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   1249篇
  免费   78篇
  国内免费   16篇
耳鼻咽喉   2篇
儿科学   28篇
妇产科学   10篇
基础医学   187篇
口腔科学   17篇
临床医学   88篇
内科学   287篇
皮肤病学   4篇
神经病学   104篇
特种医学   25篇
外科学   222篇
综合类   5篇
预防医学   34篇
眼科学   88篇
药学   145篇
中国医学   3篇
肿瘤学   94篇
  2023年   13篇
  2022年   30篇
  2021年   63篇
  2020年   31篇
  2019年   35篇
  2018年   42篇
  2017年   20篇
  2016年   31篇
  2015年   26篇
  2014年   35篇
  2013年   29篇
  2012年   56篇
  2011年   71篇
  2010年   34篇
  2009年   31篇
  2008年   64篇
  2007年   68篇
  2006年   64篇
  2005年   61篇
  2004年   65篇
  2003年   76篇
  2002年   74篇
  2001年   22篇
  2000年   31篇
  1999年   27篇
  1998年   27篇
  1997年   19篇
  1996年   19篇
  1995年   9篇
  1994年   16篇
  1993年   8篇
  1992年   13篇
  1991年   14篇
  1990年   10篇
  1989年   13篇
  1988年   6篇
  1987年   9篇
  1986年   11篇
  1985年   7篇
  1984年   7篇
  1983年   6篇
  1982年   6篇
  1981年   4篇
  1980年   6篇
  1979年   6篇
  1978年   3篇
  1977年   5篇
  1973年   3篇
  1972年   3篇
  1971年   2篇
排序方式: 共有1343条查询结果,搜索用时 343 毫秒
11.
In order to achieve a complete prognosis for early gastric carcinoma, a greater effort must be made to improve its present treatment, considering the small percentage of patients who still die from recurrence despite the prompt initiation of surgery. Over the past 9 years, 26 patients with early gastric carcinoma have undergone surgical resection after receiving preoperative chemotherapy in the form of oral 5-FU or 5-DFUR in our institute. The effectiveness of preoperative chemotherapy was evaluated by histopathological examination of the resected stomachs. Of a total of 24 patients with depressed type gastric cancer, 19 were histologically found to have a cancerless area within the cancerous lesion, 8 of whom were classified as being over Grade 1b. Gross changes were observed in 13 of these 24 patients. The frequency of multiple early gastric cancer occurring in patients who had not received chemotherapy was 11.6%, whereas in those who had received chemotherapy it was 3.8%. The findings of this study thus indicate that preoperative chemotherapy is useful for reducing minute cancer foci and microscopic metastatic lesions.  相似文献   
12.
13.
PURPOSE: To report a case of iris-nevus syndrome accompanied by disruption of the blood-aqueous barrier in the iris which was confirmed angiographically and histopathologically. CASE: The patient was a 39-year-old woman. She noticed blurred vision in the left eye which was diagnosed as left glaucoma. Specular microscopy revealed low endothelial cell density in the left cornea. The left iris showed atrophy with clusters of nodular iris nevus and distorted pupil. The left iridocorneal angle was closed with peripheral anterior synechia. FINDINGS: Indocyanine green iris angiography revealed more vessels on the surface of the left iris than on the right. In fluorescein iris angiography, the dye leaked from the iris vessels in areas where the iris showed advanced atrophy. The trabecular tissue obtained by trabeculectomy from the patient's left eye showed histopathologically a lining of corneal endothelial cells on the surface of the iris. The density of the vessels was high in the iris stroma. Some cells covering the vessel wall showed degeneration with opening of the zonula occludens. Schlemm's canal had narrowed lumina, and the intertrabecular spaces were closed. CONCLUSION: Disruption of the blood-aqueous barrier may occur in iris-nevus syndrome.  相似文献   
14.
The in vitro activity of FK041, a new orally active cephem antibiotic, against a wide variety of clinical isolates of bacteria was investigated and compared with those of cefdinir (CFDN) and cefditoren (CDTR). FK041 exhibited broad spectrum activity against reference strains of Gram-positive and Gram-negative aerobes and anaerobes. FK041 was active against clinical isolates of Gram-positive organisms except Enterococcus faecalis with MIC90s less than 1.56 microg/ml. FK041 was more active than CFDN and CDTR against Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus agalactiae and was comparable to CFDN and CDTR against Streptococcus pyogenes and Streptococcus pneumoniae. FK041 had no activity against methicillin-resistant staphylococci, like CFDN and CDTR. FK041 showed moderate activity against penicillin-resistant S. pneumoniae with an MIC range of 0.05 approximately 3.13 microg/ml, and was superior to CFDN but inferior to CDTR. Against clinical isolates of many Gram-negative organisms such as Neisseria gonorrhoeae, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis, FK041 had good activity comparable or superior to those of CFDN and CDTR. However, it was inferior to CDTR in activity against Moraxella catarrhalis, Haemophilus influenzae, Morganella morganii, and Serratia marcescens, and was inactive against Pseudomonas aeruginosa. With FK041 a small difference between MIC and MBC against S. aureus, E. coli, K. pneumoniae, and H. influenzae was found, indicating that its action is bactericidal against these species. FK041 was stable to group 2beta-lactamase hydrolysis but was unstable to group 1beta-lactamase hydrolysis. The stability of FK041 to these enzymes was similar to those of CFDN and CDTR. FK041 showed high affinity for the main penicillin-binding proteins (PBPs) of S. aureus (PBP 3, 2, and 1) and E. coli (PBP 3, 4, lbs, 2, and 1a).  相似文献   
15.
16.
Pyoderma gangrenosum (PG) is an extra-intestinal skin lesion in inflammatory bowel disease (IBD) as is erythema nodosum. Vedolizumab (VED) is a monoclonal antibody that targets α4β7 integrin and has an intestinal selective mechanism. Despite good therapeutic effects on colitis, the effect on extra-intestinal manifestations (EIMs) remains unclear. Here we report a case of ulcerative colitis complicated by PG during treatment with VED, which was successfully treated with prednisolone in combination with adsorptive granulocyte and monocyte apheresis (GMA). The patient was a 50-year-old woman with a past medical history of extensive ulcerative colitis managed by golimumab (GLM). She developed flare symptoms due to loss of response to GLM, and treatment was switched to VED. Her gastrointestinal symptoms were improved with VED treatment with less frequent bowel movements. However, infiltrative erythema with pain appeared on the right lower leg and right knee, and expanded and gradually ulcerated. Her skin lesions were treated with corticosteroid, but showed poor improvement. Therefore, granulocyte and monocyte apheresis (GMA) treatment was administered in combination with prednisolone. After 3 months, the ulcer gradually improved, and at the time of this writing, the eruptions were nearly replaced by epithelial tissue. This case study showed that patients with UC and EIMS may respond well to combination therapy of VED and GMA. GMA has a very favorable safety profile. On the other hand, the causal connection between VED and PG is still unclear. We believe that a combination therapy involving VED and GMA in IBD patients with EIMs warrants consideration.  相似文献   
17.
We report a near-fatal case of cerebral edema associated with adenovirus type 2 infection in a previously healthy 19-month-old boy. After 3 to 4 d of high fever and a series of seizures, he developed persistent loss of consciousness and irreversible respiratory arrest. Adenovirus type 2 infection was diagnosed by virus isolation from his stool and serology.  相似文献   
18.
19.
We report the case of a 38-year-old Asian man with a pericardial hemangioma on the left main coronary artery. The patient presented initially at our hospital after cardiopulmonary resuscitation following an episode of ventricular fibrillation (VF). Because of spontaneous coved-type ST segment elevation on the higher intercostal space V1 to V2 in a 12-lead electrocardiogram, documented VF in the absence of structural heart disease, and a family history of sudden death, he was diagnosed with Brugada syndrome. Transesophageal echocardiography showed a smooth-surfaced mass with well-demarcated borders, directly above the left main coronary artery. Computed tomography confirmed the presence of the mass, which showed no enhancement at early phase, but did demonstrate homogenous enhancement at delay phase by contrast material. There were no findings from either the nuclear medicine or the tumor marker investigations which indicated that the mass located just above the main coronary arteries was malignant. Therefore, taken together, these findings suggested that the tumor might be a pericardial hemangioma. The relationship between the location of the hemangioma just above the left main coronary artery and the occurrence of VF was not clear, i.e. whether the presence of the hemangioma caused the stimulation of the left main coronary artery and as a result, led to the spasm of the left main coronary artery and the occurrence of VF. Furthermore, as the tumor did not extend into any of the adjacent structures, such as the coronary arteries or the right ventricular outflow tract, surgical resection was not performed; instead, the patient received a dual chamber implantable cardioverter-defibrillator.  相似文献   
20.
Lithium ion batteries (LIB) are the most extensively researched and developed batteries. Currently, LIBs are used in various applications such as electric vehicles (EV), hybrid EVs (HEV), plug-in HEVs, and energy storage systems. However, their energy density is insufficient and further improvement is required. In this study, we propose the facile synthesis of a self-standing, junction-less 3D carbon sponge electrode (3DCS) for improving the energy density. A self-standing structure can improve the energy density by reducing non-active materials such as binders and current collectors, in electrodes. We use a kitchenware melamine sponge as the carbon precursor. The utilization of materials mass-produced by existing facilities is crucial for ensuring availability and low costs. Such characteristics are imperative for industrialization. These self-standing 3DCS electrodes, fabricated using available low-cost melamine sponges, demonstrate high charge-rate characteristics with a capacity retention of 81.8% at 4000 mA g−1 and cycle durability with 95.4% capacity retention after 500 cycles, without current collector, binder, and conductive additives. This high availability, low-cost material with excellent characteristics is beneficial for research institutions and companies that do not have facilities.

Conceptual diagram of junction-less 3D carbon sponge electrode.  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