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   6436篇
  免费   400篇
  国内免费   53篇
耳鼻咽喉   29篇
儿科学   94篇
妇产科学   69篇
基础医学   1017篇
口腔科学   147篇
临床医学   473篇
内科学   1405篇
皮肤病学   79篇
神经病学   777篇
特种医学   213篇
外科学   1071篇
综合类   28篇
现状与发展   1篇
一般理论   2篇
预防医学   335篇
眼科学   189篇
药学   474篇
中国医学   12篇
肿瘤学   474篇
  2024年   4篇
  2023年   42篇
  2022年   48篇
  2021年   236篇
  2020年   131篇
  2019年   199篇
  2018年   201篇
  2017年   123篇
  2016年   173篇
  2015年   209篇
  2014年   294篇
  2013年   328篇
  2012年   564篇
  2011年   567篇
  2010年   311篇
  2009年   271篇
  2008年   471篇
  2007年   461篇
  2006年   424篇
  2005年   405篇
  2004年   396篇
  2003年   330篇
  2002年   300篇
  2001年   30篇
  2000年   13篇
  1999年   31篇
  1998年   36篇
  1997年   51篇
  1996年   23篇
  1995年   28篇
  1994年   15篇
  1993年   18篇
  1992年   13篇
  1991年   16篇
  1990年   7篇
  1989年   7篇
  1988年   5篇
  1987年   7篇
  1985年   5篇
  1984年   5篇
  1983年   7篇
  1982年   5篇
  1981年   5篇
  1978年   8篇
  1977年   4篇
  1976年   8篇
  1975年   4篇
  1964年   4篇
  1961年   7篇
  1960年   5篇
排序方式: 共有6889条查询结果,搜索用时 281 毫秒
1.
2.
Hepatocellular carcinoma(HCC) is the most common primary hepatic malignancy, which usually arises in cirrhotic liver. When the typical enhancement pattern, consisting of late arterial hyperenhancement followed by washout, is present in nodules larger than 1 cm, HCC can be confidently diagnosed without the need for tissue biopsy. Nevertheless, HCC can display an atypical enhancement pattern, either as iso or hypovascular lesion, or hypervascular lesion without washout. Not only the enhancement pattern of HCC could be atypical, but also a variety of histological types of HCC, such as steatotic, scirrhous, fibrolamellar, or combined hepatocellular-cholangiocellular carcinoma could raise diagnostic dilemmas. In addition, distinct morphological types of HCC or different growth pattern can occur. Awareness of these atypical and rare HCC presentations on magnetic resonance imaging is important for accurate differentiation from other focal liver lesions and timely diagnosis, which allows optimal treatment of patients.  相似文献   
3.
Retinal organoid technology enables generation of an inexhaustible supply of three‐dimensional retinal tissue from human pluripotent stem cells (hPSCs) for regenerative medicine applications. The high similarity of organoid‐derived retinal tissue and transplantable human fetal retina provides an opportunity for evaluating and modeling retinal tissue replacement strategies in relevant animal models in the effort to develop a functional retinal patch to restore vision in patients with profound blindness caused by retinal degeneration. Because of the complexity of this very promising approach requiring specialized stem cell and grafting techniques, the tasks of retinal tissue derivation and transplantation are frequently split between geographically distant teams. Delivery of delicate and perishable neural tissue such as retina to the surgical sites requires a reliable shipping protocol and also controlled temperature conditions with damage‐reporting mechanisms in place to prevent transplantation of tissue damaged in transit into expensive animal models. We have developed a robust overnight tissue shipping protocol providing reliable temperature control, live monitoring of the shipment conditions and physical location of the package, and damage reporting at the time of delivery. This allows for shipping of viable (transplantation‐competent) hPSC‐derived retinal tissue over large distances, thus enabling stem cell and surgical teams from different parts of the country to work together and maximize successful engraftment of organoid‐derived retinal tissue. Although this protocol was developed for preclinical in vivo studies in animal models, it is potentially translatable for clinical transplantation in the future and will contribute to developing clinical protocols for restoring vision in patients with retinal degeneration.  相似文献   
4.
ABSTRACT

Using nationally representative data from the National Longitudinal Study of Adolescent Health (a.k.a., Add Health), this study examines the impact of school climate and share of vulnerable groups of students on self-perceived discrimination and violence involvement in high school. Violence involvement is operationalized as victimization and perpetration of physical violence. Five categories of vulnerability status are analyzed: the emotionally disabled, learning disabled, physically disabled, obese and LGB. Results suggest that relatively higher odds of violence involvement for individuals who were members of vulnerable groups as adolescents are fully explained by school climate and an extensive set of individual-level controls. While the share of vulnerable groups in school is not consistently correlated with violence involvement, school climate is found to be highly predictive of self-perceived discrimination and violence involvement. Consequently, we believe that improving school climate is the most effective strategy for reducing violence involvement of vulnerable youth in school.  相似文献   
5.
6.
7.
8.
9.
The aims of this study were: (i) To investigate the activity of recombinant AMPs HNP-1 and hBD-1 in combination with cefotaxime against Staphylococcus aureus strains (MSSA and MRSA) in vitro using checkerboard method; (ii) To investigate the activity of HNP-1 and hBD-1 encapsulated in silicon nanoparticles (niosomes) in the treatment of MRSA-infected wound in rats. For this S. aureus strains (MSSA and MRSA) were isolated from patients with diabetic foot infection. Cefotaxime, recombinant HNP-1 and hBD-1 (in all possible combinations with each other) were used for testing by the checkerboard method. Two niosomal topical gels with HNP-1/hBD-1 were prepared to treat MRSA-infected wounds in rats. Gels were administered once a day, the control group–without treatment. Wound healing rate was calculated on the 4th, 9th and 16th days of the experiment and compared using one-way ANOVA with Bonferroni correction. MIC of HNP-1 for MSSA and MRSA was the same–1 mg/L. MIC of hBD-1 for MSSA and MRSA was also the same–0.5 mg/L. Topical gels with niosomal HNP-1 (or hBD-1) showed a significantly faster wound healing in comparison with the control. The data obtained open up prospects for use of AMPs encapsulated in silica nanoparticles for the development of new antibiotics.  相似文献   
10.

The co-occurrence of HIV and alcohol use disorder (AUD) amplifies risk for neural injury and neurocognitive deficits. However, the substantial neurocognitive heterogeneity across HIV+/AUD+ individuals suggests inter-individual differences in vulnerability to the neurotoxicity of comorbid HIV/AUD. Genetic variation in alcohol dehydrogenase (ADH), which metabolizes ethanol, may contribute to inter-individual neurocognitive variability. We evaluated associations between five ADH single-nucleotide polymorphisms (SNPs) and neurocognition in men stratified by HIV and lifetime AUD status. Neurobehavioral assessments were administered to 153 men. Three-way ANOVAs examined the interaction of HIV, AUD, and ADH SNPs on global and domain-specific demographically corrected T scores. Follow-up ANCOVAs adjusted for age, estimated verbal IQ, depression, and remote non-alcohol substance use disorders. HIV/AUD groups differed globally and for verbal fluency, working memory, executive function, and processing speed T scores specifically, with HIV+/AUD+ exhibiting the poorest performance. ADH4 (rs1126671) was associated with large effects on working memory (d?=???1.16, p?=?.001) and executive function (d?=???0.77, p?=?.028) selectively in HIV+/AUD+, which remained significant in ANCOVA models. ADH1A (rs3819197) moderated the deleterious effects of HIV+/AUD+ on processing speed such that HIV+/AUD+ related to slower information processing in A allele carriers but not GG homozygotes (ps?<?0.03). Preliminary findings suggest genetic variation in the ADH pathway moderates the deleterious neurocognitive effects of comorbid HIV/AUD. Differential metabolism of heavy ethanol exposure may compromise neurocognition under conditions of neurobiological stress, such as in HIV infection. The functional effects on ethanol metabolism of ADH SNPs examined in this study remain poorly understood, warranting further examination of pharmacokinetic mechanisms mediating ADH gene-neurobehavior relationships in HIV.

  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