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   987篇
  免费   76篇
  国内免费   3篇
耳鼻咽喉   3篇
儿科学   42篇
妇产科学   68篇
基础医学   147篇
口腔科学   12篇
临床医学   59篇
内科学   203篇
皮肤病学   7篇
神经病学   90篇
特种医学   28篇
外国民族医学   1篇
外科学   282篇
综合类   13篇
预防医学   33篇
眼科学   14篇
药学   16篇
肿瘤学   48篇
  2023年   7篇
  2022年   14篇
  2021年   41篇
  2020年   16篇
  2019年   32篇
  2018年   35篇
  2017年   33篇
  2016年   23篇
  2015年   24篇
  2014年   37篇
  2013年   38篇
  2012年   51篇
  2011年   64篇
  2010年   35篇
  2009年   32篇
  2008年   50篇
  2007年   52篇
  2006年   50篇
  2005年   53篇
  2004年   35篇
  2003年   30篇
  2002年   48篇
  2001年   22篇
  2000年   30篇
  1999年   28篇
  1998年   9篇
  1997年   7篇
  1996年   6篇
  1995年   5篇
  1994年   6篇
  1993年   6篇
  1992年   9篇
  1991年   7篇
  1990年   8篇
  1989年   9篇
  1988年   8篇
  1987年   7篇
  1986年   6篇
  1981年   3篇
  1980年   3篇
  1979年   4篇
  1975年   4篇
  1973年   7篇
  1971年   5篇
  1961年   3篇
  1960年   3篇
  1955年   4篇
  1943年   3篇
  1940年   5篇
  1935年   5篇
排序方式: 共有1066条查询结果,搜索用时 46 毫秒
1.
Lymphoid neogenesis is the process by which ectopic lymphoid accumulations that resemble lymph nodes arise in nonlymphoid tissues. Such lymphoid accumulations, known as tertiary lymphoid organs (TLO), are observed in chronic autoimmunity and they propagate immune pathology by setting up local antigen presenting sites. Whether lymphoid neogenesis occurs in transplanted organs and contributes to rejection is not well understood. To begin to address this question, we retrospectively analyzed 319 murine cardiac allografts for microscopic evidence of lymph-node-like structures. We found 78 allografts that had either classical TLO, characterized by discrete T- and B-cell zones and high endothelial venules (HEV) expressing peripheral node addressin (PNAd) (n = 34), or PNAd(+) HEV without organized lymphoid accumulations (n = 44). These changes were present in both short- and long-lived allografts and were invariably associated with rejection. Importantly, they occurred in 78% of allografts undergoing chronic rejection (n = 85) but in only 7% of allografts undergoing primarily acute rejection (n = 184). These findings indicate that, like autoimmunity, alloimmunity is associated with lymphoid neogenesis in the target organ and suggest a role for local T-cell activation in chronic allograft rejection.  相似文献   
2.
3.
Background Application of linear stapling devices for extrahepatic vascular control in liver surgery has been well-established. However, the technique for use of stapling devices in hepatic parenchymal transection is not well defined. Purpose To describe the safety and efficacy of our technique for use of vascular stapling devices in hepatic parenchymal transection during open right hepatic lobectomy is the purpose of this study. Methodology We reviewed our experience with 101 consecutive open right hepatic lobectomies performed by a single surgeon between January 2003 and July 2006, in which vascular staplers were utilized for the parenchymal transection phase. Results Of the 101 patients who underwent resection, 53 (52%) were female. The mean age was 58 years. Malignant disease was the indication for resection in the majority of patients (88%). Of those with cancer, 78% (69 of 89) had metastatic colorectal cancer, 6% (5 of 89) had metastatic neuroendocrine tumor, 4% (4 of 89) had hepatocellular carcinoma, 4% (4 of 89) had cholangiocarcinoma, and the remaining 8% were other metastatic cancers. Twelve patients (12%) underwent resection for hepatic adenoma or symptomatic benign disease (FNH or hemangioma). Forty-eight patients (48%) underwent a major ancillary procedure at the time of hepatic resection. Thirty-nine patients (39%) had a nonanatomic wedge resection of a left lobe lesion, 27 patients (27%) had one or more lesions treated with radiofrequency ablation (RFA), and 6 patients (6%) were treated with a synchronous bowel resection. The median total operative time was 336 min (range 155–620 min). A Pringle maneuver for temporary vascular inflow occlusion was utilized in all cases, with a median time of 9 min (range 4–17 min). Ten patients (10%) required blood transfusion during surgery or in the postoperative period. The maximum transfusion was 2 U of packed red blood cells (PRBC) in seven patients and 1 U of PRBC in three patients. The mean nadir postoperative hematocrit was 28.2. All patients with malignant disease had tumor-free margins at the completion of the procedure. The average hospital length of stay was 6.0 days. One patient (1%) developed a clinically significant bile leak requiring a postoperative endoscopic retrograde cholangiography (ERCP). No patient required reoperation. The 30 and 60-day postoperative survival was 100%. Conclusion These findings indicate that application of vascular stapling devices for parenchymal transection in major hepatic resection is a safe technique, with low transfusion requirements and minimal postoperative bile leak. The technique allows for rapid transection of the entire right hepatic lobe in under 10 min. Short video clips of the technique will be demonstrated. Presented at the 2007 American Hepato–Pancreato–Biliary Association, Las Vegas, Nevada, April 19–22, 2007 (oral presentation/video presentation).  相似文献   
4.
5.
J Dvorak  J Hayek  R Zehnder 《Spine》1987,12(8):726-731
Nine healthy adults and 43 patients with cervical spine injury were examined by using functional (computerized tomography) CT scanning. The ranges of axial rotation at the levels occiput C0-C1, C1-C2, and C2-C3 were measured. A rotation at C0-C1 greater than 8 degrees; at C1-C2, 56 degrees; or a right-left difference C0-C1 greater than 5 degrees and C1-2 greater than 8 degrees indicates hypermobility. A rotation at segment C1-C2 of less than 28 degrees indicates hypomobility. Surgical stabilization of rotatory instability could be considered as a possible therapeutic procedure.  相似文献   
6.
We have evaluated the effects on islet function of several manipulations of the substrate and tissue culture conditions in the short term culture of human islets. Specifically, we have studied the influence of several matrices, additions to the medium, and the use of basic fibroblast growth factor (FGF)-saporin mitotoxins to eliminate fibroblastoid cells from the cultures. The human islets were obtained from the Human Islet Transplant Center at Washington University Medical Center (St. Louis, MO). Substrates used to facilitate islet attachment were poly-L-lysine, gelatin, Matrigel, collagen, and bovine corneal endothelial cell matrix. RPMI-1640 medium was supplemented with either 22.2 mM glucose or 10 micrograms/mL human insulin. FGF-saporin mitotoxin was used at a concentration of 10 nM. The greatest improvement in islet cell function in either static or stimulated situations was obtained when we used bovine corneal endothelial cell matrix as the matrix, supplemented the medium with a high concentration of glucose or insulin, and eliminated fibroblast-like cells by exposing the cultures to basic FGF-saporin mitotoxin. The conditions described in this report could greatly improve the culture of human islets for use in clinical and laboratory research.  相似文献   
7.
OBJECTIVE: Epilepsy with mutation of the CDKL5 gene causes early seizures and is a variant of Rett syndrome (MIM (312750), which is reported typically as infantile spasms. The purpose of this study was to analyze the epileptic histories and EEGs of patients with the CDKL5 mutation. METHODS: We reviewed the epilepsy histories and electroclinical analyses of three girls aged 9.5, 7.4, and 9.4 years, each with a mutation of the CDKL5 gene. RESULTS: We revealed the presence of an encephalopathy that started by 1.5 months of age. At first, seizures involved tonic spasms or complex partial seizures, and were complicated by the later appearance of complex partial, tonic, and unexpectedly, myoclonic seizures. This form of epilepsy was drug resistant. Routine and prolonged video EEGs both displayed a homogeneous electroclinical pattern consisting of (a) unique background with diffuse high voltage sharp waves of 6-7 Hz, and absence of the typical rhythmic frontal-central theta activity present in Rett syndrome; (b) unique awake and sleep background, with diffuse, high voltage, continuous sharp waves with multifocal and diffuse spikes; (c) rhythmic, diffuse, 15 Hz activity accompanied clinically by tonic seizures; (d) intercritical pattern with pseudoperiodic, diffuse, sharp waves or pseudoperiodic, diffuse spike and polyspike or wave discharges; and (e) diffuse, spike, polyspike and wave discharges accompanied by massive or focal myoclonias or both. CONCLUSIONS: Patients with the CDKL5 mutation have an early onset, epileptic encephalopathy in infancy that evolves into myoclonic seizures in childhood with a unique EEG pattern. SIGNIFICANCE: Recognizing this type of encephalopathy could be useful in prompting clinicians to proceed further with their diagnostic work in patients not fitting the criteria of classical Rett syndrome.  相似文献   
8.
9.
We report on a boy with severe growth and mental retardation, syndactyly of toes and facial anomalies. This phenotype can easily be classified in the group of craniodigital syndromes, but it is difficult to make a more clearly defined diagnosis, based on other minor anomalies, because of the presence of overlapping features. On the basis of various pathognomic features, we conclude that our patient could be an additional case of Filippi syndrome. Moreover, newly recognised features in this patient may be due to variability in phenotypic expression.  相似文献   
10.
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