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   7471篇
  免费   353篇
  国内免费   39篇
耳鼻咽喉   30篇
儿科学   117篇
妇产科学   61篇
基础医学   912篇
口腔科学   189篇
临床医学   481篇
内科学   1937篇
皮肤病学   83篇
神经病学   584篇
特种医学   240篇
外科学   1246篇
综合类   26篇
预防医学   222篇
眼科学   251篇
药学   552篇
中国医学   3篇
肿瘤学   929篇
  2023年   59篇
  2022年   103篇
  2021年   153篇
  2020年   101篇
  2019年   123篇
  2018年   140篇
  2017年   112篇
  2016年   132篇
  2015年   151篇
  2014年   196篇
  2013年   225篇
  2012年   376篇
  2011年   419篇
  2010年   231篇
  2009年   223篇
  2008年   350篇
  2007年   451篇
  2006年   405篇
  2005年   398篇
  2004年   373篇
  2003年   325篇
  2002年   310篇
  2001年   225篇
  2000年   215篇
  1999年   209篇
  1998年   96篇
  1997年   63篇
  1996年   50篇
  1995年   54篇
  1994年   65篇
  1993年   57篇
  1992年   152篇
  1991年   137篇
  1990年   104篇
  1989年   107篇
  1988年   99篇
  1987年   95篇
  1986年   105篇
  1985年   83篇
  1984年   55篇
  1983年   53篇
  1980年   24篇
  1979年   30篇
  1977年   42篇
  1973年   30篇
  1972年   27篇
  1971年   30篇
  1970年   33篇
  1969年   48篇
  1968年   31篇
排序方式: 共有7863条查询结果,搜索用时 15 毫秒
91.
BACKGROUND: Little information has been available until now about the clinical efficacy of tonsillectomy on long-term renal survival of patients with idiopathic immunoglobulin A nephropathy (IgAN). METHODS: To investigate the effect of tonsillectomy on long-term renal survival, we reviewed the clinical course of 118 patients with idiopathic biopsy-diagnosed IgAN from 1973 to 1980. Of those, 48 patients received tonsillectomy and 70 patients did not. The starting point of observation was defined as the time of the diagnostic renal biopsy, and the end point as when requiring the first dialysis. Up to 2001, the mean observation time was 192.9 +/- 74.8 months (48-326 months). Renal survival and impact of covariates were evaluated by Kaplan-Meier analysis and Cox proportional hazards regression model. RESULTS: Age, gender, amount of urinary protein excretion, serum creatinine, serum IgA, blood pressure, and histopathologic findings at the time of renal biopsy and treatments during the observation period were not significantly different between patients with and without tonsillectomy. Five (10.4%) of the patients with tonsillectomy and 18 (25.7%) of the patients without tonsillectomy finally required dialysis therapy (chi-square test, P = 0.0393). By Kaplan-Meier analysis, renal survival rates were 89.6% and 63.7% at 240 months in the patients with and without tonsillectomy, respectively, and were significantly different (log-rank test, P = 0.0329). In the multivariate Cox regression model, tonsillectomy (hazard ratio, 0.22; 95% CI, 0.06 to 0.76; P = 0.0164) had a significant effect on renal outcome. CONCLUSION: These results indicate that tonsillectomy has a favorable effect on long-term renal survival in patients with IgAN.  相似文献   
92.
We examined the effects of early blockade of CD62 selectin-mediated adhesive interactions in steatotic rat liver models of ex vivo cold ischemia followed by reperfusion or transplantation by administration of P-selectin glycoprotein ligand-1 (rPSGL-Ig). In the model of cold ischemia/reperfusion, livers pretreated ex vivo with rPSGL-Ig at harvesting from obese Zucker rats showed significantly decreased portal resistance, increased bile production, and diminished hepatic endothelial neutrophil infiltration, as compared with untreated controls. Pretreatment of fatty livers with rPSGL-Ig prior to transplantation extended the survival of lean Zucker rat recipients from 40% to 90%. This effect correlated with significantly improved liver function, depressed neutrophil activity, and decreased histologic features of hepatocyte injury. Intragraft expression of CD62 P-selectin was similar in both recipient groups. rPSGL-Ig treatment decreased intragraft infiltration by CD3/CD25 cells, diminished expression of pro-inflammatory TNFalpha, IL-6, iNOS, IL-2 and IFN-gamma, without significantly affecting mRNA levels coding for anti-inflammatory IL-4. Thus, rPSGL-Ig blockade of CD62-mediated adhesive interactions protects against severe ischemia/reperfusion injury suffered otherwise by steatotic rat livers. These findings document the potential utility of rPSGL-Ig in increasing the transplant donor pool through modulation of marginal steatotic livers.  相似文献   
93.
BACKGROUND: A combination of pseudoaneurysm and arteriovenous fistula of the middle meningeal artery is rare. We describe a case of traumatic pseudoaneurysm of the middle meningeal artery, which subsequently formed a fistula with the cavernous sinus. CASE DESCRIPTION: A 23-year-old man suffered from blunt head trauma and skull fractures. Sixteen days later, he suddenly experienced headache and a bruit was auscultated over the left ear. Three-dimensional computed tomographic angiography revealed dilatation of the left middle meningeal artery. The dilation proved to be a pseudoaneurysm on cerebral angiograms and it was also found to have formed a fistula with the cavernous sinus. Both lesions were successfully obliterated by endovascular embolization using microcoils. CONCLUSION: Head injury may lead to asymptomatic pseudoaneurysm or dural arteriovenous fistula. Neurosurgeons should always bear in mind the possibility of such vascular injuries after blunt head trauma to prevent any hemorrhagic complications.  相似文献   
94.
Background The incidence of aberrant bile duct injury associated with laparoscopic cholecystectomy (LC) has not yet been adequately examined. This study aimed to clarify the types of normal cystic ducts and the incidence of aberrant extrahepatic bile ducts, and to search for a method of avoiding injuries during LC. Methods Aberrant hepatic ducts were retrospectively categorized into five types according to the pattern of the cystic ducts and the accessory hepatic ducts by preoperative endoscopic retrograde cholangiography or multidetector three-dimensional computed tomography using drip infusion cholangiography. The aberrant bile ducts were classified as type A (merging at the right side of the common bile duct), type B (merging at the anterior side), or type C (merging at the posterior left side). Results The intrahepatic bile ducts and cystic duct were clearly shown for 1,044 of the 1,278 patients who underwent LC. Secondary branches of aberrant cystic ducts were observed in 37 cases (3.5%), and accessory hepatic ducts were observed in 30 cases (2.9%). A comparison of the difficulties encountered with LC for each type based on the merging patterns of cystic ducts showed that type C needed a much longer operation time for LC than the other types. Conclusions A preoperative evaluation of the bile duct tract and the accessory hepatic duct before LC is important. Patients with a cystic duct merging normally into the posterior left side of the common hepatic duct (type C) experienced difficulty when undergoing LC. The authors have safely performed LC with the use of an endoscopic nasobiliary drainage tube in type D cases (cystic duct merging with the right hepatic duct), in type IV cases (cystic duct merging with an accessory hepatic duct).  相似文献   
95.

Purpose

Pancreatic neuroendocrine tumor (PNET) is relatively rare and has a generally better prognosis than does pancreatic cancer. However, as its prognosis in patients with lymph node metastasis (LNM) is unclear, lymph node dissection for PNET is controversial. Our study aimed to clarify the significance of LNM in PNET.

Methods

We retrospectively examined 83 PNET patients who underwent pancreatic resections with lymph node dissection at Kumamoto University Hospital, Saiseikai Kumamoto Hospital, and Kumamoto Regional Medical Center from April 2001 to December 2014. Their clinicopathological parameters were analyzed by the absence or presence of LNM, and with regard to the disease-free survival (DFS) and overall survival (OS). A predictive score of LNM was also made using the age, tumor size, primary tumor location, and tumor function.

Results

Although the 5-year OS was 74.8% for LNM+ and 94.6% for LNM? (P?=?0.002), LNM was not an independent risk factor for the OS in a multivariate analysis. However, tumors larger than 1.8 cm were found to be an independent prognostic factor, and the cut-off value for the predictive score was 1.69.

Conclusions

Although LNM was not an independent prognostic factor, lymph node dissection is recommended for patients whose predictive score is larger than 1.69.
  相似文献   
96.

Objective

The purpose of this study was to investigate the differences between spinal metastasis and osteoporotic compression fractures on plain X-ray images, focusing on asymmetrical vertebral collapse and fracture level.

Materials and methods

This study included 180 patients with pathological collapse from spinal metastasis (188 vertebrae) who were treated at our institution and 70 patients (92 vertebrae) with osteoporotic compression fractures. Anteroposterior X-ray images of the lower thoracic and lumbar spine were evaluated for asymmetrical collapse deformity.

Results

Asymmetrical collapse was found in 134 vertebrae (71.3%) with metastasis, and in 20 osteoporotic vertebrae (21.7%); this difference was significant (p < 0.0001). The asymmetrical collapse angle in spinal metastasis patients ranged from 0 to 18°, with a mean of 7.0 and a standard deviation (SD) of 4.5. In contrast, the asymmetrical collapse angle in patients with osteoporotic fractures ranged from 0 to 13°, with a mean of 3.1 and a SD of 2.8. The difference in collapse angle between the two groups was statistically significant (p < 0.001). The cutoff value to suspect spinal metastasis was determined to be 5° or more (sensitivity 0.67, specificity 0.74). Fracture at Th10 or below L3 was found in 20.2% of spinal metastasis patients; only 3% of osteoporotic fractures occurred at these levels.

Conclusion

Asymmetrical collapse with an angle of 5° or more and fractures at atypical levels on plain radiographs can be useful clues to spinal metastasis.  相似文献   
97.

Purpose

To clarify the risk factors for complications after diverting ileostomy closure in patients who have undergone rectal cancer surgery.

Methods

The study group comprised 240 patients who underwent a diverting ileostomy at the time of lower anterior resection or internal anal sphincter resection, in our department, between 2004 and 2015. Univariate and multivariate analyses of 18 variables were performed to establish which of these are risk factors for postoperative complications.

Results

The most common complications were intestinal obstruction and wound infection. Univariate analysis showed that an age of 72 years or older (p?=?0.0028), an interval between surgery and closure of 6 months or longer (p?=?0.0049), and an operation time of 145 min or longer (p?=?0.0293) were significant risk factors for postoperative complications. Multivariate analysis showed that age (odds ratio, 3.4236; p?=?0.0025), the interval between surgery and closure (odds ratio, 3.4780; p?=?0.0039), and operation time (odds 2.5179; p?=?0.0260) were independent risk factors.

Conclusions

Age, interval between surgery and closure, and operation time were independent risk factors for postoperative complications after diverting ileostomy closure. Thus, temporary ileostomy closure should be performed within 6 months after surgery for rectal cancer.
  相似文献   
98.

Purpose

The aim of the study was to investigate posttraumatic stress disorder (PTSD) in mothers of children who have undergone surgery for congenital disease at a pediatric surgery department.

Methods

A questionnaire survey was carried out in 145 mothers of children who had undergone surgery and were still alive. For comparison, the mothers were categorized into 3 groups according to the severity of their child's disease.

Results

Of the 145 mothers, 29 (20%) were likely to be diagnosed as having developed PTSD at the time of the survey. Posttraumatic stress disorder symptoms correlated with factors such as anxiety and condition of the child. In terms of the disease severity of the child, factors such as anxiety tended to be observed more frequently in the higher disease severity group, whereas the proportion of mothers likely to be diagnosed as having developed PTSD was smallest in the moderate-severity group.

Conclusions

Twenty percent of the mothers of children had probably developed PTSD. In the moderate-severity group, there seemed to be a factor that alleviated PTSD symptoms. Because mothers provided effective care for the symptoms of children in the moderate-severity group, this observation suggests that participation of the mother in their child's treatment might prevent them from developing PTSD symptoms.  相似文献   
99.
We report a rare case of simultaneous repair for Cor triatriatum (CT), partially unroofed coronary sinus (CS) with persistent left superior vena cava (PLSVC), moderately severe tricuspid regurgitation, and atrial flutter 35 years after radical operation for tetralogy of Fallot (TOF). A 40-year-old woman underwent patch closure of atrial septal defect as to drain blood from left SVC to right atrium (RA), excision of diaphragm in left atrium (LA), tricuspid annuloplasty, and cryoablation. Postoperative course was uneventful with successful anatomical correction.  相似文献   
100.
Congenital absence of the portal vein (CAPV) is a rare malformation of the splanchnic venous system. Although CAPV is usually detected in the pediatric age group, our patient was a 35-year-old woman. She had been diagnosed with CAPV in 1996 when she was 27 years old. In 1998, she was placed on hemodialysis due to chronic renal failure. After several episodes of encephalopathy in 2002, liver transplantation (LT) was recommended to her and her family. Since there was no suitable living donor candidate, she was put on the waiting list for a deceased donor liver transplant in Japan. In 2004, her ammonia level increased to around 300 microg/dl, and she went into a coma lasting for three days. After recovering from this event, she underwent a living domino transplantation using a whole liver donated by a familial amyloid polyneuropathy (FAP) patient. Her portal vein, which had drained directly into the inferior vena cava (IVC), was transected together with a cuff of the IVC wall and anastomosed to the graft liver portal vein in an end-to-end fashion. In conclusion, liver transplantation proved to be a safe and effective way to save this patient and improve her quality of life.  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