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   7498篇
  免费   329篇
  国内免费   22篇
耳鼻咽喉   122篇
儿科学   86篇
妇产科学   86篇
基础医学   927篇
口腔科学   178篇
临床医学   372篇
内科学   1719篇
皮肤病学   133篇
神经病学   556篇
特种医学   182篇
外科学   1542篇
综合类   33篇
预防医学   182篇
眼科学   192篇
药学   632篇
中国医学   34篇
肿瘤学   873篇
  2023年   44篇
  2022年   67篇
  2021年   133篇
  2020年   69篇
  2019年   100篇
  2018年   122篇
  2017年   102篇
  2016年   129篇
  2015年   131篇
  2014年   146篇
  2013年   219篇
  2012年   316篇
  2011年   339篇
  2010年   174篇
  2009年   180篇
  2008年   301篇
  2007年   336篇
  2006年   321篇
  2005年   316篇
  2004年   330篇
  2003年   346篇
  2002年   310篇
  2001年   272篇
  2000年   337篇
  1999年   264篇
  1998年   84篇
  1997年   46篇
  1996年   42篇
  1995年   52篇
  1994年   42篇
  1993年   49篇
  1992年   195篇
  1991年   154篇
  1990年   199篇
  1989年   195篇
  1988年   176篇
  1987年   173篇
  1986年   191篇
  1985年   134篇
  1984年   94篇
  1983年   70篇
  1981年   28篇
  1980年   28篇
  1979年   73篇
  1978年   54篇
  1977年   40篇
  1975年   31篇
  1974年   39篇
  1973年   33篇
  1972年   33篇
排序方式: 共有7849条查询结果,搜索用时 15 毫秒
81.
AIMS: To investigate the relation between localised amyloidosis and immunocytic dyscrasia. METHODS: Open lung biopsy specimens from a 72 year old man with multiple nodules in the right middle and lower lung were stained with haematoxylin-eosin, Congo red, and antibodies against IgG, IgA, IgM, and kappa and lambda light chains. Semi-nested PCR amplification for the immunoglobulin heavy chain (IgH) gene was performed using consensus primers for the VDJ region of the IgH gene, FR3A, LJH, and VLJH. RESULTS: The biopsy specimens contained eosinophilic amorphous material stained with Congro red and anti-kappa light chain, and surrounded by inflammatory cells intermingled with plasma cells. Plasma cells in the adjacent amorphous material showed cytoplasmic staining with anti-kappa. Polymerase chain reaction revealed a discrete amplified band of apparently uniform size with background smear. CONCLUSIONS: Primary AL type localised amyloidosis involves local accumulation of monoclonal plasma cells and their secreted products, as in nodular cutaneous amyloidosis. Localised AL type nodular amyloidosis is a separate entity in amyloidosis.  相似文献   
82.
Human primary hepatocellular carcinoma (PLC/342), carried by nude mice, produces hepatitis B core particles as well as hepatitis B surface antigen particles. Core particles purified form PLC/342 tumors displayed epitopes of hepatitis B core antigen (HBcAg) but not epitopes of hepatitis B e antigen (HBeAg) on their surface, unlike core particles prepared from Dane particles, derived from plasma of asymptomatic carriers, that expressed epitopes of both HBcAg and HBeAg. Core particles obtained from PLC/342 tumors were applied to the determination of antibody to HBcAg (anti-HBc) by passive hemagglutination. The assay detected anti-HBc not only in individuals with persistent infection with hepatitis B virus and in those who had recovered from transient infection, but also in patients with acute type B hepatitis, indicating that it can detect anti-HBc of either IgG or IgM class. A liberal availability of core particles from tumors carried by nude mice, taken together with an easy applicability of the method, would make the passive hemagglutination for anti-HBc a valuable tool in clinical and epidemiological studies, especially in places where sophisticated methods are not feasible.  相似文献   
83.
84.
BACKGROUND: In Japan in 1993, the Japanese Society of Allergology (JSA) developed guidelines for diagnosis and management of asthma (JGL), which were based on the concept that asthma is a chronic inflammatory disorder of the airway. METHODS: This survey study was intended to investigate the recognition and utilization of JGL among physicians who had treated asthma. The survey comprised two methods: a quantitative mail survey and a qualitative door-to-door survey conducted by trained interviewers. RESULTS: In the mail survey, a total of 1028 physicians responded; 552 members of the JSA and 476 nonmembers. Ninety-four percent of JSA members were aware of adult asthma management guidelines, while 53% of nonmembers were aware of them. Although approximately half of the physicians, both members and nonmembers, found differences between the asthma management policies in JGL and their previous policies, most of them utilized JGL once they read it. In the qualitative door-to-door survey, 80-90% of physicians evaluated JGL as good after they read it. CONCLUSIONS: JGL was recognized and utilized by most JSA members, but only half of nonmember physicians were aware of JGL, although they utilized JGL after they read it. Further action to implement JGL among nonspecialist physicians is needed to improve management of asthma.  相似文献   
85.
86.
A photografting technique to produce functional groups of silanol able to induce apatite nucleation was attempted on polyethylene substrate for biomimetic formation of bone-mineral-like apatite layer on its surface. The polyethylene surface was subjected to vapor-phase photografting of vinyltrimethoxysilane and subsequently to hydrolysis. The photografting formed methoxysilyl groups on the polyethylene substrate, which was changed into silanol groups successively by the hydrolysis in a hydrochloric solution. The polyethylene modified in this way formed a dense and homogeneous bone-mineral-like apatite layer in a solution with ion concentrations 1.5 times that of human blood plasma. This result indicates that the biomimetic process in combination with a polymeric grafting technique might provide a homogeneous bone-mineral-like apatite coating even on polymer fibers to be woven into an apatite-polymer composite with three-dimensional structure analogous to that of natural bone.  相似文献   
87.
AIMS: We investigated a rare case of small vessel vasculitis (SVV) limited to pleuropulmonary manifestations, possibly induced by endotoxin, to determine the activation of immuno-mediated cells and endothelia in the pleuropulmonary circulation. METHODS AND RESULTS: A 44-year-old man with a high fever was X-rayed, revealing bilateral pleural effusion and atelectasis in the chest. His laboratory data were within normal limits except for a high white blood cell count and a high C-reactive protein level. Autoantibodies including anti-neutrophil cytoplasmic antibody were negative. Endotoxin was detected in his sera, but repeated cultures of sputa, urine, blood and the pleural effusion were negative for bacteria. Video-assisted thoracic surgery was performed and lung and parietal pleura specimens were obtained. Histology showed arterioles or small arteries infiltrated by monocytes or neutrophils with fibrinoid necrosis and acute or chronic venulitis. A diagnosis of SVV in the lung and pleura was made. Immunohistochemistry revealed that interleukin (IL)-1beta was expressed in monocytes and vascular cell adhesion molecule (VCAM)-1 on endothelial cells in the vasculitic lesions in the lung. CONCLUSIONS: Endotoxin possibly induced the inflammation in this apparently unique case of pleuropulmonary small vessel vasculitis. Immunohistochemistry revealed the expression of IL-1beta and VCAM-1 which may have caused activation of monocytes and endothelial cells within the vasculitic lesions.  相似文献   
88.
The effectiveness of the clinical pathway for laparoscopic cholecystectomy was evaluated, and the efficiency of medical care was analyzed. The duration of hospitalization and the number of National Health Insurance (NHI) points for medical service fees were compared between 86 patients treated after introduction of the clinical pathway (pathway group) and 56 patients treated before introduction of the clinical pathway (pre-pathway group). In the pathway group, variance from the pathway occurred in 24 patients (27.9%) due to postponement of discharge in 7 patients, to earlier discharge in 5 patients, and to insertion of a bile duct catheter in 5 patients. Total and postoperative hospitalization times were significantly shorter in the pathway group than in the pre-pathway group (8.0 +/- 1.6 vs 13.7 +/- 9.0 days, p<0.0001, 5.4 +/- 1.1 vs 6.5 +/- 2.2 days, p<0.0001, respectively). In the pathway group, the total number of NHI points was lower and the number of points per day was higher. By simulation, the total number of NHI points for the 5-day pathway (discharge on postoperative day 3 or earlier) was significantly lower than that for the current 7-day pathway. Moreover, the weekly profit per bed with the 3-day pathway (discharge on postoperative day 1) was more than twice that with the current pathway. The results suggest that the clinical pathway for laparoscopic cholecystectomy is beneficial for patients and useful for the introduction of diagnosis procedure combination in our hospital.  相似文献   
89.
The method of electrical impedance measurement was tested for its usefulness in monitoring of extra-cellular fluid (ECF) in the dog submandibular gland during salivary secretion. Measurements were performed during rest and stimulated state with or without blood supply. During stimulation with blood supply, the conductivities of the gland decreased to some extent. During stimulation without blood supply, the decrease in conductivities was markedly enhanced. The decrease of ECF compartment during stimulation without blood supply was ascertained by the stereological measurement. Coincidence of conductivity decrease and histologically observed decrease of ECF compartment supports the usefulness of impedance measurement for monitoring of ECF during secretory activity of gland tissue. The present study also shows that the interlobular space decreased mainly during stimulation when blood supply is absent. This indicates that, among ECF space, the interlobular space plays an important role as a fluid reservoir in the salivary gland.  相似文献   
90.
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