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   11469篇
  免费   575篇
  国内免费   52篇
耳鼻咽喉   88篇
儿科学   207篇
妇产科学   190篇
基础医学   1880篇
口腔科学   228篇
临床医学   1033篇
内科学   2280篇
皮肤病学   237篇
神经病学   1359篇
特种医学   572篇
外科学   1918篇
综合类   52篇
一般理论   2篇
预防医学   354篇
眼科学   211篇
药学   733篇
中国医学   25篇
肿瘤学   727篇
  2023年   73篇
  2022年   97篇
  2021年   224篇
  2020年   132篇
  2019年   183篇
  2018年   208篇
  2017年   189篇
  2016年   236篇
  2015年   291篇
  2014年   367篇
  2013年   472篇
  2012年   720篇
  2011年   747篇
  2010年   441篇
  2009年   439篇
  2008年   689篇
  2007年   717篇
  2006年   670篇
  2005年   669篇
  2004年   625篇
  2003年   597篇
  2002年   574篇
  2001年   101篇
  2000年   82篇
  1999年   84篇
  1998年   127篇
  1997年   106篇
  1996年   77篇
  1995年   77篇
  1994年   76篇
  1993年   64篇
  1992年   45篇
  1991年   33篇
  1990年   31篇
  1989年   34篇
  1988年   30篇
  1937年   33篇
  1936年   34篇
  1935年   36篇
  1933年   47篇
  1932年   75篇
  1931年   35篇
  1930年   45篇
  1929年   35篇
  1928年   61篇
  1927年   57篇
  1926年   39篇
  1925年   34篇
  1924年   43篇
  1922年   31篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
Reduced tolerance of steatotic livers to ischemic injury is considered to correlate with impaired microcirculation. The aim of this study was to investigate the impact of heat-shock preconditioning (HSPC) on microcirculatory failure after ischemia/reperfusion (I/R) in steatotic livers by means of intra-vital fluorescence microscopy. Obese Zucker rats were used. In the HS group, rats underwent whole-body hyperthermia followed by 60-min partial liver ischemia. In group IR, rats were exposed only to ischemia. Microcirculation parameters (sinusoidal perfusion rate, sinusoidal diameter, leukocyte-endothelial interaction) were significantly better preserved in the HS group than in the IR group. Liver enzymes, oxygenated glutathione/reduced glutathione (GSSG/GSH) ratio, and electron microscopy showed less damage in the HS group. A marked expression of heat shock protein 72 (HSP72) and heme oxygenase (HO-1) was found only in the livers of group HS. HSPC mitigated the I/R injury of steatotic livers by preventing post-ischemic failure of microcirculation. This beneficial effect was found to be associated with the induction of HSP72 and HO-1.  相似文献   
132.
BACKGROUND: The purpose of the study was to evaluate the effects of cyclosporine (CsA), FK 506 and mycophenolate mofetil (MMF) on graft-infiltrating leukocytes (CD4, CD8, CD11a, CD18) after cardiac transplantation in rats. METHODS: Three hundred forty animals were transplanted and randomly divided into 4 groups: CsA, 3 mg/kg/d (n = 74); MMF, 40 mg/kg/d (n = 96); FK 506, 0.3 mg/kg/d (n = 96); and a control group receiving no immunosuppressive therapy (n = 74). Three or 4 animals from each group were killed at intervals of 1 to 4 days up to Day 60. Immunohistochemistry was performed using monoclonal antibodies (MAb) against CD4, CD8, CD11a and CD18. Positively stained cells were analyzed in the perivascular space (PVS) of intra- and epicardial arteries. Statistical analysis was performed using area-under-the-curve assessment with an extended t-test. RESULTS: CsA and FK 506 reduced the presence graft-infiltrating leukocytes (CD4, CD8, CD11a, CD18) in the PVS of intra- and epicardial arteries when compared with control animals. MMF therapy resulted in a further significant reduction in infiltrating leukocytes when compared with the 2 calcineurin inhibitors. MMF had a faster onset of action than the calcineurin inhibitors. CsA and FK 506 required 12 to 20 additional days to achieve the reducing effect of graft infiltration seen in MMF-treated animals. CONCLUSION: MMF possesses potent infiltration-blocking properties and its application leads to a greater reduction of cellular infiltration in the course of transplant rejection when compared with calcineurin inhibitors.  相似文献   
133.
Intraoperative magnetic resonance imaging (MRI) has been used for years to update neuronavigation and for intraoperative resection control. For this purpose, low-field (0.1-0.2 T) MR scanners have been installed in the operating room, which, in contrast to machines using higher magnetic field strength, allowed the use of standard anesthetic and surgical equipment. However, these low-field MR systems provided only minor image quality and a limited battery of MR sequences, excluding functional MRI, diffusion-weighted MRI, or MR angiography and spectroscopy. Based on these advantages, a concept using high-field MRI (1.5 T) with intraoperative functional neuronavigational guidance has been developed that required adaptation of the anesthetic regimen to working in the close vicinity to the strong magnetic field. In this paper the authors present their experience with the first 80 consecutive patients who received anesthesia in a specially designed radio frequency-shielded operating room equipped with a high-field (1.5 T) MR scanner. We describe the MR-compatible anesthesia equipment used including ventilator, monitoring, and syringe pumps, which allow standard neuroanesthesia in this new and challenging environment. This equipment provides the use of total intravenous anesthesia with propofol and remifentanil allowing rapid extubation and neurologic examination following surgery. In addition, extended intraoperative monitoring including EEG monitoring required for intracranial surgery is possible. Moreover, problems and dangers related to the effects of the strong magnetic field are discussed.  相似文献   
134.
OBJECTIVE: The aim of this study was to assess the value of sonoelastography (SE) for prostate cancer detection in comparison with systematic biopsy findings. MATERIAL AND METHODS: Four hundred and ninety two PSA screening volunteers (mean age: 61.9+/-8.6) with an total PSA >1.25 ng/mL and a free to total PSA ration of <18% underwent SE of the prostate before 10 core systematic prostate biopsy. Tissue elasticity of the peripheral zone was investigated only. Tissue elasticity was displayed from red (soft) to green (intermediate) and to blue (hard). Only hard lesions (blue) were considered to be suspicious for prostate cancer. The peripheral zone of the prostate was divided in 3 regions on each side: base, mid-gland, apex. A different investigator performed systematic biopsy, and the biopsy findings were compared with the SE findings. RESULTS: In 125 of 492 patients (25.4%) systematic biopsy demonstrated prostate cancer. Cancer was detected in 321 of 2952 (11%) outer gland areas (74 in the base, 106 in the mid-gland, 141 in the apex). The Gleason score ranged from 3 to 10 (mean: 6.5). In SE 533 of 2952 (18.1%) suspicious areas were detected and 258 of these areas (48.4%) showed cancer. Most of the false-positive findings (275/533 areas; 51.6%) were associated with chronic inflammation and atrophy especially at the basal prostate areas. The sensitivity by entire organ was calculated with 86% and the specificity 72%. The analysis by outer gland areas showed the highest sensitivity in the apex (79%). The specificity by outer gland areas ranged between 85% and 93%. The correlation between SE findings and biopsy results was high (p<0.001). CONCLUSION: Sonoelastography findings showed a good correlation with the systematic biopsy results. The best sensitivity and specificity was found in the apex region. Sonoelastography seems to offer a new approach for differentiation of tissue stiffness of the prostate and may therefore improve prostate cancer detection.  相似文献   
135.
The purpose was to assess the sensitivity of a CAD software prototype for the detection of pulmonary embolism in MDCT chest examinations with regard to vessel level and to assess the influence on radiologists' detection performance. Forty-three patients with suspected PE were included in this retrospective study. MDCT chest examinations with a standard PE protocol were acquired at a 16-slice MDCT. All patient data were read by three radiologists (R1, R2, R3), and all thrombi were marked. A CAD prototype software was applied to all datasets, and each finding of the software was analyzed with regard to vessel level. The standard of reference was assessed in a consensus read. Sensitivity for the radiologists and CAD software was assessed. Thirty-three patients were positive for PE, with a total of 215 thrombi. The mean overall sensitivity for the CAD software alone was 83% (specificity, 80%). Radiologist sensitivity was 77% = R3, 82% = R2, and R1 = 87%. With the aid of the CAD software, sensitivities increased to 98% (R1), 93% (R2), and 92% (R3) (p<0.0001). CAD performance at the lobar level was 87%, at the segmental 90% and at the subsegmental 77%. With the use of CAD for PE, the detection performance of radiologists can be improved.  相似文献   
136.
Boerhaave’s syndrome is a life-threatening disease with a high mortality. With regard to the heterogeneity of treatment strategies, no comparative studies exist and recommendations remain controversial. Seventeen cases of Boerhaave’s syndrome operated on between 1989 and 2000 at our hospital were reviewed retrospectively to compare the time period between perforation and diagnosis, and the morbidity and mortality among the different treatment options. In addition, we conducted a meta-analysis of the literature including all series containing five or more patients and compared the findings with our own data. Our patients with a perforation history of less than 12 hours showed significantly fewer signs of sepsis compared to patients with a history of more than 12 hours. In a comparison of patients with primary repair vs. patients treated with esophageal resection or an exclusion operation, no differences were found. In the literature, patients with a long period of perforation (more than 24 hours) were treated more often with an esophageal resection than patients with primary repair. In cases of Boerhaave’s syndrome, primary suturing of the esophageal perforation should be reserved only for those patients presenting within 12 hours after perforation. In all other cases, depending on the extent of the tissue damage, a two-stage esophageal resection with cervical esophagostomy and gastrostomy is recommended as the safest treatment.  相似文献   
137.
138.
We report on a Mycobacterium marinum infection in a diabetic woman 8 years after undergoing a combined pancreas-kidney transplantation. This is, to our knowledge, the first case report on an isolated skin infection with atypical mycobacteria after simultaneous pancreas-kidney transplantation. A genetic probe categorization revealed an infection with M. marinum. Skin tuberculosis caused by M. marinum is an uncommon complication in kidney or pancreas-kidney transplant recipients, hence the diagnosis can be delayed.  相似文献   
139.
Gettman MT  Peschel R  Neururer R  Bartsch G 《European urology》2002,42(5):453-7; discussion 457-8
PURPOSE: Laparoscopic pyeloplasty is an accepted therapy for primary ureteropelvic junction obstruction (UPJO), however difficulty associated with intracorporeal suturing has limited widespread clinical application. We report our initial experience of laparoscopic pyeloplasty performed with the daVinci robotic system matched to procedures performed with standard laparoscopic techniques. PATIENTS AND METHODS: From June 2001 until August 2001, six patients underwent definitive management of primary UPJO using the daVinci robotic system. In four patients an Anderson-Hynes pyeloplasty was performed, while in two patients Fengerplasty was performed. Using demographic and preoperative information, each patient in the daVinci-assisted group was matched to a corresponding patient with primary UPJO undergoing laparoscopic pyeloplasty with standard techniques between November 1999 and June 2001. Perioperative results and follow-up data were subsequently compared. RESULTS: Treatment groups were identical with regard to surgical procedure, gender, and side of UPJO. The length of hospitalization was 4 days for all patients, regardless of treatment group. Estimated blood loss was <50 cc in all cases. For Anderson-Hynes pyeloplasty, the mean overall operative and suturing times were 140 and 70 min using the daVinci system and 235 and 120 min using standard techniques, respectively. For the Fengerplasty, the mean overall operative and suturing times were 78 and 13 minutes using the daVinci system and 100 and 28 minutes using standard techniques, respectively. No complications were observed and there were no open conversions. CONCLUSION: Anderson-Hynes pyeloplasty and Fengerplasty are feasible using either conventional laparoscopic techniques or the daVinci robotic system. In this initial pilot study, procedures performed with the daVinci robotic system resulted in overall decreased operative time, however factors responsible for the decreased operative time remain to be defined. Long-term prospective follow-up of procedures performed with or without the daVinci robotic system for surgeons with limited experience in laparoscopic management of UPJO is warranted to delineate the true efficacy of the device.  相似文献   
140.
Urinary incontinence (UI) and erectile dysfunction (ED) after radical prostatectomy (RP) can impose a strong burden. While most studies focus on certain time points after RP when analyzing functional outcome, there is paucity of evidence on late functional recovery in patients with UI or ED at 12 mo after RP. Using longitudinal patient data from a large European single-center, we show that the chance of regaining continence among patients (n = 974) with UI (≥1 pad/24 h) at 12 mo after RP was 38.6% after 24 mo and 49.7% after 36 mo. The corresponding rates for patients (n = 1115) with ED (defined as International Index of Erectile Function-5 score <18) at 12 mo after RP were 30.8% at 24 mo and 36.5% at 36 mo after RP. Patients with postoperative UI or ED 12 mo after RP should be counseled about their good chance of achieving continence or potency in the course of time.

Patient summary

We analyzed the probability of functional recovery among patients with urinary incontinence (UI) and erectile dysfunction (ED) 12 mo after radical prostatectomy. We found that up to 49.7% (36.5%) of patients with UI (ED) regain function within the next 24 mo and should be informed about these encouraging numbers.  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