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   11818篇
  免费   599篇
  国内免费   105篇
耳鼻咽喉   119篇
儿科学   276篇
妇产科学   127篇
基础医学   1209篇
口腔科学   217篇
临床医学   790篇
内科学   3176篇
皮肤病学   164篇
神经病学   717篇
特种医学   405篇
外科学   2389篇
综合类   61篇
预防医学   247篇
眼科学   153篇
药学   801篇
中国医学   19篇
肿瘤学   1652篇
  2023年   88篇
  2022年   180篇
  2021年   322篇
  2020年   194篇
  2019年   236篇
  2018年   285篇
  2017年   254篇
  2016年   291篇
  2015年   317篇
  2014年   377篇
  2013年   455篇
  2012年   756篇
  2011年   804篇
  2010年   463篇
  2009年   391篇
  2008年   634篇
  2007年   682篇
  2006年   719篇
  2005年   737篇
  2004年   693篇
  2003年   681篇
  2002年   692篇
  2001年   205篇
  2000年   200篇
  1999年   209篇
  1998年   133篇
  1997年   107篇
  1996年   101篇
  1995年   89篇
  1994年   99篇
  1993年   89篇
  1992年   113篇
  1991年   140篇
  1990年   93篇
  1989年   115篇
  1988年   119篇
  1987年   73篇
  1986年   57篇
  1985年   43篇
  1984年   35篇
  1983年   41篇
  1982年   16篇
  1980年   13篇
  1979年   32篇
  1978年   14篇
  1976年   10篇
  1973年   11篇
  1971年   15篇
  1969年   14篇
  1966年   15篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
PURPOSE: Vascular endothelial growth factor (VEGF) is known as a multifunctional protein with roles in angiogenesis stimulation and apoptosis inhibition. We hypothesized that intracavernous administration of VEGF would recover erectile dysfunction due to diabetes by protection from apoptosis in the penile cavernosum. MATERIALS AND METHODS: A total of 30, 6-month-old male Sprague-Dawley rats were divided into 2 large groups, namely 20 with diabetes and 10 healthy controls. The diabetic group received intraperitoneal injection of streptozotocin (STZ) to induce diabetes. Intracavernous injection of VEGF was administered to randomly selected STZ diabetic rats 6 weeks after STZ injections. Erectile functional studies were performed in 10 STZ and 10 STZ plus VEGF rats at 12 weeks. After completion of the functional study the penile crura were collected for molecular and immunohistochemical studies. RESULTS: Mean intracavernous pressure in the diabetic group was significantly lower than in controls and low pressure was significantly recovered by VEGF treatment. Gene expression of pro-apoptotic and anti-apoptotic factors were present in the control, diabetic and VEGF treated groups. However, anti-apoptotic protein expression was lacking in the diabetic group and it was recovered by VEGF treatment. The apoptotic index in the diabetic group was significantly higher than in controls and this index was significantly decreased in the VEGF treated group. CONCLUSIONS: The decrease in and recovery of intracavernous pressure correlated significantly with a variation in anti-apoptotic protein expression in the diabetic and VEGF treated groups. To our knowledge this is the first study to show that intracavernous injection of VEGF restores erectile dysfunction through the inhibition of apoptosis in diabetic rats.  相似文献   
102.
The Japanese Society of Nuclear Medicine has recently published the consensus guidelines for pediatric nuclear medicine. This article is the English version of the guidelines. Part 1 proposes the dose optimization in pediatric nuclear medicine studies. Part 2 comprehensively discusses imaging techniques for the appropriate conduct of pediatric nuclear medicine procedures, considering the characteristics of imaging in children.  相似文献   
103.
In this study, we analyzed the extent of regression of left ventricular hypertrophy in patients who received small St. Jude Medical (SJM) aortic valves and compared the results with those of another group receiving larger valves. Eighty-eight patients received either 19 or 21 mm valves (Group 1, 25 patients) or either 23 or 25 mm valves (Group 2, 53 patients). Echocardiographic studies were done before the operation and 5 years postoperatively. At follow-up a significant reduction in the left ventricular mass was found for both patient groups (p < 0.0001). Doppler echocardiography derived pressure gradients for both groups were obtained during the follow-up period. As expected, the patients in Group 1 had higher peak pressure gradients than did those in Group 2. However, there was no significant difference between the 2 groups or any significant correlations between peak pressure gradients and body surface area (BSA). Actuarial survival was 84.7% at 15 years for Group 1 and 85.9% at 17 years for Group 2. Actuarial freedom from valve related events was 91.4 % at 15 years for Group 1 and 82.7% at 17 years for Group 2. There was no significant difference in survival or valve related event free curves between the 2 groups. After implantations of SJM valves in small aortic roots, significant left ventricular mass regression was obtained, and the results were comparable to those for valves of other sizes. The long-term performance of aortic valve replacement with small valves was satisfactory as judged by improvement in the functional class of patients and survival statistics, the durability of the prosthesis, and valve related morbidity comparable to that of valves of other sizes.  相似文献   
104.
A 66-year-old male was admitted to our hospital because of pyrexia, chest pain and hemosptum. Inflammatory findings were made and salmonella enteritidis was detected by bacterial examination of sputum and stool. Enhanced chest CT examination disclosed a descending thoracic aortic aneurysm which had ruptured into the left lower lobe of the lung. Under a diagnosis of ruptured mycotic descending thoracic aortic aneurysm, an emergency operation was performed. A left posterolateral thoracotomy carried out after axillo-bilateral femoral bypass grafting. A pseudoaneurysm of the descending thoracic aorta had ruptured into the left lower lobe of the lung. After resection of the aneurysm, closure of both ends of the intact descending thoracic aorta and a left lower lobectomy were carried out. An ascending aorta-infrarenal abdominal aorta bypass was performed because of insufficien visceral arterial blood flow through the axillo-bilateral femoral bypass. The patient’s immediate postoperative recovery was complicated by paraplegia. Chloramphenicol and levofloxacin were administered for three months, after which his recovery followed a good course.  相似文献   
105.
OBJECTIVE: The prognosis of prostate cancer has been evaluated by clinical stage or pathological grade. PSA parameters including PSA density and PSA doubling time have not always precisely reflected the prognosis of prostate cancer. The aim of this study was to evaluate PSA parameters and extension of disease (EOD) grade as prognostic factors for relapsed prostate cancer. METHODS: The relationship between PSA parameters or EOD grade, and survival of 29 stage D patients with relapsed prostate cancer after initial hormone therapy was examined. RESULTS: Only EOD grade was an independent prognostic factor, even for cause-specific survival period and survival period after relapse. CONCLUSION: EOD grade was a significant prognostic factor, and in particular, very useful as a prognostic factor for patients with bone metastasis. PSA value was not always associated with tumor volume, and therefore it is not an independent prognostic factor.  相似文献   
106.
BACKGROUND: We previously reported that intratracheal delivery (ITD) of alloantigen generated regulatory cells in mice. Here, we examined the effect of various doses of conventional immunosuppressants (FK506, cyclosporine A, azathioprine, mycophenolate mofetil, and rapamycin) on inducing regulatory cells in our model. METHODS: CBA mice (primary recipients) were given C57BL/6 splenocytes by ITD and either no additional treatment or various doses of an immunosuppressant. Seven days later, splenocytes from these mice were adoptively transferred into naive secondary CBA recipients that underwent C57BL/6 cardiac grafting the same day. RESULTS: Adoptive transfer from primary recipients given ITD of splenocytes alone induced prolonged allograft survival in secondary recipients (median survival time [MST], 50 days), suggesting that regulatory cells were generated. When ITD of alloantigen was combined with daily administration of 0.1 mg/kg FK506 or 0.2 mg/kg rapamycin, graft survival was similarly prolonged (MST 55 and 50 days, respectively). When combined with 20 or 40 mg/kg MMF or 0.4 mg/kg rapamycin, the majority of recipients demonstrated indefinite survival (MST, >100 days in all groups). When ITD of alloantigen was combined with 0.3, 0.5, or 1.0 mg/kg FK506; 5, 10, or 25 mg/kg cyclosporine A; or 1.0 or 2.0 mg/kg azathioprine, allografts were rejected acutely (MST 7-13 days). CONCLUSION: Generation of regulatory cells by ITD of alloantigen was facilitated by mycophenolate mofetil and high doses of rapamycin but abrogated by cyclosporine A, azathioprine, and high doses of FK506. Low doses of rapamycin and of FK506 did not interfere with generation of regulatory cells.  相似文献   
107.
Tetranectin was originally purified from human serum on the basis of plasminogen kringle 4-binding properties. Tetranectin enhances plasminogen activation by a tissue-type plasminogen activator so that it has been suggested to play a role in tissue remodeling. We have generated mice with a targeted disruption of the tetranectin gene to elucidate the biological function of tetranectin. In this study, we showed that wound healing was markedly delayed in tetranectin-null mice compared with wild-type mice. A single full-thickness incision was made in the dorsal skin. By 14 days after the incision, the wounds fully healed in all wild-type mice based on the macroscopic closure; in contrast, the progress of wound healing in the tetranectin null mice appeared to be impaired. In histological analysis, wounds of wild-type mice showed complete reepithelialization and healed by 14 days after the incision. However, those of tetranectin-null mice never showed complete reepithelialization at 14 days. At 21 days after the injury, the wound healed and was covered with an epidermis. These results supported the fact that tetranectin may play a role in the wound healing process.  相似文献   
108.
Objective:   The management of lower urinary tract symptoms that persist after radical prostatectomy remains to be established. We investigated whether an α1-blocker, naftopidil, improves LUTS in patients ≥1 year after radical prostatectomy.
Methods:   A total of 29 male patients received 25 mg/day of naftopidil for the first week, then 75 mg/day for 4 weeks. The frequency-volume chart, international prostate symptom score and quality of life index (QOL) were examined before and at the end of the 5-week administration in all subjects.
Results:   Total international prostate symptom score (I-PSS) and I-PSS subtotals associated with voiding symptoms and storage symptoms were significantly decreased at 5 weeks compared with baseline ( P  < 0.001 each). QOL index was significantly improved with naftopidil for 5 weeks ( P  < 0.001). From analyses of the frequency-volume chart, mean and maximum volume/void were significantly increased ( P  < 0.05 each).
Conclusion:   Lower urinary tract symptoms detected in patients ≥1 year after radical prostatectomy were markedly improved with administration of naftopidil at 75 mg/day. These symptoms could represent a novel target for medical treatment by improved understanding of the symptom pathology in the near future.  相似文献   
109.
Background/purpose  Pancreatic fistula, which is one of the main causes of late postpancreatectomy hemorrhage (PPH), is a common complication of pancreatoduodenectomy (PD). It may erode the anastomosis site and vascular wall in its vicinity, resulting in pseudoaneurysm formation and/or the rupture of major vessels. To protect the vessels near the area for pancreaticojejunostomy from potential pancreatic fistula, we have adopted a surgical option by which such vessels are separated from the pancreaticojejunostomy using a pedicled falciform ligament. We reviewed 36 patients who underwent PD that included this option. Methods  After the PD was completed (before reconstructions), the pedicled falciform ligament was spread widely on the major vessels exposed during resection, and was fixed to the surrounding retroperitoneal connective tissue. These procedures enabled the complete separation of these vessels from the pancreaticojejunostomy. Results  The mobilization and placement of the falciform ligament in the space between the pancreaticojejunostomy and the major vessels were successfully carried out without any complications. Although ten (28%) patients developed pancreatic fistula and three (8%) developed intraabdominal infection, none of the patients developed late PPH. Conclusions  The present surgical option is technically simple and easy, and may be an effective prophylactic measure against late PPH following PD.  相似文献   
110.
Background and Objectives  Dickkopf-1 (DKK1) is the inhibitor of the canonical Wnt signaling pathway, however it is highly transactivated in various cancers, suggesting the presence of unknown mechanism. Its implication in human esophageal squamous cell carcinoma (ESCC) has not been sufficiently investigated. Patients and Methods  We evaluated DKK1 protein expression in resected specimens from 170 patients with ESCC by immunohistochemistry. Tumors were categorized as positive or negative for DKK1. The relationships between DKK1 expression in ESCC and various clinicopathological parameters and prognosis (disease-free survival; DFS) were analyzed separately. Results  Immunohistochemically, 72 (42.4%) tumors were DKK1 positive while no significant staining was observed in the normal squamous epithelium except for few basal cells. There was no significant relationship between DKK1 expression in ESCC and any of the clinicopathological parameters tested in this study. Patients with DKK1-positive tumors had poorer DFS than those with negative ESCC (5-year DFS; 31.5% versus 53.6%, P = 0.0062). Univariate analysis showed a significant relationship between pT [hazard ratio (HR) = 2.944, 95% confidence interval (CI) = 1.713–5.059, P < 0.0001], number of pN (HR = 2.836, 95% CI = 1.866–4.309, P < 0.0001), lymphatic invasion (HR = 2.892, 95% CI = 1.336–6.262, P = 0.0070), and DKK1 expression (HR = 1.763, 95% CI = 1.167–2.663, P = 0.0071) and DFS. Multivariate analysis including the above four parameters identified pT (HR = 2.053, 95% CI = 1.157–3.645, P = 0.0140), pN number (HR = 2.107, 95% CI = 1.362–3.260, P = 0.0008), and DKK1 expression (HR = 1.813, 95% CI = 1.195–2.751, P = 0.0052) as independent and significant prognostic factors for DFS. Conclusion  Our data suggest the usefulness of DKK1 as a novel predictor of poor prognosis of patients with ESCC after curative resection and also as a therapeutic target for future tailored therapies against ESCC.  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