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   15231篇
  免费   682篇
  国内免费   126篇
耳鼻咽喉   182篇
儿科学   237篇
妇产科学   89篇
基础医学   1688篇
口腔科学   462篇
临床医学   1152篇
内科学   3597篇
皮肤病学   432篇
神经病学   951篇
特种医学   722篇
外科学   2698篇
综合类   78篇
一般理论   1篇
预防医学   547篇
眼科学   328篇
药学   1266篇
中国医学   36篇
肿瘤学   1573篇
  2023年   91篇
  2022年   207篇
  2021年   346篇
  2020年   208篇
  2019年   265篇
  2018年   358篇
  2017年   249篇
  2016年   324篇
  2015年   332篇
  2014年   413篇
  2013年   509篇
  2012年   869篇
  2011年   939篇
  2010年   569篇
  2009年   425篇
  2008年   803篇
  2007年   838篇
  2006年   823篇
  2005年   775篇
  2004年   739篇
  2003年   703篇
  2002年   676篇
  2001年   344篇
  2000年   362篇
  1999年   372篇
  1998年   200篇
  1997年   126篇
  1996年   126篇
  1995年   127篇
  1994年   99篇
  1993年   83篇
  1992年   247篇
  1991年   219篇
  1990年   236篇
  1989年   245篇
  1988年   191篇
  1987年   209篇
  1986年   168篇
  1985年   178篇
  1984年   123篇
  1983年   91篇
  1982年   52篇
  1981年   68篇
  1979年   103篇
  1978年   44篇
  1977年   55篇
  1974年   52篇
  1971年   40篇
  1969年   47篇
  1968年   41篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
The incidence and factors associated with multiple primary cancer were surveyed and analyzed from April 1978 through December 1990 in our clinic. Fifty-nine cases with multiple primary cancers were selected for study from among 579 cases with malignant head and neck region tumors. The cancers involved the larynx in 17 cases (8.4%), oral cavity in 14 (19.4%), oropharynx in 13 (41.9%), hypopharynx in 7 (8.0%) and nasal cavity or paranasal sinus in 7 (8.0%). Twenty-one cases (35.6%) arose synchronously within one year. From our observations, heavy drinking and smoking were most strongly suspected to be risk factors for induction of malignancy. Most multiple primary cancers in the head and neck region were observed to coexistent in a "so called multicentric zone" consisting of the oral area, pharyngeal area, larynx, esophagus, stomach, and tracheobronchial tree. To avoid overlooking concealed cancer in the multicentric zone, upper gastro-intestinal endoscopy, bronchial endoscopy, chest X-ray and sputum examination should be performed for screening of patients with head and neck malignancies.  相似文献   
103.
A 29-year-old male with Down's syndrome presented with severe headache and vomiting. Computed tomography demonstrated subarachnoid hemorrhage. Left carotid angiography showed severe stenosis of the middle cerebral artery 2 cm distal to its origin, as well as abnormal hyper-vascularization near the stenosis site similar to that seen in moyamoya disease. Right carotid angiography showed no abnormalities. However, slight stenosis of the distal part of the bilateral vertebral arteries was noted. There was no aneurysm. We judged that the subarachnoid hemorrhage had been caused by rupture of the moyamoya-like vessel. Some patients with Down's syndrome have anatomical vascular abnormality and vascular fragility. The cerebral vascular abnormality found in this case may be part of the systemic vascular abnormalities associated with Down's syndrome. The vascular changes in some adult patients with Down's syndrome may be a sign of premature aging, and long-term studies with periodic vascular examination of patients with Down's syndrome need to be performed.  相似文献   
104.
105.
106.
We investigated the effect of CYP2D6 genotypes on plasma levels of haloperidol (HAL) and reduced haloperidol (RHAL) in 88 Japanese schizophrenic inpatients being treated with HAL. Some subjects carrying CYP2D6*5 allele (CYP2D6*1/CYP2D6*5, CYP2D6*5/CYP2D6*10) showed extremely high concentrations of both HAL and RHAL, and the groups with CYP2D6*5 allele seemed to have higher plasma concentrations of HAL (1.14+/-0.69 ng/ml/mg) and RHAL (1.10+/-1.05 ng/ml/mg) than the other groups. Among those without CYP2D6*5 allele, there were no significant differences in plasma concentrations of HAL and RHAL between those without CYP2D6*10 allele (HAL=0.68+/-0.31 ng/ml/mg, RHAL=0.28+/-0.37 ng/ml/mg), those with one CYP2D6*10 (HAL=0.70+/-0.23 ng/ml/mg, RHAL=0.31+/-0.16 ng/ml/mg) and those with two CYP2D6*10 alleles (HAL=0.69+/-0.14 ng/ml/mg, RHAL=0.40+/-0.09 ng/ml/mg), although there was a tendency of higher plasma concentration of RHAL in those with two CYP2D6*10 alleles. At a lower daily dosage of HAL (<10 mg/day), the subjects with two or one CYP2D6*10 allele(s) showed significantly higher plasma concentrations of RHAL (0.43+/-0.23 ng/ml/mg, 0.34+/-0.16 ng/ml/mg) than those without CYP2D6*10 allele (0.18+/-0.16 ng/ml/mg). The results of this study indicate that CYP2D6*10 allele plays significant but modest role in HAL metabolism in Japanese; nevertheless, we should not lump CYP2D6*10 allele with CYP2D6*5 allele because these two mutated alleles seem to have different impacts in the metabolism of HAL.  相似文献   
107.
BACKGROUND: Our goal was to test the intragraft mRNA expression and production of two chemokines that are potent chemoattractants for antigen-primed T cells, interferon-gamma inducible protein 10 (IP-10) and monokine-induced by IFN-gamma, (Mig), in allogeneic heart grafts. METHODS: Syngeneic or allogeneic A/J (H-2a) hearts were heterotopically transplanted to wild-type, CD4-/-, CD8alpha-/-, or IFN-gamma-/- C57BL/6 (H-2b) recipients. To test expression of IP-10 and Mig, grafts were removed 1-8 days posttransplant for RNA isolation and Northern blot analysis. To test the potential recipient leukocyte populations mediating intraallograft expression of IP-10 and Mig, recipients were treated with anti-NK 1.1, anti-CD4, and/or anti-CD8 monoclonal antibodies before transplantation. RESULTS: Allogeneic heart grafts transplanted to wild-type, but not IFN-gamma-/-, recipients expressed IP-10 and Mig at day +2 posttransplant that increased thereafter until rejection was completed. Expression of IP-10 and Mig in isografts was low or undetectable. Cardiac allografts from CD8+ T cell depleted, but not NK cell or CD4+ T cell depleted, recipients had low to undetectable expression of IP-10 and Mig on day +2 posttransplant. Similarly, cardiac allografts from CD8-/-, but not CD4-/-, recipients had low to undetectable expression of IP-10 and Mig on day +2 posttransplant. CONCLUSIONS: Early intraallograft expression of Mig and IP-10 during primary rejection of cardiac allografts is dependent on the activities of recipient CD8+ T cells.  相似文献   
108.
In this study, we analyzed the extent and pattern of regression of left ventricular (LV) hypertrophy after aortic valve replacement in patients with aortic stenosis (AS) and compared the results with those of another group of patients with aortic regurgitation (AR). Seventy patients who underwent isolated aortic valve replacement were divided into 2 groups. Group 1 was comprised of 29 patients who underwent aortic valve replacement for aortic stenosis, and Group 2 of 41 patients who underwent aortic valve replacement for aortic regurgitation. A third group of 10 healthy subjects served as a healthy control group. Echocardiographic studies were done before the operation and 5 years postoperatively. At follow-up, a significant reduction in the left ventricular mass was found in both groups, but it remained significantly greater than in the healthy control group. The ratio of LV wall thickness to radius (th/r) in Group 1 decreased significantly, and at follow-up it was within the normal value. In Group 2, the th/r ratio increased, and at follow-up it was within the normal value. After aortic valve replacement, the wall thickness remained significantly greater than normal for patients with AS, and the chamber radius remained significantly greater than normal for patients with AR. For these reasons, LV hypertrophy still existed in both groups at postoperative follow-up. The actuarial survival rate was 85.3% at 16 years for Group 1 and 83.4% at 18 years for Group 2. There was no significant difference in the long-term survival rates between the 2 groups. Actuarial freedom from valve-related events was 91.9% at 16 years for Group 1 and 82% at 18 years for Group 2. There was no significant difference in the valve-related event free curves between groups. After 5 years of follow-up, th/r reached normal for both groups, indicating remodeling of the LV geometry after aortic valve replacement.  相似文献   
109.
Treatment of Lethal Midline Granuloma Type Nasal T-Cell Lymphoma   总被引:7,自引:0,他引:7  
Nasal T-cell lymphoma of the LMG type (LMG-NTL) is characterized by progressive, unrelenting ulceration, and necrosis of the nasal cavity and midline facial tissues. The clinical behavior of this tumor in 16 patients is compared with that of a nasal lymphoma of non-LMG-NTL type (non-LMG-NTL) in 8 patients and a paranasal sinus lymphoma (PSL) in 6 patients. All patients had stage I or II disease. Fourteen of the 16 patients with LMG-NTL received chemotherapy before and/or after radiotherapy. Cause-specific 5-year survival rates for patients with LMG-NTL, non-LMG-NTL, and PSL were 22%, 75%, and 67%, respectively. Seven patients with LMG-NTL, had complete response, although 3 recurred, whereas it was incomplete in 9 patients. The data indicates that it is desirable to deliver 50 Gy or more to achieve in-field control of LMG-NTL.  相似文献   
110.
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