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   1417篇
  免费   86篇
  国内免费   13篇
耳鼻咽喉   5篇
儿科学   23篇
妇产科学   41篇
基础医学   146篇
口腔科学   29篇
临床医学   111篇
内科学   376篇
皮肤病学   14篇
神经病学   136篇
特种医学   58篇
外科学   262篇
综合类   1篇
预防医学   40篇
眼科学   10篇
药学   111篇
中国医学   1篇
肿瘤学   152篇
  2023年   21篇
  2022年   17篇
  2021年   28篇
  2020年   20篇
  2019年   29篇
  2018年   33篇
  2017年   20篇
  2016年   44篇
  2015年   45篇
  2014年   60篇
  2013年   73篇
  2012年   124篇
  2011年   114篇
  2010年   50篇
  2009年   45篇
  2008年   77篇
  2007年   102篇
  2006年   77篇
  2005年   92篇
  2004年   82篇
  2003年   81篇
  2002年   50篇
  2001年   18篇
  2000年   20篇
  1999年   22篇
  1998年   10篇
  1997年   10篇
  1996年   18篇
  1995年   4篇
  1994年   6篇
  1993年   9篇
  1992年   9篇
  1991年   10篇
  1990年   8篇
  1989年   10篇
  1988年   18篇
  1987年   12篇
  1986年   10篇
  1985年   8篇
  1984年   5篇
  1983年   3篇
  1981年   4篇
  1980年   2篇
  1979年   2篇
  1978年   2篇
  1976年   2篇
  1975年   2篇
  1973年   1篇
  1971年   1篇
  1969年   3篇
排序方式: 共有1516条查询结果,搜索用时 359 毫秒
1.
Capello  E.  Vuolo  L.  Gualandi  F.  Van Lint  M. T.  Roccatagliata  L.  Bonzano  L.  Pardini  M.  Uccelli  A.  Mancardi  Gianluigi 《Neurological sciences》2009,30(2):175-175
Autologous haematopoietic stem-cell transplantation has been evaluated over the last years as a possible new therapeutic strategy in severe forms of multiple sclerosis unresponsive to the approved therapies. Up to now, more than 400 patients have been treated and numerous are the phase I and phase II studies which addressed the feasibility of this treatment, the efficacy, side effects and transplant-related mortality. The clinical response is strongly related to the intensity of the conditioning regimen utilized as well as to the phase of the disease course in which the therapy is carried out. Rapidly evolving multiple sclerosis with a relapsing–remitting clinical course and MRI signs of activity are the cases that can take more advantage. The risk of mortality, which dropped in the last years to 2–3%, is still the main problem of this powerful therapy.  相似文献   
2.
Two new T cell subsets may be involved in allergic rhinitis (AR) pathogenesis: Th17 and T regulatory cells, mainly producing IL-17 and TGF-β respectively. Successful Sublingual Immunotherapy (SLIT) induces relevant immunological changes, thus the aim of this study was to evaluate serum IL-17 and TGF-β levels in AR patients treated with SLIT for 2 years. Patients' blood samples were collected before initiating SLIT (baseline), three months after the end of the first pre-seasonal SLIT course, and at the end of the second pre-seasonal course. IL-17 was detectable only in the most severe allergic patients. SLIT significantly induced an increase in serum TGF-β levels. There was moreover a significant relationship between TGF-β and symptom severity and drug use at the end of the study. Therefore, this study provides clinically relevant evidence that two pre-seasonal SLIT courses may significantly affect serum TGF-β levels.  相似文献   
3.
4.
5.
This study was performed to investigate the relative role of noradrenaline (NA) and dopamine (DA) carrier blockade in the effects of psychostimulants on DA transmission in the rat prefrontal cortex (PFCX). To this end, changes of extracellular DA and NA in the PFCX and of extracellular DA in the nucleus accumbens (NAc) were measured following the administration of amphetamine and cocaine, which are known to bind to both DA and NA carriers, or GBR 12909, a selective DA carrier blocker. After non-intravenous injection, amphetamine (0.25 and 0.5 mg/kg, s.c.) and cocaine (5 and 10 mg/kg, i.p.) increased extracellular DA in the PFCX to a larger extent than in the NAc, while the reverse applied to GBR 12909 (2.5 and 5 mg/kg, i.p.). These differences were obtained in spite of the fact that the three drugs elicited at each dose level a similar peak increase of extracellular DA in the NAc. Amphetamine and cocaine also increased extracellular NA in the PFCX and this effect was quantitatively similar to that on extracellular DA in the same area. Intravenous doses of cocaine and GBR 12909, corresponding to those which maintain self-administration in the rat, while equieffective in raising extracellular DA in the NAG, had different effects on extracellular DA in the PFCX. In fact, in contrast to cocaine, GBR 12909 increased extracellular DA in the PFCX to a lesser extent than in the NAc or did not modify it at all. The peak increase of extracellular DA in the PFCX was highly correlated to that of NA in the same area but was poorly correlated to the increase of extracellular DA in the NAc. These results suggest that amphetamine and cocaine increase extracellular DA in the PFCX largely through the blockade of the NA carrier. Direct evidence for this hypothesis was provided by the observation that, when the NA carrier was blocked by reverse dialysis of the PFCX with desipramine (1 μM), cocaine and GBR 12909 lost their differences in the ability to increase extracellular DA in the PFCX.  相似文献   
6.
Background We previously found that glomerular epithelial cells play an important role in the formation of adhesive lesions. Glomerular sclerotic lesions develop after the inital adhesive lesions. Methods Two series of experiments were done with spontaneously diabetic WBN/Kob rats. These rats develop segmental glomerular sclerotic lesions with aging. The first series of experiments was intended to clarify the kinetics of glomerular cells on progressive glomerular damage in these rats. The second series of experiments was designed to study the relationship between proliferation (judged by % bromodeoxyuridine-positive cells) of glomerlar epithelial cells and sclerotic lesions with adhesions. Results In the first series, rats having increased proteinuria showed segmental glomerular sclerotic lesions with adhesions. At the same time, increased labeling indices of tuft cells and epithelial cells of Bowman's capsule were observed. In the second series, no significant increase in the labeling indices of tuft cells with sclerotic lesions was observed, compared to tuft cells without sclerotic lesions. In sclerotic lesions with adhesion, bromodeoxyurdine-positive cells were observed that were not distinguishable as podocytes or epithelial cells of Bowman's capsule. The highest labelling index was noted in the epithelial cells of Bowman's capsules with sclerosis. Conclusion This study shows that the proliferation of glomerular epithelial cells (mainly epithelial cells of Bowman's capsule) occurs in glomerular sclerotic lesions with adhesions.  相似文献   
7.
To elucidate the significance of angiotensin II (AID-induced hypertension chemotherapy, changes of tissue blood flow both in normal subcutis and in tumors (AH109A, LY80) were measured with the hydrogen gas clearance method. A newly-developed anesthetic machine was used to keep the animals' condition constant. Tissue blood flow in normal subcutis and tumors always fluctuated with time under normotension. The nature and the rate of fluctuation in tumor Wood flow were almost identical in two different types of tumors. However, the fluctuation of blood flow in tumor and that in normal subcutis were almost always inversely related when blood flows in these different tissues were measured simultaneously, i.e., when tissue blood flow in normal subcutis decreased, tumor blood flow increased, and vice versa. The findings supported the idea that the connection mode between the tumor vascular bed and normal vascular bed is a parallel circuit. Vascular resistance in the normal vascular bed under All-induced hypertension seemed to be greater than that under normotension, because the All-increased tumor blood flow always exceeded the maximum tumor blood flow under normotension. Due to the fluctuations of tumor blood flow, no-flow or low-flow areas, resistant to delivery of anti-cancer drugs, moved sporadically within the tumor under the normotensive condition. However, good conditions for drug delivery to tumor tissue were induced by All-induced hypertension.  相似文献   
8.
A 34-years-old floor-layer developed optic neuropathy and motor neuron disease after being accidentally exposed to a solvent mixture containing methanol and other substances. Optic neuropathy is a complication of methanol poisoning, but the onset of a motor neuron disorder resembling amyotrophic lateral sclerosis after the exposure to these substances has not been previously described. The temporal onset of the clinical symptoms, biological plausibility, young age of the patient and absence of neurological disorders in the family history raises suspicion of a possible causative relationship.  相似文献   
9.
The binding of [3H]hemicholinium ([3H]HCh-3) to sodium-dependent high-affinity choline uptake sites provides a useful neuroanatomical and functional marker of the cholinergic system. We examined the autoradiographic distribution of [3H]HCh-3 binding sites in the forebrain of young (4–6 months) and old (32 months) rats. There was a widespread reduction of [3H]HCh-3 binding site density in the aged rat brain. This loss presented regional differences with maximal reduction in the medial and posterior striatum (55%) and in the dentate gyrus (47%), in limbic areas such as basolateral amygdala, tubercle olfactorium and piriform cortex the autoradiographic signal was about 25–30% lower. In aged hippocampus and cerebral cortex the density of [3H]HCh-3 binding sites was about 40% lower, the difference between young and senescent animals being less evident in the medial septum and basal nucleus. No significant alterations were observed in interpeduncular nucleus from old rats. These data are in agreement with the functional results obtained by measuring other cholinergic parameters in the aged rat and confirm the vulnerability of cholinergic system during aging  相似文献   
10.
Triggering Receptor Expressed on Myeloid cells (TREM)2 deficiency originates a genetic syndrome characterized by bone cysts and presenile dementia, named Nasu-Hakola disease (NHD). Early onset dementia and marked involvement of frontal regions are features characterizing both NHD and other kinds of neurodegenerative disorders, such as Frontotemporal Lobar Degeneration (FTLD), and, in some cases, Alzheimer's disease (AD). Three Single Nucleotide Polymorphisms (SNPs) in TREM2 coding region were screened by allelic discrimination in a population of probable AD patients as well as FTLD patients as compared with age-matched controls. In addition, mutation scanning of the coding region of TREM2 gene was carried out in 7 patients with early onset AD (EOAD), 16 FTLD, and 20 controls. None of the SNPs analyzed was present, either in patients or controls. Moreover, mutation scanning of the five exons of TREM2 failed to detect the presence of novel polymorphisms. These data demonstrate that TREM2 coding region is highly conserved, implying a crucial role of this receptor. Further studies, including a functional analysis, are certainly required to clarify the role of TREM2 in neurodegenerative processes.  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