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   828篇
  免费   59篇
  国内免费   4篇
耳鼻咽喉   10篇
儿科学   54篇
妇产科学   19篇
基础医学   116篇
口腔科学   33篇
临床医学   96篇
内科学   163篇
皮肤病学   25篇
神经病学   34篇
特种医学   15篇
外科学   67篇
综合类   15篇
现状与发展   1篇
一般理论   2篇
预防医学   79篇
眼科学   30篇
药学   51篇
中国医学   6篇
肿瘤学   75篇
  2023年   13篇
  2022年   34篇
  2021年   36篇
  2020年   16篇
  2019年   23篇
  2018年   42篇
  2017年   25篇
  2016年   24篇
  2015年   30篇
  2014年   38篇
  2013年   48篇
  2012年   79篇
  2011年   83篇
  2010年   30篇
  2009年   30篇
  2008年   46篇
  2007年   54篇
  2006年   35篇
  2005年   42篇
  2004年   42篇
  2003年   36篇
  2002年   30篇
  2001年   5篇
  2000年   5篇
  1999年   6篇
  1998年   2篇
  1997年   4篇
  1996年   6篇
  1995年   2篇
  1994年   4篇
  1993年   3篇
  1992年   2篇
  1991年   1篇
  1990年   2篇
  1989年   3篇
  1988年   2篇
  1986年   1篇
  1984年   1篇
  1983年   1篇
  1981年   1篇
  1980年   1篇
  1979年   2篇
  1977年   1篇
排序方式: 共有891条查询结果,搜索用时 15 毫秒
31.
32.
Introduction: Breast cancer stands the second prominent cause of death among women. For its efficient treatment, Lapatinib (LAPA) was developed as a selective tyrosine kinase inhibitor of receptors, overexpressed by breast cancer cells. Various explored delivery strategies for LAPA indicated its controlled release with enhanced aqueous solubility, improved bioavailability, decreased plasma protein binding, reduced dose and toxicity to the other organs with maximized clinical efficacy, compared to its marketed tablet formulation.

Areas covered: This comprehensive review deals with the survey, performed through different electronic databases, regarding various challenges and their solutions attained by fabricating delivery systems like nanoparticles, micelle, nanocapsules, nanochannels, and liposomes. It also covers the synthesis of novel LAPA-conjugates for diagnostic purpose.

Expert opinion: Unfortunately, clinical use of LAPA is restricted because of its extensive albumin binding capacity, poor oral bioavailability, and poor aqueous solubility. LAPA is marketed as the oral tablet only. Therefore, it becomes imperative to formulate alternate efficient multiparticulate or nano-delivery systems for administration through non-oral routes, for active/passive targeting, and to scale-up by pharmaceutical scientists followed by their clinical trials by clinical experts. LAPA combinations with capecitabine and letrozole should also be tried for breast cancer treatment.  相似文献   

33.
Symmetrical drug-related intertriginous and flexural exanthema (SDRIFE) is an adverse drug reaction which has been reported to be caused by various drugs. In this report, we describe a case induced by ranitidine, a drug which has not been previously reported to cause SDRIFE.KEY WORDS: Erythema, ranitidine, SDRIFE  相似文献   
34.
An efficient and environmentally sustainable domino protocol has been presented for the synthesis of structurally diverse spiroannulated pyrimidophenazines involving a four component reaction of 2-hydroxynaphthalene-1,4-dione, benzene-1,2-diamine, cyclic ketones and amino derivatives in the presence of erbium doped TiO2 nanoparticles as a recyclable and reusable heterogeneous acid catalyst. The present synthetic protocol features mild reaction conditions with operational simplicity, excellent yield with high purity, short reaction time and high atom economy with the use of a recoverable and reusable environmentally sustainable heterogeneous catalyst.

An efficient and environmentally sustainable domino protocol has been presented for the synthesis of structurally diverse spiroannulated pyrimidophenazines using erbium doped TiO2 nanoparticles as a recyclable and reusable heterogeneous acid catalyst.  相似文献   
35.
Being reminded of the inherently finite nature of human existence has been demonstrated to elicit strivings for sexual reproduction and the formation and maintenance of intimate relationships. Recently, it has been proposed that the perception of potential mating partners is influenced by mortality salience. Using functional magnetic resonance imaging, we investigated the neurocognitive processing of attractive opposite-sex faces after priming with death-related words for heterosexual men and women. Significant modulations of behavioral and neural responses were found when participants were requested to decide whether they would like to meet the presented person. Men were more in favor of meeting attractive women after being primed with death-related words compared to a no-prime condition. Increased neural activation could be found under mortality salience in the left anterior insula and the adjacent lateral prefrontal cortex (lPFC) for both men and women. As previously suggested, we believe that the lPFC activation reflects an approach-motivated defense mechanism to overcome concerns that are induced by being reminded of death and dying. Our results provide insight on a neurocognitive level that approach motivation in general, and mating motivation in particular is modulated by mortality salience.  相似文献   
36.

Background

Mast cells and neuroimmune interactions regulate the severity of intestinal radiation mucositis, a dose-limiting toxicity during radiation therapy of abdominal malignancies.

Aim

Because endocannabinoids (eCB) regulate intestinal inflammation, we investigated the effect of the cannabimimetic, palmitoylethanolamide (PEA), in a mast competent (+/+) and mast cell-deficient (Ws/Ws) rat model.

Methods

Rats underwent localized, fractionated intestinal irradiation, and received daily injections with vehicle or PEA from 1 day before until 2 weeks after radiation. Intestinal injury was assessed noninvasively by luminol bioluminescence, and, at 2 weeks, by histology, morphometry, and immunohistochemical analysis, gene expression analysis, and pathway analysis.

Results

Compared with +/+ rats, Ws/Ws rats sustained more intestinal structural injury (p = 0.01), mucosal damage (p = 0.02), neutrophil infiltration (p = 0.0003), and collagen deposition (p = 0.004). PEA reduced structural radiation injury (p = 0.02), intestinal wall thickness (p = 0.03), collagen deposition (p = 0.03), and intestinal inflammation (p = 0.02) in Ws/Ws rats, but not in +/+ rats. PEA inhibited mast cell-derived cellular immune response and anti-inflammatory IL-6 and IL-10 signaling and activated the prothrombin pathway in +/+ rats. In contrast, while PEA suppressed nonmast cell-derived immune responses, it increased anti-inflammatory IL-10 and IL-6 signaling and decreased activation of the prothrombin pathway in Ws/Ws rats.

Conclusions

These data demonstrate that the absence of mast cells exacerbate radiation enteropathy by mechanisms that likely involve the coagulation system, anti-inflammatory cytokine signaling, and the innate immune system; and that these mechanisms are regulated by PEA in a mast cell-dependent manner. The eCB system should be explored as target for mitigating intestinal radiation injury.  相似文献   
37.
38.
Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - The aim of this study was to develop PCR assay for simultaneous detection of tissues from cattle and buffalo...  相似文献   
39.
Background

Vaccination prevents severe morbidity and mortality from COVID-19 in the general population. The immunogenicity and efficacy of SARS-CoV-2 vaccines in patients with antibody deficiency is poorly understood.

Objectives

COVID-19 in patients with antibody deficiency (COV-AD) is a multi-site UK study that aims to determine the immune response to SARS-CoV-2 infection and vaccination in patients with primary or secondary antibody deficiency, a population that suffers from severe and recurrent infection and does not respond well to vaccination.

Methods

Individuals on immunoglobulin replacement therapy or with an IgG less than 4 g/L receiving antibiotic prophylaxis were recruited from April 2021. Serological and cellular responses were determined using ELISA, live-virus neutralisation and interferon gamma release assays. SARS-CoV-2 infection and clearance were determined by PCR from serial nasopharyngeal swabs.

Results

A total of 5.6% (n?=?320) of the cohort reported prior SARS-CoV-2 infection, but only 0.3% remained PCR positive on study entry. Seropositivity, following two doses of SARS-CoV-2 vaccination, was 54.8% (n?=?168) compared with 100% of healthy controls (n?=?205). The magnitude of the antibody response and its neutralising capacity were both significantly reduced compared to controls. Participants vaccinated with the Pfizer/BioNTech vaccine were more likely to be seropositive (65.7% vs. 48.0%, p?=?0.03) and have higher antibody levels compared with the AstraZeneca vaccine (IgGAM ratio 3.73 vs. 2.39, p?=?0.0003). T cell responses post vaccination was demonstrable in 46.2% of participants and were associated with better antibody responses but there was no difference between the two vaccines. Eleven vaccine-breakthrough infections have occurred to date, 10 of them in recipients of the AstraZeneca vaccine.

Conclusion

SARS-CoV-2 vaccines demonstrate reduced immunogenicity in patients with antibody deficiency with evidence of vaccine breakthrough infection.

  相似文献   
40.
Majority of the urban adolescent girl students (n = 76) from middle socioeconomic group correctly reported that breast milk is the best food for infants (95%), and it has protective antibodies (98%). However, most of them (92%) had incorrect knowledge about the role of diet in breast milk secretion and continuation of breastfeeding while mother is suffering from tuberculosis (92%), malaria (84%).  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