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   3158017篇
  免费   271494篇
  国内免费   13768篇
耳鼻咽喉   43722篇
儿科学   100393篇
妇产科学   81639篇
基础医学   508408篇
口腔科学   84436篇
临床医学   278979篇
内科学   557453篇
皮肤病学   86186篇
神经病学   272952篇
特种医学   125429篇
外国民族医学   361篇
外科学   497652篇
综合类   96783篇
现状与发展   23篇
一般理论   2169篇
预防医学   264712篇
眼科学   71272篇
药学   214846篇
  22篇
中国医学   9200篇
肿瘤学   146642篇
  2021年   54670篇
  2020年   34888篇
  2019年   57863篇
  2018年   70355篇
  2017年   53671篇
  2016年   59185篇
  2015年   73545篇
  2014年   107721篇
  2013年   172912篇
  2012年   84393篇
  2011年   83399篇
  2010年   114386篇
  2009年   119719篇
  2008年   71252篇
  2007年   73273篇
  2006年   84322篇
  2005年   80382篇
  2004年   82270篇
  2003年   73606篇
  2002年   63688篇
  2001年   89442篇
  2000年   82030篇
  1999年   85148篇
  1998年   63563篇
  1997年   61885篇
  1996年   59574篇
  1995年   55032篇
  1994年   49233篇
  1993年   45968篇
  1992年   58655篇
  1991年   55327篇
  1990年   52523篇
  1989年   51892篇
  1988年   48438篇
  1987年   47338篇
  1986年   45372篇
  1985年   45561篇
  1984年   43140篇
  1983年   39955篇
  1982年   39858篇
  1981年   37606篇
  1980年   35567篇
  1979年   35125篇
  1978年   32181篇
  1977年   29733篇
  1976年   27295篇
  1975年   25827篇
  1974年   26311篇
  1973年   25154篇
  1972年   23691篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
991.
992.

Background

Clear cell renal cell carcinoma (ccRCC) is known to occur across the adult lifetime traversing the spectrum of age-related organismal changes. Little is known as to how the aging process may affect the course of renal cell carcinoma (RCC) and the repertoire of genes involved.

Methods

Using The Cancer Genome Atlas (n?=?436) and Cancer Genomics of the Kidney (n?=?89) datasets, we applied regression analysis to examine associations between patient age and gene expression profiles in ccRCC tumors and normal kidney tissues. Pathway enrichment analysis was performed to identify cellular process that is affected by aging in ccRCC. Moreover, connectivity mapping analysis was used to predict age-dependent response to drug treatments.

Results

Our analysis revealed different age-dependent gene expression spectra in ccRCC and normal kidney tissues. These findings were significant and independently reproducible in both datasets examined. Age up-regulated genes, showing higher expression in older patients, were significantly enriched (false discovery rate <0.05) in normal tissues for pathways associated with immune response and extracellular matrix organization, whereas age up-regulated genes in tumors were enriched for metabolism and oxidation pathways. Strikingly, age down-regulated genes in normal cells were also enriched for metabolism and oxidation, while those in tumors were enriched for extracellular matrix organization. Further in silico analysis of potential drug targets predicted preferential efficacy of Phosphoinositide 3-kinase inhibitor or immunotherapy in association with age.

Conclusion

We report on previously unrecognized associations between age and molecular underpinnings of RCC, including age-associated expression of genes implicated in RCC development or treatment.  相似文献   
993.
994.
Introduction: Tamoxifen dominates the anti-estrogenic therapy in the early and metastatic breast cancer setting. Tamoxifen has a complex metabolism, being mainly metabolized by CYP2D6 into its 30–100 times more potent metabolite, endoxifen. Recently, a phase I study in which endoxifen as an orally z-endoxifen hydrochloride has been successfully evaluated.

Areas covered: the principal pharmacogenetic and non-genetic differences in the pharmacology of tamoxifen and endoxifen are evaluated. To this end, references from PubMed, Embase or Web of Science, among others, were reviewed As non-genetic factors, important differences and similarities such age, or adherence to tamoxifen therapy are comprehensively illustrated. Additionally, since CYP2D6 genotypes are considered the main limitation of tamoxifen, many studies have investigated the association between the worsened clinical outcomes in patients with non-functional CYP2D6 genotypes. In this review, an overview of the research on this field is presented. Also, a summary describing the literature about individualizing tamoxifen therapy with endoxifen concentrations and its limitations is listed.

Expert opinion: z-endoxifen hydrochloride is only investigated in the metastatic setting, still more research is required before its place in therapeutics is known. Similarly, monitoring tamoxifen efficacy based on endoxifen concentrations might not be overall recommended due to the limited evidence available.  相似文献   

995.
996.
997.
Objectives: There is a paucity of reporting on surgical outcomes of isolated posterior cruciate ligament reconstruction (PCLR). We hypothesize that isolated PCL injuries failing nonoperative treatment achieve good outcomes and are able to return to sport following PCLR.

Methods: A retrospective analysis was performed to identify patients with isolated PCL injuries that underwent reconstruction between 2001 and 2014. Patients with multi-ligamentous injury or another concomitant knee pathology were excluded. Medical records were reviewed for demographic, clinical and operative data. Patients were contacted for administration of a telephone-based questionnaire which included the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation form, Lysholm-Tegner scales, Marx activity scale (MAS), return to sport status, and patient satisfaction instruments.

Results: A total of 15 isolated PCL reconstructions in 14 patients with a mean age of 27.5 years (range 17–43) met the study inclusion criteria; mean follow up was 6.3 years (range 1.4–15.2). Pre-operatively, the primary complaint was knee instability in all patients; on physical examination, lack of a firm end point during posterior drawer testing was found in 93% (14/15) of the knees. In total, 12 of 15 knees underwent transtibial, single-bundle PCLR and three of 15 underwent tibial inlay, double bundle PCLR. Graft types included: quadriceps autograft (7/15), Achilles allograft (6/15), and hamstring autograft (2/15). There were no graft failures in our patient cohort. At most recent follow up the mean scores respectively on the IKDC form, Lysholm-Tegner scales and MAS were (standard deviation): 77.3 (16.5), 83.1 (17.9), 6.13 (2.6), and 7.1 (6.0). All fourteen patients were athletes prior to their injury and 79% (11/14) returned to sport and overall patient satisfaction was 9.2/10.

Conclusions: Isolated PCLR provides good outcomes at mean medium-term follow up with restoration of function, high rate of return to sport and overall patient satisfaction.  相似文献   

998.
999.
Recent focus on the neonatal intestinal microbiome has advanced our knowledge of the complex interplay between the intestinal barrier, the developing immune system, and commensal and pathogenic organisms. Despite the parallel role of the infant skin in serving as both a barrier and an interface for priming the immune system, large gaps exist in our understanding of the infantile cutaneous microbiome. The skin microbiome changes and matures throughout infancy, becoming more diverse and developing the site specificity known to exist in adults. Delivery method initially determines the composition of the cutaneous microbiome, though this impact appears transient. Cutaneous microbes play a critical role in immune system development, particularly during the neonatal period, and microbes and immune cells have closely intertwined, reciprocal effects. The unique structure of newborn skin influences cutaneous microbial colonization and the development of dermatologic pathology. The development of the infantile skin barrier and cutaneous microbiome contributes to future skin pathology. Atopic dermatitis flares and seborrheic dermatitis have been linked to dysbiosis, while erythema toxicum neonatorum is an immune response to the establishment of normal bacterial skin flora. Physicians who care for infants should be aware of the impact of the infantile skin microbiome and its role in the development of pathology. A better understanding of the origin and evolution of the skin microbiome will lead to more effective prevention and treatment of pediatric skin disease.  相似文献   
1000.
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