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   13982篇
  免费   813篇
  国内免费   54篇
耳鼻咽喉   106篇
儿科学   340篇
妇产科学   276篇
基础医学   1924篇
口腔科学   555篇
临床医学   1828篇
内科学   2668篇
皮肤病学   149篇
神经病学   1426篇
特种医学   416篇
外科学   1972篇
综合类   68篇
一般理论   9篇
预防医学   1039篇
眼科学   201篇
药学   1010篇
中国医学   9篇
肿瘤学   853篇
  2023年   114篇
  2022年   113篇
  2021年   262篇
  2020年   223篇
  2019年   265篇
  2018年   360篇
  2017年   294篇
  2016年   391篇
  2015年   383篇
  2014年   497篇
  2013年   794篇
  2012年   868篇
  2011年   929篇
  2010年   684篇
  2009年   689篇
  2008年   845篇
  2007年   860篇
  2006年   839篇
  2005年   820篇
  2004年   749篇
  2003年   668篇
  2002年   649篇
  2001年   135篇
  2000年   109篇
  1999年   145篇
  1998年   145篇
  1997年   114篇
  1996年   97篇
  1995年   74篇
  1994年   96篇
  1993年   79篇
  1992年   86篇
  1991年   77篇
  1990年   50篇
  1989年   60篇
  1988年   68篇
  1987年   67篇
  1986年   70篇
  1985年   73篇
  1984年   78篇
  1983年   66篇
  1982年   69篇
  1981年   52篇
  1980年   53篇
  1979年   56篇
  1978年   56篇
  1977年   49篇
  1976年   44篇
  1975年   44篇
  1954年   90篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
181.
182.
We compared the efficacy of the Medoff sliding plate (MSP) with 3 other screw-plate systems for fixation of unstable intertrochanteric fractures in a randomized multicenter trial of 569 elderly patients. The MSP has biaxial dynamic capacity along both the neck and the shaft of the femur unlike the other systems, which lack dynamic capacity along the shaft. 268 fractures were operated on with the MSP, and 301 with the dynamic hip screw (DHS), with or without a trochanteric stabilizing plate (DHS/TSP) or with the dynamic condylar screw (DCS). The MSP had recently been shown to the surgeons.The patients in the groups were similar as regards age, domestic situation, preinjury walking ability and type of fracture. We followed the patients clinically and radiographically for at least 1 year. There was no significant difference in walking ability at follow-up or rate of return to home. Fixation failure occurred in 18/268 fractures operated on with the MSP, in 8/238 with the DHS, in 3/49 with the DHS/TSP and in 1/14 with the DCS. The difference in the rate of fixation failure was not statistically significant when the MSP group was compared to the 3 other groups. In 14 of the 18 fixation failures in the MSP group, the biaxial dynamic capacity of the MSP had not been used due to technical errors by surgeons, unfamiliar with the new method. No selection bias was found regarding fracture types in the 2 subgroups of patients with correct or inadequate biaxial dynamization. Extramedullary fixation of unstable intertrochanteric fractures with these implants showed a low failure rate. When using the MSP, biaxial dynamization must be correctly performed.  相似文献   
183.
184.
185.
Chronic myeloproliferative neoplasms (MPN), encompassing essential thrombocythaemia (ET), polycythaemia vera (PV) and myelofibrosis (PMF), are featured by a chronic inflammatory state which is pronounced in myelofibrosis The value of YKL‐40 as a biomarker of disease burden has been demonstrated in several different diseases, including cancer, diabetes mellitus and cardiovascular diseases. A state of chronic inflammation is shared by them all, YKL‐40 also being involved in the severity of chronic endothelial inflammation, which today is considered of crucial importance for the development of atherosclerosis. The MPNs being cancers with a heavy burden of cardiovascular diseases we hypothesised that circulating YKL‐40 might reflect the inflammatory process and potentially serve as a novel disease marker. Using ELISA, we measured YKL‐40 in 15 patients with ET, 16 patients with PV, 17 patients with PMF and 30 healthy controls. YKL‐40 was significantly elevated in PMF vs. control subjects, PMF levels median 43 ng/mL vs. controls median 28 ng/mL, P = 0.033. An increase from ET over PV may reflect the integrated impact of disease processes in MPNs.  相似文献   
186.
Despite major improvements concerning its diagnosis and treatment, pancreatic ductal adenocarcinoma (PDAC) remains an aggressive disease with an extremely poor prognosis. Pathology, as interface discipline between basic and clinical medicine, has substantially contributed to the recent developments and has laid the basis for further progress. The definition and classification of precursor lesions of PDAC and their molecular characterization is a fundamental step for the potential identification of biomarkers and the development of imaging methods for early detection. In addition, by integrating findings in humans with the knowledge acquired through the investigation of transgenic mouse models for PDAC, a new model for pancreatic carcinogenesis has been proposed and partially validated in individuals with genetic predisposition for PDAC. The introduction and validation of a standardized system for pathology reporting based on the axial slicing technique has shown that most pancreatic cancer resections are R1 resections and that this is due to inherent anatomical and biological properties of PDAC. This standardized assessment of prognostic relevant parameters represents the basis for the successful conduction of multicentric studies and for the interpretation of their results. Finally, recent studies have shown that distinct molecular subtypes of PDAC exist and are associated with different prognosis and therapy response. The prospective validation of these results and the integration of molecular analyses in a comprehensive pathology report in the context of individualised cancer therapy represent a major challenge for the future.  相似文献   
187.
188.
189.
190.
The aim was to study the relation between risk attitude and knowledge in technical, patient-oriented, and organizationally related behavior within oral radiology. A questionnaire was mailed to 2000 randomly selected dentists listed in the register of the Swedish Dental Society, with a response rate of 69.3%. Regression analysis was used for analyzing the effects of the independent variables knowledge, risk attitude, continuing education in oral radiology, counties with specialists in oral radiology, type of practice, work experience, and sex on three categories of dependent variables: 1) technical behaviors: type of film, type of collimator, dose level, frequency of change of chemicals; 2) patient-oriented behaviors: use of patient protection barriers, strict indications for performing full-mouth X-ray examinations and bitewing radiography on new patients and recall patients; and 3) organizationally related behaviors: delegation of X-ray examinations to dental auxiliaries, influence on choice of collimator, influence on choice of film. Knowledge and education had strong direct effects for most of the dependent variables. The technical behaviors were mainly influenced by knowledge, education, and risk attitude, while organizationally related behaviors were influenced by type of practice and sex. The patient-oriented behaviors were influenced by a number of independent variables, such as education, type of practice, work experience, and sex. The present results indicate that both knowledge and the organizational context of dentists influence work.  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