全文获取类型
收费全文 | 415871篇 |
免费 | 38730篇 |
国内免费 | 28439篇 |
专业分类
耳鼻咽喉 | 3145篇 |
儿科学 | 5637篇 |
妇产科学 | 4718篇 |
基础医学 | 44713篇 |
口腔科学 | 6935篇 |
临床医学 | 58573篇 |
内科学 | 55633篇 |
皮肤病学 | 4601篇 |
神经病学 | 19636篇 |
特种医学 | 15023篇 |
外国民族医学 | 236篇 |
外科学 | 35687篇 |
综合类 | 79150篇 |
现状与发展 | 98篇 |
一般理论 | 36篇 |
预防医学 | 31908篇 |
眼科学 | 11650篇 |
药学 | 45613篇 |
484篇 | |
中国医学 | 27752篇 |
肿瘤学 | 31812篇 |
出版年
2024年 | 1432篇 |
2023年 | 5931篇 |
2022年 | 15530篇 |
2021年 | 19896篇 |
2020年 | 15771篇 |
2019年 | 12793篇 |
2018年 | 13172篇 |
2017年 | 12872篇 |
2016年 | 11782篇 |
2015年 | 18471篇 |
2014年 | 23110篇 |
2013年 | 21507篇 |
2012年 | 31788篇 |
2011年 | 35509篇 |
2010年 | 24527篇 |
2009年 | 20142篇 |
2008年 | 24226篇 |
2007年 | 23885篇 |
2006年 | 22727篇 |
2005年 | 21454篇 |
2004年 | 14305篇 |
2003年 | 13683篇 |
2002年 | 11250篇 |
2001年 | 9499篇 |
2000年 | 9126篇 |
1999年 | 8936篇 |
1998年 | 5603篇 |
1997年 | 5403篇 |
1996年 | 4187篇 |
1995年 | 3930篇 |
1994年 | 3322篇 |
1993年 | 2123篇 |
1992年 | 2588篇 |
1991年 | 2280篇 |
1990年 | 1914篇 |
1989年 | 1671篇 |
1988年 | 1386篇 |
1987年 | 1292篇 |
1986年 | 1052篇 |
1985年 | 753篇 |
1984年 | 426篇 |
1983年 | 322篇 |
1982年 | 169篇 |
1981年 | 197篇 |
1980年 | 147篇 |
1979年 | 179篇 |
1978年 | 98篇 |
1977年 | 70篇 |
1973年 | 66篇 |
1972年 | 60篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Da-Nian Zhu, Long-Mei Xue, Peng Li. Effect of central muscarine receptor blockade. with DKJ-21 on the blood pressure and heart rote in stress-induced hypertensive rats.
The experiments were performed on Wistar or Sprague-Dawley rats of both sexes divided at random into stress and control groups. The rats in the stress groups were put into cages and subjected to electric foot-shocks and noises for 9-15 days, which caused an increase in blood pressure (BP) and heart rate (HR). In hypertensive rats DKJ-21 (4mg/lml) was injected intravenously (i.v.), and 0.5-1.0h after administration the BP and HR dropped from the high level to normotensive level. In normotensive rats, however, administration of DKJ-21 had no effect on BP or HR. In separate groups of normotensive rats, pretreatment of DKJ-21 (4 mg/l ml, i.v.) blocked the pressor and tachycardiac effect induced by microinjection of physostigmine (0.4μg/0.1 /μl/site), corticosterone (40μg/0.1μl/site) or aldosterone (40 μg/0.1 μl/site) into the rostral ventrolateral medulla (rVLM). Furthermore, DKJ-21 also attenuated the enhancement of the pressor response to stimulation of the defense area in the midbrain, which was induced by microinjection of drugs (mentioned above) into the rVLM. These results indicate that i.v. DKJ-21 can selectively block the muscarinic receptors in the rVLM in stress-induced hypertensive rats, which suggests that abnormal enhancement of cholinergic mechanism in the rVLM may be related to hypertensive effects of corticoids in this area. 相似文献
The experiments were performed on Wistar or Sprague-Dawley rats of both sexes divided at random into stress and control groups. The rats in the stress groups were put into cages and subjected to electric foot-shocks and noises for 9-15 days, which caused an increase in blood pressure (BP) and heart rate (HR). In hypertensive rats DKJ-21 (4mg/lml) was injected intravenously (i.v.), and 0.5-1.0h after administration the BP and HR dropped from the high level to normotensive level. In normotensive rats, however, administration of DKJ-21 had no effect on BP or HR. In separate groups of normotensive rats, pretreatment of DKJ-21 (4 mg/l ml, i.v.) blocked the pressor and tachycardiac effect induced by microinjection of physostigmine (0.4μg/0.1 /μl/site), corticosterone (40μg/0.1μl/site) or aldosterone (40 μg/0.1 μl/site) into the rostral ventrolateral medulla (rVLM). Furthermore, DKJ-21 also attenuated the enhancement of the pressor response to stimulation of the defense area in the midbrain, which was induced by microinjection of drugs (mentioned above) into the rVLM. These results indicate that i.v. DKJ-21 can selectively block the muscarinic receptors in the rVLM in stress-induced hypertensive rats, which suggests that abnormal enhancement of cholinergic mechanism in the rVLM may be related to hypertensive effects of corticoids in this area. 相似文献
92.
Eleven (3%) of 340 patients with hepatocellular carcinoma (HCC) presented with obstructive jaundice. The tumor extensively infiltrated the major bile ducts in eight patients. Jaundice was relieved by endoscopic endoprosthesis in four patients, nasobiliary drainage in two patients, percutaneous transhepatic stenting in one patient, and surgical intubation in one patient. The survival interval of these eight patients (mean +/- SD) was 35 +/- 20 days. Three patients had tumor fragments in the common bile ducts. In two patients, major hepatic resection was done after initial tube decomposition of the biliary system. One patient remained tumor-free on follow-up at 24 months, and the other patient had recurrent tumor detected on follow-up at 17 months after surgery. The tumor was irresectable in the third patient. Multiple surgical and endoscopic procedures kept the bile duct patent for 17 months before the patient died of the disease. Not all patients who present with obstructive jaundice due to HCC are terminally ill. With proper management, good palliation and occasional cure are possible. 相似文献
93.
应用神经组织化学技术观察了兔角膜NA能神经及AchE阳性神经在角膜损伤后的再生,证实术后1月,两种神经均有再生轴突进入植片;术后3月可见交界区和植床内神经密度明显增加;同时,对术后两种神经再生的功能意义进行了讨论。 相似文献
94.
95.
96.
P J O'Brien E Ling H M Williams S Brotherton T Salerno J H Lumsden C D Ianuzzo 《The Canadian journal of cardiology》1988,4(5):243-250
This study was undertaken to test the hypothesis that a compensatory response of the heart to a chronic and continuous, metabolic and heart rate overload was an increase in the calcium sequestering activity of the myocardial sarcoplasmic reticulum. Calcium sequestering activity was estimated by determination of the calcium-dependent ATPase (Ca2+-ATPase) activity of isolated microsomes. Chronic rate overload was modelled by comparing: dysthyroid and control rats; control swine and swine with implanted cardiac pacemakers set at 180 beats/min; and different species of mammals with widely different heart rates. The myocardial sarcoplasmic reticulum Ca2+-ATPase pump activity was significantly increased by 39% for hyperthyroid rats compared to control rats and by 87% for control rats compared to thyroidectomized rats; by 63% for paced swine compared to control swine; and by 43% for rats compared to guinea pigs, by 140% for guinea pigs compared to dogs and by 120% for dogs compared to cows. These data indicate that calcium sequestering activity of myocardial sarcoplasmic reticulum increases in equivalent proportion to the chronotropic demand and that heart rate is a hemodynamic correlate of the sarcoplasmic reticulum Ca2+-ATPase activity. 相似文献
97.
98.
99.
From July 1989, to June 1996, 160 patients with congenital bile duct dilatation (CBD) were treated at our institution. The
incidence of CBD at our institution has increased annually. In approximately 90% of patients with CBD there was associated
anomalous arrangement of the pancreaticobiliary ductal system, and we concluded that this was one of the main causes of CBD.
Pediatric endoscopic retrograde cholangiopancreatography was first introduced to China in 1989, and has been successfully
performed in 90.2% of 92 patients at our institution. We found that age at diagnosis was closely related to the subtype, complications,
and mortality of CBD. The subtype also correlated with the presenting symptoms. One hundred and forty-seven of the 160 patients
underwent surgery. Of these 147 patients, 136 (92.5%) were cured with normal liver function and 9 (6.1%) improved with liver
impairment. Two patients died, one of postoperative pneumonia and one of liver failure. We conclude that early radical surgery
and careful postoperative follow-up are essential in the prevention of CBD complications such as cholangitis, pancreatitis,
biliary stones, and development of carcinoma.
This article is based on a special lecture delivered before the 19th meeting of the Japanese Society of Pancreatico-biliary
Maljunction, on September 14, 1996, in Tokyo 相似文献
100.
益气平喘丸的药理研究 总被引:7,自引:0,他引:7
本实验结果表明,益气平喘丸具有明显的平喘止咳祛痰作用,并能显著增加免疫低下小鼠的免疫器官重量及碳粒廓清速率,使正常大鼠血清皮质醇浓度显著升高及肾上腺内维C 含量明显降低。 相似文献