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   30906篇
  免费   2983篇
  国内免费   1666篇
耳鼻咽喉   41篇
儿科学   186篇
妇产科学   278篇
基础医学   3190篇
口腔科学   63篇
临床医学   2421篇
内科学   6030篇
皮肤病学   71篇
神经病学   539篇
特种医学   685篇
外国民族医学   60篇
外科学   3931篇
综合类   5750篇
现状与发展   3篇
预防医学   797篇
眼科学   49篇
药学   2177篇
  29篇
中国医学   1334篇
肿瘤学   7921篇
  2024年   117篇
  2023年   579篇
  2022年   1224篇
  2021年   1516篇
  2020年   1237篇
  2019年   1059篇
  2018年   912篇
  2017年   1122篇
  2016年   1380篇
  2015年   1361篇
  2014年   2020篇
  2013年   2034篇
  2012年   1708篇
  2011年   1794篇
  2010年   1375篇
  2009年   1277篇
  2008年   1376篇
  2007年   1602篇
  2006年   1323篇
  2005年   1284篇
  2004年   1020篇
  2003年   857篇
  2002年   817篇
  2001年   783篇
  2000年   739篇
  1999年   573篇
  1998年   554篇
  1997年   479篇
  1996年   443篇
  1995年   455篇
  1994年   407篇
  1993年   311篇
  1992年   250篇
  1991年   261篇
  1990年   214篇
  1989年   189篇
  1988年   179篇
  1987年   125篇
  1986年   78篇
  1985年   82篇
  1984年   83篇
  1983年   66篇
  1982年   54篇
  1981年   48篇
  1980年   52篇
  1979年   36篇
  1978年   22篇
  1977年   25篇
  1976年   19篇
  1975年   11篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
应用双抗体夹心ELISA法对87例消化道疾病患者胃液可溶性白细胞介素-2受体(sIL-2R)水平进行测定。结果表明,胃癌患者胃液sIL-2R水平明显高于慢性浅表性胃炎及十二指肠溃疡患者(P相似文献   
32.
Bloodflowvariationandenergymetabolisminthegastricmucosafollowing7.5%hypertonicsalineresuscitationWangJunyi(王俊义);WuGuosheng;(吴...  相似文献   
33.
宋柏根  李义清 《肿瘤》1993,13(5):201-204
投用致癌剂的对照组其胃肿瘤发生率为22.2%。若同时给予40%Z醇液空腹灌胃,则胃肿瘤发生率达55.9%。如在给乙醇液前15分钟,先给予4%的辣椒煎液灌胃,则胃肿瘤发生率只有20.0%,相近于对照组的水平(后2组差别有极显著意义,P<0.01)。这种给损伤剂(乙醇)之前先给予微刺激剂(辣椒)所产生的胃粘膜的保护作用,是通过促使胃粘膜上皮细胞合成内源性前列腺素(PGs)来实现的,是一种“适应性细胞保护”机制。这种保护胃粘膜的作用可降低胃肿瘤的发生率。  相似文献   
34.
Because gastric cancers located in the upper third of the stomach are difficult to detect at an early stage, the surgical results remain poor. We performed R4 gastrectomy as a radical procedure for 25 patients, involving complete resection of the latero-aortic and interaorticovenous lymph modes above and below the left renal vein, in combination with the ordinary R2 or R3 gastrectomy (the R4 group). These patients were compared with 156 others who underwent R2 gastrectomy alone (the R2 group). There were no significant differences in operation time, blood loss, or the incidence of complications between the two groups; however, when the survival rates of the patients with tumors invading beyond the subserosa were compared, the 5-year survival rate was found to be significantly higher in the R4 group than in the R2 group. Furthermore, in patients with para-aortic nodal involvement, a significant survival advantage was observed in the R4 group, as compared with the R2 group. These results suggest that the R4 gastrectomy is a rational approach for patients with advanced gastric cancer located in the upper third of the stomach.  相似文献   
35.
Background: Numerous investigators have attempted to identify prognostic indicators for successful outcome following bariatric surgery. The purpose of this study was to determine whether degree of obesity affects outcome in super obese [>225% ideal body weight (IBW)] versus morbidly obese patients (160-225% IBW) undergoing gastric restrictive/bypass procedures. Methods: Since 1984, 157 patients underwent either gastric bypass or vertical banded gastroplasty. Super obese (78) and morbidly obese (79) patients were followed prospectively, documenting outcome and complications. Results: Super obese patients reached maximum weight loss 3 years following bariatric surgery, exhibiting a decrease in body mass index (BMI) from 61 to 39 kg/m2 and an average loss of 42% excess body weight (EBW). Morbidly obese patients had a decrease in BMI from 44 to 31 kg/m2 and carried 39% EBW at 1 year. After their respective nadirs, each group began to regain the lost weight with the super obese exhibiting a current BMI of 45 kg/m2 (61% EBW) versus 34 kg/m2 (52% EBW) in the morbidly obese at 72 months cumulative follow-up. Currently, loss of 50% or more of EBW occurred in 53% of super obese patients versus 72% of morbidly obese (P < 0.01). Twenty-six percent of super obese patients returned to within 50% of ideal body weight (IBW) while 71% of morbidly obese were able to reach this goal (P < 0.01). Co-morbidities and complications related to surgery were similar in each group. Conclusions: Super obese patients have a greater absolute weight loss after bariatric surgery than do morbidly obese patients. Using commonly utilized measures of success based on weight, morbidly obese patients tend to have better outcomes following bariatric surgery.  相似文献   
36.
Summary The adherence, growth, and electrophysiologic properties of guinea pig gastric mucous epithelial cells were investigated using porous membrane filters. We also tested three commercially available Ussing-type chambers that were designed to be used with the various porous membrane supports. Overall, the 0.45-µm Falcon-Cyclopore porous membrane was found to be very favorable for the consistent attachment and growth of our cells. This same filter also gave good results in the detection of periodic acid Schiff-positive mucous glycoprotein and Nile red neutral lipid fluorescence in the gastric mucous cells. Our cells grew poorly on collagen-coated Costar-Snapwells and Millipore Millicell-CM porous filters. For measurement of transepithelial potential difference resistance, and short-circuit current, the Costar-Snapwell with the Costar-Snapwell Diffusion-chamber system was superior in design and operation when compared to the Costar Transwell-COL, Falcon-Cyclopore, or Anotec-Anocell porous inserts used with conventional Ussing-chambers. The gastric mucous cells grew best on ICN-Cellagen membranes, but these filters routinely detached from their plastic holder and therefore could not be used for Ussing-chamber studies. The large 24.5-mm, 0.40-µm pore size Costar-Transwell-COL and the 24.1-mm, 0.45-µm Falcon-Cyclopore membranes gave good results when used in a modified horizontal-chamber for microelectrode analysis of membrane potentials and resistances of the gastric mucous cell monolayers.  相似文献   
37.
正常人及胃癌患者胃蛋白酶原C基因多态性研究   总被引:2,自引:0,他引:2  
以PGC301为探讨,对10例胃癌组织及11例正常人体组织基因组DNA中胃蛋白酶原C基因的EcoR I限制性片段长度多态性作了观察分析。发现在正常人体有三种常见等位片段,分别为20kb、5.7kb及3.6kb;一种稀有片段,3.5kb。在胃癌患者,未发现与正常人体不同的等位片段。但是,稀有片段及稀有杂交带型的出现频率高于正常组。这一结果对深入探讨胃蛋白酶原C基因稀有片段及稀有杂交带型对胃癌的诊断价  相似文献   
38.
39.
采用石蜡切片免疫组化法,测定了48例胃癌组织中雌激素受体的分布。结果阳性者17例,阳性率35.4%;同时测定12例非肿瘤性胃粘膜(慢性炎症及胃溃疡)作为对照,结果仅1例阳性(8.3%),两者之间有明显差异(P<0.01)。各年龄组及性别间差异均无统计学意义。将胃癌分成分化型及未分化型(包括印戒细胞癌)两组,结果显示未分化型癌的阳性率(61.5%)比分化型者(18.2%)明显增高(P<0.0l)。表示雌激素在癌的发生、发展中有明显的刺激作用,癌细胞的生长及恶性度对雌激素有一定依赖性。临床上应用内分泌疗法对雌激素受体阳性肿瘤进行辅助治疗是行之有效的。  相似文献   
40.
本文利用细胞集落形成测定细胞存活率的方法,检测了仓鼠细小病毒(PVH-1)对2株不同分化程度的胃癌细胞的抑制作用。同时收集感染后48h、72h、96h、144h的胃癌细胞,利用电镜观察胃癌细胞的变化。结果表明,PVH-1能抑制不同分化程度的胃癌细胞株,其敏感性与胃癌细胞的分化程度有关。  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