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   1425篇
  免费   49篇
  国内免费   4篇
耳鼻咽喉   8篇
儿科学   39篇
妇产科学   20篇
基础医学   355篇
口腔科学   6篇
临床医学   166篇
内科学   351篇
皮肤病学   20篇
神经病学   52篇
特种医学   44篇
外科学   107篇
综合类   12篇
预防医学   58篇
眼科学   12篇
药学   119篇
中国医学   6篇
肿瘤学   103篇
  2022年   14篇
  2021年   55篇
  2020年   22篇
  2019年   14篇
  2018年   25篇
  2017年   20篇
  2016年   20篇
  2015年   23篇
  2014年   37篇
  2013年   68篇
  2012年   97篇
  2011年   87篇
  2010年   61篇
  2009年   68篇
  2008年   89篇
  2007年   91篇
  2006年   81篇
  2005年   80篇
  2004年   74篇
  2003年   67篇
  2002年   58篇
  2001年   7篇
  1999年   8篇
  1998年   10篇
  1997年   9篇
  1996年   13篇
  1995年   14篇
  1994年   11篇
  1993年   11篇
  1992年   16篇
  1991年   8篇
  1990年   5篇
  1989年   7篇
  1988年   12篇
  1987年   10篇
  1986年   6篇
  1985年   18篇
  1984年   6篇
  1983年   16篇
  1982年   9篇
  1981年   14篇
  1980年   12篇
  1979年   11篇
  1978年   10篇
  1977年   9篇
  1974年   4篇
  1973年   4篇
  1971年   6篇
  1968年   4篇
  1912年   5篇
排序方式: 共有1478条查询结果,搜索用时 0 毫秒
101.
BACKGROUND AND AIM: Amphotericin B (AmB) desoxycholate remains as one of the most efficacious agents currently available for the treatment of systemic fungal infections; however, amphotericin B colloidal dispersion (ABCD) has been developed because of AmB desoxycholate nephrotoxicity. The goal of our study was to compare the effect of administration of AmB desoxycholate and ABCD on renal functions and renal morphology in rats. RESULTS: Amophotericin B desoxycholate as well as ABCD causes damage to renal tubuli and polyuria. Amophotericin desoxycholate causes considerably more severe damage to tubuli than ABCD, but the morphological damage to renal glomeruli is minimal in both formulas. In tubular cells, AmB desoxycholate causes severe damage to mitochondria, vacuolation of cytoplasm, and increased values of volume density of peroxisomes. CONCLUSION: None of these formulas causes a decrease in glomerular filtration in rats when animals are properly hydrated.  相似文献   
102.
BACKGROUND AND AIM: The European Society of Cardiology initiated the EuroHeart Failure Survey to obtain more data about the quality of care in patients hospitalised with suspected heart failure (HF). The Czech Republic was 1 of the 24 European Society countries included in the survey. The aim of this report is to extend the original follow-up period of 12 weeks out to 4 years to assess mortality. METHODS: All admitted patients were screened according to the EuroHeart Survey Protocol, over a 6-week period in six hospitals in Pilsen, Prague and Brno in the year 2000. Annual mortality and cause of death were obtained from the Prague Institute for Health Statistical Information (UZIS Praha). RESULTS: A total of 2365 patients were screened and about 25% of all admitted patients fulfilled the criteria for HF. About 14% of patients died between admission and the 12-week follow-up, 36% of male and 42% of female patients died during the 4-year follow-up (2000-2003). Cardiovascular diseases were the main causes of death (92%). Deceased patients were significantly older, had lower haemoglobin and total plasma cholesterol level, and had renal insufficiency and higher levels of big endothelin and BNP than the survivors. Mortality risk was increased independently by positive history of previous myocardial infarction OR=2.39 (1.59-3.59), by age OR=1.03 (1.01-1.05) and by plasma creatinine level OR=1.04 (1.01-1.07). Treatment with diuretics and digoxin was associated with a higher risk of death; by contrast, a protective effect of beta-blockers and statins was found in these HF patients. CONCLUSION: Patients with HF were older and had a poor prognosis; approximately one third of the patients will die within 3 years.  相似文献   
103.
The authors conducted an 8-year prospective non-randomised study to determine whether dexrazoxane (ICRF-187) would reduce late anthracycline-induced cardiotoxicity in patients treated in childhood for haematological malignancy. The authors examined prospectively 75 patients (40 male/35 female) aged 2–17 years (median 6.5 years) at the time of diagnosis. The cardioprotection was given to 53 patients (26 male/17 female) and the standard protocol was used in 22 patients (14 male/8 female). The prospective echocardiographic evaluation was done before and after the chemotherapy and every year during the follow-up period. Dynamic stress echocardiography (DSE) was assessed in the final year. The clinical cardiotoxicity was not diagnosed. Higher cumulative doses of anthracycline were given in the dexrazoxane group (234±58 mg/m2, median 240 mg/m2 versus 203±86 mg/m2, median 210 mg/m2, P <0.04) and a significantly higher percentage of patients received cumulative doses >240 mg/m2 of anthracycline ( P <0.05). During the follow-up period, the fractional shortening (FS) declined in the no-dexrazoxane group only in the 8th year and was significantly lower compared to the dexrazoxane group ( P <0.05). The pathological decrease in FS was present in 24% of patients; 41% in the no-dexrazoxane and 17% in the dexrazoxane groups, respectively ( P <0.05). DSE demonstrated lower rest EF and cardiac index (CI) in the no-dexrazoxane group ( P <0.05); however, neither the response of EF and CI to the stress echocardiography nor the exercise tolerance significantly differed between sub-groups. A higher number of patients in the dexrazoxane group had very good exercise tolerance (ET) >3 Watts/kg ( P <0.05) and a lower number responded with a decreased ET <2 Watts/kg ( P <0.05) compared to the no-dexrazoxane group. Conclusion:Dexrazoxane seems to reduce the risk of late subclinical cardiotoxicity. Dexrazoxane-treated patients revealed better exercise tolerance; however the haemodynamic response to the stress was no different in both sub-groups.  相似文献   
104.
OBJECTIVE: The detection of sentinel nodes is performed in various types of malignant disease. The aim of this study was to evaluate the results of the radiodetection of sentinel nodes, based on the use of Tc-colloid, during the surgical treatment of rectal cancer. METHODS: In 2003-2004, 42 patients (24 males and 18 females; average ages of 62.4 and 67 years, respectively) were examined during rectal carcinoma surgical procedures. Miles abdominoperineal rectal resection was performed in nine cases; 33 patients underwent low anterior rectum resection by total mesorectal excision. On the day of the operation, a transanal submucosal infiltration of colloid labelled with radioactive 99mTc was performed; infiltration was performed strictly peritumorally. After the operation, radiodetection of the surgical specimens (using a hand-held gamma probe) was performed. The areas of higher radioactivity were marked. The specimens were then examined by a histopathologist. The nodes found closest to the marked areas were considered to be 'sentinel nodes'. The results of scintigraphy and postoperative radiodetection were checked by histological examination. All the discovered lymph nodes were examined by haematoxylin and eosin staining; when this was negative, immunohistochemical examination with cytokeratin was used for the sentinel nodes. RESULTS: In 36 of the 42 patients, the data obtained by scintigraphy and radiodetection were in agreement with histopathological proof of a sentinel node. The sensitivity of the method in this group of patients was 86% (95% confidence limits: 70.75-94.05). CONCLUSIONS: The scintigraphic method of detection of sentinel nodes in total mesorectal excision is not therapeutic, but diagnostic, and demonstrates a high level of reliability. It can be used to indicate the nodes that should be examined to detect the presence of possible micrometastases immunohistochemically. However, this method cannot be used for all detected nodes as it is very demanding. In the evaluated group of patients, there were no intraoperative or postoperative complications caused by this diagnostic method.  相似文献   
105.
Computer image monitoring was used for evaluation of dental arch changes. A new special device captured geometrically calibrated images permitting comparison of several different dental casts. In the first part of this study 792 sets of study casts were screened. Measurements of dental arch width between reference points of canines, first premolars and first molars were made: upper jaw: men: canines: 35.1 +/- 0.13 mm; first premolars: 37.5 +/- 0.13 mm; first molars: 48.1 +/- 0.19 mm; women: canines: 33.4 +/- 0.13 mm; first premolars: 35.6 +/- 0.15 mm; first molars: 46.7 +/- 0.19 mm. In the second part of the study, changes between initial, post-treatment and post-retention alignment (5-years after orthodontic therapy) of upper and lower dental arch of 36 subjects were analyzed. Upper and lower arch compression in first premolars and molars area was visible before treatment. We conclude that computer image monitoring can be used for evaluation of dental arch changes during the different steps of treatment.  相似文献   
106.
Commensal microflora (normal microflora, indigenous microbiota) consists of those micro-organisms, which are present on body surfaces covered by epithelial cells and are exposed to the external environment (gastrointestinal and respiratory tract, vagina, skin, etc.). The number of bacteria colonising mucosal and skin surfaces exceeds the number of cells forming human body. Commensal bacteria co-evolved with their hosts, however, under specific conditions they are able to overcome protective host responses and exert pathologic effects. Resident bacteria form complex ecosystems, whose diversity is enormous. The most abundant microflora is present in the distal parts of the gut; the majority of the intestinal bacteria are Gram-negative anaerobes. More than 50% of intestinal bacteria cannot be cultured by conventional microbiological techniques. Molecular biological methods help in analysing the structural and functional complexity of the microflora and in identifying its components. Resident microflora contains a number of components able to activate innate and adaptive immunity. Unlimited immune activation in response to signals from commensal bacteria could pose the risk of inflammation; immune responses to mucosal microbiota therefore require a precise regulatory control. The mucosal immune system has developed specialised regulatory, anti-inflammatory mechanisms for eliminating or tolerating non-dangerous, food and airborne antigens and commensal micro-organisms (oral, mucosal tolerance). However, at the same time the mucosal immune system must provide local defense mechanisms against environmental threats (e.g. invading pathogens). This important requirement is fulfilled by several mechanisms of mucosal immunity: strongly developed innate defense mechanisms ensuring appropriate function of the mucosal barrier, existence of unique types of lymphocytes and their products, transport of polymeric immunoglobulins through epithelial cells into secretions (sIgA) and migration and homing of cells originating from the mucosal organised tissues in mucosae and exocrine glands. The important role of commensal bacteria in development of optimally functioning mucosal immune system was demonstrated in germ-free animals (using gnotobiological techniques). Involvement of commensal microflora and its components with strong immunoactivating properties (e.g. LPS, peptidoglycans, superantigens, bacterial DNA, Hsp) in etiopathogenetic mechanism of various complex, multifactorial and multigenic diseases, including inflammatory bowel diseases, periodontal disease, rheumatoid arthritis, atherosclerosis, allergy, multiorgan failure, colon cancer has been recently suggested. Animal models of human diseases reared in defined gnotobiotic conditions are helping to elucidate the aetiology of these frequent disorders. An improved understanding of commensal bacteria-host interactions employing germ-free animal models with selective colonisation strategies combined with modern molecular techniques could bring new insights into the mechanisms of mucosal immunity and also into pathogenetic mechanisms of several infectious, inflammatory, autoimmune and neoplastic diseases. Regulation of microflora composition (e.g. by probiotics and prebiotics) offers the possibility to influence the development of mucosal and systemic immunity but it can play a role also in prevention and treatment of some diseases.  相似文献   
107.
108.
Three cases of pediatric primary parapharyngeal space tumors, namely a Burkitt's lymphoma, lipoblastoma and a ganglioneuroma are described here, along with a literature review. These disorders are very rare, accounting for less than 20% of all parapharyngeal neoplasms. In comparison to adults, there are differences in pathomorphologic spectrum of pediatric parapharyngeal tumors. The authors describe the prevalence of malignant tumors, mainly soft tissues sarcomas. The salivary gland tumors and paragangliomas which dominate in adult populations, are extremely rare in pediatric populations where the most common benign tumor to be encountered is that of neurogenic origin. It follows that these features modify the diagnostic and therapeutic approach.  相似文献   
109.
The substituted benzimidazole omeprazole, used for the treatment of human peptic ulcer disease, inhibits the growth of the metronidazole-resistant bovine pathogen Tritrichomonas foetus in vitro (MIC at which the growth of parasite cultures is inhibited by 50%, 22 microg/ml [63 microM]). The antitrichomonad activity appears to be due to the inhibition of pyruvate decarboxylase (PDC), which is the key enzyme responsible for ethanol production and which is strongly upregulated in metronidazole-resistant trichomonads. PDC was purified to homogeneity from the cytosol of metronidazole-resistant strain. The tetrameric enzyme of 60-kDa subunits is inhibited by omeprazole (50% inhibitory concentration, 16 microg/ml). Metronidazole-susceptible T. foetus, which expresses very little PDC, is only slightly affected. Omeprazole has the same inhibitory effect on T. foetus cells grown under iron-limited conditions. Similarly to metronidazole-resistant cells, T. foetus cells grown under iron-limited conditions have nonfunctional hydrogenosomal metabolism and rely on cytosolic PDC-mediated ethanol fermentation.  相似文献   
110.
Telomere length was evaluated by terminal repeat fragment method (TRF) in 50 patients with myelodysplastic syndromes (MDS) and acute myelogenous leukemia (AML) arising from MDS and in 21 patients with untreated primary AML to ascertain, whether telomere erosion was associated with progression of MDS towards overt leukemia. Heterogeneity of TRF among MDS FAB subgroups (P=0.004) originated from its shortening in increased number of patients during progression of the disease. Chromosomal aberrations were present in 32% MDS patients with more eroded telomeres (P=0.022), nevertheless a difference between mean TRF in the subgroups with normal and abnormal karyotype diminished during progression of MDS. A negative correlation between individual TRF and IPSS value (P=0.039) showed that telomere dynamics might serve as a useful prognostic factor for assessment of an individual MDS patient's risk and for decision of an optimal treatment strategy.  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