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   3108篇
  免费   224篇
  国内免费   9篇
耳鼻咽喉   50篇
儿科学   80篇
妇产科学   45篇
基础医学   466篇
口腔科学   29篇
临床医学   278篇
内科学   640篇
皮肤病学   87篇
神经病学   378篇
特种医学   165篇
外科学   259篇
综合类   34篇
一般理论   2篇
预防医学   225篇
眼科学   59篇
药学   267篇
中国医学   8篇
肿瘤学   269篇
  2024年   2篇
  2023年   23篇
  2022年   59篇
  2021年   92篇
  2020年   57篇
  2019年   66篇
  2018年   86篇
  2017年   72篇
  2016年   95篇
  2015年   112篇
  2014年   116篇
  2013年   181篇
  2012年   238篇
  2011年   217篇
  2010年   119篇
  2009年   125篇
  2008年   238篇
  2007年   189篇
  2006年   198篇
  2005年   207篇
  2004年   172篇
  2003年   143篇
  2002年   143篇
  2001年   51篇
  2000年   47篇
  1999年   32篇
  1998年   30篇
  1997年   22篇
  1996年   15篇
  1995年   12篇
  1994年   10篇
  1993年   9篇
  1992年   20篇
  1991年   8篇
  1990年   14篇
  1989年   10篇
  1988年   9篇
  1987年   15篇
  1986年   12篇
  1985年   11篇
  1984年   14篇
  1983年   14篇
  1982年   7篇
  1981年   7篇
  1980年   3篇
  1979年   4篇
  1978年   4篇
  1976年   2篇
  1975年   2篇
  1973年   2篇
排序方式: 共有3341条查询结果,搜索用时 15 毫秒
91.
We describe our findings in a 46,XY female with a clinical features of Genitopatellar syndrome (GPS) and confirmed hermaphroditism with ovotestes, and five additional patients with GPS. GPS is a genetic disorder characterized by renal and genital anomalies, joint dislocation, aplastic or hypoplastic and often displaced patellae, minor facial anomalies, and mental retardation. The genital anomalies clearly distinguish GPS from nail-patella syndrome (NPS) that has similar features, but additionally shows hypoplastic finger- and toenails as found in the 46,XY female. In our patients no mutation was found in the coding regions of WNT4, WNT7A, TBX4, and LMX1B. Fluorescent in situ hybridization (FISH) and array-based comparative genome hybridization (aCGH) analysis showed a 3 Mb deletion of LMX1B, NR6A1, and NR5A1 (SF1) in the 46,XY female. This is the first report of a microdeletion causing haploinsuffiency of LMX1B and NR5A1. The deletion of LMX1B is responsible for the knee anomalies and the deletion of NR5A1 likely causes the sex reversal. Cytogenetic analysis of the five additional patients with diagnosed GPS failed to identify a similar microdeletion, or inversion of a potentially regulatory element between the two genes. This suggests that the locus 9q33-9q34 can be excluded for GPS and that the presented case is unique in its combination of GPS and NPS features caused by a microdeletion associated with loss of function of LMX1B and NR5A1.  相似文献   
92.
Efficient monitoring of HIV-1-specific T-cells is crucial for the development of HIV-1 vaccines and immunotherapies. Currently, mainly peptides and vaccinia vectors are used for detection of HIV-1-specific cytotoxic T-lymphocytes (CTL), however, as HIV-1 is a variable virus, it is unknown to what extent the T-cell response against the autologous virus is under- or overestimated by using antigens from heterologous viral strains. Therefore, we established a new method for immunomonitoring of CTL using electroporation of peripheral blood mononuclear cells (PBMC) with mRNA derived from autologous viral strains. From six HIV-1-infected patients virus derived mRNA was produced after PCR-based cloning of autologous gag (n=5) and/or nef genes (n=3) from plasma and electroporated into PBMC from patients and healthy donors. Electroporation of PBMC with mRNA resulted in efficient protein expression with good induction of γ-interferon (γ-IFN) release by specific T-cells comparable to peptide pools and better than recombinant vaccinia viruses. Three mRNA encoded autologous Gag proteins and one autologous mRNA encoded Nef protein were better recognized by autologous PBMC in comparison to heterologous mRNA encoded Gag or Nef proteins (SF2 or HXB2). However, in one case each, mRNA encoded autologous Gag or Nef, respectively, was recognized less efficiently due to the presence of CTL escape mutations. In summary, electroporation of PBMC with mRNA is a very efficient, easy and rapid method for immunomonitoring of HIV-1-specific T-cell responses against autologous viral strains. Our data demonstrate that patients' CTL responses against autologous viral strains may be under- or overestimated by using antigens from heterologous viral strains.  相似文献   
93.
The biosynthesis pathway for riboflavin (vitamin B(2)), the precursor of the essential cofactors flavin mononucleotide and flavin adenine dinucleotide, is present in bacteria and plants but is absent in vertebrates. Due to their conservation in bacterial species and their absence in humans, the riboflavin synthesis genes should be well suited either for detection of bacterial DNA in human specimens or for the differentiation of pathogenic bacteria by molecular techniques. A DNA fragment carrying the genes ribD, ribC, and ribE, which encode homologues of riboflavin deaminase (RibD) and subunits of riboflavin synthetase (RibC and RibE), respectively, was isolated from a plasmid-based DNA library of the human pathogen Bartonella henselae by complementation of a ribC mutation in Escherichia coli. Sequence analysis of the ribC gene region in strains of B. henselae, which were previously shown to be genetically different, revealed that the ribC gene is highly conserved at the species level. PCR amplification with primers derived from the ribC locus of B. henselae was used to isolate the corresponding DNA regions in B. bacilliformis, B. clarridgeiae, and B. quintana. Sequence analysis indicated that the riboflavin synthesis genes are conserved and show the same operon-like genetic organization in all four Bartonella species. Primer oligonucleotides designed on the basis of localized differences within the ribC DNA region were successfully used to develop species-specific PCR assays for the differentiation of B. henselae, B. clarridgeiae, B. quintana, and B. bacilliformis. The results obtained indicate that the riboflavin synthesis genes are excellent targets for PCR-directed differentiation of these emerging pathogens. The PCR assays developed should increase our diagnostic potential to differentiate Bartonella species, especially B. henselae and the newly recognized species B. clarridgeiae.  相似文献   
94.
95.
Ververi‐Brady syndrome (VBS, # 617982) is a rare developmental disorder, and loss‐of‐function variants in QRICH1 were implicated in its etiology. Furthermore, a recognizable phenotype was proposed comprising delayed speech, learning difficulties and dysmorphic signs. Here, we present four unrelated individuals with one known nonsense variant (c.1954C > T; p.[Arg652*]) and three novel de novo QRICH1 variants, respectively. These included two frameshift mutations (c.832_833del; p.(Ser278Leufs*25), c.1812_1813delTG; p.(Glu605Glyfs*25)) and interestingly one missense mutation (c.2207G > A; p.[Ser736Asn]), expanding the mutational spectrum. Enlargement of the cohort by these four individuals contributes to the delineation of the VBS phenotype and suggests expressive speech delay, moderate motor delay, learning difficulties/mild ID, mild microcephaly, short stature and notable social behavior deficits as clinical hallmarks. In addition, one patient presented with nephroblastoma. The possible involvement of QRICH1 in pediatric cancer assumes careful surveillance a key priority for outcome of these patients. Further research and enlargement of cohorts are warranted to learn about the genetic architecture and the phenotypic spectrum in more detail.  相似文献   
96.
Current paradigms suggest that, despite the heterogeneity of myeloid-derived suppressor cells (MDSC), all Gr-1(+) CD11b(+) cells can exert suppressive function when exposed to inflammatory stimuli. In vitro evaluation shows that MDSC from multiple tissue sites have suppressive activity, and in vivo inhibition of MDSC enhances T-cell function; however, the relative capacity of MDSC present at localized inflammatory sites or in peripheral tissues to suppress T-cell responses in vivo has not been directly evaluated. In the current study, we observed that during a tissue-specific inflammatory response, MDSC inhibition of CD8(+) T-cell proliferation and IFN-γ production was restricted to the inflammatory site. Using a prostate-specific inflammatory model and a heterotopic prostate tumor model, we showed that MDSC from inflammatory sites or from tumor tissue possess immediate capacity to inhibit T-cell function, whereas those isolated from peripheral tissues (spleens and liver) were not suppressive without activation of iNOS by exposure to IFN-γ. These data suggest that MDSC are important regulators of immune responses in the prostate during acute inflammation and the chronic inflammatory setting of tumor growth, and that regulation of T-cell function by MDSC during a localized inflammatory response is restricted in vivo to the site of an ongoing immune response.  相似文献   
97.

Objective

“Michael's Game” is a card game which aims at familiarizing healthcare professionals and patients with cognitive therapy of psychotic symptoms. The present study tests the feasibility and the impact of the intervention in naturalistic settings.

Methods

135 patients were recruited in 11 centres. They were assessed pre- and post-tests with the Beck Cognitive Insight Scale (BCIS) and the Peters Delusion Inventory-21 items (PDI-21).

Results

Data about 107 patients were included in the entire analyses. Significant improvements were observed on BCIS subscales as well as a reduction of severity of conviction and preoccupation scores on the PDI-21. The intervention has a moderate effect on the PDI-21 preoccupation and conviction as well as the BCIS subscales. Patients who benefit the most from the program are patients who have a low degree of self-reflectiveness and patients who are concomitantly preoccupied by their symptoms.

Conclusion

The present study supports the feasibility and effectiveness of “Michael's Game” in naturalistic settings.

Practical implications

The game seems to be a useful tool for patients with psychotic disorders.  相似文献   
98.
99.
IntroductionMen with erectile dysfunction (ED) are typically older and have one or more underlying cardiovascular conditions.AimTo determine the efficacy and safety of a new orodispersible tablet (ODT) formulation of vardenafil for the treatment of ED, and whether age, or the presence of underlying conditions affects treatment outcomes.MethodsThis is an integrated analysis of data from two phase III, double‐blind, multicenter, randomized, parallel‐group, placebo‐controlled studies that compared 10 mg on‐demand vardenafil ODT with placebo in a general population of men with ED, stratified so that approximately 50% of patients were aged ≥65 years. Results were reported by age (<65 vs. ≥65 years) and presence/absence of diabetes, dyslipidemia, or hypertension.Main Outcome MeasuresPrimary measures were the erectile function domain of the International Index of Erectile Function (IIEF‐EF) and Sexual Encounter Profile questions 2 (SEP2) and 3 (SEP3).ResultsOf the 701 men randomized (51% aged ≥65 years), 686 were included in the intent‐to‐treat population (placebo, n = 334; vardenafil ODT, n = 352). Vardenafil ODT was significantly superior to placebo for all primary efficacy measures, regardless of age, baseline ED severity, or underlying condition (P < 0.0001 for vardenafil vs. placebo for each endpoint). IIEF‐EF scores and SEP2/3 success rates in older patients and men with underlying conditions were not significantly different to those of younger patients or men without underlying conditions. Adverse events (AEs) were mostly mild to moderate in severity, occurring with higher incidence in the vardenafil vs. placebo group. The most frequently reported drug‐related AEs in the vardenafil group were headache, flushing, nasal congestion, dizziness, and dyspepsia, consistent with the known safety profile of phosphodiesterase type 5 inhibitors.ConclusionsVardenafil ODT significantly improves erectile function in men with ED regardless of age, baseline ED severity, or underlying condition. Sperling H, Gittelman M, Norenberg C, Ulbrich E, and Ewald S. Efficacy and safety of an orodispersible vardenafil formulation for the treatment of erectile dysfunction in elderly men and those with underlying conditions: An integrated analysis of two pivotal trials. J Sex Med 2011;8:261–271.  相似文献   
100.
Primary Sjögren's syndrome (pSS) is a complex systemic autoimmune disease with heterogeneous disease manifestations. Genetic predisposition, hormonal and environmental factors are all thought to contribute to disease etiology and pathogenesis. A better understanding of the disease pathogenesis is required in order to establish new targeted therapies. We analysed MAPK/ERK and JAK/STAT signalling networks in peripheral blood mononuclear cells (PBMCs) upon stimulation with interferon alpha 2b (IFN‐α2b) by flow cytometry to define potentially dysfunctional intracellular signalling pathways involved in disease pathogenesis. Cells derived from pSS patients displayed small but significant increases in basal phosphorylation levels of numerous signalling proteins compared to cells from healthy donors. The phosphorylation profiles following stimulation with IFNα2b differed significantly between pSS patients and healthy donors, especially regarding STAT1 Y701. PCA further grouped patients according to clinical characteristics. Type I IFN induced gene expression was found to negatively correlate with the IFN‐α2b induced phosphorylation of STAT3 S727 in T cells and positively with pSTAT1 Y701 in B cells. Increases in pSTAT1 Y701 were associated with the presence of autoantibodies. Our results indicate involvement of both STAT3 S727 and STAT1 Y701 pathways in pSS patients. Therapies targeting these pathways might therefore be beneficial for certain subgroups of patients.  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