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   409篇
  免费   46篇
  国内免费   2篇
耳鼻咽喉   4篇
儿科学   22篇
妇产科学   5篇
基础医学   74篇
口腔科学   29篇
临床医学   34篇
内科学   82篇
皮肤病学   12篇
神经病学   22篇
特种医学   61篇
外科学   50篇
综合类   12篇
预防医学   6篇
药学   15篇
  1篇
肿瘤学   28篇
  2022年   2篇
  2021年   5篇
  2020年   7篇
  2019年   2篇
  2018年   10篇
  2017年   4篇
  2016年   11篇
  2015年   24篇
  2014年   26篇
  2013年   27篇
  2012年   20篇
  2011年   13篇
  2010年   27篇
  2009年   12篇
  2008年   8篇
  2007年   5篇
  2006年   6篇
  2005年   8篇
  2004年   4篇
  2003年   3篇
  2002年   3篇
  2001年   9篇
  2000年   2篇
  1999年   7篇
  1998年   20篇
  1997年   20篇
  1996年   30篇
  1995年   15篇
  1994年   21篇
  1993年   13篇
  1992年   4篇
  1991年   2篇
  1990年   5篇
  1989年   4篇
  1988年   15篇
  1987年   4篇
  1986年   6篇
  1985年   10篇
  1984年   6篇
  1983年   8篇
  1982年   3篇
  1981年   2篇
  1980年   3篇
  1979年   3篇
  1977年   7篇
  1976年   4篇
  1975年   3篇
  1965年   1篇
  1963年   1篇
  1961年   1篇
排序方式: 共有457条查询结果,搜索用时 31 毫秒
51.
H. pylori infection has recently been associated with various vascular disorders. The aim of this study was to investigate its role in primary headache, a pathology strictly associated with vascular alterations. A total of 200 subjects affected by primary headache were evaluated. H. pylori infection was diagnosed by the 13C urea breath test. Headache was classified in tension-type headache, cluster headache, and migraine with or without aura. Prevalence of H. pylori infection and gastrointestinal (GI) symptoms were evaluated. H. pylori infection was found in 40% of the patients; prevalence of migraine without aura was found to be significantly greater in infected patients. The positive group showed no significant differences in the prevalence of the GI symptoms evaluated. In 30 infected patients, it was assessed whether the eradication of the bacterium was able to reduce frequency, intensity, and duration of clinical attacks of headache. After eradication, clinical attacks of headache completely disappeared in 17% of patients. Moreover, intensity, duration, and frequency of headache attacks were reduced in 69% of the remaining subjects. In conclusion, H. pylori infection is common in primary headache; bacterium eradication appears to be related to a significant reduction in clinical attacks of the disease.  相似文献   
52.
Datta  R; Banach  D; Kojima  H; Talanian  RV; Alnemri  ES; Wong  WW; Kufe  DW 《Blood》1996,88(6):1936-1943
The response of human myeloid leukemia cells to treatment with 1-beta- arabinofuranosylcytosine (ara-C) includes the induction of apoptosis. Ara-C induced apoptosis is associated with proteolytic cleavage of poly(ADP-ribose) polymerase (PARP) and protein kinase C (PKC) delta. However, the signals involved in this response are unknown. The present studies show that ara-C treatment of U-937 cells is associated with induction of a protease activity that cleaves the tetrapeptides Ac-DEVD- pNA and Ac-DMOD-pNA found at the cleavage sites of PARP and PKC delta, respectively. The ara-C-induced protease activity was sensitive to overexpression of the anti-apoptotic protein Bcl-xL and the baculovirus protein p35. By contrast, overexpression of the cowpox virus protein CrmA blocked apoptosis induced by engagement of the Fas receptor but not that induced by ara-C. CrmA overexpression also had no detectable effect on ara-C-induced cleavage of PKC delta. The results further show that ara-C induces activation of the CPP32 protease by a CrmA- insensitive and p35-sensitive mechanism. Similar results were obtained with cisplatinum, etoposide, and camptothecin. These findings indicate that ara-C and other DNA-damaging agents activate a CrmA-insensitive apoptotic pathway involving CPP32 and that these signals differ from those associated with apoptosis induced by the Fas receptor.  相似文献   
53.

Background

The effect of dialysis treatment is complex, with both clinical and socio-psychological effects. In this study, we aimed to assess the psychological status of this growing population of end-stage renal disease.

Methods

Using the Short Form of Depression, Anxiety and Stress Scale (DASS21) questionnaire, we aimed (1) to measure the psychological states of hemodialysis (HD) or peritoneal dialysis (PD) subjects from 15 sites, (2) to compare DASS21 scores between HD and PD, and (3) to identify the associated demographic and medical factors of better psychological states.

Results

A total of 1,332 were eligible for analysis. Stress (48%) recorded the highest negative emotional states, followed by depression (37%) and anxiety (20%). By multivariate analysis, normal body mass index weight status, religion and absence of coronary artery disease were associated with lower score for depression, anxiety and stress, respectively. Tertiary education was associated with the lowest score in depression and anxiety, whereas HD had a lower score in stress than PD. A younger age was associated with worse DASS21 score of anxiety and stress.

Conclusions

Obesity, religion and coronary artery disease were significantly associated with all 3 symptoms of depression, anxiety and stress. Older age has a protective effect on anxiety and stress. Further study is needed to evaluate the relationship between these significant factors and each psychological state.  相似文献   
54.
Private health insurance plays a key role in financing dental care in Australia. Having private dental insurance has been associated with higher levels of access to dental care, visiting for a check‐up and receiving a favourable pattern of services. Associations with better oral health have also been reported. In the absence of any existing review, this paper aims to systematically review the relationship between dental insurance and dental service use and/or oral health outcomes in Australia. A systematic search of online databases and subsequent sifting resulted in 36 publications, 33 of which were cross sectional and three cohort analyses. Dental service outcomes were more commonly reported than oral health outcomes. There was considerable heterogeneity in the outcome measures reported, for both service use and health outcomes. Overall, the majority of the evidence was from cross sectional studies and few studies reported analyses adjusted for confounding factors. The consolidated evidence points towards a positive association between dental insurance and dental visiting. Dentally insured adults are likely to have more regular access to dental care and have a more favourable pattern of service use than the uninsured. However, evidence of associations between dental insurance and oral health are mixed.  相似文献   
55.
56.
PIXY321 is a novel fusion protein of recombinant human granulocyte- macrophage colony-stimulating factor and interleukin-3 that exhibits biologic effects of both its parent cytokines in vitro and in preclinical studies. To evaluate the clinical safety and hematopoietic effects of this hybrid cytokine, PIXY321 was administered by subcutaneous injection twice daily at doses of 25 to 1,000 micrograms/m2/day over 14 days to 24 patients with sarcoma before chemotherapy as part of a phase I trial. The treatment was associated with significant increases in white blood cell, neutrophil, platelet, and reticulocyte counts (all P < .001). The increase in neutrophil count was dose-related and was seen during treatment with the cytokine, whereas the increase in platelet count was gradual and peaked after the cessation of the cytokine treatment and was not clearly dose related. PIXY321 treatment also increased bone marrow (BM) cellularity and the percentage of BM cells in S phase (P < .001). In addition, there was a significant increase in the number of CD34+ cells and committed and multipotential progenitors in the peripheral blood. The ex vivo expansion capacity of peripheral blood and BM progenitor cells was preserved after the in vivo treatment with PIXY321. The treatment was well tolerated, with the most common side-effect being injection site reactions. The results of this study show the biologic and clinical activity of a genetically engineered fusion molecule of two hematopoietic cytokines in humans with normal hematopoietic function.  相似文献   
57.
Braziel  RM; Sussman  E; Jaffe  ES; Neckers  LM; Cossman  J 《Blood》1985,66(1):128-134
B cell neoplasms are clonal expansions of B lymphocytes thought to be frozen at various points along the normal B cell differentiation pathway. We studied cell suspensions from lymph nodes involved by follicular (nodular) non-Hodgkin's lymphoma to determine the capacity of the malignant B cells to secrete immunoglobulin (Ig). Neoplastic B cells from all 14 follicular lymphomas secreted monoclonal immunoglobulin in culture when appropriate signals were provided. In most cases, maximal Ig secretion occurred when autologous T cells were removed by E rosette depletion, replaced with allogeneic normal T cells, and the cultures were exposed to 12-O-tetradecanoylphorbol-13- acetate. Autologous T cells exerted a suppressor effect on Ig secretion in 8/8 cases studied, diminishing the response of the malignant B cells to allogeneic T cells. This suppressor effect did not correlate with the percentage of cells staining with anti-Leu-2a or with "helper- suppressor" (Leu-3a-Leu-2a) ratios of the lymph node T cells. Our findings demonstrate that the arrested differentiation of most follicular lymphomas is reversible and implicate a T cell-mediated host immunoregulatory mechanism affecting Ig secretion in vivo. An additional contribution of our results is the demonstration of a cell culture system for synthesis of sufficient monoclonal Ig for use as an immunogen in production of anti-idiotype antibodies.  相似文献   
58.
Cossman  J; Jaffe  ES 《Blood》1981,58(1):20-26
Surface receptors specific for either the C4b (CR1) or C3d (CR2) component of complement were examined on the neoplastic cells from 30 cases of non-Hodgkin's lymphoma of B-cell origin and on cells derived from 9 normal lymphoid tissues. Lymphocyte suspensions from non- neoplastic peripheral blood, tonsils, and lymph node contained three categories of complement receptor lymphocytes (CRL): cells with receptors for both C4b and C3d (CR1+, CR2+); cells with receptors for C4b but not C3d (CR1+, CR2-), and cells with receptors for C3d but not C4b (CR1-, CR2+). The mean of the proportion of total CRL expressing receptors only of C3d (CR1-, CR2+) was 0.35 for non-neoplastic tissues and 0.28 for malignant lymphomas of follicular center cell (FCC) origin. However, the proportion of cells with this phenotype was significantly higher in well differentiated lymphocytic lymphomas (WDL) and chronic lymphocytic leukemia (CLL) (0.65) and in intermediately differentiated lymphocytic lymphomas (IDL) (0.59). Histologic compartmentalization of the CRL subtypes was observed in frozen sections of normal lymphoid tissue. CR1+ cells were present in lymphoid follicles interfollicular areas, and in splenic red pulp. CR2+ cells were confined to lymphoid follicles. These findings strongly suggest that complement receptor phenotypes may be useful markers of B-cell differentiation.  相似文献   
59.
Ghetie  MA; Picker  LJ; Richardson  JA; Tucker  K; Uhr  JW; Vitetta  ES 《Blood》1994,83(5):1329-1336
In this report, we extend our previous findings that IgG or F(ab')2 fragments of HD37 anti-CD19 antibody (Ab) in combination with the immunotoxin (IT), RFB4-anti-CD22-deglycosylated ricin A chain (dgA) (but neither reagent alone), prolonged the survival of SCID mice with disseminated human Daudi lymphoma (SCID/Daudi mice) to 1 year at which time they still remained tumor-free. We explored the mechanisms by which the HD37 Ab exerts antitumor activity in vivo by studying its activity in vitro. We found that it has antiproliferative activity (IC50 = 5.2 - 9.8 x 10(-7) mol/L) on three CD19+ Burkitt's lymphoma cell lines (Daudi, Raji, and Namalwa) but not on a weakly CD19-positive (CD19lo) pre-B cell tumor (Nalm-6). The inhibitory effect was manifested by cell cycle arrest, but not apoptosis. Results using three additional anti-CD19 Abs, suggest that the affinity of the antibody and possibly the epitope which it recognizes may effect its capacity to transmit a signal that induces cell cycle arrest. Hence, therapeutically useful Abs may exert anti-tumor activity by a variety of mechanisms, each of which should be evaluated before undertaking clinical trials in humans.  相似文献   
60.
We examined if height loss in older women predicts risk of hip fractures, other nonspine fractures, and mortality, and whether this risk is independent of both vertebral fractures (VFx) and bone mineral density (BMD) by dual‐energy X‐ray absorptiometry. Among 3124 women age 65 and older in the Study of Osteoporotic Fractures, we assessed the association with measured height change between year 0 (1986–1988) and year 15 (2002–2004) and subsequent risk of radiologically confirmed hip fractures, other nonspine fractures, and mortality assessed via death certificates. Follow‐up occurred every 4 months for fractures and vital status (>95% contacts complete). Cox proportional hazards models assessed risk of hip fracture, nonspine fracture, and mortality over a mean of 5 years after height change was assessed (ie, after final height measurement). After adjustment for VFx, BMD, and other potential covariates, height loss >5 cm was associated with a marked increased risk of hip fracture [hazard ratio (HR) 1.50, 95% confidence interval (CI) 1.06, 2.12], nonspine fracture (HR 1.48; 95% CI 1.20, 1.83), and mortality (1.45; 95% CI 1.21, 1.73). Although primary analyses were a subset of 3124 survivors healthy enough to return for a year 15 height measurement, a sensitivity analysis in the entire cohort (n = 9677) using initial height in earlier adulthood [self‐reported height at age 25 (?40 years) to measured height age >65 years (Year 0)] demonstrated consistent results. Height loss >5 cm (2″) in older women was associated with a nearly 50% increased risk of hip fracture, nonspine fracture, and mortality—independent of incident VFx and BMD. © 2012 American Society for Bone and Mineral Research  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