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   7271篇
  免费   348篇
  国内免费   28篇
耳鼻咽喉   149篇
儿科学   62篇
妇产科学   82篇
基础医学   828篇
口腔科学   154篇
临床医学   490篇
内科学   1926篇
皮肤病学   181篇
神经病学   396篇
特种医学   457篇
外科学   1152篇
综合类   39篇
预防医学   282篇
眼科学   103篇
药学   628篇
中国医学   40篇
肿瘤学   678篇
  2023年   24篇
  2022年   64篇
  2021年   111篇
  2020年   60篇
  2019年   97篇
  2018年   116篇
  2017年   100篇
  2016年   126篇
  2015年   130篇
  2014年   175篇
  2013年   208篇
  2012年   345篇
  2011年   361篇
  2010年   186篇
  2009年   211篇
  2008年   360篇
  2007年   349篇
  2006年   372篇
  2005年   377篇
  2004年   344篇
  2003年   347篇
  2002年   306篇
  2001年   264篇
  2000年   280篇
  1999年   275篇
  1998年   96篇
  1997年   53篇
  1996年   58篇
  1995年   48篇
  1994年   44篇
  1993年   34篇
  1992年   180篇
  1991年   148篇
  1990年   139篇
  1989年   141篇
  1988年   124篇
  1987年   125篇
  1986年   124篇
  1985年   113篇
  1984年   80篇
  1983年   55篇
  1981年   28篇
  1979年   51篇
  1977年   42篇
  1975年   24篇
  1974年   26篇
  1971年   37篇
  1969年   29篇
  1968年   29篇
  1967年   24篇
排序方式: 共有7647条查询结果,搜索用时 687 毫秒
941.
The authors present a case of sphenoid ridge meningioma presenting as subarachnoid hemorrhage. A 56-year-old man came to our hospital with a complaint of severe headache developed during evacuation of the bowels. Computed tomogram on admission revealed a mass lesion of high density, which was homogeneously enhanced with contrast media, in the medial part of the left sphenoid ridge, but no evidence of the intracranial hemorrhage. Nevertheless, the cerebrospinal fluid obtained by lumbar puncture was bloody, indicating the occurrence of subarachnoid hemorrhage. Cerebral angiograms showed no abnormality except for the downward displacement of the suprachnoidal segment of the left internal carotid artery. During the operation, the adhesion between the tumor and the cortical vein was observed and the subarachnoid hemorrhage was recognized exclusively around the vein. These findings indicates that the present hemorrhage may be derived from the vein. In the previous reports of meningioma associated with intracranial hemorrhage, the origin of hemorrhage and the pathophysiological mechanism for hemorrhage have been speculated from both operative and histological findings. In consideration of these speculations, we discussed the possible mechanism for the breakdown of the cortical vein in the present case.  相似文献   
942.
Several cell adhesion molecules are expressed in the developing inner ear. The present study focused on gicerin, a novel member of the immunoglobulin superfamily, in an attempt to improve our understanding of the development and regeneration of chick inner ear. Gicerin is known to homophilically interact with itself and to bind to neurite outgrowth factor (NOF). The data collected herein show that gicerin is highly expressed in auditory epithelium and acoustic ganglion during early embryogenesis. The immunoreactivity of gicerin in the auditory epithelium decreases more rapidly than that in the acoustic ganglion as the mature hair cells become distinguishable. At the post-hatch stage, the expression of gicerin is not observed. In contrast, NOF was expressed on the basement membranes around the auditory epithelium, and in the acoustic ganglion during development and after birth, but not in the auditory epithelium. Following noise damage, gicerin is transiently re-expressed on the damage receptor epithelium when active cell proliferation is observed in the epithelium. This positive reaction immediately disappears as immature short hair cells appear. These results suggest that gicerin may be associated with cell proliferation in the auditory epithelium, and play a role in neurite extension of the acoustic ganglion cells in conjunction with NOF.  相似文献   
943.
Previously, we detected a subset of gamma delta T cells in the newborn mouse thymus that responded to the mycobacterial heat shock protein Hsp60, as well as with what seemed to be a self-antigen. All of these cells expressed V gamma 1, most often in association with V delta 6+. It was not clear, however, whether similar, mature gamma delta cells with Hsp60 reactivity are common outside of the thymus, or rather, whether they are largely eliminated during development. From the data presented here, we estimate that gamma delta cells responding to Hsp60 comprise 10-20% of normal splenic and lymph node gamma delta T cells. Such cells, derived from adult spleen, always express a V gamma 1-J gamma 4-C gamma 4 gamma chain, although not all cells with this gamma chain show Hsp60 reactivity. Many of these V gamma 1+ cells also express V delta 6-J delta 1-C delta, though fewer than in V gamma 1+ cells from the newborn thymus. Extensive diversity is evident in both the gamma and delta chain junctional amino acids of the receptors of these cells, indicating that they may largely develop in the thymus of older animals or undergo peripheral expansion. Finally, we found that all such cells responding to both a putative self-antigen and to mycobacterial Hsp60 respond to a 17-amino acid synthetic peptide representing amino acids 180-196 of the Mycobacterium leprae Hsp60 sequence. This report demonstrates that a large subset of Hsp60-reactive peripheral lymphoid gamma delta T cells preexists in normal adult mice, all members of which respond to a single segment of this common heat shock protein.  相似文献   
944.
A combined tongue flap and V-Y advanced flap were used for reconstruction of the lower lip after radical excision of squamous cell carcinoma. This V-Y advancement flap is useful because the procedure does not require any difficult technique, and preservation of the orbicularis oris muscle and the branch of the mental artery and nerve are possible. The vermilion is reconstructed with a tongue flap, with almost no disturbance in the patients' speaking or eating and satisfactory cosmetic results. We describe this procedure in two cases.  相似文献   
945.
Right ventricular myxoma in elderly is vey rare and this is the 36th case report of right ventricular myxoma in Japan. A healthy 71-year-old female with no symptoms or constitutional signs except heart murmur was hospitalized. Findings of transthoracic echocardiogram, CT scan, MRI and angiocardiogram demonstrated a mobile tumor in the right ventricular outflow tract. Transesophageal echocardiogram clearly revealed that the stalk was arising from the right ventricular free wall. Under cardiac arrest, right atriotomy was made and a gelatinous tumor (4.5 × 2 × 2 cm in size, 7.3 g in weight) was excised with 5 mm of surrounding endocardium and a few millimeters of underlying myocardium through the tricuspid valve. Histopathologically, the tumor was diagnosed as a myxoma. Her postoperative course was uneventful.  相似文献   
946.
We report a successful treatment of massive bleeding due to spontaneous splenic rupture after mitral valve replacement. A 61-year-old man was admitted to our hospital for intermittent high fever. An echocardiogram demonstrated a large vegetation on the posterior cusp of the mitral valve and mitral regurgitation of moderate degree. Staphylococcus epidermidis was cultured from his arterial blood. He underwent a mitral valve replacement after 3 weeks of antimicrobiological therapy with penicillin G crystalline and minocycline hydrochloeide. The patient fell into hemorrhagic shock on postoperative day 11 after complaining dull pain on his left upper abdomen for 3 days. A computed tomography demonstrated a splenic rupture and massive hematoma in the retroperitoneum. A splenic arterial embolization was done before splenectomy. The blood and clot of 2800 g were sucked from peritoneal and retroperitoneal cavities. There were no mycotic aneurysms nor abscess but the torn capsule on the swelled and partially necrotic spleen. The patient discharged uneventfully on postoperative day 43. Infective endocarditis frequently causes splenic infarction but rarely splenic rupture. Anticoagulation therapy after mitral valve replacement might have emphasized the bleeding in the patinet.  相似文献   
947.
HMRZ-86 was designed as a new chromogenic cephalosporin to detect extended-spectrum β-lactamases (ESBLs) and similar evolved β-lactamases, such as metallo-β-lactamases, derepressed AmpC, and extended oxacillinase. We report here our investigation of the kinetic parameters of several types of β-lactamases to show the enzymatic characteristics of HMRZ-86. The Michaelis constant (K m values of HMRZ-86 for ESBLs were twice to three and half times as high as those of nitrocefin, and the maximum velocity (Vmax) was one-fifth that of nitrocefin. The K m and Vmax of HMRZ-86 for AmpC were both smaller than those of nitrocefin. The kinetic parameters of HMRZ-86 for metallo β-lactamase (MBL) were very variable, depending on the type of buffer solution used and the concentration of zinc ions. For MBL, the K m values of HMRZ-86 were higher than those of nitrocefin, but the Vmax values were almost the same as those of nitrocefin. Although the chemical structure of HMRZ-86 is similar to that of nitrocefin, we think the enzymatic reactivities of the two entities for β-lactamases are very different.  相似文献   
948.
The causes of recalcitrant cutaneous ulcerations are various and complex. Self-injury is one of them, and self-injected substances have also been reported. In our case, autologous menstrual blood was used, resulting in incurable cutaneous ulcerations and inappropriate operations being performed several times by plastic surgeons. Meticulous care is indispensable for treatment of patients with Munchausen’s syndrome.  相似文献   
949.
We developed a new arthroscopic-assisted drilling method through the radius in a distal-to-proximal direction for osteochondritis dissecans (OCD) of the elbow. Only 1 drill hole is created in the radius by use of a single 1.8-mm K-wire inserted from the shaft of the radius approximately 3 cm distal to the humeroradial joint into the joint, which allows drilling of the entire OCD lesion. The forearm is supinated so that the tip of the K-wire is at the lateral side of the lesion in the humeral capitellum, and drilling is performed at 30° elbow flexion. The flexion angle is changed from 30° to 60° to 90° to 120° while maintaining supination, to drill in 4 sites (1 site for each angle of flexion) of the lateral side of the OCD lesion. Next, we move the forearm from supination to pronation so that the tip of the K-wire is placed in the medial side of the lesion in the humeral capitellum, and as with the lateral side, drilling is performed in 4 sites. With this technique, the entire OCD lesion can be vertically drilled under arthroscopic guidance. This method is minimally invasive, and an early return to sports could be possible.  相似文献   
950.
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