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   6032篇
  免费   268篇
  国内免费   36篇
耳鼻咽喉   44篇
儿科学   51篇
妇产科学   88篇
基础医学   650篇
口腔科学   65篇
临床医学   419篇
内科学   1786篇
皮肤病学   45篇
神经病学   274篇
特种医学   152篇
外科学   987篇
综合类   73篇
一般理论   1篇
预防医学   294篇
眼科学   30篇
药学   428篇
中国医学   6篇
肿瘤学   943篇
  2023年   35篇
  2022年   66篇
  2021年   91篇
  2020年   52篇
  2019年   59篇
  2018年   100篇
  2017年   67篇
  2016年   80篇
  2015年   99篇
  2014年   139篇
  2013年   166篇
  2012年   280篇
  2011年   275篇
  2010年   170篇
  2009年   173篇
  2008年   277篇
  2007年   308篇
  2006年   339篇
  2005年   324篇
  2004年   274篇
  2003年   304篇
  2002年   276篇
  2001年   248篇
  2000年   263篇
  1999年   236篇
  1998年   75篇
  1997年   70篇
  1996年   46篇
  1995年   39篇
  1994年   52篇
  1993年   36篇
  1992年   151篇
  1991年   125篇
  1990年   124篇
  1989年   123篇
  1988年   99篇
  1987年   102篇
  1986年   95篇
  1985年   70篇
  1984年   53篇
  1983年   45篇
  1982年   20篇
  1979年   36篇
  1978年   20篇
  1977年   26篇
  1973年   21篇
  1971年   20篇
  1970年   23篇
  1969年   24篇
  1967年   20篇
排序方式: 共有6336条查询结果,搜索用时 15 毫秒
41.
To investigate the process of carcinogenesis in gastric cancer, we studied the histological features of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-treated rats. Samples of the gastric mucosa from both MNNG-treated and control rats were histologically examined every 2 months, for 10 months. In 40% of the MNNG-treated rats, atrophy in the gastric mucosa was observed after 2 months, and regenerative epithelium was observed after 4 months, followed by adenomatous proliferation and disappearance of the tight junction electron microscopically after 6 months. A small intestinal cancer had developed in 2 rats at 6 months. While gastric cancer had developed in 3 rats at 8 months, and in one of these 3 rats, peritoneal dissemination was observed macroscopically and histologically. These results suggested that adenomatous proliferation and disappearance of the tight junction observed electron microscopically were characteristic pathological features of precancerous lesions in the stomach in MNNG-treated rat.  相似文献   
42.
A retrospective study of 25 patients treated for primary gastric lymphoma was made to investigate a number of problems related to treatments and report the factors influencing prognosis. In the 5-year-survival rate according to Working Formulation classification, either survival rate of low-grade type or intermediate-grade type was higher than that of high-grade type. Both the 5-year-survival rate of cases without lymph node metastasis and that of cases that involved perigastric lymph nodes were higher than that of cases that involved distant gastric lymph nodes. Those surviving five years after perigastric lymph node metastasis had received D3 or D4 dissection and postoperative multicombined chemotherapy. Tumors invading only to the submucosal layer had received D2 dissection and were not treated by postoperative multicombined chemotherapy, and recurrence was not recognized in these cases. Of 9 cases infiltrating into the musclaris propria or serosa without lymph node metastasis, 8 cases were treated by postoperative multicombined chemotherapy and were alive without recurrence, but one case without postoperative multicombined chemotherapy died by recurrence. Therefore, adequate therapy for gastric lymphoma with infiltrating into submucosal layer is gastrectomy with D2 lymph node dissection, and postoperative multicombined chemotherapy is not necessary. The cases with perigastric lymph node metastasis, or the cases with invading from muscularis propria to serosa require D3 or D4 lymph node dissection with postoperative multicombined chemotherapy. But the cases with distant gastric lymph node metastasis or invading adjacent structure or high-grade type histologically (WF classification) require preoperative chemotherapy.  相似文献   
43.
44.

Objective

To determine the value of using the Roter Interaction Analysis System during objective structured clinical examinations (OSCEs) to assess pharmacy students'' communication competence.

Methods

As pharmacy students completed a clinical OSCE involving an interview with a simulated patient, 3 experts used a global rating scale to assess students'' overall performance in the interview, and both the student''s and patient''s languages were coded using the Roter Interaction Analysis System (RIAS). The coders recorded the number of utterances (ie, units of spoken language) in each RIAS category. Correlations between the raters'' scores and the number and types of utterances were examined.

Results

There was a significant correlation between students'' global rating scores on the OSCE and the number of utterances in the RIAS socio-emotional category but not the RIAS business category.

Conclusions

The RIAS proved to be a useful tool for assessing the socio-emotional aspect of students'' interview skills.  相似文献   
45.
46.
We herein report two cases of potentially life-threatening arrhythmia due to hyperkalemia triggered by the excessive consumption of “Hoshi-Imo” (dried sweet potato). Both patients with chronic renal disease on renin-angiotensin-aldosterone system inhibitors presented at the emergency room with non-specific symptoms. Electrocardiograms revealed potentially life-threatening arrhythmia due to hyperkalemia in both cases: sinus arrest with a ventricular escape rhythm, tall and peaked T waves; and a widened QRS complex in a nearly sine-wave configuration without discernible P wave. Both patients fully recovered after intensive care for hyperkalemia. Physicians should recognize the excessive consumption of “Hoshi-Imo” may lead to the development of life-threatening arrhythmia, especially in patients with risk factors for hyperkalemia.  相似文献   
47.
48.
49.
50.
The c-kit receptor ligand functions as a mast cell chemoattractant.   总被引:15,自引:4,他引:15  
Mast cells accumulate at sites of neovascularization, solid tumors, and many immune reactions. Such accumulation requires directed migration of mature mast cells or their precursors. The nature of the chemoattractants that regulate mast cell motility and the identity of the receptors that mediate the chemotactic response are poorly understood. We have tested the ability of stem cell factor (SCF), a mast cell growth factor, to stimulate mast cell migration. Our results show that SCF is a potent mast cell attractant that stimulates directional motility of both mucosal and connective tissue-type mast cells. The activity is potentiated by costimulation with interleukin-3 (IL-3), another mast cell chemoattractant. SCF, a known ligand for the c-kit tyrosine kinase receptor, was unable to stimulate motility in W42 mutant mast cells, which have a defective c-kit tyrosine kinase. However, W42 mast cells were still able to migrate in response to IL-3. These results show that SCF is a chemotactic factor as well as a growth factor and that the c-kit receptor can transduce signals leading to both cell proliferation and increased directional cell motility.  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