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   2369篇
  免费   141篇
  国内免费   14篇
耳鼻咽喉   33篇
儿科学   84篇
妇产科学   62篇
基础医学   208篇
口腔科学   62篇
临床医学   214篇
内科学   516篇
皮肤病学   61篇
神经病学   134篇
特种医学   113篇
外科学   409篇
综合类   76篇
一般理论   4篇
预防医学   172篇
眼科学   75篇
药学   155篇
中国医学   28篇
肿瘤学   118篇
  2023年   33篇
  2022年   53篇
  2021年   97篇
  2020年   65篇
  2019年   90篇
  2018年   100篇
  2017年   75篇
  2016年   84篇
  2015年   69篇
  2014年   112篇
  2013年   113篇
  2012年   214篇
  2011年   178篇
  2010年   98篇
  2009年   87篇
  2008年   128篇
  2007年   127篇
  2006年   134篇
  2005年   112篇
  2004年   76篇
  2003年   71篇
  2002年   57篇
  2001年   30篇
  2000年   26篇
  1999年   31篇
  1998年   11篇
  1997年   8篇
  1996年   8篇
  1995年   7篇
  1994年   5篇
  1992年   15篇
  1991年   14篇
  1990年   17篇
  1989年   15篇
  1988年   13篇
  1987年   10篇
  1986年   20篇
  1985年   14篇
  1984年   10篇
  1983年   8篇
  1981年   6篇
  1979年   7篇
  1978年   7篇
  1977年   7篇
  1976年   7篇
  1974年   7篇
  1970年   5篇
  1969年   7篇
  1967年   3篇
  1966年   5篇
排序方式: 共有2524条查询结果,搜索用时 62 毫秒
41.
42.
While Pakistan has made progress toward achieving Millennium Development Goal 5 for maternal health, it is unlikely to achieve the target; further, it is also not on track for Millennium Development Goal 4 regarding child health. Two low-cost, temperature stable and life-saving drugs, misoprostol and chlorhexidine, can respectively avert maternal and newborn deaths, and are particularly pertinent for poor and marginalized areas which bear the brunt of maternal and newborn deaths in Pakistan. In response, Mercy Corps led focused advocacy efforts to promote changes in policies, protocols, and regulatory environments for misoprostol (2012–2014) and for chlorhexidine (2014). These short-duration advocacy projects facilitated significant policy gains, such as inclusion of misoprostol and chlorhexidine into province-specific essential drug lists, development and endorsement of clinical protocols for the two drugs by provincial health departments, inclusion of misoprostol into pre-service training curriculum for several health cadres, and application for registration of chlorhexidine (at the concentration required for newborn care) by two pharmaceutical companies. These results were achieved by a consultative and evidence-based process which generated feedback from community members, program implementers, and policymakers, and ultimately put the government in the driver’s seat to facilitate change. Community Action Dialogue forums were linked with provincial-level Technical Working Groups and Provincial Steering Committees, who passed on endorsed recommendations to the Health Secretary. The key factors which facilitated change were the identification of champions within the provincial health departments, prioritization of relationship building and follow-up, focus on concrete advocacy aims rather than broad objectives, and the use of multi-stakeholder forums to secure an enabling environment for the policy changes to take root. While these advocacy initiatives resulted in significant policy changes in Pakistan’s devolved health system, to ensure these policy changes have an impact on health outcomes, Pakistan should focus on the scale-up of appropriate use of chlorhexidine and misoprostol. Further, future policy initiatives in Pakistan should make use of similar multi-stakeholder policy forums, while ensuring a third party to facilitate the process so that civil society and community voices are not lost in the policy development discussion.  相似文献   
43.
44.
AbstractChronic critical limb ischemia (CLI) occurs when arterial perfusion is reduced below a threshold level that results in rest pain and/or tissue breakdown in the lower extremities. Importantly, it is associated with high cardiovascular morbidity and mortality. Without prompt revascularization, CLI may result in loss of a limb (i.e. amputation) and/or life. The goal of endovascular therapy is the re-establishment of pulsatile, straight-line flow to the distal extremity. Percutaneous transluminal angioplasty (PTA) has been shown to be effective and safe in the setting of CLI, with limb salvage rates that compare favorably with surgical procedures. Stents are indicated for failed PTA, while adjunctive therapies such as lasers, thermal angioplasty and atherectomy devices lack data demonstrating improved efficacy compared with conventional lower extremity interventions. In addition to successful revascularization, the institution of lifestyle changes, atherosclerotic risk factor modification, and pharmacologic therapies are indicated to reduce cardiovascular morbidity and mortality.  相似文献   
45.
46.
Coronavirus disease 2019 (COVID‐19) is caused by SARS‐CoV‐2, a novel coronavirus strain. Some studies suggest that COVID‐19 could be an immune‐related disease, and failure of effective immune responses in initial stages of viral infection could contribute to systemic inflammation and tissue damage, leading to worse disease outcomes. T cells can act as a double‐edge sword with both pro‐ and anti‐roles in the progression of COVID‐19. Thus, better understanding of their roles in immune responses to SARS‐CoV‐2 infection is crucial. T cells primarily react to the spike protein on the coronavirus to initiate antiviral immunity; however, T‐cell responses can be suboptimal, impaired or excessive in severe COVID‐19 patients. This review focuses on the multifaceted roles of T cells in COVID‐19 pathogenesis and rationalizes their significance in eliciting appropriate antiviral immune responses in COVID‐19 patients and unexposed individuals. In addition, we summarize the potential therapeutic approaches related to T cells to treat COVID‐19 patients. These include adoptive T‐cell therapies, vaccines activating T‐cell responses, recombinant cytokines, Th1 activators and Th17 blockers, and potential utilization of immune checkpoint inhibitors alone or in combination with anti‐inflammatory drugs to improve antiviral T‐cell responses against SARS‐CoV‐2.  相似文献   
47.
We report clinical findings that extend the phenotype of the ∼550 kb 16p11.2 microdeletion syndrome to include a rare, severe, and persistent pediatric speech sound disorder termed Childhood Apraxia of Speech (CAS). CAS is the speech disorder identified in a multigenerational pedigree (‘KE'') in which half of the members have a mutation in FOXP2 that co-segregates with CAS, oromotor apraxia, and low scores on a nonword repetition task. Each of the two patients in the current report completed a 2-h assessment protocol that provided information on their cognitive, language, speech, oral mechanism, motor, and developmental histories and performance. Their histories and standard scores on perceptual and acoustic speech tasks met clinical and research criteria for CAS. Array comparative genomic hybridization analyses identified deletions at chromosome 16p11.2 in each patient. These are the first reported cases with well-characterized CAS in the 16p11.2 syndrome literature and the first report of this microdeletion in CAS genetics research. We discuss implications of findings for issues in both literatures.  相似文献   
48.
Malaria is wide spread in poor world and its burden has been assessed by the enumeration of malarial parasites in blood of patients. This study was designed to find a relationship between social structure, and spread of malaria in Khyber agency. The average parasite density was 2050 parasite/μl in Khyber Agency. Due to economic and social setup most of the people have habit of sleeping in open air thus playing role in high malaria prevalence and Plasmodium vivax remains the prevalent species. Genetic study performed on 110 Blood samples showed less genetic diversity for both Plasmodium vivax and Plasmodium falciparum. Eight alleles were distinguished both for Pvmsp 3α and Pvmsp 3β in total of 20 and 39 amplified samples of P. vivax respectively. Out of 17 samples amplified for P. falciparum 11 showed genotype K1 and 10 for MAD at Pfmsp-1 while 14 alleles were identified for 3D7/1C and two for FC27 of corresponding families of Pfmsp-2 gene. This shows that Plasmodium parasites are not genetically diverse in Khyber agency.  相似文献   
49.
50.
We have examined platelet functional responses and characterized a novel signaling defect in the platelets of a patient suffering from a chronic bleeding disorder. Platelet aggregation responses stimulated by weak agonists such as adenosine diphosphate (ADP) and adrenaline were severely impaired. In comparison, both aggregation and dense granule secretion were normal following activation with high doses of collagen, thrombin, or phorbol-12 myristate-13 acetate (PMA). ADP, thrombin, or thromboxane A2 (TxA2) signaling through their respective Gq-coupled receptors was normal as assessed by measuring either mobilization of intracellular calcium, diacylglycerol (DAG) generation, or pleckstrin phosphorylation. In comparison, Gi-mediated signaling induced by either thrombin, ADP, or adrenaline, examined by suppression of forskolin-stimulated rise in cyclic AMP (cAMP) was impaired, indicating dysfunctional Galphai signaling. Immunoblot analysis of platelet membranes with specific antiserum against different Galpha subunits indicated normal levels of Galphai2,Galphai3,Galphaz, and Galphaq in patient platelets. However, the Galphai1level was reduced to 25% of that found in normal platelets. Analysis of platelet cDNA and gDNA revealed no abnormality in either the Galphai1 or Galphai2 gene sequences. Our studies implicate the minor expressed Galphai subtype Galphai1 as having an important role in regulating signaling pathways associated with the activation of alphaIIbbeta3 and subsequent platelet aggregation by weak agonists.  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