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   5717篇
  免费   294篇
  国内免费   40篇
耳鼻咽喉   39篇
儿科学   93篇
妇产科学   37篇
基础医学   872篇
口腔科学   103篇
临床医学   343篇
内科学   1504篇
皮肤病学   49篇
神经病学   477篇
特种医学   208篇
外国民族医学   1篇
外科学   860篇
综合类   17篇
预防医学   88篇
眼科学   195篇
药学   360篇
中国医学   7篇
肿瘤学   798篇
  2023年   42篇
  2022年   81篇
  2021年   147篇
  2020年   88篇
  2019年   94篇
  2018年   125篇
  2017年   109篇
  2016年   123篇
  2015年   150篇
  2014年   175篇
  2013年   222篇
  2012年   363篇
  2011年   327篇
  2010年   206篇
  2009年   182篇
  2008年   288篇
  2007年   302篇
  2006年   301篇
  2005年   308篇
  2004年   320篇
  2003年   312篇
  2002年   325篇
  2001年   140篇
  2000年   127篇
  1999年   129篇
  1998年   82篇
  1997年   65篇
  1996年   60篇
  1995年   56篇
  1994年   56篇
  1993年   33篇
  1992年   81篇
  1991年   61篇
  1990年   49篇
  1989年   55篇
  1988年   54篇
  1987年   49篇
  1986年   40篇
  1985年   31篇
  1984年   22篇
  1983年   28篇
  1982年   16篇
  1981年   14篇
  1979年   18篇
  1978年   24篇
  1974年   15篇
  1971年   14篇
  1969年   16篇
  1968年   15篇
  1966年   13篇
排序方式: 共有6051条查询结果,搜索用时 15 毫秒
11.
The author analyzed codon 347 of the rhodopsin gene using PCR (polymerase chain reaction) amplification and restriction enzymes in 19 unrelated Japanese families including 28 patients with autosomal dominant retinitis pigmentosa (ADRP). An allele of codon 347 mutation was found in a family (father and daughter). Sequence analysis shows that the mutation is from CCG to CTG. This mutation appears to be the cause of one form of ADRP, since it was also found in Japanese cases of ADRP which have a different racial background from families reported by Dryja et al.  相似文献   
12.
We have previously reported that KML1-7 cells cloned from a lupus-prone MRL/l mice produced a soluble factor that preferentially expanded anti-DNA antibody production across the H-2 barrier. We purified this factor, a 55-kDa protein that we termed nucleobindin (Nuc). Nuc showed not only induction of anti-ssDNA IgG antibody in cultures of B cells from MRL/l mice (greater than 16 weeks old), but also growth activity. Furthermore, antibodies against existing cytokines have so far not been shown to block Nuc activity on these B cells. In view of the fact that Nuc did not boost anti-ssDNA IgG antibody production in cultures of spleen cells of comparable age from MRL/n mice, which develop a mild form of lupus after the age of one year, Nuc may act on pre-activated B cells to help IgG anti-DNA antibody production. Taken together, Nuc is a new kind of growth and differentiation factor associated with lupus syndrome.  相似文献   
13.
14.
The dose of (-)deprenyl (2.0 mg/kg/day, sc, for 3 weeks) which significantly increased activities of superoxide dismutase (SOD) and catalase in the striatum of young male rats significantly reduced these activities in young female rats but did not change the SOD activity in old female rats. In order to clarify these effects, different doses of the drug were continuously infused sc for 3 weeks in three groups of rats (young males and young and old females). When a 10-fold smaller dose (0.2 mg/kg/day) was applied in young female rats, activities of both SOD and catalase were significantly increased, while a higher dose of 0.5 mg/kg/day was ineffective and a lower dose of 0.1 mg/kg/day was substantially less effective. In old female rats, doses of both 0.5 and 1.0 mg/kg/day were equally effective in elevating activities of SOD and catalase, while a lower dose of 0.1 mg/kg/day was less effective. The activity of glutathione peroxidase (GSH Px) remained unchanged in all groups, except for a significant decrease in the activity of non-selenium-dependent GSH Px in both young and old female rats given the highest drug dose (2.0 mg/kg/day). Furthermore, activities of all three enzymes remained unchanged in the hippocampus in most groups. The results indicate that (-)deprenyl significantly increases activities of both SOD and catalase in the striatum, but not in hippocampus of rats, and that the optimal dose is very different depending on the sex and age of the animal.  相似文献   
15.
Infectious intracavernous carotid artery aneurysms usually present with ophthalmoplegia and/or signs of cavernous sinus thrombosis. We report an unusual case in which a patient with AIDS presented with intractable epistaxis secondary to rupture of a giant infectious intra-cavernous carotid artery aneurysm. Culture of the aneurysm grew mycobacterium avium intracellulare (MAI). The patient was treated successfully by excision of the aneurysm and reconstruction of the internal carotid artery with a saphenous vein interposition graft.  相似文献   
16.
Abstract: The Self-Rating Body Image (SRBI) test was used to determine whether the patients with eating disorders such as anorexia nervosa or bulimia showed their body image disturbance or not. The SRBI was completed by 120 subjects who consisted of 30 low weight (LW) controls, 30 normal weight (NW) controls, 30 high weight (HW) controls, 18 anorexic patients (AN) and 12 bulimic patients (BN). The AN group had a significantly greater dissatisfaction with the scales of the body shape, visceral organ and face image of the SRBI than the weight-matched LW group. The BN group had a significantly greater dissatisfaction with the visceral organ image than the weight-matched NW group. However, no significant difference in the body shape and face images between the BN and NW groups was found. Our results suggest that the anorexic patients may disturb more parts of the body image than the bulimic patients though both the anorexic and bulimic patients showed the disturbance of body image.  相似文献   
17.
Abstract: A 63-year-old man was hospitalized because of jaundice and anorexia. An upper gastrointestinal series and hypotonic duodenography revealed circumferential sclerosis and stenosis of the duodenal wall. Endoscopic examination disclosed an ulcer, the upper margin of which was located at the papilla of Vater. The papilla was situated in the base of the ulcer. Endoscopic retrograde cholangiopancreatography disclosed mild dilatation of the common bile, intrahepatic bile and pancreatic ducts, but with neither severe stenosis nor occlusion. Nevertheless, there was some degree of circumferential compression and mild stenosis of the terminal portions of the bile and pancreatic ducts, as potential causes of obstructive jaundice in this patient. Computed tomographic examination of the abdomen revealed a tumorous lesion at the duodenal bulb. Because malignancy in the duodenum could not be ruled out, a pancreatoduodenectomy was performed. Histopathological examination showed a postbulbar duodenal ulcer, associated with inflammation of the papillary orifice and fibrosis of the region near the papilla. There was no evidence of a tumorous lesion. In this case, a postbulbar duodenal ulcer may have caused obstructive jaundice.  相似文献   
18.
Mixed dysembryoplastic neuroepithelial tumor and ganglioglioma   总被引:3,自引:0,他引:3  
We report a case of a 15-year-old girl with new onset seizures, who had a mixed dysembryoplastic neuroepithelial tumor (DNT) and ganglioglioma of the right parieto-occipital lobe. The tumor appeared well demarcated and exhibited a low T1 and a high T2 signal on magnetic resonance imaging. Architecturally it was in large part intracortical and multinodular, but also featured a leptomeningeal component. The former corresponded to DNT, a proliferation of oligodendroglia-like cells (OLCs) arranged in nodules, as well as comprising a diffuse internodular element featuring “floating neurons” in a mucoid matrix. The leptomeningeal portion of the lesion was a ganglioglioma consisting of large neurons and astrocytes in association with marked desmoplasia. Spacially, the two components abutted one another but appeared distinct. Immunohistochemistry showed the neurons of the ganglioglioma to be positive for class III β-tubulin, synaptophysin, and chromogranin A, whereas the astrocytic cells stained only for glial fibrillary acidic protein. Most OLCs in the DNT were positive for S-100 protein. This apparently mixed lesion suggests that a close histogenetic relationship exists between DNT and ganglioglioma. We postulate that the pluripotential progenitor cells residing in the subpial granular layer may have given rise to the cortical DNT and to the leptomeningeal ganglioglioma. To our knowledge, this is the first detailed histological, immunochemical and ultrastructural report of a mixed DNT and ganglioglioma. Received: 11 August 1997 / Revised, accepted: 24 November 1997  相似文献   
19.
20.
A case of small fibrolamellar hepatocellular carcinoma (HCC) coexistent with a HCC of common type is herein reported. A 56-year-old man was diagnosed as having multi-nodular type HCC with liver cirrhosis. The serum alpha-fetoprotein (AFP) level was slightly increased. The patient underwent a partial caudate lobectomy and lateral segmentectomy. Histologically, both resected tumors were small HCCs measuring less than 2 cm in diameter. One was a fibrolamellar type located in the caudate lobe, while the other was the common type in the lateral segment of the liver. Positive immunohistochemical staining for AFP was observed in the tumor cells of the HCC of common type but was not observed in the fibrolamellar HCC. We also reviewed previously reported cases of fibrolamellar HCC in Japan, and discussed the clinicopathologic implications of this disease.  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