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   310449篇
  免费   30054篇
  国内免费   23368篇
耳鼻咽喉   2485篇
儿科学   2721篇
妇产科学   3413篇
基础医学   37012篇
口腔科学   4976篇
临床医学   43847篇
内科学   44623篇
皮肤病学   2727篇
神经病学   17032篇
特种医学   11373篇
外国民族医学   216篇
外科学   30563篇
综合类   53855篇
现状与发展   78篇
一般理论   33篇
预防医学   19542篇
眼科学   9450篇
药学   33389篇
  352篇
中国医学   19288篇
肿瘤学   26896篇
  2024年   3944篇
  2023年   5220篇
  2022年   13123篇
  2021年   16372篇
  2020年   12874篇
  2019年   10777篇
  2018年   11272篇
  2017年   10086篇
  2016年   9588篇
  2015年   14288篇
  2014年   17598篇
  2013年   15214篇
  2012年   22790篇
  2011年   25586篇
  2010年   16018篇
  2009年   12502篇
  2008年   15916篇
  2007年   15962篇
  2006年   15960篇
  2005年   15902篇
  2004年   9589篇
  2003年   8797篇
  2002年   7377篇
  2001年   6477篇
  2000年   7101篇
  1999年   7854篇
  1998年   5112篇
  1997年   5114篇
  1996年   3996篇
  1995年   3780篇
  1994年   3127篇
  1993年   2092篇
  1992年   2371篇
  1991年   1978篇
  1990年   1692篇
  1989年   1430篇
  1988年   1227篇
  1987年   1077篇
  1986年   826篇
  1985年   667篇
  1984年   396篇
  1983年   245篇
  1982年   130篇
  1981年   136篇
  1980年   97篇
  1979年   105篇
  1978年   16篇
  1974年   9篇
  1973年   8篇
  1969年   9篇
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
71.
Attention‐deficit hyperactivity disorder (ADHD) is the most common psychiatric disorder in children and adolescents, which is characterized by behavioral problems such as attention deficit, hyperactivity, and impulsivity. As the receptors of the major excitatory neurotransmitter in the mammalian central nervous system (CNS), glutamate receptors (GluRs) are strongly linked to normal brain functioning and pathological processes. Extensive investigations have been made about the structure, function, and regulation of GluR family, describing evidences that support the disruption of these mechanisms in mental disorders, including ADHD. In this review, we briefly described the family and function of GluRs in the CNS, and discussed what is recently known about the role of GluRs in ADHD, that including GluR genes, animal models, and the treatment, which would help us further elucidate the etiology of ADHD.  相似文献   
72.
CCCTC‐binding factor (CTCF) is an important regulator for global genomic organization and gene expression. CTCF gene had been implicated in a novel disorder characterized by intellectual disability, feeding difficulty, developmental delay and microcephaly. So far, four patients have been reported with de novo CTCF mutations. We reported three additional Chinese patients with de novo variants in CTCF. The new evidence helped to establish the clinical validity between CTCF and the emerging disorder. We described the consistent phenotypes shared by all patients and revealed additional clinical features such as delayed or abnormal teeth development and a unique pattern of the eyebrow that may help to define a potential recognizable neurodevelopmental disorder. We also reported the first CTCF patient treated with recombinant human growth hormone. Follow‐up and more case studies will further our understanding to the clinical presentations of this novel disorder and the prognosis of patients with this disorder.  相似文献   
73.
74.
Cobalamin (cbl) C disease is a rare autosomal recessive inheritance disease, which is the most common cobalamin metabolic disorder. Its clinical phenotype involves multiple systems with varying degrees of severity, where in mild cases can be asymptomatic for many years, whereas severe cases may cause death during the neonatal period. The disease is caused by mutations in the MMACHC gene located on chromosome 1p34.1 that contains 5 exons; among which, exons 1–4 have an 849 bp coding sequence that encodes a protein containing 282 amino acids. Through clinical physical examination and laboratory tests, especially blood and urine screening, we found 28 cblC pediatric patients with clinical manifestations, such as mental retardation, motor development delay, epilepsy, metabolic acidosis, vomiting and diarrhea. By Sanger sequencing, we found homozygous or compound heterozygous mutations of MMACHC in 27 of the patients, and single heterozygous mutation of MMACHC in one of them. The c.609G > A, c.658-660delAAG, c.80A > G and c.482G > A mutations accounted for 43.64% (24/55), 10.91% (6/55), 9.09% (5/55) and 7.27% (4/55) of all the mutations, respectively. This spectrum finding is basically consistent with the previously reported data in Chinese patients. The most common c.609G > A mutation may likely lead to early-onset cblC disease. In previous literature involving a large sample of Caucasian cblC cases, the mutation spectrum of MMACHC gene is almost completely different from that of the Chinese population. The most common mutations in the Caucasian population were c.271dupA, c.394C > T and c.331C > T, which account for 48.05% (542/1128), 13.65% (154/1128) and 7.36% (83/1128) of all the mutant alleles, respectively. The c.271dupA mutation and c.331C > T mutation were mainly associated with early-onset cblC in children less than 1 year old, whilst the c.394C > T mutation was mainly associated with late-onset cblC patients characterised by isolated acute nervous system abnormalities. We also analysed the cause behind the different mutation spectrum of MMACHC gene between the Chinese and Caucasian populations.  相似文献   
75.
烧伤治疗60余年,虽然烧伤感染发生率有所下降,但是耐药菌形势日益严峻。从认识烧伤肠源性感染,到异体皮覆盖创面、经验性使用抗菌药物,对于构成抵抗病原菌第1道屏障具有重要意义,有助于防止脓毒症的发生与发展。烧伤免疫从宿主角度探讨机体抗菌消炎的内在机制,由此产生的中西药免疫调理策略,为抵抗病原菌筑起第2道免疫屏障。利用现代医学技术,对烧伤感染进行对症和对因治疗,使烧伤感染发生率明显降低。今后还要探讨如何应用新技术快速检测病原微生物,寻找反映机体免疫状态的标志物,以及追踪烧伤感染对免疫系统的长期影响。  相似文献   
76.
77.
The objective of this article is to evaluate whether the tumoricidal activity of mouse IFN R−/− nature killer (NK) cells is induced by Newcastle disease virus hemagglutinin-neuraminidase (NDV-HN) stimulation, and to investigate what is the mechanism of the HN-stimulated NK cells to kill mouse hepatoma cell line in vitro. The mouse IFN R−/− NK cells were stimulated for 16 hr with 500 ng/mL NDV-HN in 1640 medium. Quantify the cytotoxic activities of NK cells against mouse hepatoma cells (Hepa1-6) by flow cytometry. Granzymes B (GrB) and Fas/FasL concentrations in the supernatants of IFN R−/− NK cells medium were determined by specific ELISA assay. The expression of cell surface GrB and Fas was determined by Western blot. NDV-HN stimulation enhanced tumoricidal activity of IFN R−/− NK cells toward Hepa1-6 in vitro. Treating with anti-HN neutralizing mAb induced significant decline in the cytotoxicity of IFN R−/− NK cells toward Hepa1-6 cell line (P < 0.05). After treating with anti-HN protein (1 μL/mL), Syk-specific inhibitor Herbimycin A(250 ng/mL) and NF-κB inhibitor PDTC (500 ng/mL) downregulated the tumoricidal activity of HN-stimulated IFN R−/− NK cells (P < 0.05). Moreover, significant suppressions in the production of GrB and Fas/FasL were observed in HN-stimulated IFN R−/− NK cells (P < 0.05). Thus, we concluded that killer activation receptors pathway is involved in the IFN-γ-independent GrB and Fas/FasL expression of NDV-HN-stimulated IFN R−/− NK cells, and these are activated by Syk and NF-κB. Anat Rec, 302:1718–1725, 2019. © 2019 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association for Anatomy  相似文献   
78.
T cell replete HLA-mismatched haploidentical transplantation (HIDT) with post-transplant cyclophosphamide is increasingly becoming an acceptable treatment approach for patients lacking timely access to a suitably matched related donor transplant (MRDT) or matched unrelated donor transplant (MUDT). Multiple recent registry and single-center studies have shown comparable overall survival (OS) and disease-free survival (DFS) rates among HIDT, MRDT, and MUDT with a significantly lower risk of acute and chronic graft-versus-host disease (GVHD) among HIDT recipients. Candidates for allogeneic hematopoietic stem cell transplantation (HSCT) often have access to multiple donor sources, and a relevant question is whether outcomes can be improved with a younger HLA-mismatched haploidentical donor (≤35 years) rather than an older matched related donor (≥35 years) or matched unrelated donor (≥35 years). We analyzed 406 consecutive allogenic HSCT recipients, with a median age of 54 years (range, 19 to 77), after a MRDT with a donor age of ≥35 years (n = 222), MUDT with a donor age of ≥35 years (n = 91), and HIDT with a donor age of ≤35 years (n = 93). Median follow-up time for survivors was 51.5 months. Compared with MRDT and MUDT, HIDT recipients had a similar median age at time of HSCT, hematopoietic cell transplant comorbidity index, disease risk index distribution, and donor recipient sex matching. The survival estimates and relapse incidence at 3 years post-HSCT were OS (64% for MRDT, 54% for MUDT, and 62% for HIDT), DFS (55% for MRDT, 44% for MUDT, and 58% for HIDT), Transplant related mortality (TRM) (19% for MRDT, 16% for MUDT, and 18% for HIDT), and relapse (26% for MRDT, 37% for MUDT, and 24% for HIDT). HIDT recipients had better 3-year relapse rates compared with MUDT recipients (24% versus 37%, P= .048), with similar DFS and OS in a univariate analysis. MRDT recipients had a better relapse rate (26% versus 37%, P = .042) compared with MUDT recipients. Recipients of HIDT also had significantly lower rates of moderate to severe chronic GVHD compared with MRDT and MUDT recipients (P = .01). Multivariable analysis showed no effect of donor on OS, DFS, relapse, and TRM. Recipients of HIDT from a young donor ≤35 years had similar OS, lower rates of chronic GVHD, and better chronic GVHD-free, relapse-free survival compared with patients undergoing transplantation with an MRD or a MUD donor ≥35 years. This study suggests that given a situation where a choice between a young haploidentical relative and an older matched unrelated donor is to be made, one can achieve similar survival with a haploidentical donor and significantly lower rates of chronic GVHD.  相似文献   
79.
HLA haplotype mismatches have been associated with an elevated risk of acute graft-versus-host disease (aGVHD) in patients undergoing HLA-matched unrelated donor (URD) hematopoietic cell transplantation (HCT). The gamma block (GB) is located in the central MHC region between beta and delta blocks (encoding HLA-B and -C and HLA-DQ and -DR antigens, respectively) and contains numerous inflammatory and immune regulatory genes, including Bf, C2, and C4 genes. A single-center study showed that mismatches in SNPs c.2918+98G, c.3316C, and c.4385C in the GB block (C4 SNPs) were associated with higher risk of grade III-IV aGVHD. We investigated the association of GB SNP (GBS) mismatches with outcomes after 10/10 and 9/10 URD HCT (n?=?714). The primary outcome was acute GVHD. Overall survival, disease-free survival, transplantation-related mortality, relapse, chronic GVHD, and engraftment were also analyzed. DNA samples were GBS genotyped by identifying 338 SNPs across 20 kb using the Illumina NGS platform. The overall 100-day incidence of aGVHD grade II-IV and II-IV were 41% and 17%, respectively. The overall incidence of matching at all GBSs tested and at the C4 SNPs were 23% and 81%, respectively. Neither being matched across all GB SNPs tested (versus mismatched) nor having a higher number of GBS mismatches was associated with transplantation outcomes. There was no association between C4 SNP mismatches and outcomes except for an unexpected significant association between having 2 C4 SNP mismatches and a higher hazard ratio (HR) for relapse (association seen in 15 patients only; HR, 3.38, 95% confidence interval, 1.75 to 6.53; P?=?.0003). These data do not support the hypothesis that mismatching at GB is associated with outcomes after HCT.  相似文献   
80.
Pharmacogenetics influences oral tacrolimus exposure; however, little data exist regarding i.v. tacrolimus. We investigated the impact of genetic polymorphisms in CYP3A4, CYP3A5, and ABCB1 on i.v. tacrolimus exposure and toxicity in adult patients receiving an allogeneic hematopoietic stem cell transplant for hematologic malignancies. Germline DNA was extracted from buccal swabs and genotyped for CYP3A4, CYP3A5, and ABCB1 polymorphisms. Continuous i.v. infusion of tacrolimus .03 mg/kg/day was initiated on day +5 post-transplant, and steady-state blood concentrations were measured 4days later. We evaluated the association between phenotypes and prevalence of nontherapeutic target concentrations (below or above 5 to 15 ng/mL) as well as tacrolimus-related toxicities. Of 63 patients, 28.6% achieved the target concentration; 71.4% were >15ng/mL, which was more common in CYP3A4 intermediate/normal metabolizers (compared with rapid) and those with at least 1 ABCB1 C2677T loss-of-function allele (P < .05). ABCB1 C2677T was significantly associated with concentrations >15ng/mL (odds ratio, 6.2; 95% confidence interval, 1.8 to 23.6; P = .004) and tacrolimus-related toxicities (odds ratio, 7.5; 95% confidence interval, 1.6 to 55.2; P = .02). ABCB1 C2677T and CYP3A4 are important determinants of i.v. tacrolimus exposure, whereas ABCB1 C2677T also impacts tacrolimus-related toxicities in stem cell transplants.  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