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   32872篇
  免费   2076篇
  国内免费   264篇
耳鼻咽喉   438篇
儿科学   597篇
妇产科学   490篇
基础医学   4056篇
口腔科学   1549篇
临床医学   2711篇
内科学   8846篇
皮肤病学   392篇
神经病学   3336篇
特种医学   1302篇
外科学   5266篇
综合类   94篇
一般理论   6篇
预防医学   1358篇
眼科学   540篇
药学   1714篇
中国医学   72篇
肿瘤学   2445篇
  2023年   333篇
  2022年   392篇
  2021年   1253篇
  2020年   745篇
  2019年   1022篇
  2018年   1207篇
  2017年   956篇
  2016年   1068篇
  2015年   1131篇
  2014年   1459篇
  2013年   1777篇
  2012年   2777篇
  2011年   2679篇
  2010年   1502篇
  2009年   1365篇
  2008年   2148篇
  2007年   2260篇
  2006年   2031篇
  2005年   1846篇
  2004年   1644篇
  2003年   1496篇
  2002年   1299篇
  2001年   269篇
  2000年   242篇
  1999年   242篇
  1998年   241篇
  1997年   202篇
  1996年   153篇
  1995年   140篇
  1994年   126篇
  1993年   106篇
  1992年   117篇
  1991年   94篇
  1990年   80篇
  1989年   54篇
  1988年   86篇
  1987年   62篇
  1986年   44篇
  1985年   64篇
  1984年   52篇
  1983年   43篇
  1982年   46篇
  1981年   28篇
  1980年   24篇
  1979年   41篇
  1978年   30篇
  1977年   22篇
  1974年   21篇
  1973年   31篇
  1972年   26篇
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
41.
Benzo[a]pyrene diol epoxide adducts with hemoglobin (Hb) weremeasured to detect human exposure to environmental benzo[a]pyrenefrom traffic exhaust. Benzo[a]pyrene tetrahydrotetrols (BPTs)released from Hb after acid hydrolysis were quantitated by gaschromatography-mass spectrometry after immunoaffinity chromatography.Fifty three newspaper vendors were enrolled. The median adductconcentration was 0.3 fmol BPTs/mg Hb in high density traffic-exposedvendors and  相似文献   
42.
Neutrophil oxidative metabolism, C3d and beta 2 microglobulin levels, were assessed in nine consecutive patients undergoing cardiopulmonary bypass surgery with polypropylene hollow fiber oxygenators for open cardiac operations. Generation of oxygen free radicals by neutrophils was measured as luminol-enhanced chemiluminescence after stimulation with opsonized Zymosan and phorbol myristate acetate. A significant increase in light emission was detected by using both of the chemiluminescence stimulators. Moreover, a remarkable and significant increase in C3d levels was found already at 10 min. Conversely minimal changes in levels of beta 2 microglobulin were detected during cardiopulmonary bypass surgery. These data suggest that the impact of the patient blood with the foreign surface of cardiopulmonary bypass results in activation of phagocyte cells with increased potential in oxygen consumption. These effects could be partially complement-mediated.  相似文献   
43.
Summary The endoscopic insertion of self-expanding mesh stents in four patients affected by obstructing rectal malignant tumors is reported. The preliminary experience shows that, in the short term, normal defecation was achieved, with no complications. Longer follow-up is necessary to evaluate the duration and the quality of the palliative effect.  相似文献   
44.
To confirm recent observations about the relationship between immunosuppression and the recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT), we retrospectively analyzed 70 consecutive HCC patients who underwent LT and received cyclosporine (CsA)-based immunosuppression. CsA trough blood levels, measured with the same technique (fluorescence polarization immunoassay), were analyzed at different time points after transplantation. The exposure to the drug was calculated with the trapezoidal rule in each patient. CsA was associated with steroids in 26 patients and steroids and azathioprine in 44 patients. HCC recurred in 7 patients (10.0%). Different immunosuppressive schedules (CsA and steroids vs. CsA, steroids, and azathioprine) or the cumulative dosage of steroids and azathioprine did not influence HCC recurrence that was associated instead with CsA exposure (278.3 +/- 86.4 ng/mL in recurrent vs. 169.9 +/- 33.3 in tumor-free patients; P < 0.001); CsA exposure above 189.6 ng/mL was related to HCC recurrence at the receiver operating characteristic analysis (ROC). The relationship between CsA exposure; various clinical (sex, age, viral- vs. non-viral-related cirrhosis, preoperative vs. incidental diagnosis of HCC, alpha-fetoprotein [AFP] blood level), pathologic (pathologic tumor staging [pT] stage, presence of Milan criteria), and histologic (grading, presence of microvascular tumor invasion) parameters; and tumor recurrence were assessed. AFP (P = 0.032), microvascular tumor invasion (P = 0.044), and CsA exposure (P < 0.001) influenced recurrence-free survival at the univariate analysis; CsA exposure was the only independent prognostic determinant at multivariate analysis (P < 0.001). High CsA exposure favors tumor recurrence; CsA blood levels should be kept to the effective minimum in HCC patients. In the presence of pathologic and histologic risk factors, specific immunosuppressive protocols should be considered.  相似文献   
45.
Despite recent advances in understanding the immunopathogenesis of oral lichen planus (LP), the initial triggers of lesion formation and the essential pathogenic pathways are unknown. It is therefore not surprising that the clinical management of oral LP poses considerable difficulties to the dermatologist and the oral physician. A consensus meeting was held in France in March 2003 to discuss the most controversial aspects of oral LP. Part 1 of the meeting report focuses on (1) the relationship between oral LP and viral infection with special emphasis on hepatitis C virus (HCV), and (2) oral LP pathogenesis, in particular the immune mechanisms resulting in lymphocyte infiltration and keratinocyte apoptosis. Part 2 focuses on patient management and therapeutic approaches and includes discussion on malignant transformation of oral LP.  相似文献   
46.
In this review article, we shall focus our attention on the initial steps in the research career of José A. Campos-Ortega and the studies he undertook. Particular emphasis will be placed on how these early experiences shaped his personality and his future scientific contributions.  相似文献   
47.
48.
49.
Papillary thyroid microcarcinomas (PTMs) are small tumors (< or =1 cm of diameter) that belong to the well-differentiated low-risk carcinomas of the thyroid, which are characterized by benign behavior, probably of little clinical significance, and do not affect patients' survival. They are found in otherwise normal thyroids or in multinodular goiters with a clinical frequency varying substantially according to different series. Sometimes, PTM may be associated with lymph node metastases at presentation and/or locoregional recurrences during follow-up. Distant metastases are extremely rare, but have been reported. Although deaths related to PTM are almost unknown, PTM raises therapeutic implications. This review addresses the issue of definition, treatment, and follow-up of PTM.  相似文献   
50.
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