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   47622篇
  免费   4837篇
  国内免费   3253篇
耳鼻咽喉   425篇
儿科学   1004篇
妇产科学   540篇
基础医学   5013篇
口腔科学   723篇
临床医学   6115篇
内科学   6459篇
皮肤病学   520篇
神经病学   2606篇
特种医学   1870篇
外国民族医学   13篇
外科学   5345篇
综合类   8899篇
现状与发展   11篇
一般理论   4篇
预防医学   3853篇
眼科学   1004篇
药学   5122篇
  38篇
中国医学   2659篇
肿瘤学   3489篇
  2024年   187篇
  2023年   732篇
  2022年   1897篇
  2021年   2387篇
  2020年   1819篇
  2019年   1559篇
  2018年   1677篇
  2017年   1574篇
  2016年   1394篇
  2015年   2091篇
  2014年   2682篇
  2013年   2568篇
  2012年   3595篇
  2011年   3817篇
  2010年   2812篇
  2009年   2219篇
  2008年   2641篇
  2007年   2591篇
  2006年   2539篇
  2005年   2207篇
  2004年   1719篇
  2003年   1778篇
  2002年   1503篇
  2001年   1218篇
  2000年   1016篇
  1999年   810篇
  1998年   488篇
  1997年   434篇
  1996年   306篇
  1995年   258篇
  1994年   257篇
  1993年   178篇
  1992年   254篇
  1991年   241篇
  1990年   200篇
  1989年   189篇
  1988年   196篇
  1987年   139篇
  1986年   155篇
  1985年   139篇
  1984年   120篇
  1983年   70篇
  1982年   58篇
  1981年   70篇
  1979年   97篇
  1978年   56篇
  1974年   57篇
  1973年   73篇
  1972年   58篇
  1971年   62篇
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
31.
本文从理论上提出了红细胞沉降速度的准确概念,阐明了红细胞沉降过程所包含的物理和生理信息,提出了一种新型测量红细胞沉降速度及其它特征参数的方法,并给出了其主体、硬件和软件设计要点。  相似文献   
32.
Diabetes in NOD mice is an autoimmune disease which is characterized by the infiltration of islets of Langerhans by large numbers of T cells. Some of these infiltrating T cells are clearly islet-cells-specific; however, many or most of these T cells could be attracted nonspecificity into these lesions. To study NOD pancreas-infiltrating T cells, we fused these cells with BW5147 to make T cell hybridomas. Ninety-four pancreas-derived T hybrids were analyzed of which 12 responded specifically to islet cells by secreting IL-2. Only CD3+, CD4+ hybrids responded to islet cells in our assay, and a large proportion of these hybrids were islet-cell reactive. T cell receptor (TCR) V beta element usage was heterogeneous in islet-reactive hybridomas.  相似文献   
33.
30余种氨基酸、40余种非挥发性有机酸和20余种碱基核苷类化合物在一块薄层板上完成多相同步色谱分析;用紫外灯-吖啶试剂-镉茚三酮试剂实行组合显色定位分析。改善了尿液中非挥发性有机酸的溶剂萃取法,尿中三类化合物提取物的同步多相色谱分离效果良好。  相似文献   
34.
Acetazolamide is a weak diuretic used to decrease production of aqueous humor in the eye. Hemodialysis patients undergoing ocular surgery may benefit from acetazolamide; however, no pharmacokinetic data are available for this group of patients. We report a patient who received acetazolamide 250 mg every 6 hours after ophthalmic surgery and developed reversible neurological side effects associated with very high plasma concentrations. Using pharmacokinetic analysis, we suggest an alternate administration of acetazolamide for end-stage renal patients.  相似文献   
35.
To determine the potential impact of recombinant human erythropoietin (EPO) therapy in patients undergoing autologous bone marrow transplantation (BMT) and colony-stimulating factor therapy, we assayed endogenous serum EPO levels and noted blood transfusion requirements in relapsed non-Hodgkin's lymphoma patients treated with high-dose chemo-radiation therapy and autologous BMT. Hematocrit and reticulocyte counts were determined daily, and hematocrit was maintained in the 25-30% range by transfusion according to criteria established by our hospital transfusion committee. EPO levels were measured by radioimmunoassay and were determined at baseline, throughout therapy, and 2 and 3 months after BMT. Serum EPO levels increased more than 25-fold above baseline in most subjects after initiating chemoradiation therapy. No correlation was noted between serum EPO and hematocrit, reticulocyte count or serum creatinine. Total red blood cell units transfused ranged from 4 to 15 (mean 7.7). Mean total donor exposures (red blood cell plus platelet units transfused) were 83.6 units (range 16-175). Serum EPO levels increased early in the course of preparation for autologous BMT and remained elevated for at least 2-3 weeks thereafter although at a lower level. Red blood cell transfusions were required despite very high EPO levels after BMT. Red cell transfusions, moreover, accounted for only 9.2% (69 of 746) of total donor exposures and only 5.8% (42 of 746) of donor exposures during the interval when pharmacologic doses of erythropoietin might be of benefit. In contrast to the potential benefit of colony-stimulating factors such as G-CSF and GM-CSF in BMT, our study suggests limited value for erythropoietin therapy in this setting.  相似文献   
36.
Meckel's diverticulum is the most common congenital anomaly of the small intestine, occurring in about 2 % of the population. The most common complications associated with a Meckel's diverticulum include obstruction, bleeding, and inflammation (7, 9, 11, 18-20). The estimated lifetime risk of developing symptoms with a Meckel's diverticulum is 4-6 % (16), with the risks of complications decreasing with age. Stones within Meckel's diverticulum are recognized as a rare complication in the adult population (13,15). However, it has not been reported in the pediatric age group. The authors describe a 19-month-old male who presented with intermittent abdominal pain and vomiting, chronic microcytic anemia and a calcified stone in the lower abdomen, who was found to have a Meckel's enterolith.  相似文献   
37.
38.
39.
40.
OBJECTIVE: To study the expression of neuron-specific enolase (NSE) and olfactory marker protein (OMP) in the developing olfactory mucosa of human fetuses. METHOD: The expression of NSE and OMP in the olfactory mucosa of 6 human fetuses (12, 16, 20, 24, 28 and 34 weeks) was studied using the technique of immunohistochemistry. RESULTS: NSE immunological positive reactions were seen in all 6 fetal mucosa from gestational 12 (G12) to G34, with plenty of positive-stained dual-pole neuron cells. At G12, the positive cells aligned tightly, the cell bodies were localized in the lower portion of olfactory epithelium and the positive-stained area occupied upper 2/3 of fetal nasal mucosa. With the development, the positive cells gradually became multilayer, but the density and the relative area of positive-cells reduced. At G34, the positive cells were located only in upper 1/3 of nasal mucosa. OMP-positive reactions were localized in a few dual-pole neurons at G12, the number was much less than NSE-positive cells in the same fetus. With the development, the OMP-positive cells gradually increased with most of the cell bodies located in the upper portion of epithelium, but number still relatively less than the NSE-positive cells at the same age. CONCLUSION: At G12, there were lots of olfactory neuron in the olfactory mucosa and only a few olfactory neurons had became mature. With the development, the olfactory epithelial area reduced but the number of mature olfactory neurons increased. At the last trimester, fetal olfactory sensor was almost matured.  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