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   5348篇
  免费   407篇
  国内免费   21篇
耳鼻咽喉   22篇
儿科学   191篇
妇产科学   144篇
基础医学   939篇
口腔科学   45篇
临床医学   690篇
内科学   1144篇
皮肤病学   107篇
神经病学   543篇
特种医学   112篇
外国民族医学   6篇
外科学   488篇
综合类   18篇
现状与发展   1篇
一般理论   3篇
预防医学   542篇
眼科学   116篇
药学   299篇
  1篇
中国医学   2篇
肿瘤学   363篇
  2023年   63篇
  2022年   102篇
  2021年   221篇
  2020年   119篇
  2019年   169篇
  2018年   212篇
  2017年   158篇
  2016年   138篇
  2015年   199篇
  2014年   265篇
  2013年   314篇
  2012年   394篇
  2011年   431篇
  2010年   232篇
  2009年   166篇
  2008年   333篇
  2007年   310篇
  2006年   310篇
  2005年   269篇
  2004年   259篇
  2003年   216篇
  2002年   178篇
  2001年   62篇
  2000年   47篇
  1999年   51篇
  1998年   54篇
  1997年   38篇
  1996年   43篇
  1995年   32篇
  1994年   32篇
  1993年   26篇
  1992年   21篇
  1991年   27篇
  1990年   15篇
  1989年   21篇
  1988年   23篇
  1987年   9篇
  1986年   22篇
  1985年   18篇
  1984年   13篇
  1983年   13篇
  1982年   16篇
  1980年   13篇
  1979年   12篇
  1978年   7篇
  1977年   8篇
  1975年   6篇
  1974年   14篇
  1973年   8篇
  1971年   9篇
排序方式: 共有5776条查询结果,搜索用时 31 毫秒
61.
AIDS and Behavior - We previously demonstrated that village community mobilization (CM) was associated with reduced HIV incidence among adolescent girls and young women (AGYW) in South Africa....  相似文献   
62.
AIDS and Behavior - Adolescents and young adults (AYA; 13–24 years-old) comprise 22% of new HIV infections in the United States (US), most of whom live in the South. We used the...  相似文献   
63.
The overall objective of this study was to analyze the effects of a combined prenatal and postnatal (entire gestational human chronic drinking model) ethanol exposure on T-cell development in mice. Specifically, this study evaluated the effects of chronic exposure to prenatal ethanol on lymphocyte makeup and proliferative capabilities of postnatal offspring's (4 and 12 weeks) peripheral lymphoid tissues. Chronic exposure regimens were conducted over the entire gestational period and through postnatal day 14 or 21. Thymus, spleen, and intestinal intraepithelial lymphocytes were harvested and analyzed by flow cytometry for percentages of T-cell subsets. Splenic lymphocytes were also analyzed for their ability to proliferate in response to a T-cell mitogen. Limited effects of chronic ethanol exposure were seen.  相似文献   
64.
Cyclic neutropenia is a rare hematologic disorder, characterized by repetitive episodes of fever, mouth ulcers, and infections attributable to recurrent severe neutropenia. Fluctuations in blood cells are due to oscillatory production of cells by the bone marrow. Recent genetic, molecular, and cellular studies have shown that autosomal-dominant cyclic neutropenia and sporadic cases of this disease are due to a mutation in the gene for neutrophil elastase (ELA2), located at 19p13.3. This enzyme is synthesized in neutrophil precursors early in the process of primary granule formation. It is currently presumed that the mutant neutrophil elastase functions aberrantly within the cells to accelerate apoptosis of the precursors, resulting in effective and oscillatory production. Cyclic neutropenia is effectively treated with granulocyte colony-stimulating factor (G-CSF), usually at doses of 1 to 5 microg/kg/d (median dose, 2.5 microg/kg/d). Long-term, daily, or alternate-day administration reduces fever, mouth ulcers, and other inflammatory events associated with this disorder. Leukemic transformation is not a recognized risk for cyclic neutropenia, with or without treatment with G-CSF.  相似文献   
65.
The evolution of instrumentation in terms of separation and detection allowed a real improvement of the sensitivity and analysis time. However, the analysis of ultra-traces of toxins in complex samples requires often a step of purification and even preconcentration before their chromatographic analysis. Therefore, immunoaffinity sorbents based on specific antibodies thus providing a molecular recognition mechanism appear as powerful tools for the selective extraction of a target molecule and its structural analogs to obtain more reliable and sensitive quantitative analysis in environmental, food or biological matrices. This review focuses on immunosorbents that have proven their efficiency in selectively extracting various types of toxins of various sizes (from small mycotoxins to large proteins) and physicochemical properties. Immunosorbents are now commercially available, and their use has been validated for numerous applications. The wide variety of samples to be analyzed, as well as extraction conditions and their impact on extraction yields, is discussed. In addition, their potential for purification and thus suppression of matrix effects, responsible for quantification problems especially in mass spectrometry, is presented. Due to their similar properties, molecularly imprinted polymers and aptamer-based sorbents that appear to be an interesting alternative to antibodies are also briefly addressed by comparing their potential with that of immunosorbents.  相似文献   
66.
We report herein a case of blastoid variant mantle cell lymphoma (MCL) with both aberrant phenotype and unusual genetics. Unexpectedly, lymphoma cells were CD5 and CD10+. Standard karyotype and FISH techniques showed that tumor cells carried two distinct translocations which had not been reported together in a same tumor. The first translocation juxtaposed the immunoglobulin lambda light chain locus with CCND1 locus, leading to Cyclin D1 overexpression. The second translocation revealed MYC rearrangement with a non-immunoglobulin gene partner located on the short arm of chromosome 4. The interpretation of the case on tissue sections alone could have been challenging. Indeed, the lack of CD5 and expression of CD10 associated with MYC rearrangement detected on interphasic nuclei could support the diagnosis of diffuse large B-cell lymphoma or Burkitt lymphoma. This distinction is also especially important as these lymphoma subtypes require specific treatment.  相似文献   
67.

Objective

Newborn screening (NBS) identifies genetic carriers for sickle cell hemoglobinopathy and cystic fibrosis. We aimed to identify factors during initial NBS carrier results disclosure by primary care providers (PCPs) that influenced parents’ experiences and reactions.

Methods

Open-ended responses from telephone interviews with 270 parents of carriers were analyzed using mixed-methods. Conventional content analysis identified influential factors; chi-square tests analyzed relationships between factors and parent-reported reactions.

Results

Parents reported positive (35%) or negative (31%) reactions to results disclosure. Parents’ experiences were influenced by specific factors: content messages (72%), PCP traits (47%), and aspects of the setting (30%). Including at least one of five specific content messages was associated (p < 0.05) with positive parental reactions; omitting at least one of four specific content messages was associated (p < 0.05) with negative parental reactions. Parents reported positive reactions when PCPs avoided jargon or were perceived as calm. Parents reported negative reactions to jargon usage and results disclosure by voicemail.

Conclusion

Parents identified aspects of PCP communication which influenced their reactions and results disclosure experiences.

Practice implications

Our findings suggest ways PCPs may improve communication of carrier results. PCPs should provide specific content messages and consider how their actions, characteristics, and setting can influence parental reactions.  相似文献   
68.
European Journal of Clinical Microbiology & Infectious Diseases - Molecular diagnosis on nasopharyngeal swabs (NPS) is the current standard for COVID-19 diagnosis, but saliva may be an...  相似文献   
69.

Purpose

It has been demonstrated that exercise-induced dehydration (EID) does not impair, and ad libitum drinking optimizes, cycling time-trial (TT) performance. However, the idea that EID ≥ 2 % bodyweight (BW) impairs endurance performance is well ingrained. No study has tested the impact of EID upon running TT performance. We compared the effects of thirst-driven (TD) vs. programmed fluid intake (PFI) aimed at maintaining EID-associated BW loss <2 % on half-marathon performance.

Methods

Ten trained distance runners underwent, in a randomized, crossover fashion, two, 21.1 km running TTs on a treadmill (30 °C, 42 % relative humidity) while facing a wind speed matching running speed and drinking water (1) according to thirst sensation (TD) or (2) to maintain BW loss <2 % of their pre-exercise BW (PFI), as recommended by the American College of Sports Medicine.

Results

Despite that PFI significantly reduced EID from 3.1 ± 0.6 (TD) to 1.3 ± 0.7 % BW (PFI), mean rectal temperature from 39.4 ± 0.4 to 39.1 ± 0.3 °C, mean body temperature from 38.1 ± 0.4 to 37.7 ± 0.2 °C and mean heart rate from 175 ± 9 to 171 ± 8 bpm, neither half-marathon time (TD 89.8 ± 7.7; PFI 89.6 ± 7.7 min) nor running pace (TD 4.3 ± 0.4; PFI 4.2 ± 0.4 min/km) differed significantly between trials.

Conclusion

Albeit providing trivial cardiovascular and thermoregulatory advantages, in trained distance runners, PFI (1,380 ± 320 mL/h) offers no performance benefits over TD fluid intake (384 ± 180 mL/h) during a half-marathon raced under warm conditions.  相似文献   
70.
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