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   10978篇
  免费   413篇
  国内免费   76篇
耳鼻咽喉   93篇
儿科学   227篇
妇产科学   127篇
基础医学   1396篇
口腔科学   300篇
临床医学   604篇
内科学   2630篇
皮肤病学   234篇
神经病学   849篇
特种医学   531篇
外科学   1822篇
综合类   27篇
一般理论   1篇
预防医学   373篇
眼科学   174篇
药学   709篇
中国医学   17篇
肿瘤学   1353篇
  2023年   46篇
  2021年   176篇
  2020年   75篇
  2019年   107篇
  2018年   167篇
  2017年   134篇
  2016年   178篇
  2015年   176篇
  2014年   252篇
  2013年   301篇
  2012年   528篇
  2011年   569篇
  2010年   319篇
  2009年   283篇
  2008年   569篇
  2007年   666篇
  2006年   640篇
  2005年   721篇
  2004年   702篇
  2003年   669篇
  2002年   651篇
  2001年   211篇
  2000年   200篇
  1999年   232篇
  1998年   196篇
  1997年   170篇
  1996年   135篇
  1995年   144篇
  1994年   145篇
  1993年   131篇
  1992年   185篇
  1991年   147篇
  1990年   161篇
  1989年   141篇
  1988年   160篇
  1987年   142篇
  1986年   121篇
  1985年   104篇
  1984年   72篇
  1983年   62篇
  1982年   58篇
  1981年   57篇
  1980年   47篇
  1979年   62篇
  1978年   47篇
  1977年   38篇
  1976年   32篇
  1975年   32篇
  1973年   34篇
  1971年   32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.
Kohmoto  Tomohiro  Masuda  Kiyoshi  Shoda  Katsutoshi  Takahashi  Rizu  Ujiro  Sae  Tange  Shoichiro  Ichikawa  Daisuke  Otsuji  Eigo  Imoto  Issei 《Gastric cancer》2020,23(3):403-417
Gastric Cancer - We aimed to identify novel tumor-promoting drivers highly expressed in gastric cancer (GC) that contribute to worsened prognosis in affected patients. Genes whose expression was...  相似文献   
4.
5.
6.
The effect of electric charge on the hepatic disposition of macromolecules was studied in the rat. Charged derivatives of dextran (T-70) and bovine serum albumin (BSA), mitomycin C–dextran conjugates (MMC-D), and lactosaminated BSA (Lac-BSA) were employed as model macromolecules. After intravenous injection, cationic macromolecules were rapidly eliminated from plasma because of their extensive hepatic uptake, while anionic and neutral macromolecules were slowly eliminated. Cationic macromolecules were recovered from parenchymal and nonparenchymal hepatic cells at a cellular uptake (per unit cell number) ratio of 1.4–3.2, while that of Lac-BSA was 14. During liver perfusion using a single-pass constant infusion mode, cationic macromolecules were continuously extracted by the liver, with extraction ratios at steady-state (E ss) ranging between 0.03 and 0.54, whereas anionic and neutral macromolecules were almost completely recovered in the outflow at steady state. The E ss for cationized BSA (Cat-BSA) and cationic MMC-Dcat were concentration dependent and decreased at low temperatures and in the presence of colchicine and cytochalasin B. The possible participation of the internalization process in the uptake of cationic macromolecules by hepatocytes was suggested.  相似文献   
7.
8.
9.
Some physiological substances, including acetylcholine and nitric oxide, are useful candidates for stimulation of intestinal absorption of drugs. In the present study, we elucidated the ability of epinephrine (Epi) to stimulate the intestinal absorption of drugs. We evaluated the ability of Epi to enhance absorption of macromolecules using dextran (Mw 4000 Da), which is poorly absorbed from the intestine, as a model compound in situ in a closed loop of the rat jejunum. Treatment of the jejunum with Epi resulted in significant increase in absorption of dextran in a dose-dependent fashion. The area under the curve (AUC) from 0 to 4 h in the Epi-treated jejunum was 13-fold higher than that in the vehicle-treated jejunum. The absorption-enhancing activity of Epi was 40-fold higher than that of caprate, a clinically used absorption-enhancer of drugs. In the experimental conditions used in this study, histological injury of the mucosa and perturbation of the mucosal membrane were not observed in the Epi-treated jejunum. Treatment with an antagonist of alpha-adrenergic receptors attenuated the stimulation of intestinal absorption by Epi, and treatment with an agonist of alpha-adrenergic receptors resulted in enhancement of intestinal absorption. While an antagonist of beta-adrenergic receptors enhanced the absorption-enhancing effect of Epi, an agonist of beta-adrenergic receptors stimulated intestinal absorption. These results indicate that stimulation of adrenergic receptors may be a novel strategy for intestinal absorption of drugs.  相似文献   
10.
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