全文获取类型
收费全文 | 40696篇 |
免费 | 1854篇 |
国内免费 | 181篇 |
专业分类
耳鼻咽喉 | 688篇 |
儿科学 | 668篇 |
妇产科学 | 742篇 |
基础医学 | 5320篇 |
口腔科学 | 1224篇 |
临床医学 | 2879篇 |
内科学 | 9529篇 |
皮肤病学 | 546篇 |
神经病学 | 3353篇 |
特种医学 | 1355篇 |
外科学 | 7000篇 |
综合类 | 182篇 |
一般理论 | 2篇 |
预防医学 | 1487篇 |
眼科学 | 627篇 |
药学 | 3426篇 |
中国医学 | 78篇 |
肿瘤学 | 3625篇 |
出版年
2022年 | 401篇 |
2021年 | 691篇 |
2020年 | 343篇 |
2019年 | 484篇 |
2018年 | 584篇 |
2017年 | 450篇 |
2016年 | 550篇 |
2015年 | 600篇 |
2014年 | 778篇 |
2013年 | 1028篇 |
2012年 | 1661篇 |
2011年 | 1775篇 |
2010年 | 1028篇 |
2009年 | 872篇 |
2008年 | 1706篇 |
2007年 | 1848篇 |
2006年 | 1814篇 |
2005年 | 1772篇 |
2004年 | 1744篇 |
2003年 | 1782篇 |
2002年 | 1740篇 |
2001年 | 1619篇 |
2000年 | 1773篇 |
1999年 | 1498篇 |
1998年 | 476篇 |
1997年 | 388篇 |
1996年 | 357篇 |
1995年 | 298篇 |
1994年 | 278篇 |
1993年 | 249篇 |
1992年 | 1105篇 |
1991年 | 919篇 |
1990年 | 900篇 |
1989年 | 943篇 |
1988年 | 831篇 |
1987年 | 831篇 |
1986年 | 784篇 |
1985年 | 769篇 |
1984年 | 528篇 |
1983年 | 423篇 |
1982年 | 220篇 |
1979年 | 482篇 |
1978年 | 274篇 |
1977年 | 251篇 |
1975年 | 207篇 |
1974年 | 223篇 |
1972年 | 206篇 |
1971年 | 231篇 |
1969年 | 230篇 |
1968年 | 216篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Two cases of subcortical hemorrhage with asymptomatic occlusion of the main trunk of cerebral artery
We report two cases of asymptomatic occlusion of the main trunk of the cerebral artery associated with subcortical hemorrhage in the area fed by collateral circulation. The first patient, a 51-year-old female who had suffered from untreated hypertension for 20 years, was hospitalized in a state of coma. Computed tomography (CT) revealed a subcortical hemorrhage in the right parietal lobe as well as subdural and subarachnoid hemorrhages. Cerebral angiography disclosed occlusion of the right internal carotid artery at its origin. The region normally supplied by the right anterior (ACA) and middle cerebral (MCA) arteries was supplied instead by the posterior cerebral artery via leptomeningeal anastomosis. The hematoma was removed and the patient was discharged 1 month later. The second patient was a 54-year-old female who had suffered from uncontrollable hypertension for 27 years and was hospitalized after sudden development of stupor, right hemiparesis and motor aphasia. CT demonstrated a subcortical hemorrhage in the left parietal lobe. Cerebral angiography disclosed occlusion of the left MCA at its origin. The area normally fed by the left MCA was supplied instead by the ACA by way of leptomeningeal anastomosis. One month after operation the patient was transferred to another hospital for rehabilitation of right hemiparesis. Both of these middle-aged women had long-standing hypertension. The hemorrhages were thought to result from rupture of the leptomeningeal anastomosis, which had developed as collateral vessels. It is probable that the relatively weak leptomeningeal anastomosis could no longer withstand the increased blood flow brought on by the hypertension. 相似文献
22.
Changes in the levels of urea cycle enzymes and polyamine metabolism in the liver of rats treated with alpha-naphthylisothiocyanate (ANIT), an inducer of experimental cholestasis, were studied. Activities of arginase increased approximately two-fold compared to the control values during the period of 24-72 hours after oral administration of ANIT (100 mg/kg), while activities of ornithine carbamyltransferase and ornithine aminotransferase decreased. The activity of ornithine decarboxylase was elevated by approximately 20- and 10-fold at 12 and 60 hours, respectively, after ANIT administration. Putrescine concentration doubled 24-48 hours after the ANIT administration, but spermidine level rose more slowly and reached the level of 1.5-fold of the control level in 36-72 hours. Spermine concentration decreased initially but increased in 96 hours. These results suggest that the increased activity of urea cycle accounts for the increase in the ornithine content and that the putrescine and spermidine acts as the initiator of recovery of the liver damaged by ANIT treatment. 相似文献
23.
24.
J Kusakari K Hozawa T Hanazima S Suzuki T Takasaka N Sasano 《Archives of oto-rhino-laryngology》1987,244(4):246-248
We report a case of cylindrical cell papilloma of the paranasal sinuses. This tumor originated in the medial wall of the left maxillary sinus of a 69-year-old man and extended to the surrounding tissues. Pathological study of tissue sections from the tumor showed typical findings of cylindrical cell papilloma with no evidence of associated malignancy. Histochemical and electron microscopic examinations revealed a large number of mitochondria in the cytoplasm of the tumor cells. The tumor was removed through a Denker's approach. The patient did well following surgery and there has been no sign of recurrence in a 2-year follow-up study. 相似文献
25.
Toshihiko Imakiire Yuichi Kikuchi Muneharu Yamada Taketoshi Kushiyama Keishi Higashi Naomi Hyodo Kojiro Yamamoto Takashi Oda Shigenobu Suzuki Soichiro Miura 《Hypertension research》2007,30(7):635-642
The mechanisms of hypertensive nephrosclerosis are not fully understood. In experimental models of the disease, inflammatory reactions such as macrophage infiltration play an important role. In human hypertensive nephrosclerosis, however, there have been few studies examining the role of inflammation histologically. We investigated whether the number of infiltrating macrophages was increased in human hypertensive nephrosclerosis, and evaluated the effects of a blockade of the renin-angiotensin system on clinical and histological findings. We examined macrophage infiltration using immunohistochemistry in renal biopsy specimens obtained from 16 patients with hypertensive nephrosclerosis, 5 patients with IgA nephropathy, 5 patients with membranous nephropathy, and 5 patients with minimal change nephrotic syndrome. The number of infiltrating macrophages in glomeruli was significantly larger in the patients with hypertensive nephrosclerosis than in those with minimal change nephrotic syndrome. The patients with hypertensive nephrosclerosis were divided into groups based on their use of antihypertensive agents at the time of renal biopsy. We investigated the effects of antihypertensive agents on clinical findings, macrophage infiltration, and monocyte chemoattractant protein-1 expression. There was no difference in clinical findings between the hypertensive groups. The numbers of infiltrating macrophages and monocyte chemoattractant protein-1-positive cells in glomeruli were significantly smaller in patients treated with an angiotensin-converting enzyme inhibitor or angiotensin II type 1 receptor blocker, whereas calcium channel blockers had no influence on histological findings. In conclusion, inflammation is involved in the progression of human hypertensive nephrosclerosis and the inflammatory process is inhibited by blocking the renin-angiotensin system. 相似文献
26.
Mikio Mikami Chisei Tei Kyoko Takehara Shinichi Komiyama Atsushi Suzuki Takanori Hirose 《International journal of gynecological pathology》2003,22(2):205-208
A 38-year-old female presented with a lower abdominal mass. During the operation the mass was found to be retroperitoneal and was excised. Gross examination revealed a mucin-containing cystic lesion with a mural nodule. On microscopic examination, the cystic areas were lined by an invasive mucinous adenocarcinoma and the nodule was composed of an anaplastic sarcomatoid tumor that was immunoreactive for cytokeratin. This present case is the 21st example of a retroperitoneal primary mucinous cystadenocarcinoma and the fourth with a mural nodule. Three of four cases with a mural nodule, including our case, had a rapidly fatal outcome. 相似文献
27.
28.
29.
Positron emission tomography was performed on six patients with Rett syndrome to investigate cerebral blood flow and oxygen metabolism, and the results were compared with the concurrent clinical status of the patients. The cerebral metabolic rate of oxygen (CMRO2) was low in five patients, and oxygen extraction fraction was low in four patients; both had a tendency to decline with advancing age. Although the cause is unknown, it is suggested that impaired oxidative metabolism exists in Rett syndrome. An analysis of the distribution among brain regions showed that the ratios of values for the frontal cortex to those for the temporal cortex for both cerebral blood flow and CMRO2 were lower than those for the controls, which may indicate the loss of hyperfrontality in Rett syndrome. 相似文献
30.