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   18071篇
  免费   1531篇
  国内免费   37篇
耳鼻咽喉   128篇
儿科学   690篇
妇产科学   522篇
基础医学   2351篇
口腔科学   229篇
临床医学   2044篇
内科学   3402篇
皮肤病学   307篇
神经病学   2009篇
特种医学   298篇
外国民族医学   5篇
外科学   1946篇
综合类   143篇
一般理论   67篇
预防医学   2711篇
眼科学   262篇
药学   1148篇
  1篇
中国医学   39篇
肿瘤学   1337篇
  2024年   35篇
  2023年   253篇
  2022年   394篇
  2021年   912篇
  2020年   552篇
  2019年   756篇
  2018年   860篇
  2017年   613篇
  2016年   628篇
  2015年   696篇
  2014年   903篇
  2013年   1155篇
  2012年   1602篇
  2011年   1617篇
  2010年   827篇
  2009年   668篇
  2008年   1147篇
  2007年   1196篇
  2006年   966篇
  2005年   904篇
  2004年   815篇
  2003年   729篇
  2002年   541篇
  2001年   75篇
  2000年   61篇
  1999年   63篇
  1998年   112篇
  1997年   76篇
  1996年   39篇
  1995年   49篇
  1994年   40篇
  1993年   39篇
  1992年   30篇
  1991年   18篇
  1990年   18篇
  1989年   21篇
  1988年   8篇
  1987年   10篇
  1986年   15篇
  1985年   17篇
  1984年   15篇
  1983年   7篇
  1982年   14篇
  1981年   16篇
  1980年   15篇
  1979年   7篇
  1977年   12篇
  1975年   7篇
  1974年   10篇
  1970年   6篇
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
71.
72.
OBJECTIVE: To measure alterations in SPA1, A2, and D gene expression in various forms of inflammatory chronic rhinosinusitis (CRS). STUDY DESIGN AND SETTING: Sinus mucosal biopsies were performed in patients with allergic fungal rhinosinusitis (AFS), CRS with nasal polyposis, cystic fibrosis (CF), and controls. SP mRNA was measured with quantitative polymerase chain reaction. RESULTS: Patients with CF (n = 4) showed significantly increased SPA1 (82-fold), SPA2 (100-fold), and SPD (47-fold) mRNA (P < 0.05) when compared with controls (n = 5). Patients with CRS with nasal polyposis (n = 5) also demonstrated elevated SPA1 (27-fold), SPA2 (13-fold), and SPD (13-fold). Patients with AFS (n = 7) had increased SPA1 (5-fold), SPA2 (9-fold), and SPD (17-fold), but were not statistically significant. CONCLUSION: SPA1, A2, and D are upregulated in various forms of CRS, but are significantly elevated in cystic fibrosis CRS. SIGNIFICANCE: Understanding the role of SPs in CRS will help develop novel treatment approaches for sinonasal pathoses.  相似文献   
73.
Positive affect predicts improved lip movement in facial movement disorder.   总被引:1,自引:0,他引:1  
OBJECTIVES: Positive affect in individuals with a facial movement disorder may promote lip corner movement (zygomaticus major) during smiling. We investigated whether a positive affect marker (orbicularis oculi activity) observed in an initial clinic visit of individuals with facial movement disorder (N = 28) predicted increased lip corner movement at a subsequent visit. STUDY DESIGN AND SETTING: In this clinical outcomes study, lip corner movement was assessed with the use of automated facial analysis. Asymmetry of movement was compared in individuals who smiled with or without the positive affect marker at an initial clinic visit. RESULTS: The positive affect marker at the initial visit was associated with a reduction in the asymmetry of the lip corner movement at the second visit. CONCLUSION: Positive affect predicts improved facial movement outcomes in patients with facial movement disorders. SIGNIFICANCE: Positive emotion in facial movement patients may be an important factor in recovery of facial movement during therapy.  相似文献   
74.
75.
This research represents the first controlled treatment study of hypnosis and cognitive- behavioral therapy (CBT) of acute stress disorder (ASD). Civilian trauma survivors (N=87) who met criteria for ASD were randomly allocated to 6 sessions of CBT, CBT combined with hypnosis (CBT-hypnosis), or supportive counseling (SC). CBT comprised exposure, cognitive restructuring, and anxiety management. CBT-hypnosis comprised the CBT components with each imaginal exposure preceded by a hypnotic induction and suggestions to engage fully in the exposure. In terms of treatment completers (n=69), fewer participants in the CBT and CBT-hypnosis groups met criteria for posttraumatic stress disorder at posttreatment and 6-month follow-up than those in the SC group. CBT-hypnosis resulted in greater reduction in reexperiencing symptoms at posttreatment than CBT. These findings suggest that hypnosis may have use in facilitating the treatment effects of CBT for posttraumatic stress.  相似文献   
76.
Pastore LM  Carter RA  Hulka BS  Wells E 《Maturitas》2004,49(4):292-303
OBJECTIVE: To examine the prevalence and correlates of self-reported urogenital symptoms (dryness, irritation or itching, discharge, dysuria) among postmenopausal women aged 50-79. DESIGN: A cross-sectional analysis based on n=98,705 women enrolled in the US-based Women's Health Initiative observational study and clinical trials. Urogenital symptoms, symptom severity (mild, moderate, severe), and all covariates were self-reported through questionnaires at enrollment. Prevalence rates of each urogenital symptom were examined and logistic regression was used to identify potential correlates. RESULTS: Prevalence rates for each symptom were: dryness, 27.0%; irritation or itching, 18.6%; discharge, 11.1%; and dysuria, 5.2%. Four factors were correlated with two or more symptoms: Hispanic ethnicity (adjusted odds ratio (AOR)=2.1-3.1 versus white women across all symptoms), obesity (AOR=2.2 severe discharge versus none, AOR=3.6 severe irritation/itching versus none), treated diabetes (pills or shots) compared to no diabetes (AOR=2.4 severe dysuria versus none, AOR=3.2 severe irritation/itching versus none), and vaginal cream HRT/ERT compared to those who never used HRT/ERT (AOR=4.4 severe dryness versus none, AOR=4.6 severe irritation/itching versus none). Factors not associated with the symptoms included sexual activity, age, years since menopause, current smoking, marital status, gravidity, and natural versus surgical menopause. CONCLUSIONS: This is the first report to document urogenital symptoms by race/ethnicity among an exclusively postmenopausal population. We found an elevated prevalence of urogenital symptoms among women who are Hispanic, obese, and/or diabetic. Confirmation of our findings in these subgroups, and, if confirmed, analysis on why these populations are at greater risk, are areas for future research.  相似文献   
77.
Steatosis is a frequent pathologic stage in alcoholic liver disease (ALD). Although the mechanisms for increased susceptibility of steatotic liver to injury have been postulated, the ability of these hepatocytes to proliferate and withstand injury is unknown. There are conflicting reports on the status of hepatocyte regeneration following chronic alcohol ingestion. Hence, the objective of this study was to investigate the temporal dynamics between the pattern of liver injury and hepatocyte proliferation during the steatosis stage of ALD. Alcoholic steatosis was induced in male Sprague-Dawley rats by feeding an ethanol (EtOH)-containing Lieber-DeCarli liquid diet for a period of 5 weeks. Microvesicular steatosis was evident in H&E sections by three weeks in the EtOH-treated rats, which further developed into panlobular macrovesicular steatosis by 5 weeks. Plasma transaminase activities indicated progressive increase in liver injury peaking at 3 weeks with significant but mild decrease at 4 and 5 weeks. CYP2E1 protein and activity was significantly increased in EtOH-fed rats as measured by Western blot and pNP hydroxylation assay. PCNA analysis of liver sections indicated that EtOH-treated rats had a significantly higher number of cells in S phase of cell division at weeks 1 (3.20 +/- 0.19), 2 (7.03 +/- 0.92), and 3 (4.23 +/- 1.41) when compared to controls (1.5 +/- 0.22). NF-kappaB DNA binding and Cyclin D1 proteins increased significantly in the EtOH-treated rats corresponding with enhanced hepatic proliferation. These data suggest the transient decline in liver injury during alcoholic steatosis is due to enhanced NF-kappaB-dependent hepatocyte proliferation.  相似文献   
78.
The role of human T cells in the induction and regulation, upon cell/cell contact, of inflammatory responses by monocytic cells was investigated. The production of interleukin (IL)-1β and IL-1 receptor antagonist (IL-1Ra) by the monocytic THP-1 cell line was measured upon contact with either Th1 or Th2 cell clones. CD4+ T cell clones specific for purified protein derivative of Mycobacterium tuberculosis, predominantly Th1 [high interferon (IFN)-γ and low IL-4 producers], or tetanus toxoid, predominantly Th2 (low IFN-γ and high IL-4 producers), were generated. Cell membranes from antigen-stimulated, but not from resting T cell clones induced dose-dependent cytokine production by THP-1 cells. Th1 clones induced higher levels of IL-1β production (484–806 pg/ml) than did Th2 clones (21–114 pg/ml). In contrast, Th1 clones induced lower levels of IL-1Ra (0.9–7.8 ng/ml) than did Th2 clones (7.0–49.6 ng/ml). Similar results were obtained when T cell clones were activated by cross-linked CD3 and CD28. IL-1β production by THP-1 cells correlated with IFN-γ production by T cell clones but was unaffected by IFN-γ neutralization. IL-1Ra production by THP-1 cells correlated with IL-4 production by T cells and was partially inhibited by IL-4 neutralization. These data indicate that activated Th1 and Th2 cells express different molecules on the cell surface able to induce distinct pro-inflammatory (IL-1β) or anti-inflammatory (IL-1Ra) responses in monocytes. This differential induction of molecules with opposite effects on inflammation stresses the functional heterogeneity in CD4+ T cells.  相似文献   
79.
Myeloablative conditioning allogeneic hematopoietic cell transplantation (HCT) puts patients at greater risk for significant cognitive and quality of life decline compared with recipients of reduced-intensity conditioning or autologous HCT. Vorinostat, a histone deacetylase inhibitor, has been shown to have neuroprotective and neurorestorative effects in preclinical models of neurologic diseases. Thus, within the context of a myeloablative conditioning phase II clinical trial of vorinostat combined with tacrolimus and methotrexate for graft-versus-host disease prophylaxis, we conducted an ancillary study to evaluate feasibility of assessing associations between vorinostat and neurocognitive function and quality of life (ClinicalTrials.gov NCT02409134). Nine patients (mean age, 53 years; range, 36 to 66) underwent computerized neuropsychological testing (Cogstate) and completed surveys of mood (Patient Health Questionnaire-9), anxiety (General Anxiety Disorder-7), and quality of life (Functional Assessment of Cancer Therapy–General). Control cohorts from a separate concurrent longitudinal study (19 autologous and 18 allogeneic HCT patients, who matched the vorinostat patients on relevant medical and demographic variables) completed the same test battery. All allogeneic patients received busulfan-based myeloablative conditioning and were transplanted with HLA-matched unrelated donors. The total neurocognitive performance score of vorinostat patients did not change significantly across the study duration (ie, baseline, day 30, day 100, and day 160). Depression, anxiety, and quality of life also did not differ significantly across time. In univariate analyses (analysis of variance), vorinostat-treated patients showed no difference in neurocognitive function or quality of life compared with autologous and allogeneic control subjects. However, when medical variables were accounted for in a linear mixed effects regression model, the total neurocognitive performance of vorinostat-treated patients was comparable with autologous control subjects. Notably, autologous control subjects performed significantly better than allogeneic control subjects (estimate, .64; standard error, .23; P ≤ .01). Moreover, a smaller percentage of vorinostat-treated patients were classified as mildly, moderately, or severely impaired across neurocognitive domains as well as time points compared with both control cohorts. Thus, vorinostat may have neurorestorative or neuroprotective effects in the HCT setting. Accordingly, we recognize the need for a future, full-scale randomized controlled trial to further examine this hypothesis.  相似文献   
80.
The supply of naive T cells by the thymus normally requires precursor T cell proliferation within the thymus and would be particularly important in the setting of HIV infection when both naive and memory T cells are progressively depleted. As a robust, quantitative index of intrathymic proliferation, the ratio of different T cell receptor excision circles (TRECs), molecular markers of distinct T cell receptor rearrangements occurring at different stages of thymocyte development, was measured in peripheral blood-mononuclear cells (PBMCs). This ratio has the virtue that it is a "signature" of thymic emigrants throughout their entire life and, thus, can be measured in peripheral cell populations that are easy to obtain. Using the new assay, we evaluated the effect of HIV infection on intrathymic precursor T cell proliferation by longitudinal analysis of PBMCs from recently infected individuals. Our findings reveal a substantial reduction in intrathymic proliferation. The analysis also indicates the existence of a compensatory mechanism acting to sustain the numbers of recent thymic emigrants (RTEs) in the periphery.  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