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   2708篇
  免费   155篇
  国内免费   12篇
耳鼻咽喉   11篇
儿科学   70篇
妇产科学   46篇
基础医学   340篇
口腔科学   90篇
临床医学   214篇
内科学   581篇
皮肤病学   67篇
神经病学   302篇
特种医学   204篇
外科学   334篇
综合类   21篇
预防医学   138篇
眼科学   102篇
药学   177篇
中国医学   12篇
肿瘤学   166篇
  2023年   31篇
  2022年   40篇
  2021年   80篇
  2020年   41篇
  2019年   62篇
  2018年   88篇
  2017年   59篇
  2016年   70篇
  2015年   69篇
  2014年   99篇
  2013年   110篇
  2012年   175篇
  2011年   220篇
  2010年   119篇
  2009年   93篇
  2008年   167篇
  2007年   203篇
  2006年   197篇
  2005年   160篇
  2004年   148篇
  2003年   161篇
  2002年   132篇
  2001年   24篇
  2000年   23篇
  1999年   24篇
  1998年   17篇
  1997年   16篇
  1996年   9篇
  1995年   9篇
  1994年   11篇
  1993年   9篇
  1992年   24篇
  1991年   17篇
  1990年   19篇
  1989年   9篇
  1988年   14篇
  1987年   16篇
  1986年   13篇
  1985年   11篇
  1984年   13篇
  1983年   11篇
  1982年   6篇
  1980年   5篇
  1979年   5篇
  1978年   7篇
  1977年   4篇
  1976年   4篇
  1975年   6篇
  1973年   5篇
  1971年   4篇
排序方式: 共有2875条查询结果,搜索用时 703 毫秒
1.
Pancreatic metastasis of malignant melanoma is rarely diagnosed while the patient is alive. We report a case of metastatic melanoma of the pancreas in a 35-year-old woman presenting with a solid mass of the pancreas. Her past medical history included a radical hysterectomy 2 years previously for malignant melanoma of the vagina. Twelve months later, lung metastasis was also resected. EUS-guided fine needle aspiration (EUS-FNA) identified that the pancreatic tumor was histologically and immunohistochemically identical to the surgical specimen of her lung neoplasm. Imaging studies including US, CT, and MRI have limited value to distinguish the tumors from primary ductal adenocarcinoma. EUS-FNA can provide tissue diagnosis from pancreatic masses, specifically when other modalities have failed.  相似文献   
2.
3.
A 52-year-old woman who had had 6 months of chemotherapy using mitomycin C and cisplatin for cervical cancer presented with hemolytic uremic syndrome. Conventional plasmapheresis using whole-plasma fraction was ineffective. However, plasmapheresis using the cryosupernatant fraction dramatically improved symptoms of hemolytic anemia and thrombocytopenia in this case. The activity of factor VIII in the cryosupernatant fraction of plasma as a replacement fluid decreased after removal of cryoprecipitate, indicating effective removal of von Willebrand factor. The pathogenesis of her hemolytic uremic syndrome may have been associated with von Willebrand factor multimers contained in the cryoprecipitate of plasma. Similar use of the cryosupernatant fraction of plasma could not be found in other reports of cases of hemolytic uremic syndrome. Plasmapheresis using the cryosupernatant fraction of plasma may improve refractory hemolytic uremic syndrome.  相似文献   
4.
5.
6.
Intracranial MR imaging was performed in five patients with achondroplasia. All patients had narrowing of the subarachnoid space at the level of the foramen magnum that was mainly due to protrusion of the posterior aspect. Three patients had compressive deformities of the brainstem and/or upper cervical spine. Among them, two patients had deformities of the pons. Relative upward displacement of the brainstem was seen in all patients. Hydrocephalus was seen in three patients.  相似文献   
7.
Background: In Japan a new long‐term care insurance (LTCI) system, the so‐called ‘Kaigo‐Hoken’, was started in April 2000. The present study analyzes the change in the type of destination after discharge from a senile dementia therapy ward before and after the implementation of LTCI at Fukuoka Prefectural Onga Hospital, Japan. Methods: The present study examines data from 199 inpatients discharged from the Fukuoka Prefectural Onga Hospital that had been diagnosed with dementia and met the DSM IV criteria for Alzheimer's type, vascular dementia or other type of dementia. For the purposes of comparison two periods were defined, ‘the first period’ was defined as the period from 1 April 1999 to 31 March 2000, before LTCI was implemented, while ‘the second period’ was defined as the period from 1 April 2000 to 31 March 2001, after LTCI had started. Subject data was analyzed on the basis of where the subject had resided pre‐admission and their destination after discharge using the following classifications: nursing home or geriatric care facility, hospitalization, home and death. Results: While the certification rate of inpatients regarding long‐term care increased slightly in the second period, no significant change was observed based on where the subject had resided pre‐admission and their destination after discharge between the first and second periods. Conclusions: While LTCI is essential for Japan, it is necessary that people with dementia in senile dementia therapy wards are encouraged to return to their homes under the care and support of LTCI.  相似文献   
8.
To investigate the usefulness of the frontal assessment battery (FAB) as a brief assessment for diagnosis in patients with dementia, we examined cognitive function using the FAB, Mini-mental state examination (MMSE), Kana-hiroi test, and Raven's colored progressive matrices (RCPM). Subjects were 82 senile patients having amnesia as a complaint including 28 Alzheimer's disease (AD), 14 frontotemporal dementia (FTD), 17 vascular dementia (VD), 13 mild cognitive impairment (MCI), and 10 healthy persons. We discussed the difference of scores in different types of dementia. In the FAB, the scores of healthy persons and MCI were much higher compared with the scores of all types of dementia. There were high correlation between FAB and MMSE, Kana-hiroi test, and RCPM. Although some subjects showed normal score in MMSE and/or RCPM, they showed low score in FAB. Based on this, FAB is efficient for the differential diagnosis of dementia as brief screening tool.  相似文献   
9.
MRI and SPECT findings in amyotrophic lateral sclerosis   总被引:1,自引:0,他引:1  
Summary MRI was performed in 21 patients and single photon emission computed tomography (SPECT) withN-isopropyl-p-123I iodoamphetamine in 16 patients, to visualize upper motor neurone lesions in amyotrophic lateral sclerosis. T2-weighted MRI revealed high signal along the course of the pyramidal tract in the internal capsule and cerebral peduncle in 4 of 21 patients. SPECT images were normal in 4 patients, but uptake was reduced in the cerebral cortex that includes the motor area in 11.  相似文献   
10.
Polymeric peptides containing defined repetitive or cyclic structures of RGDT sequence, (RGDT)n (n = 1 to 11) and cyclo(RGDT)n (n=2 to 4), at a dose of 500 μg exhibited an inhibitory effect on experimental lung metastasis upon co-injection with tumor cells and the magnitude of the effect increased in parallel with the increase of degree of repetition of the RGDT sequence. The conjugation of (RGDT)n (n = 1, 5, 11) with poly(ethylene glycol), PEG as a polymeric carrier led to enhanced inhibition of lung metastasis in proportion to the degree of RGDT sequence repetition and in a dose-dependent manner. Multiple i.v. administrations of PEG-(RGDT)11, at 2-day and 3-day intervals before the excision of primary tumors, effectively inhibited spontaneous lung metastasis by s.c. inoculation of tumors, whereas (RGDT)11 exhibited inhibition of lung metastasis only when given at 2-day intervals. This indicates that the conjugation of PEG with (RGDT)n allowed the prolongation of administration interval, implying a sustained inhibitory effect on tumor metastasis. In support of this supposition, a decrease in the arrest of radiolabeled tumor cells in the lungs was observed when PEG-(RGDT)11 was co-injected i.v. with tumor cells, or injected i.v. one day before tumor inoculation. In contrast, (RGDT)11 significantly inhibited the tumor cell arrest in the lungs only upon co-injection with tumor cells. We also noted that (RGDT)n, cyclo(RGDT)n and PEG-(RGDT)11 inhibited tumor cell invasion into Matrigel in a concentration-dependent manner and in proportion to the degree of RGDT sequence repetition, indicating that the peptide-mediated antimetastatic effect is partly associated with the anti-invasive potential. Thus, the conjugation of anti-cell adhesive and antimetastatic RGDT peptide with PEG might provide a therapeutically promising basis for the prevention of cancer metastasis (“anti adhesion therapy”).  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