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   26512篇
  免费   1389篇
  国内免费   102篇
耳鼻咽喉   153篇
儿科学   398篇
妇产科学   409篇
基础医学   3252篇
口腔科学   827篇
临床医学   1872篇
内科学   6487篇
皮肤病学   522篇
神经病学   2383篇
特种医学   1139篇
外科学   4101篇
综合类   96篇
预防医学   731篇
眼科学   432篇
药学   2006篇
中国医学   64篇
肿瘤学   3131篇
  2023年   114篇
  2022年   185篇
  2021年   445篇
  2020年   270篇
  2019年   371篇
  2018年   444篇
  2017年   370篇
  2016年   459篇
  2015年   457篇
  2014年   639篇
  2013年   737篇
  2012年   1201篇
  2011年   1366篇
  2010年   720篇
  2009年   679篇
  2008年   1195篇
  2007年   1260篇
  2006年   1200篇
  2005年   1230篇
  2004年   1200篇
  2003年   1140篇
  2002年   1200篇
  2001年   958篇
  2000年   963篇
  1999年   954篇
  1998年   343篇
  1997年   276篇
  1996年   256篇
  1995年   213篇
  1994年   185篇
  1993年   179篇
  1992年   680篇
  1991年   583篇
  1990年   619篇
  1989年   608篇
  1988年   513篇
  1987年   470篇
  1986年   462篇
  1985年   415篇
  1984年   288篇
  1983年   240篇
  1980年   101篇
  1979年   245篇
  1978年   149篇
  1977年   134篇
  1975年   100篇
  1974年   97篇
  1972年   105篇
  1971年   107篇
  1969年   101篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) is a rare and poorly understood ischemic colitis that occurs in the rectosigmoid colon of predominantly young, previously healthy, male patients. A 76‐year‐old Japanese man presented to our hospital with a 1‐year history of worsening diarrhea, lower abdominal pain, and weight loss (−6 kg). Laboratory evaluation revealed white blood cell count of 13 200/μL, C‐reactive protein level of 2.0 mg/dL (normal range, 0.0–0.3), and negative results for stool culture (including Clostridium difficile). Colonoscopy showed circumferential and edematous narrowing of the sigmoid colon with deep longitude ulceration. Biopsy was done and examination of the specimen demonstrated no specific ischemia. The patient was treated with bowel rest, antibiotics, and i.v. fluids; however, his symptoms worsened. Finally, sigmoidectomy was carried out. Histological examination demonstrated significant myointimal hyperplasia of mesenteric veins leading to thickening and stenosis of the venous lumen. Therefore, the final diagnosis was IMHMV. Three months following sigmoidectomy, he was asymptomatic.  相似文献   
3.
4.
5.
6.
Although many single nucleotide polymorphism (SNP) studies have reported an association of atopy, allergic diseases and total serum immunoglobulin E (IgE) levels, almost all of these studies sought risk factors for the onset of these allergic diseases. Furthermore, many studies have analyzed a single gene and hardly any have analyzed environmental factors. In these analyses, the results could be masked and the effects of other genes and environmental factors may be decreased. Here, we described the correlation between four genes [interleukin (IL)-4 (C-590T), IL-4 receptor (A1652G), FCER1B (G6842A) and STAT6 (G2964A)] in connection with IgE production; the role of IL-10 (C-627A) as a regulatory cytokine of allergy; and the severity of food allergy (FA) and atopic eczema (AE) in 220 Japanese allergic children. In addition to these SNPs, environmental factors, i.e., patient's attitude, indoor environment, and so on, were also investigated in this study. Our study was retrospective, and the correlation was analyzed by our defined clinical scores divided into three terms: worst symptoms, recent symptoms and general amelioration at the most recent examination during the disease course. Our results indicated that IL-10 AA, the genotype with lower IL-10 production, is associated with higher IgE levels in the serum (p < 0.0001, estimate; 0.912). Marginal liver abnormalities were observed in the subject group with both FA and AE (p < 0.1191, estimate; 0.1490). Our defined clinical scores enabled evaluation of various aspects of disease severity. Based on the scores, while no single SNP selected in this study determined severity, the combination of the SNP with laboratory data and environmental factors appeared to determine severity.  相似文献   
7.
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   
8.
9.
10.
Experiments were performed on spinalized rats, transected at the Cl level. The intravenous administration of TRH and its analog YM-14673 (N alpha-[(S)-4-oxo-2-azetidinyl) carbonyl]-L-histidyl-L-prolinamide dehydrate) produced marked increases in the amplitude of mono- and polysynaptic reflex potentials and those of the withdrawal flexor reflexes. The effects of YM-14673 were stronger and longer-lasting than those of TRH. The stimulant action of TRH and YM-14673 on the flexor reflexes was not antagonized by prazosin, chlorpromazine, haloperidol or cyproheptadine, suggesting no involvement of the release of catecholamines or serotonin in the stimulant effects of TRH and its analog. Therefore, YM-14673 may be beneficial for the treatment of several spinal motor neuron diseases.  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