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   1365篇
  免费   79篇
  国内免费   8篇
耳鼻咽喉   14篇
儿科学   120篇
妇产科学   33篇
基础医学   93篇
口腔科学   14篇
临床医学   92篇
内科学   264篇
皮肤病学   35篇
神经病学   106篇
特种医学   67篇
外科学   303篇
综合类   26篇
预防医学   50篇
眼科学   45篇
药学   117篇
中国医学   2篇
肿瘤学   71篇
  2023年   10篇
  2022年   17篇
  2021年   38篇
  2020年   22篇
  2019年   33篇
  2018年   50篇
  2017年   33篇
  2016年   39篇
  2015年   38篇
  2014年   65篇
  2013年   76篇
  2012年   111篇
  2011年   114篇
  2010年   61篇
  2009年   58篇
  2008年   81篇
  2007年   81篇
  2006年   61篇
  2005年   56篇
  2004年   41篇
  2003年   26篇
  2002年   30篇
  2001年   26篇
  2000年   39篇
  1999年   16篇
  1998年   19篇
  1997年   10篇
  1996年   8篇
  1995年   11篇
  1994年   15篇
  1993年   11篇
  1992年   16篇
  1991年   11篇
  1990年   8篇
  1989年   12篇
  1988年   17篇
  1987年   11篇
  1986年   8篇
  1985年   9篇
  1984年   9篇
  1983年   7篇
  1982年   6篇
  1980年   3篇
  1977年   3篇
  1976年   3篇
  1975年   3篇
  1971年   2篇
  1968年   2篇
  1967年   3篇
  1924年   2篇
排序方式: 共有1452条查询结果,搜索用时 0 毫秒
991.
OBJECTIVE: To determine whether color flow Doppler sonography (CFDS) is useful in differentiating Graves vs non-Graves thyrotoxicosis during pregnancy, when nuclear imaging is contraindicated. METHODS: Ten pregnant women with thyrotoxicosis were divided into Graves, and non-Graves, disease groups and were evaluated by CFDS for thyroid volume, vascularity, and inferior thyroid artery (ITA) flow velocity. Each patient was matched with a euthyroid woman of the same pregnancy duration. RESULTS: Of the 10 patients, 3 were diagnosed with Graves disease, 4 with gestational toxicosis, and 3 with destructive thyroiditis. Those in the Graves disease group had a greater thyroid gland volume (18.9+/-1.5 cm3 vs 12.1+/-2.4 cm3; P<0.05), greater thyroid vascularity, and greater ITA flow velocity than those in the non-Graves disease group (92+/-13 cm/s vs 20.4+/-2.4 cm/s; P<0.05). There was no significant difference in the corresponding values between the patients with gestational toxicosis and those with destructive thyroiditis or between them and their healthy controls. CONCLUSION: Thyroid evaluation by CFDS is useful for the differential diagnosis of thyrotoxicosis in pregnant women.  相似文献   
992.
993.
BACKGROUND: CXC chemokines, IL-8 and GRO, play a role in the recruitment of neutrophils in the human. The functional orthologues in the rat and mouse are CINC/KC and MIP-2. The lack of IL-8 made these animals less useful to study the role of IL-8 and GRO. METHODS: Guinea pig (gp) cDNA libraries were screened for GRO and IL-1beta. A gp genomic library was screened with a gpGRO cDNA probe. Expression of gpIL-8, gpGRO, gpTNFalpha, and gpIL-1beta was investigated by Northern analysis and/or by in situ hybridization. RESULTS: Two gpGRO cDNAs, a 3.0-kb gpGRO genomic DNA, and a gpIL-1beta cDNA were cloned. gpGRO and gpIL-8 mRNA were detected in different tissues including lungs 1 h after intraperitoneal injection of lipopolysaccharide (LPS) into guinea pigs. gpGRO, gpIL-8, gpTNFalpha, and gpIL-1beta expression peaked at 3 h in the lungs. Both gpGRO and gpIL-8 mRNA were detected in the cells in alveolar spaces and bronchial epithelial cells. However, gpGRO mRNA, but not gpIL-8, was also expressed in endothelial cells and vascular smooth muscle cells. CONCLUSIONS: gpGRO and gpIL-8 mRNA rapidly accumulated in the lungs of guinea pigs after LPS injection. Expression of gpIL-8 and gpGRO mRNA appeared to be independent from TNFalpha- or IL-1beta-stimulation in this model. A high level expression of gpGRO in vascular cells suggest an important role of GRO in the sequestration of neutrophils and multi-organ injuries induced by LPS. The guinea pig will provide an excellent model to study the roles of IL-8 and GRO, important inflammatory mediators in the human.  相似文献   
994.
995.
996.

Background  

To determine whether posterior-only approach using pedicle screws in neuromuscular scoliosis population adequately addresses the correction of scoliosis and maintains the correction over time.  相似文献   
997.
Introduction : HIV‐infected pregnant and breastfeeding adolescents are a particularly vulnerable group that require special attention and enhanced support to achieve optimal maternal and infant outcomes. The objective of this paper is to review published evidence about antenatal care (ANC) service delivery and outcomes for HIV‐infected pregnant adolescents in low‐income country settings, identify gaps in knowledge and programme services and highlight the way forward to improve clinical outcomes of this vulnerable group. Discussion : Emerging data from programmes in sub‐Saharan Africa highlight that HIV‐infected pregnant adolescents have poorer prevention of mother‐to‐child HIV transmission (PMTCT) service outcomes, including lower PMTCT service uptake, compared to HIV‐infected pregnant adults. In addition, the limited evidence available suggests that there may be higher rates of mother‐to‐child HIV transmission among infants of HIV‐infected pregnant adolescents. Conclusions : While the reasons for the inferior outcomes among adolescents in ANC need to be further explored and addressed, there is sufficient evidence that immediate operational changes are needed to address the unique needs of this population. Such changes could include integration of adolescent‐friendly services into PMTCT settings or targeting HIV‐infected pregnant adolescents with enhanced retention and follow‐up activities.  相似文献   
998.
Increasing costs in discovering and developing new molecular entities and the continuing debate on limited company pipelines mean that pharmaceutical companies are under significant pressure to maximize the value of approved products. Life cycle management in the context of drug development comprises activities to maximize the effective life of a product. Life cycle approaches can involve new formulations, new routes of delivery, new indications or expansion of the population for whom the product is indicated, or development of combination products. Life cycle management may provide an opportunity to improve upon the current product through enhanced efficacy or reduced side effects and could expand the therapeutic market for the product. Successful life cycle management may include the potential for superior efficacy, improved tolerability, or a better prescriber or patient acceptance. Unlike generic products where bioequivalence to an innovator product may be sufficient for drug approval, life cycle management typically requires a series of studies to characterize the value of the product. This review summarizes key considerations in identifying product candidates that may be suitable for life cycle management and discusses the application of pharmacokinetics and pharmacodynamics in developing new products using a life cycle management approach. Examples and a case study to illustrate how pharmacokinetics and pharmacodynamics contributed to the selection of dosing regimens, demonstration of an improved therapeutic effect, or regulatory approval of an improved product label are presented.  相似文献   
999.
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