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   12091篇
  免费   886篇
  国内免费   47篇
耳鼻咽喉   87篇
儿科学   374篇
妇产科学   317篇
基础医学   1708篇
口腔科学   269篇
临床医学   1422篇
内科学   2491篇
皮肤病学   325篇
神经病学   1227篇
特种医学   216篇
外科学   1017篇
综合类   78篇
一般理论   16篇
预防医学   1442篇
眼科学   238篇
药学   831篇
中国医学   46篇
肿瘤学   920篇
  2023年   128篇
  2022年   204篇
  2021年   496篇
  2020年   285篇
  2019年   380篇
  2018年   401篇
  2017年   297篇
  2016年   360篇
  2015年   360篇
  2014年   460篇
  2013年   653篇
  2012年   947篇
  2011年   965篇
  2010年   538篇
  2009年   448篇
  2008年   762篇
  2007年   749篇
  2006年   702篇
  2005年   689篇
  2004年   589篇
  2003年   593篇
  2002年   513篇
  2001年   61篇
  2000年   51篇
  1999年   53篇
  1998年   97篇
  1997年   92篇
  1996年   91篇
  1995年   71篇
  1994年   61篇
  1993年   61篇
  1992年   38篇
  1991年   46篇
  1990年   31篇
  1989年   32篇
  1988年   37篇
  1987年   34篇
  1986年   33篇
  1985年   32篇
  1984年   37篇
  1983年   44篇
  1982年   42篇
  1981年   41篇
  1980年   48篇
  1979年   15篇
  1978年   21篇
  1977年   26篇
  1975年   16篇
  1974年   15篇
  1973年   15篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
The calcifying cystic odontogenic tumor is a rare benign odontogenic lesion. This report documents a case of this lesion associated with odontoma arising from the anterior maxilla in a 14-year-old boy. The diagnosis was confirmed based on computerized tomography findings, which clearly depicted the internal structures obscured in conventional images.  相似文献   
32.
33.
34.
Crry (complement receptor 1–related protein/gene y) is a key cellular complement regulator in rodents. It is also present in Fx1A, the renal tubular preparation used to immunize rats to induce active Heymann nephritis (HN), a model of membranous nephropathy. We hypothesized that rats immunized with anti-Fx1A develop autoantibodies (auto-Abs) to Crry as well as to the megalin-containing HN antigenic complex, and that anti-Crry Abs promote the development of injury in HN by neutralizing the complement regulatory activity of Crry. Rats immunized with Fx1A lacking Crry remained free of proteinuria and glomerular deposits of C3 during a 10-wk follow-up despite typical granular immunoglobulin (Ig)G deposits in glomeruli. Anti-Fx1A auto-Abs were present in their sera at levels that were not different from sera pooled from proteinuric rats with HN induced with nephritogenic Fx1A. Passive administration of sheep anti-Crry Abs to rats immunized with Crry-deficient Fx1A led to proteinuria and glomerular C3 deposition, which were not seen in such rats injected with preimmune IgG, nor in rats with collagen-induced arthritis injected with anti-Crry IgG. To directly examine the role of Crry in HN, rats were immunized with Crry-deficient Fx1A reconstituted with rCrry. This led to typical HN, with 8 out of 15 rats developing proteinuria within 14 wk. Moreover, the extent of glomerular C3 deposition correlated with proteinuria, and anti-Crry Abs were present in glomerular eluates. Thus, Crry is a key nephritogenic immunogen in Fx1A. Formation of neutralizing auto-Abs to Crry impairs its function, leading to unrestricted complement activation by Abs reactive with the HN antigenic complex on the epithelial cell surface.  相似文献   
35.
p = 0.0007) and tumor necrosis (TN) (HMC: p = 0.0050). Univariate analysis showed that AMC or HMC was a statistically significant predictor of overall survival in all patients ( p = 0.0086 and p = 0.0307, respectively). Multivariate analysis showed that AMC was an independent predictor of node status when we fitted a model with node status, BVI, and either AMC or HMC; but HMC was not independent. However, when we fitted a model including all 11 of the other indicators and AMC or HMC, the node status, HG, and LI were independent predictors, but AMC and HMC were not. Although AMC was a better method than HMC for evaluating angiogenesis, we cannot confirm angiogenesis as a significant independent prognostic factor associated with long-term survival in Japanese breast cancer patients.  相似文献   
36.
Hexane and methanol extracts of heartwood, bark/sapwood and leaves of twelve taxa of Juniperus from the United States were assayed for antifungal and antibacterial activities. The hexane extract of the heartwood of several junipers appeared comparable in antibacterial activity to streptomycin. Antibacterial activity of the hexane extracts from the bark/sapwood of J. monosperma and J. californica were comparable to streptomycin. No appreciable antibacterial activities were found in the leaf extracts from any species examined. No antifungal activities comparable to amphotericin B were found in either hexane or methanol extracts of the heartwood nor from the bark/sapwood. Antifungal activity against Cryptococcus neoformans comparable to amphotericin B was found in the hexane extract of the leaves of J. occidentalis var. australis. The methanol extracts from the leaves of J. osteosperma and J. californica had antifungal activities comparable to amphotericin B against Trichophyton mentagrophytes.  相似文献   
37.
A simple enzyme immunoassay has been developed based on measuring antibodies to synthetic peptides corresponding to sequences in the Epstein-Barr nuclear antigen (EBNA). This assay, which is reproducible, quantitative, and simple to perform and interpret, can be an effective tool to aid in the diagnosis of infectious mononucleosis and nasopharyngeal carcinoma.  相似文献   
38.
A 528-bed community teaching hospital redesigned its patient care delivery system, implementing a collaborative practice model on the 30-bed inpatient rehabilitation unit in April 1990. This model is a patient-centered delivery model that encourages the healthcare team to facilitate the achievement of patient outcomes within effective time frames and with an appropriate use of resources. The collaborative practice model includes a nurse case manager's role for the staff nurse, which had as its framework the concept of nursing case management. Tested project management techniques were used to ensure a successful implementation process. Various strategies, such as using project teams and providing educational programs, were used to respond to the issues of role conflict and overlap, especially between social workers and nurse case managers. The implementation of this model provided a number of benefits, including improved interdisciplinary relationships and decreased length of stay.  相似文献   
39.
Effects of different inspiratory concentrations of sevoflurane (fluorometyl-1,1,1,3,3,3,-hexafluoro-2-propylether) on blood pressure, heart rate and efferent activities of cardiac sympathetic, cardiac parasympathetic and renal sympathetic nerves were examined using rats either under the resting condition or during noxious mechanical stimulation of a hindpaw. Under the resting condition, an increase in the inspiratory concentration of sevoflurane from 2.1% to 4.2% gradually caused a decrease in blood pressure and heart rate. With the increase in the sevoflurane concentration, cardiac sympathetic nerve activity decreased, whereas renal sympathetic nerve and cardiac parasympathetic nerve activities did not change significantly. When noxious mechanical stimulation was applied to a hind-paw by pinching, blood pressure and heart rate, renal sympathetic and cardiac sympathetic nerve activities all increased at the 2.1% concentration of sevoflurane. The responses of these parameters were attenuated at the 3.1% concentration of sevoflurane and almost disappeared at the 4.2% concentration. Cardiac parasympathetic nerve activity did not change significantly during the pinching stimulation throughout the 2.1–4.2% concentration increase.(Kurosawa M, Meguro K, Nagayama T et al.: Effects of sevoflurane on autonomic nerve activities controlling cardiovascular functions in rats. J Anesth 3: 109–117, 1989)  相似文献   
40.
A sensitive and accurate flow cytometry (FCM) based method has been developed to detect and quantitate a novel marine fish iridovirus (Singapore grouper iridovirus, SGIV) after amplification in cell cultures. Confluent grouper cell (GP) monolayers were infected with SGIV. When advanced cytopathic effect (CPE) appeared, the cell cultures were fixed and permeabilized, and then reacted with monoclonal antibodies specific against SGIV, followed by a second antibody conjugated with FITC (anti-mouse IgG-FITC). A Coulter EPICS Elite ESP flow cytometer was used to directly detect and analyze the percentage of virus-infected cells. Three fixation and permeabilization methods were evaluated. The kinetics of the virus infection process was determined. The FCM procedure enables large amounts of cells to be screened rapidly for infectivity, and it can also detect low levels of virus infection. As early as 8 h after inoculation with the virus, 0.34% of infected cells were detected in cell culture. The maximum level of infection was obtained at 72 h. The efficiency and reliability of the FCM procedure were compared with those of the standard methods of immunofluorescence microscopy and PCR.  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