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   1379篇
  免费   101篇
  国内免费   48篇
耳鼻咽喉   4篇
儿科学   78篇
妇产科学   29篇
基础医学   180篇
口腔科学   20篇
临床医学   175篇
内科学   312篇
皮肤病学   16篇
神经病学   70篇
特种医学   141篇
外国民族医学   1篇
外科学   128篇
综合类   22篇
预防医学   38篇
眼科学   37篇
药学   113篇
中国医学   1篇
肿瘤学   163篇
  2023年   8篇
  2022年   9篇
  2021年   19篇
  2020年   10篇
  2019年   16篇
  2018年   27篇
  2017年   9篇
  2016年   13篇
  2015年   18篇
  2014年   28篇
  2013年   32篇
  2012年   50篇
  2011年   42篇
  2010年   43篇
  2009年   37篇
  2008年   33篇
  2007年   73篇
  2006年   44篇
  2005年   53篇
  2004年   50篇
  2003年   30篇
  2002年   48篇
  2001年   51篇
  2000年   40篇
  1999年   48篇
  1998年   53篇
  1997年   41篇
  1996年   46篇
  1995年   35篇
  1994年   28篇
  1993年   33篇
  1992年   38篇
  1991年   30篇
  1990年   28篇
  1989年   48篇
  1988年   52篇
  1987年   45篇
  1986年   36篇
  1985年   29篇
  1984年   22篇
  1983年   18篇
  1982年   11篇
  1981年   6篇
  1980年   8篇
  1979年   14篇
  1978年   8篇
  1977年   16篇
  1976年   7篇
  1975年   7篇
  1969年   5篇
排序方式: 共有1528条查询结果,搜索用时 59 毫秒
71.
It is now recognised that epithelial-stromal interactions are important in a wide range of disease processes including neoplasia and inflammation. Metalloproteinases are central to matrix degradation and remodelling, which are key events in tumour invasion and metastasis and may also be involved in tissue changes occurring in chronic inflammation. Immunohistochemistry was performed on sections from 50 patients with pancreatic cancer (n = 27), ampullary cancer (n = 12), low bile duct cancer (n = 3), neuroendocrine tumours (n = 3) and chronic pancreatitis (n = 5), using antibodies raised against collagenase (MMP2), stromelysin (MMP3) and tissue inhibitor of metalloproteinase (TIMP1) and developed using the avidin-biotin complex method. Abundance of MMP2, MMP3 and TIMP1 was greater in pancreatic and ampullary cancer than any other pathology and immunoreactivity in the malignant epithelial cells in pancreatic and ampullary cancer was greater than in the stromal tissues (in pancreatic cancer: MMP2 100% vs 37%, MMP3 93% vs 15%, TIMP1 93% vs 4%, P < 0.0001). There were strong correlations between the immunoreactivity of the two antibodies for MMP2 (P < 0.0001), between MMP2 and TIMP1 (P < 0.0001) and between MMP3 and TIMP1 (P < 0.0001). The immunoreactivity for TIMP1 in pancreatic and ampullary cancers with lymph node metastases was significantly less compared with those cases without lymph node metastases (P < 0.02) and there was an association between increased immunoreactivity for MMP2 and the degree of tumour differentiation (P < 0.01). The results implicate MMP2, MMP3 and TIMP1 in the invasive phenotype of pancreatic and ampullary cancer.  相似文献   
72.
73.
The production of cytotoxic T cells with specificity for cancer cells is a rapidly evolving branch of cancer therapeutics. A variety of approaches aim to amplify anti-tumour cytotoxic T cell responses using purified peptides, tumour cell lysates or recombinant HLA/peptide complexes in differing antigen presenting systems. Using a two-step biotin-streptavidin antibody targeting system, recombinant HLA-class I/peptide complexes were attached to the surface of B cells via the anti-CD20 B9E9-scFvSA antibody-streptavidin fusion protein. Flow cytometry with a conformation dependant monoclonal antibody to HLA class I indicated that targeted HLA-class I/peptide complexes remain on the surface of B cells in culture for periods in excess of 72 h. PBMCs were stimulated in vitro for 8-14 days using the autologous B cells as antigen presenting cells. Following a single cycle of stimulation specific cytotoxic T cell responses to targeted HLA-A2 complexes containing the M1, BMLF1 and Melan A peptides could be demonstrated by tetramer staining and Cr release assays. With the HLA-A2/BMLF1 complex up to 2.99% of CD8+ve cells were tetramer positive producing 20% lysis (E : T 10 : 1) of CIR-A2 target cells in an in vitro cytotoxicity assay compared to baseline levels of 0.09% tetramer +ve and 2% lysis in the unstimulated population. PBMCs from a healthy donor treated with two cycles of stimulations with targeted HLA-A2/Melan A complexes, demonstrated expansion of the melanA tetramer +ve population from 0.03% to 1.4% producing 15% lysis of Melan A pulsed target cells. With further consideration to the key variables of HLA/peptide complex density, the ratio of stimulator to effector cells and optimum cytokine support, this system should offer an easy and effective method for the in vitro amplification of specific cytotoxic T cell responses and warrants development for the in vivo induction of cytotoxic T cell responses in cancer therapy.  相似文献   
74.
INTRODUCTION: Irregular work schedules often results in a disruption of the normal circadian rhythm that can causes sleepiness when wakefulness is required and insomnia during the main sleep episode. METHOD: Two physicians using the Sleep-EVAL system interviewed 817 staff members of a psychiatric hospital. The interviews were done during the working hours. In addition to a series of questions to evaluate sleep and mental disorders, the evaluation included a standard questionnaire assessing work conditions, work schedule and their consequences. Three work schedules were assessed: (1) fixed daytime schedule (n=442), (2) rotating daytime shifts (n=323) and (3) shift or nighttime work (n=52). RESULTS: Subjects working on rotating daytime shifts were younger than the two other groups and had a higher proportion of women. Participants working on rotating daytime shifts reported more frequently than the fixed daytime schedule workers to have difficulty initiating sleep (20.1% vs. 12.0%). The sleep duration of shift or nighttime workers was shorter than that of the two other groups. Furthermore, subjects working rotating daytime schedule reported to have shorter sleep duration of about 20 min when they are assigned to the morning shift. Work-related accidents were two times more frequent among the rotating daytime workers (19.5%) compared with the fixed daytime schedule workers (8.8%) and the group of nighttime or shift workers (9.6%). Sick leaves in the previous 12 months were also more frequently reported in the rotating daytime schedule group (62.8%) as compared with the daytime group (38.5%, P<.001); 51.9% of nighttime or shift workers took sick leave. CONCLUSIONS: Working on a rotating daytime shifts causes significant sleep disturbances. As consequences, these workers are more likely to feel sleepy at work and are more likely to have work-related accidents and sick leaves.  相似文献   
75.
Incidence of drug-induced hepatic injuries: a French population-based study   总被引:24,自引:0,他引:24  
The incidence of hepatic adverse drug reactions (ADRs) remains unknown in the general population. The goal of this population-based study was to assess the incidence and seriousness of hepatic ADRs. All new cases of symptomatic drug-induced hepatic injuries were collected by 139 trained physicians (general practitioners [GPs] and specialists) between November 1997 and November 2000 in an area containing 81,301 inhabitants who could not go elsewhere for medical care. Over 3 years, 34 cases of hepatic ADRs were collected, 82% of them in outpatients. Global crude annual incidence rate was 13.9 +/- 2.4 per 100,000 inhabitants; corresponding standardized annual global rate was 8.1 +/- 1.5. There was no difference between urban and rural areas. Standardized incidence female/male ratio was 0.86 (0.26-2.90) until 49 years of age and 2.62 (1.00-6.92) after this age. Diagnosis was carried out by GPs in half of the cases. The outcome was recovery for 32 patients and death for 2. The main drugs implicated were anti-infectious, psychotropic, hypolipidemic agents, and nonsteroidal anti-inflammatory drugs (NSAIDs). Our results suggest that the number of hepatic ADRs in the French population would be 16 times greater than the number noted by spontaneous reporting to French regulatory authorities. In conclusion, the incidence and seriousness of drug-induced hepatitis are largely underestimated in the general population. These results may be useful for further evaluation of drug-induced hepatotoxicity.  相似文献   
76.
临床资料 2003-02/2004—10,难治性青光眼36例36眼,(男19,女17)例;年龄37—81(平均59.6)岁;术前视力:无光感6例,光感15例,手动13例,眼前数指2例;术前眼压:在5.59—10.77(平均8.01)kPa;1例系玻切术后继发性青光眼,35例系新生血管性青光眼(其中:视网膜静脉阻塞15例,糖尿病视网膜病变18例,原因不明2例).①眼内窥镜下睫状体光凝术18例:在角膜缘环形剪开结膜,充分止血;在  相似文献   
77.
The outer supporting cells in the apical turns of the guinea pig cochlea receive a dense innervation. Our previous study (Fechner et al. [1998] J. Comp. Neurol. 400:299-300) suggested that this innervation of the Deiters' and Hensen's supporting cells was not derived from efferent fibers of the olivocochlear bundle, but its origin has not been further specified. To test the hypothesis that the innervation was afferent in origin, we traced apical afferent fibers that were retrogradely labeled by extracellular injections of horseradish peroxidase. Labeled afferent fibers were of two types: type I fibers contacted inner hair cells, whereas type II fibers crossed the tunnel and contacted outer hair cells. Significantly, most of the type II fibers also formed branches to the outer supporting cells. Although a few olivocochlear efferent fibers formed such branches, counts indicated that the overwhelming majority of the branches were produced by type II afferent fibers. These branches were not produced by basal type II fibers. Apical type II fibers also differed from basal fibers by having shorter lengths, spiraling both apically and basally, and contacting all three rows of outer hair cells. These innervation differences suggest differences in the ways that information from outer hair cells is processed in the apex versus the base of the cochlea.  相似文献   
78.
79.
ABSTRACT We report an unusual case of bilateral chronic conjunctivitis and corneal scarring in a boy with X-linked hypogammaglobulinaemia (XLH) who did not respond to the usual antibacterial and antiviral therapy. An immunofluorescence test for Chlamydia trachomatis from an eye swab was strongly positive. Within days of commencement of local and systemic tetracycline therapy, he showed marked improvement. Since conjunctival follicle formation, which depends on the presence of a B-cell population, may not occur in XLH, clinical examination in chlamydia conjunctivitis may be misleading and lead to a delay in diagnosis and treatment with resulting corneal complications, unless laboratory evidence of chlamydia infection is specifically sought.  相似文献   
80.
Objective : To describe survival patterns, use of health services and related costs for Australian children with perinatally acquired human immunodeficiency virus (HIV) infection.
Methodology : A retrospective cross-sectional survey was made of 20 children with HIV infection (91% of those diagnosed) and 13 children with maternal antibodies who subsequently seroreverted, treated at 10 medical centres. Details of disease progression and use of health services were obtained from hospital medical records. Monthly costs for three phases of infection were estimated by linking service usage rates with estimates of the unit cost of each service. The average lifetime cost was estimated by combining monthly costs and phase duration estimates from the literature.
Results : Patterns of disease progression were similar to those reported internationally, with a median survival of 8 years. Use, of health services increased with severity of illness. Mean monthly costs were $120 per month (1992 Australian dollars) for children with maternal antibodies who subsequently seroreverted, $320 per month for children with HIV infection but no acquired immunodeficiency syndrome (AIDS)-defining illness, and $1830 per month for children with AIDS. The present value of total lifetime cost for a child with HIV infection was $48174,46% of which was for treatment of AIDS.
Discussion : The mean lifetime cost for a perinatally infected child was just over half that for a man with HIV in Australia. Health service usage and costs were lower for Australian than American children with HIV.  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