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   5513篇
  免费   174篇
  国内免费   38篇
耳鼻咽喉   112篇
儿科学   115篇
妇产科学   95篇
基础医学   617篇
口腔科学   86篇
临床医学   394篇
内科学   1422篇
皮肤病学   87篇
神经病学   579篇
特种医学   189篇
外科学   949篇
综合类   26篇
预防医学   272篇
眼科学   31篇
药学   302篇
中国医学   28篇
肿瘤学   421篇
  2024年   20篇
  2023年   45篇
  2022年   85篇
  2021年   155篇
  2020年   94篇
  2019年   144篇
  2018年   167篇
  2017年   96篇
  2016年   123篇
  2015年   148篇
  2014年   206篇
  2013年   293篇
  2012年   370篇
  2011年   398篇
  2010年   254篇
  2009年   194篇
  2008年   352篇
  2007年   332篇
  2006年   308篇
  2005年   306篇
  2004年   279篇
  2003年   254篇
  2002年   237篇
  2001年   72篇
  2000年   68篇
  1999年   51篇
  1998年   57篇
  1997年   36篇
  1996年   36篇
  1995年   33篇
  1994年   27篇
  1993年   27篇
  1992年   52篇
  1991年   47篇
  1990年   37篇
  1989年   40篇
  1988年   34篇
  1987年   35篇
  1986年   26篇
  1985年   21篇
  1984年   19篇
  1983年   12篇
  1982年   14篇
  1980年   13篇
  1979年   14篇
  1977年   8篇
  1975年   9篇
  1972年   9篇
  1967年   11篇
  1966年   8篇
排序方式: 共有5725条查询结果,搜索用时 15 毫秒
1.
2.
Idiopathic Headache as a Possible Risk Factor for Phantom Tooth Pain   总被引:1,自引:0,他引:1  
Following tooth pulp extirpation, some subjects suffer from persistent pain which affects edentate sites in absence of any local pathology. As regards this peculiar pain, called phantom tooth pain (PTP), what is puzzling is the fact there is a low prevalence of PTP in a very large population showing identical conditions of tooth pulp extirpation. The present investigation indicates that PTP mainly affects migraine (M) and cluster headache (CH) sufferers, whereas it does not affect subjects who have a negative personal and family history for idiopathic headache (IH). These results circumscribe the presence of PTP to a specific section of the population. The present results, besides indicating that PTP may be the result of a peculiar neuronal predisposition relating to IH pathogenesis, suggests some practical therapeutic hints. In fact, successful anti- M and anti-CH prophylactic treatment greatly improve PTP syndrome.  相似文献   
3.
We studied the significance of free erythrocyte protoporphyrin (FEP) in relation to iron status, aluminum levels and anemia in uremic patients on chronic dialysis. All but 1 patient showed high FEP values closely related to the degree of anemia. Increased FEP levels are due to a defective heme synthesis, not related to iron deficiency or aluminum overload. Treatment of anemia with recombinant human erythropoietin reduced FEP values. We therefore hypothesize that recombinant human erythropoietin ameliorates an enzymatic defect in heme synthesis.  相似文献   
4.
A young patient developed Hodgkin's disease 11 years after surgical, chemotherapeutic and radiation treatment for stage IIIA embryonal carcinoma of the testis. The importance is stressed of establishing a tissue diagnosis when there is an unexpected course of the disease.  相似文献   
5.
Lymph node (LN) metastases represent the most important negative prognostic factor in squamous cell carcinoma (SCC) of the oral cavity, even though controversies still exist regarding their management. The aim of this study was to retrospectively analyze our experience in surgical management of SCC of the oral cavity with particular focus on the prevalence and localization of lymph nodal metastases and recurrences. The clinical records of 89 consecutive patients treated from 1983 to 2002 by concomitant surgery on both the T and N sites, excluding those undergoing salvage surgery, were reviewed. A total of 119 neck dissections (ND) were performed. Survival outcomes were calculated by the Kaplan–Meier method, while univariate comparisons by the log-rank and non-parametric tests were performed between different groups of patients. Five-year overall and determinate survivals were 50 and 57%, respectively. LN metastases were observed in 52% (56% of these showing extracapsular spread) and their presence strongly correlated with determinate survival (p < 0.0001). The prevalence of clinical and occult nodal disease was not related to the pT status. Neck levels II (59%) and I (56%) were most frequently involved. Metastases to level IV accounted for 15% of positive LN, even though 28% of them turned out to be skip metastases. Five neck recurrences were observed, only one of which was salvaged by surgery. The high prevalence of clinical and occult LN metastases in this setting suggests that ND should be performed on a nearly routine basis, even for lesions with a low-T category and a cN0 neck. Moreover, ND should always encompass level IV due to the possibility of skip metastases, particularly in tumors involving the oral tongue. In patients with a cN+ neck, levels from I to V should be addressed, particularly in the presence of metastases at levels III and IV.  相似文献   
6.
Donor-specific anti-HLA antibodies were studied by cytotoxicity crossmatching (CTXM) and flow cytometry crossmatching (FCXM) in 117 kidney transplant candidates; the same study was carried out in 33 cadaver-donor kidney recipients, during the first 3 post-transplant months, for which donor cells were available. Pre-transport evaluation showed that 82.9 % of subjects were CTXM negative/FCXM negative, 6.8 % of patients were positive in both tests, and 10.3 % were CTXM negative/FCCM positive. Post-transplant monitoring for donor-specific antibodies (Abs-DS) showed that nine recipients (27.3 %) were FCXM positive; six of them were IgG + and three IgM +. In comparing these results with the clinical course, a significant association between FCXM IgG + and rejection episodes was observed (P < 0.01).  相似文献   
7.
Renal glomerular permselectivity and vascular endothelium.   总被引:4,自引:0,他引:4  
The glomerular barrier is the kidney's physical block to the unrestricted flow of molecules from the plasma into the urinary space. Its exquisite selectivity allows solutes and water in the glomerular capillaries to pass through but it prevents the bulk of plasma proteins, most notably albumin, from crossing. Classically the barrier consists of three components: glomerular endothelium, glomerular basement membrane and glomerular epithelium (podocytes) with slit diaphragm. A lot of investigations are experimental but they are sufficient to show the pivotal role of endothelium in glomerular proteinuria. In this study the author discuss glomerular endothelium with particular emphasis on the barrier presumed to be imparted by endothelium-glomerular basement membrane-podocyte interactions. By specialized glomerular endothelial structure (caveolae, tight junctions, endothelium glycocalyx) and by circulating permeability factors (albumin, orosomucoid, apolipoproteins, Amadori's products). Concluding remarks underline the significance to study the glomerular vascular endothelial dysfunction.  相似文献   
8.
New parachlamydial 16S rDNA phylotypes detected in human clinical samples   总被引:11,自引:0,他引:11  
Chlamydiales are important intracellular bacterial pathogens, causing a wide variety of diseases in vertebrates, including humans. Besides the well-known species in the family Chlamydiaceae, new chlamydial organisms have recently been discovered, forming three new families: Parachlamydiaceae, Simkaniaceae and Waddliaceae. Parachlamydia acanthamoebae and Simkania negevensis are currently investigated as emerging human respiratory pathogens. Additional chlamydial lineages have been discovered by 16S rDNA-based molecular studies, and their implication in human infections is poorly known. By using a pan-chlamydia 16S rDNA PCR, we have searched for the presence of chlamydiae in 228 clinical samples that all previously had been shown to be PCR-negative for Chlamydophila pneumoniae: 170 respiratory samples, 45 atheromatic plaques and 13 peripheral blood mononuclear cell samples. Nine respiratory samples tested positive. Sequence analysis has allowed us to assign four sequences to Chlamydophila psittaci, three sequences to Chlamydophila felis, and two sequences to two novel phylotypes belonging to the Parachlamydiaceae. These latter sequences showed similarity values of more than 93% with each other and with the P. acanthamoebae sequence, thus belonging to novel, unrecognized species. In conclusion, this report showed that a variety of non-C. pneumoniae chlamydial respiratory infection is present in humans, and that new parachlamydiae distinct from P. acanthamoebae may be detected in human clinical samples. Future studies will be of interest in order to estimate the diversity of these novel chlamydiae in both clinical and environmental samples, as well as their possible clinical implication in human and animal infections.  相似文献   
9.
Sclerosteosis: report of a case in a black African man   总被引:3,自引:0,他引:3  
Sclerosteosis is a rare genetic disorder of bone modelling, similar to, but distinct from, van Buchem disease; it has been described almost exclusively in Afrikaners of South Africa, a white population of Dutch ancestry. Isolated cases have been reported in a girl in Japan, a boy in Spain, and in multiracial families in Brazil and USA.
Here we report a case of sclerosteosis in a black man born in Senegal. He presented with the full features of the disease: tall stature; syndactyly; nail dysplasia; massive sclerosis of the long tubular bones, the ribs, the pelvis and the skull; multiple cranial nerve involvement: optic atrophy, facial palsy and trigeminal neuralgia. Radiologic examination, visual and brainstem auditory evoked potentials, computerized tomography and magnetic resonance imaging of the skull were performed. This seems to be the first case of the disease in a black African individual, with no known relationship with Dutch ancestry.  相似文献   
10.
In rats the effects of chronic treatment with thioridazine (5 mg/kg orally administered for 22 days) were studied by means of behavioural supersensitivity to apomorphine and by means of dopamine (DA) receptors quantitative autoradiography. Locomotion and stereotypies induced by apomorphine increased after thioridazine chronic administration, whereas grooming behaviour decreased. Autoradiographic data showed an increase in DA receptors density both in the striatum and in the olfactory tubercle, to which the increase in stereotypies and locomotion could be respectively attributed. DA receptors increased also in the medial and dorsal frontal cortex. Moreover a decrease in DA receptors density appeared in the nucleus accumbens septi and in the lateral frontal cortex. Receptors decrease found in these regions might be associated with thioridazine-induced chronic inactivation of A10 DA neurons, to which the antipsychotic effect of the drug is attributed.  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