全文获取类型
收费全文 | 101196篇 |
免费 | 9129篇 |
国内免费 | 4819篇 |
专业分类
耳鼻咽喉 | 776篇 |
儿科学 | 2189篇 |
妇产科学 | 1736篇 |
基础医学 | 11528篇 |
口腔科学 | 2228篇 |
临床医学 | 9933篇 |
内科学 | 16558篇 |
皮肤病学 | 1439篇 |
神经病学 | 7710篇 |
特种医学 | 1867篇 |
外国民族医学 | 36篇 |
外科学 | 8287篇 |
综合类 | 16816篇 |
现状与发展 | 14篇 |
预防医学 | 8649篇 |
眼科学 | 2883篇 |
药学 | 9361篇 |
31篇 | |
中国医学 | 3490篇 |
肿瘤学 | 9613篇 |
出版年
2024年 | 281篇 |
2023年 | 1299篇 |
2022年 | 2898篇 |
2021年 | 3745篇 |
2020年 | 3336篇 |
2019年 | 3033篇 |
2018年 | 2977篇 |
2017年 | 3412篇 |
2016年 | 3678篇 |
2015年 | 3666篇 |
2014年 | 6362篇 |
2013年 | 7000篇 |
2012年 | 6474篇 |
2011年 | 7135篇 |
2010年 | 5984篇 |
2009年 | 5602篇 |
2008年 | 5822篇 |
2007年 | 5780篇 |
2006年 | 5217篇 |
2005年 | 4629篇 |
2004年 | 3922篇 |
2003年 | 3410篇 |
2002年 | 2822篇 |
2001年 | 2434篇 |
2000年 | 2048篇 |
1999年 | 1774篇 |
1998年 | 1533篇 |
1997年 | 1313篇 |
1996年 | 1164篇 |
1995年 | 1068篇 |
1994年 | 868篇 |
1993年 | 691篇 |
1992年 | 611篇 |
1991年 | 475篇 |
1990年 | 440篇 |
1989年 | 329篇 |
1988年 | 260篇 |
1987年 | 212篇 |
1986年 | 173篇 |
1985年 | 273篇 |
1984年 | 216篇 |
1983年 | 137篇 |
1982年 | 185篇 |
1981年 | 111篇 |
1980年 | 116篇 |
1979年 | 69篇 |
1978年 | 46篇 |
1977年 | 36篇 |
1976年 | 29篇 |
1975年 | 25篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Yoshinori Itoh Yutaka Kohgo Naoki Watanabe Yuji Kanisawa Sumio Sakamaki Minoru Takahashi Yasuo Hirayama Hiroyuki Ono Takeshi Himeno Yoshiro Niitsu 《Cancer science》1991,82(11):1203-1206
Human tumor–infiltrating lymphocytes (TILs) derived from pleural or ascitic fluid were incubated with recombinant interleukin 2 and transfected with human tumor necrosis factor (TNF) a gene by the lipofection procedure. The resulting TILs secreted significant amounts of TNF in the culture supernatant and exhibited cytotoxicity against established cell lines, such as K562 and Daudi, and autologous tumor cells. The TNF gene–transfected TILs exhibited an augmented killing of autologous tumor cells. 相似文献
92.
应用鸡卵清蛋白致敏和刺激小鼠复制过敏性气道炎症反应模型研究血小板激活因子选择性拮抗剂YM-264对抗原引起气道嗜酸性粒细胞(EOS)浸润的影响。结果发现,正常小鼠支气管肺泡灌洗液(BALF)中未见到EOS;致敏小鼠给予抗原多次反复吸入刺激后,BALF中EOS急剧增多。在YM-264治疗各组中,YM-264的不同剂量分别导致EOS数下降27.0%、48.2%及67.9%。还发现YM-264抑制EOS对气道的浸润伴随着白细胞介素(IL)-5水平的明显下降。提示YM-264通过抑制IL-5的产生从而抑制了EOS在气道的聚集。 相似文献
93.
94.
Maximal and submaximal oxygen uptake during running: how should body mass be accounted for? 总被引:1,自引:0,他引:1
J. Svedenhag 《Scandinavian journal of medicine & science in sports》1995,5(4):175-180
Oxygen uptake during running, i.e., the running economy, is an important factor in determining running performance in endurance events. The relation to performance is particularly strong when the aerobic running capacity is calculated, i.e., when running economy is related to the maximal oxygen uptake. There is considerable interindividual variation in running economy, and the reason for this is only partly understood. To some extent, this may be due to the way in which the oxygen uptake during running is usually expressed. This may expecially be true when subjects with different or changing body masses are compared. Several lines of evidence, including earlier animal studies as well as more recent human studies, favor the expression of submaximal and maximal oxygen uptake during running in terms of ml · kg−0.75 · min−1 rather than as ml · kg−1 · min−1. 相似文献
95.
96.
Stewart Shapiro Dimitris N. Tatakis Dr. Rosemary Dziak 《Calcified tissue international》1990,46(1):60-62
Summary Tumor necrosis factor α (10−10–10−8M) had no effects on cyclic AMP production by the osteoblastic osteosarcomal cells, Saos-2 and G292, or normal rat calvarial
cells. The cytokine did, however, inhibit the parathyroid hormone (PTH)-induced effect on cyclic AMP in the Saos-2 and normal
rat osteoblastic cells. This inhibitory effect did not occur on prostaglandin E2-induced cyclic AMP increases in the osteoblastic cells. Interleukin-1 (10 U/ml −100 U/ml) did not produce any effect on basal
levels or PTH-induced cyclic AMP increases in these cells. 相似文献
97.
Sinusoids are found not only in the normal liver but also in certain liver tumours, including hepatoblastoma, the most common malignant liver tumour in childhood. In this study, sinusoids in 12 hepatoblastomas, of various subtypes, and in normal liver were investigated with UEA-1 and antibodies against von Willebrand's factor, CD31 and CD34 to detect differences of possible diagnostic significance. In the normal liver, staining of sinusoids was seen with all these markers, but it was focal and confined to a few sinusoids near the portal tracts. In hepatoblastoma, the endothelial markers reacted with the sinusoids to varying extents. UEA-1 and anti-CD34 usually stained the majority of these vessels, anti-CD34 staining greater numbers of sinusoids and with greater intensity. Immunostaining revealed that both number and spatial organization of sinusoids in hepatoblastoma are dependent on the subtype. In addition to staining of endothelium, one of the two small cell hepatoblastomas exhibited strong immunoreactivity of the tumour cells for CD34. These findings show that the marked difference in sinusoidal immunoreactivity for CD34 between normal liver and hepatoblastoma could be useful for discriminating between non-neoplastic liver tissue and highly differentiated fetal hepatoblastoma. Our findings also show that small cell hepatoblastoma, in addition to acute leukaemia, should be considered when immunoreactivity for CD34 is found in small round and blue cell tumours in childhood. 相似文献
98.
本实验在离体大鼠主动脉条上,观察纤维蛋白(原)降解产物肽6A灌流对血管反应性及血管组织cGMP含量的影响,实验结果表明肽6A呈剂量依赖地显扩张离体血管,其作用在去内皮后消失;肽6A还能显提高离体血管组织cGMP含量,NO合成抑制剂L-NNA可阻断这一作用,NO前体L-精氨酸可逆转L-NNA的效应,结果提示肽6A可以通过促进血管内皮释放内皮舒张因子而扩张血管。 相似文献
99.
Dr. S. Eggstein MD G. Manthey MT T. Hirsch PhD F. Baas MA B. U. V. Specht MD E. H. Farthmann MD 《Digestive diseases and sciences》1996,41(6):1069-1075
Epidermal growth factor receptors (EGFR) andras mutations are known to play a significant role in controlling cell growth and tumor promotion. Both of them transmit mitogenic signals to the nucleus by activation of Raf-1 kinase. In this study, the expression of EGFR and mutant Ras proteins, and, for the first time, the expression, phosphorylation and kinase activity of Raf-1 kinase have been determined in paired samples of colorectal cancer and mucosa. The tumor and mucosa samples did not differ significantly with regard to Raf-1 kinase content and activity. A major difference between tumors and mucosa was found, however, in the phosphorylation of Raf-1. Most of the mucosa samples (13/20), but only 1/20 of the cancer samples, contained hyperphosphorylated Raf-1. EGFR were significantly (p=0.0025) decreased in the tumors. The decreased phosphorylation of Raf-1 in colonic carcinomas could be the result of activation of Raf-1 phosphatases or inactivation of kinases phosphorylating Raf-1. New forms of treatment based on EGFR overexpression do not seem to be suitable for the majority of colonic cancers.This work was supported by the state of Baden-Württemberg (Verbundforschungsprojekt: Aufklärung von Mechanismen der Tumorentstehung und Tumorabwehr). 相似文献
100.
免疫抑制因子对佐剂关节炎的影响 总被引:1,自引:0,他引:1
目的;研究免疫抑制因子对佐剂关节炎发病的影响。方法:检测对照组与实验组对正常小鼠淋巴细胞转化的影响。结果:脑室注射IL1的关节炎大鼠在第0、7、14、28、35d的血清具有明显的抑制淋巴细胞转移化的作用。关节炎症状加重,病程延长。结论:免疫抑制蛋白可能参与佐剂关节炎的发病,有可能是造成关节炎的原因之一。 相似文献