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   3775623篇
  免费   312677篇
  国内免费   14690篇
耳鼻咽喉   50850篇
儿科学   120233篇
妇产科学   97996篇
基础医学   592185篇
口腔科学   102534篇
临床医学   340249篇
内科学   674343篇
皮肤病学   98853篇
神经病学   317217篇
特种医学   147182篇
外国民族医学   262篇
外科学   582948篇
综合类   114553篇
现状与发展   23篇
一般理论   2367篇
预防医学   309126篇
眼科学   89795篇
药学   262444篇
  23篇
中国医学   11548篇
肿瘤学   188259篇
  2021年   56164篇
  2020年   35705篇
  2019年   58820篇
  2018年   73206篇
  2017年   55517篇
  2016年   61550篇
  2015年   75190篇
  2014年   109573篇
  2013年   175147篇
  2012年   105913篇
  2011年   107897篇
  2010年   121389篇
  2009年   124192篇
  2008年   93944篇
  2007年   98542篇
  2006年   107926篇
  2005年   102445篇
  2004年   104148篇
  2003年   93945篇
  2002年   83212篇
  2001年   136376篇
  2000年   129928篇
  1999年   122259篇
  1998年   68659篇
  1997年   65310篇
  1996年   63038篇
  1995年   58590篇
  1994年   52568篇
  1993年   48928篇
  1992年   85217篇
  1991年   81110篇
  1990年   76849篇
  1989年   75270篇
  1988年   69150篇
  1987年   67329篇
  1986年   63664篇
  1985年   62902篇
  1984年   54963篇
  1983年   49651篇
  1982年   43656篇
  1981年   41012篇
  1980年   38488篇
  1979年   44932篇
  1978年   38300篇
  1977年   34980篇
  1976年   32012篇
  1975年   30854篇
  1974年   32562篇
  1973年   31249篇
  1972年   29116篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
Platelet α-granules release growth factors (GFs) that promote healing and tissue regeneration. Platelet-rich plasma (PRP) is shown to be beneficial in treating alopecia, and however, clinical response can be inconsistent. Due to several fold enrichment of platelets secreting large quantities of GFs following PRP injections, heterogeneity in amounts of GFs secreted by platelets may contribute to inconsistent clinical responses. Herein, we evaluated factors that could potentially contribute to heterogeneous secretion of GFs by platelets. We measured platelet secretion of transforming growth factor beta1 (TGFβ1), platelet-derived growth factor (PDGF-BB), epidermal growth factor (EGF), vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF2) in aliquots of de-identified PRP samples from female patients undergoing therapy in the hair disease clinic. Although secretion of GFs by platelets was comparable in PRP samples of patients with non-cicatricial and cicatricial alopecia, a Shapiro-Wilk test for normal distribution indicated significant variability across all patient samples. The amount of GF secreted by platelets was comparable when PRP prepared from two FDA-cleared devices with distinct techniques were compared. We provide evidence of platelets secreting heterogeneous amounts of GFs within each sample as high and low secretion of random factors could be simultaneously detected. These results suggest inherent heterogeneity in secretion of GFs by platelets in patient samples that are not influenced by the device used to prepare PRP. Since some GFs could have antagonistic effects on hair growth, a balance between amounts of growth promoting and inhibiting factors may be crucial in determining clinical response to PRP therapy.  相似文献   
962.
目的 初步探讨应用艾尔巴韦/格拉瑞韦治疗慢性丙型肝炎(CHC)患者的疗效。方法 2017年3月~2018年3月仙桃市第一人民医院感染病科收治的CHC患者82例,被随机分为对照组41例和观察组41例,分别给予聚乙二醇干扰素-α联合利巴韦林治疗和艾尔巴韦/格拉瑞韦治疗,两组均连续治疗24周。采用RT- PCR法检测血清 HCV RNA,采用全基因序列测定法行病毒基因分型。比较两组早期病毒学应答(EVR)、治疗结束时病毒学应答(ETVR)和持续病毒学应答(SVR)。结果 在治疗结束时,观察组血清丙氨酸氨基转移酶(ALT)水平为(47.9±19.7)U/L,显著低于对照组【(63.5±21.2)U/L,P<0.05】,天冬氨酸氨基转移酶(AST)水平为(55.5±22.3)U/L,显著低于对照组【(81.3±25.8)U/L,P<0.05】;观察组EVR、ETVR和SVR分别为48.8%、63.4%和70.7%,与对照组的41.5%、53.7%和65.8%比,无统计学差异(P>0.05);18例观察组非HCV Ⅰ型感染者EVR、ETVR和SVR分别为88.9%、94.4%和88.9%,显著高于同组23例HCV Ⅰ型感染者(分别为52.2%、60.9%和52.2%, P<0.05),而与对照组15例非HCV Ⅰ型感染者比,无统计学差异(分别为86.7%、93.3%和73.3%, P>0.05);观察组SVR12为87.8%(36/41),显著高于对照组的73.2%(30/41,P<0.05)。结论 应用直接抗病毒(DAA)药物艾尔巴韦/格拉瑞韦治疗CHC患者近期疗效达到,但远期疗效似优于标准治疗方案, 值得临床进一步验证。  相似文献   
963.
964.
Abstract

Objective

Two similarly designed studies compared user experiences with a second-generation extra-thin-wall, 5-bevel 32?G?×?4?mm pen needle (PN) with redesigned hub versus four thinner commercially available PNs.  相似文献   
965.
966.
967.

Introduction The focus in clinical pharmacy practice is and has for the last 30–35 years been on changing the role of pharmacy staff into service orientation and patient counselling. One way of doing this is by involving staff in change process and as a researcher to take part in the change process by establishing partnerships with staff. On the background of the authors’ widespread action research (AR)-based experiences, recommendations and comments for how to conduct an AR-study is described, and one of their AR-based studies illustrate the methodology and the research methods used. Methodology AR is defined as an approach to research which is based on a problem-solving relationship between researchers and clients, which aims at both solving a problem and at collaboratively generating new knowledge. Research questions relevant in AR-studies are: what was the working process in this change oriented study? What learning and/or changes took place? What challenges/pitfalls had to be overcome? What were the influence/consequences for the involved parts? When to use If you want to implement new services and want to involve staff and others in the process, an AR methodology is very suitable. The basic advantages of doing AR-based studies are grounded in their participatory and democratic basis and their starting point in problems experienced in practice. Limitations Some of the limitations in AR-studies are that neither of the participants in a project steering group are the only ones to decide. Furthermore, the collective process makes the decision-making procedures relatively complex.

  相似文献   
968.
969.
970.
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