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   1026篇
  免费   62篇
  国内免费   3篇
耳鼻咽喉   4篇
儿科学   10篇
妇产科学   12篇
基础医学   162篇
口腔科学   14篇
临床医学   107篇
内科学   233篇
皮肤病学   10篇
神经病学   125篇
特种医学   34篇
外科学   139篇
综合类   6篇
预防医学   44篇
眼科学   10篇
药学   83篇
中国医学   2篇
肿瘤学   96篇
  2024年   1篇
  2023年   5篇
  2022年   35篇
  2021年   52篇
  2020年   22篇
  2019年   30篇
  2018年   41篇
  2017年   18篇
  2016年   23篇
  2015年   28篇
  2014年   32篇
  2013年   45篇
  2012年   91篇
  2011年   93篇
  2010年   44篇
  2009年   37篇
  2008年   78篇
  2007年   61篇
  2006年   54篇
  2005年   77篇
  2004年   58篇
  2003年   56篇
  2002年   47篇
  2001年   6篇
  2000年   2篇
  1999年   6篇
  1998年   5篇
  1997年   15篇
  1996年   3篇
  1995年   9篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1986年   2篇
  1980年   3篇
  1979年   2篇
  1978年   1篇
  1970年   1篇
排序方式: 共有1091条查询结果,搜索用时 879 毫秒
11.
Serotonin 5-HT2A receptor (5-HT2A) binding is reported to be altered in individuals with suicidal behavior, mood disorders, and aggressive-impulsive traits. Genetic association with major depression, suicidal behavior, and aggressive-impulsive traits has not been established. This study examines the possible association of the 5-HT2A gene C102T polymorphism with the receptor binding kinetics, and clinical overt phenotypes. The study population included 63 healthy volunteers and 152 subjects with mood disorders, 56 of whom had a history of suicide attempts. All were Caucasian. Platelet 5-HT2A binding kinetics (Bmax and KD) were assayed and adjusted for seasonal variation. All subjects were genotyped for the T102C polymorphism. Clinical phenotype was determined by structured clinical interview. The TT genotype was associated with higher Bmax in all subjects (F=3.53, df=2,211; p=0.03), controlling for diagnosis. Bonferroni-adjusted post hoc testing showed higher binding in the TT compared with TC genotype in the control group (F=7.56, df=2,60, p=0.001), but not in the mood-disordered subjects. No difference was found in genotype and allele distribution between the mood-disordered subjects, with and without suicide attempt history, and controls. Bmax was not related to a diagnosis of mood disorders. The TT genotype appears associated with higher platelet 5-HT2A Bmax in the healthy population, but this genotypic effect appears absent in mood disorders and unrelated to psychopathology.  相似文献   
12.
The discovery of new compounds that are able to inhibit the growth of Burkholderia cenocepacia is of primary importance for cystic fibrosis patients. Here, the mechanism of resistance to a new pyridine derivative already shown to be effective against Mycobacterium tuberculosis and to have good activity toward B. cenocepacia was investigated. Increased expression of a resistance-nodulation-cell division (RND) efflux system was detected in the resistant mutants, thus confirming their important roles in B. cenocepacia antibiotic resistance.  相似文献   
13.
14.
Historically, most vaccines have been based on killed or live‐attenuated infectious agents. Although very successful at immunizing populations against disease, both approaches raise safety concerns and often have limited production capacity. This has resulted in increased emphasis on the development of subunit vaccines. Several recombinant systems have been considered for subunit vaccine manufacture, including plants, which offer advantages both in cost and in scale of production. We have developed a plant expression system utilizing a ‘launch vector’, which combines the advantageous features of standard agrobacterial binary plasmids and plant viral vectors, to achieve high‐level target antigen expression in plants. As an additional feature, to aid in target expression, stability and purification, we have engineered a thermostable carrier molecule to which antigens are fused. We have applied this launch vector/carrier system to engineer and express target antigens from various pathogens, including, influenza A/Vietnam/04 (H5N1) virus.  相似文献   
15.
The spatial accuracy of transcranial magnetic stimulation (TMS) may be as small as a few millimeters. Despite such great potential, navigated TMS (nTMS) mapping is still underused for the assessment of motor plasticity, particularly in clinical settings. Here, we investigate the within‐limb somatotopy gradient as well as absolute and relative reliability of three hand muscle cortical representations (MCRs) using a comprehensive grid‐based sulcus‐informed nTMS motor mapping. We enrolled 22 young healthy male volunteers. Two nTMS mapping sessions were separated by 5–10 days. Motor evoked potentials were obtained from abductor pollicis brevis (APB), abductor digiti minimi, and extensor digitorum communis. In addition to individual MRI‐based analysis, we studied normalized MNI MCRs. For the reliability assessment, we calculated intraclass correlation and the smallest detectable change. Our results revealed a somatotopy gradient reflected by APB MCR having the most lateral location. Reliability analysis showed that the commonly used metrics of MCRs, such as areas, volumes, centers of gravity (COGs), and hotspots had a high relative and low absolute reliability for all three muscles. For within‐limb TMS somatotopy, the most common metrics such as the shifts between MCR COGs and hotspots had poor relative reliability. However, overlaps between different muscle MCRs were highly reliable. We, thus, provide novel evidence that inter‐muscle MCR interaction can be reliably traced using MCR overlaps while shifts between the COGs and hotspots of different MCRs are not suitable for this purpose. Our results have implications for the interpretation of nTMS motor mapping results in healthy subjects and patients with neurological conditions.  相似文献   
16.
Novel functionalized (biofunctionalization followed by cisplatin immobilization) Fe3O4@SiO2@Au nanoparticles (NPs) were designed. The encapsulation of Fe3O4 cores inside continuous SiO2 shells preserves their initial structure and strong magnetic properties, while the shell surface can be decorated by small Au NPs, and then cisplatin (cPt) can be successfully immobilized on their surface. The fabricated NPs exhibit very strong T2 contrasting properties for magnetic resonance imaging (MRI). The functionalized Fe3O4@SiO2@Au NPs are tested for a potential application in photothermal cancer therapy, which is simulated by irradiation of two colon cancer cell lines (SW480 and SW620) with a laser (λ = 808 nm, W = 100 mW cm−2). It is found that the functionalized NPs possess low toxicity towards cancer cells (∼10–15%), which however could be drastically increased by laser irradiation, leading to a mortality of the cells of ∼43–50%. This increase of the cytotoxic properties of the Fe3O4@SiO2@Au NPs, due to the synergic effect between the presence of cPt plus Au NPs and laser irradiation, makes these NPs perspective agents for potential (MRI)-guided stimulated chemo-photothermal treatment of cancer.

Novel functionalized nanoparticles, with toxicity controlled by laser irradiation, are perspective agents for potential (MRI)-guided stimulated chemo-photothermal treatment of cancer.  相似文献   
17.
18.
The research included 54 individuals of the goosander Mergus merganser L., 1758 (Anseriformes, Mergini), wintering on Lake Dabie within the administrative limits of Szczecin. Seven species of cestoda from two families were found in those ducks. Two species from the family Diphyllobothriidae were recorded: Ligula intestinalis (Linnaeus, 1758) and Schistocephalus solidus (Müller, 1776), and five species from family Hymenolepididae: Dicranotaenia mergi Yamaguti, 1940, Fimbriaria mergi Grytner-Ziecina et Cielecka, 1995, Microsomacanthus vistulae (Czaplinski, 1960), Retinometra macracanthos (von Linstow, 1877) oraz Tschertkovilepis tenuirostris (Rudolphi, 1819). Founding species Dicranotaenia mergi is the first observation of this type in Poland.  相似文献   
19.
Idiopathic pulmonary fibrosis (IPF) is an age-related fatal disease with unknown etiology and no effective treatment. In this study, we show that primary cultures of fibroblasts derived from lung biopsies of IPF patients exhibited (i) accelerated replicative cellular senescence (CS); (ii) high resistance to oxidative-stress-induced cytotoxicity or CS; (iii) a CS-like morphology (even at the proliferative phase); and (iv) rapid accumulation of senescent cells expressing the myofibroblast marker α-SMA. Our findings suggest that CS could serve as a bridge connecting lung aging and its quite frequent outcome -- pulmonary fibrosis, and be an important player in the disease progression. Consequently, targeting senescent cells offers the potential of being a promising therapeutic approach.  相似文献   
20.

Background and Objectives:

Women with endometriosis often report onset of symptoms during adolescence; however, the diagnosis of endometriosis is often delayed. The aim of this study was to describe the experience of adolescents who underwent laparoscopy for pelvic pain and were diagnosed with endometriosis: specifically, the symptoms, time from onset of symptoms to correct diagnosis, number and type of medical professionals seen, diagnosis, treatment, and postoperative outcomes.

Methods:

We reviewed a series of 25 females ≤21 years of age with endometriosis diagnosed during laparoscopy for pelvic pain over an 8-year period. These patients were followed up for 1 year after surgery.

Results:

The mean age at the time of surgery was 17.2 (2.4) years (range, 10–21). The most common complaints were dysmenorrhea (64%), menorrhagia (44%), abnormal/irregular uterine bleeding (60%), ≥1 gastrointestinal symptoms (56%), and ≥1 genitourinary symptoms (52%). The mean time from the onset of symptoms until diagnosis was 22.8 (31.0) months (range, 1–132). The median number of physicians who evaluated their pain was 3 (2.3) (range, 1–12). The adolescents had stage I (68%), stage II (20%), and stage III (12%) disease. Atypical endometriosis lesions were most commonly observed during laparoscopy. At 1 year, 64% reported resolved pain, 16% improved pain, 12% continued pain, and 8% recurrent pain.

Conclusions:

Timely referral to a gynecologist experienced with laparoscopic diagnosis and treatment of endometriosis is critical to expedite care for adolescents with pelvic pain. Once the disease is diagnosed and treated, these patients have favorable outcomes with hormonal and nonhormonal therapy.  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