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   6069篇
  免费   370篇
  国内免费   54篇
耳鼻咽喉   19篇
儿科学   110篇
妇产科学   72篇
基础医学   711篇
口腔科学   137篇
临床医学   544篇
内科学   1906篇
皮肤病学   63篇
神经病学   513篇
特种医学   190篇
外科学   907篇
综合类   20篇
预防医学   188篇
眼科学   131篇
药学   351篇
中国医学   14篇
肿瘤学   617篇
  2023年   19篇
  2022年   78篇
  2021年   138篇
  2020年   53篇
  2019年   94篇
  2018年   125篇
  2017年   101篇
  2016年   113篇
  2015年   155篇
  2014年   145篇
  2013年   166篇
  2012年   310篇
  2011年   385篇
  2010年   162篇
  2009年   160篇
  2008年   264篇
  2007年   310篇
  2006年   260篇
  2005年   297篇
  2004年   256篇
  2003年   289篇
  2002年   256篇
  2001年   219篇
  2000年   280篇
  1999年   201篇
  1998年   70篇
  1997年   41篇
  1996年   60篇
  1995年   45篇
  1994年   45篇
  1993年   36篇
  1992年   153篇
  1991年   140篇
  1990年   116篇
  1989年   149篇
  1988年   103篇
  1987年   83篇
  1986年   82篇
  1985年   82篇
  1984年   49篇
  1983年   55篇
  1982年   25篇
  1981年   21篇
  1980年   21篇
  1979年   45篇
  1978年   22篇
  1976年   20篇
  1975年   22篇
  1972年   21篇
  1971年   19篇
排序方式: 共有6493条查询结果,搜索用时 15 毫秒
1.
Background and Aims: Video capsule endoscopy (VCE) has become increasingly important as a simple method for observing the entire small intestine. The indications for VCE are obscure gastrointestinal bleeding and investigation of Crohn’s disease (CD). However, the correlation between endoscopic findings obtained by VCE and clinical findings in known cases of CD is not clear, and we therefore investigated this in the present study. Patients and methods: In 30 patients with known CD (Crohn’s disease activity index [CDAI] 0–420; median = 158.3), double contrast enteroclysis (ENT) was performed 1–3 weeks prior to VCE. The relationship between the VCE findings and hematological analysis/CDAI was examined. Results: In 17 of 30 patients, the entire small intestine could be investigated by VCE, whereas in the remaining 13 patients the terminal ileum could not be investigated. The following exhibited positive correlations: total lesions and CDAI (correlation coefficient values: rs = 0.661, adjusted P < 0.0061), ulcers and C‐reactive protein (CRP) (rs = 0.607, adjusted P < 0.0061), total lesions and CRP (rs = 0.604, adjusted P < 0.0061). Conclusions: Analysis with VCE suggests that CDAI and CRP indicate the activity of intestinal lesions in patients with known CD, and that CRP, in particular, is associated with the activity of ulcerative lesions of the intestine. This may contribute to revised guidelines for VCE in the future.  相似文献   
2.
3.
Although the prevalence of a learned voiding dysfunction and non-neurogenic neurogenic bladder (NNB), which is one type of dysfunctional elimination syndrome, is considered to be relatively rare, the association of NNB with Down syndrome (DS) has been elucidated in male patients. We herein describe the occurrence of NNB in an adult female with DS. The diagnosis was confirmed after completely ruling out any neurological or anatomical anomalies that could be related to a lower urinary tract dysfunction. She had renal dysfunction and multiple obstructive uropathies for which clean intermittent catheterization was successfully introduced.  相似文献   
4.
Previously, we reported that allogeneic skin grafts were rapidly rejected by CD28 and CD40 ligand double deficient mice mediated by CD8+ T cells. These results indicated that some elements in addition to CD28- and CD40-mediated costimulation provide stimulatory signals for the activation of donor-specific CD8+ T cells. In this report, we investigated the role of inflammation associated with transplantation on costimulation-independent priming of CD8+ T cell during graft rejection. B6 RAG1 KO mice were transplanted with BALB/c-skin and adoptively transferred with syngeneic CD8+ T cells the same day or 50 days after transplantation. When blockade of CD28- and CD40-mediated costimulation failed to prevent acute rejection of freshly transplanted skin grafts, it efficiently delayed rejection of well-healed skin grafts. These results showed that factors associated with transplantation have essential roles in inducing costimulation blockade-resistant allograft rejection. Costimulation blockade failed to prevent acute graft-infiltration of NK cells and increasing expression of intragraft IL-12 and IL-15. These factors may trigger the graft-infiltration and priming of CD8+ T cells to induce costimulation blockade-resistant allograft rejection.  相似文献   
5.
A 75-year-old man had been admitted to another hospital because of left abdominal pain, and was given a diagnosis of left hydronephrosis and acute pancreatitis. After a JJ stent insertion and medication, he was transferred to our hospital for further examinations. US and EUS revealed a chronic pancreatitis-like pattern and multicystic lesion in the pancreas head and body. At that time enhanced CT findings showed an extrapancreatic low density area to be inflammatory change, extending from the pancreas body to the left crus of the diaphragm and posteriorly the spreading from the left crus of the diaphragm via the left urinary duct into the left iliopsoas muscle, in which MRI revealed partial high intensity. ERCP and MRCP showed focal irregular narrowing of the pancreatic duct of unknown cause, and we decided that an internal pancreatic fistula due to pancreatitis had induced left ureteral obstruction, caused by a protein plug or alcohol. Follow-up 6 months later showed that extrapancreatic spreading of the low density area had markedly regressed without any change in the ureteral obstruction.  相似文献   
6.
In patients with either bilateral renal malignancies or with carcinoma occurring in a solitary kidney, the principle of en bloc removal of the tumor-bearing kidney cannot be applied. Recently we have performed surgical enucleation in two cases of asynchronous bilateral renal cell carcinoma. Case 1. A 60-year-old woman was hospitalized with diagnosis of left renal tumor 10 years tumor 10 years after right nephrectomy for renal cell carcinoma. The tumor was enucleated while occluding the renal vessels. Pathological examination revealed that the tumor (a nodule of 35 g) was renal cell carcinoma of grade I and perfectly covered by pseudocapsule. Hemodialysis was not required. The patient has been well for more than 11 months postoperatively and Ccr is 65 ml/min. Case 2. A 62-year-old man with slight elevation of serum GOT and GPT level was examined by CT, which revealed a space occupying lesion in the left kidney. He had undergone nephrectomy for renal cell carcinoma of right kidney 11 years ago. Three nodules of 56 g, 6 g and 3 g were removed by in situ enucleation. They were renal cell carcinoma of grade II and there was no malignant penetration of the pseudocapsule pathologically. After surgery hemodialysis was required 10 times for 21 days. Renal function has been refined gradually and the patient is well with 47.3 ml/min of Ccr at 4 months postoperatively. Before this report of 2 cases there were 22 cases of asynchronous bilateral renal cell carcinoma in Japanese literature.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
7.
8.
OBJECTIVE: The present study tested the hypothesis that cortical electroencephalographic (EEG) rhythms. change across normal elderly (Nold), mild cognitive impairment (MCI), and Alzheimer's disease (AD) subjects as a function of the global cognitive level. METHODS: Resting eyes-closed EEG data were recorded in 155 MCI, 193 mild AD, and 126 age-matched Nold subjects. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by LORETA. RESULTS: Occipital delta and alpha 1 sources in parietal, occipital, temporal, and 'limbic' areas had an intermediate magnitude in MCI subjects compared to mild AD and Nold subjects. These five EEG sources presented both linear and nonlinear (linear, exponential, logarithmic, and power) correlations with the global cognitive level (as revealed by mini mental state examination score) across all subjects. CONCLUSIONS: Cortical EEG rhythms change in pathological aging as a function of the global cognitive level. SIGNIFICANCE: The present functional data on large populations support the 'transitional hypothesis' of a shadow zone across normality, pre-clinical stage of dementia (MCI), and AD.  相似文献   
9.
Congenitally abnormal fibrinogen Osaka III with the replacement of gamma Arg-275 by His was found in a 38-year-old female with no bleeding or thrombotic tendency. Release of fibrinopeptide(s) by thrombin or reptilase was normal, but her thrombin or reptilase time in the absence of calcium was markedly prolonged and the polymerization of preformed fibrin monomer which was prepared by the treatment of fibrinogen with thrombin or reptilase was also markedly defective. Propositus' fibrinogen had normal crosslinking abilities of alpha- and gamma-chains. Analysis of fibrinogen chains on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) in the system of Laemmli only revealed the presence of abnormal gamma-chain with an apparently higher molecular weight, the presence of which was more clearly detected with SDS-PAGE of fibrin monomer obtained by thrombin treatment. Purified fragment D1 of fibrinogen Osaka III also seemed to contain an apparently higher molecular weight fragment D1 gamma remnant on Laemmli gels, which was digested faster than the normal control by plasmin in the presence of [ethylenebis(oxyethylenenitrilo)]tetraacetic acid (EGTA).  相似文献   
10.
A murine monoclonal antibody (MDR3M) (isotype: IgM) reactive with mdr3 gene product was generated by immunizing mice with mdr3 -specific peptide (H2N-12WRPTSAEGDFELGISSKQKRKKTKTVKMI41G-COOH) and hybridizing the primed mouse splenic B cells with X63-Ag8,6.5.3 mouse plasmacytoma cells. MDR3M did not cross-react with mdr1 gene product. This monoclonal antibody may be useful for analyzing the role of mdr3 gene product in cells and tissues.  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