correlated inversely with BMD increases at the femoral sites (r= –0,47; p = 0,02) but not at the LS. 25-OHD3 plasma levels correlated inversely with BMD increases at PF (r= –0,76; p < 0,0001). In pHPT, there is a high prevalence of BMD abnormalities. No metabolic variables had a definite influence on BMD values but a tendency was observed for lower BMD in severe pHPT. One year after parathyroidectomy, there were significant BMD increases that were more marked at femoral sites, in younger patients, in patients with preoperative osteoporosis, and in those with lower plasma levels of 25-OHD3.This article was presented at the International Association of Endocrine Surgeons meeting, Uppsala, Sweden, June 14–17, 2004.  相似文献   
28.
BACKGROUND: Subjective nonspecific upper aerodigestive symptoms (UADS) are not uncommon after thyroidectomy. Their type, duration, and prevalence, however, have not been investigated in a controlled design. The objective of this study was to investigate the prevalence of UADS after thyroidectomy. METHODS: A consecutive cohort of 60 patients who had undergone uncomplicated total (n = 38) or near total (n = 22) thyroidectomy were investigated retrospectively at a mean of 4 years after surgery. An independent unblinded researcher interviewed each patient and asked for the presence or frequency of voice changes, cough, dysphagia, neck strangling, and annual incidence of common colds, before and after thyroidectomy. Sixty patients, matched for age, sex, and smoking habits, who had undergone laparoscopic cholecystectomy during the same years served as control subjects. RESULTS: The prevalence of UADS was similar before thyroidectomy (13%) and cholecystectomy (15%). After operation, UADS had a higher prevalence among thyroidectomized patients: nonspecific voice changes (28% vs 3%), neck strangling (22% vs 0%), and impaired swallowing (15% vs 3%) (P < or = .02 in each). Neck strangling was associated with voice changes and dysphagia (P < or = .03 each). CONCLUSIONS: Subjective UADS are common long after thyroidectomy. These symptoms may be related to injury to the extrinsic perithyroidal neural plexus innervating the pharyngeal and laryngeal structures.  相似文献   
29.
30.
The molts of lepidopteran insects are typically controlled by the brain-derived prothoracicotropic hormone (PTTH) that stimulates ecdysteroidogenesis in the prothoracic glands (PGs). We report here that the larvae and pupae of the moth Sesamia nonagrioides can molt without brain (PGs must be present), suggesting that there might be a secondary source of PTTH. We addressed this issue by characterizing spatial and temporal expression patterns of the PTTH gene. To this end we identified a major part of the corresponding cDNA. Protein deduced from this cDNA fragment consisted of 128 amino acids and showed 48-85% homology with the matching regions of PTTHs known from other Lepidoptera. Quantification of PTTH expression in major body organs of the last instar larvae revealed high expression in the brain (fading in post-feeding larvae) and considerable expression in the gut (with a maximum in post-feeding larvae). The content of PTTH message in the gut was enhanced after decapitation. It is concluded that the molts of S. nonagrioides larvae are driven by PTTH gene expression in the gut.  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