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   2859篇
  免费   154篇
  国内免费   38篇
耳鼻咽喉   15篇
儿科学   69篇
妇产科学   36篇
基础医学   406篇
口腔科学   27篇
临床医学   162篇
内科学   734篇
皮肤病学   55篇
神经病学   206篇
特种医学   62篇
外科学   524篇
综合类   22篇
一般理论   1篇
预防医学   66篇
眼科学   33篇
药学   207篇
中国医学   19篇
肿瘤学   407篇
  2023年   17篇
  2022年   27篇
  2021年   38篇
  2020年   22篇
  2019年   46篇
  2018年   58篇
  2017年   50篇
  2016年   55篇
  2015年   66篇
  2014年   91篇
  2013年   96篇
  2012年   139篇
  2011年   179篇
  2010年   106篇
  2009年   62篇
  2008年   139篇
  2007年   142篇
  2006年   153篇
  2005年   172篇
  2004年   135篇
  2003年   110篇
  2002年   143篇
  2001年   99篇
  2000年   103篇
  1999年   115篇
  1998年   41篇
  1997年   28篇
  1996年   38篇
  1995年   19篇
  1994年   26篇
  1993年   20篇
  1992年   53篇
  1991年   40篇
  1990年   37篇
  1989年   44篇
  1988年   36篇
  1987年   35篇
  1986年   50篇
  1985年   37篇
  1984年   27篇
  1983年   25篇
  1982年   12篇
  1981年   14篇
  1980年   11篇
  1979年   8篇
  1978年   12篇
  1977年   10篇
  1975年   12篇
  1973年   10篇
  1966年   7篇
排序方式: 共有3051条查询结果,搜索用时 15 毫秒
31.
We herein describe the case of a 48-year-old man who presented to our hospital with abdominal distension and pain. Preoperative studies including abdominal ultrasonography and computed tomography failed to determine the cause of the pain. At laparotomy, a giant cystic tumor of the small bowel mesentery was found. Histologically, the tumor was diagnosed as a cystic lymphangioma. Although mesenteric lymphangiomas are rare, especially in adults, they should be considered as a possible cause of acute abdomen. Received: August 8, 2001 / Accepted: January 8, 2002  相似文献   
32.
 Low back pain is an enormous clinical and public health problem. When we use spinal instrumentation, measurements of spinal and leg alignment in the standing position are thought to be important. Knee joint pain has also become an enormous clinical problem in the increasing elderly population. However, the correlation between spinal alignment, particularly sacral inclination, and knee joint pain is not clear. We examined the correlation between lumbar lordosis, sacral inclination, and patellofemoral joint pain in elderly subjects. Three hundred and ninety-nine people aged 50–85 years were examined. Clinical findings and physical status were determined. Measurements and determination of total lordosis from L1 to S1 and sacral inclination were made from standing radiographs. The knee joints were evaluated by using the standing knee flexion angle, radiographs, and the patellofemoral (PF) joint grinding test. Thirty-nine percent of subjects were excluded because they had definite osteo-arthritis at the femorotibial joints. Fifty-eight percent of the subjects had felt low back pain within the previous 3 months, and 16% of the subjects complained of PF joint grinding pain. Sixteen percent of the subjects showed knee flexion when standing. There was a significant difference in sacral inclination between the groups with and without PF joint grinding pain (P < 0.01). Sacral inclination was approximately 5° less in the knee flexion group. A correlation between sacral inclination and PF joint pain is defined, and its prevalence in the elderly is reported. We speculate that this phenomenon is caused by changing of lumbar alignment. In addition, we think this is a new pathological concept that we call the knee – spine syndrome. Received: July 23, 2001 / Accepted: May 2, 2002  相似文献   
33.
Granular cell tumors are uncommon but typically histologically benign neoplasms that occasionally behave as malignant tumors. Differentiation of benign granular cell tumors from malignant counterparts with radiographic and/or histologic analysis is crucial for physicians. We retrospectively studied five cases of intramuscular granular cell tumors arising in the lower extremities. All tumors had been histologically diagnosed as benign and were resected with a wide surgical margin. The minimum followup was 1 year (mean, 45 months; range, 12–119 months) after surgery. Four patients had no local recurrence or distant metastasis (at a minimum of 18 months followup), whereas one patient with lymph node metastasis had a recurrence and distant metastasis 3 months after surgery resulting in death. Intramuscular granular cell tumors can be diagnosed based on their characteristic MRI features, such as peripheral high intensity on T2-weighed images, and histologic evaluation. The histologic criteria described by Fanburg-Smith et al. can differentiate malignant granular cell tumors from benign tumors. A wide resection seems suitable for most granular cell tumors in the extremities.  相似文献   
34.
Purpose: To evaluate the indication and advantages of venous sac embolization of pulmonary arteriovenous malformations (PAVMs) using interlocking detachable coils (IDCs). Methods: We performed percutaneous embolization in 12 PAVMs in four patients using IDCs, initially placed in the venous sac or at the feeding artery to prevent systemic migration of additional coils. We placed the IDCs in the venous sac in PAVMs with the following vascular architecture: the draining vein was larger than the feeding arteries and both vessels were interposed with the venous sac or there were short feeding arteries. Results: Complete occlusion was achieved in all 12 PAVMs without significant complications. We deployed IDCs in the venous sac in eight PAVMs and in the feeding artery in four. Conclusion: Venous sac embolization may be beneficial in PAVMs with large out-flow vessels or short feeding arteries. IDCs are suitable for this procedure.  相似文献   
35.
Parathyroid hormone (PTH) increases serum calcium (Ca) by enhancing bone resorption and renal Ca reabsorption. However, detailed mechanisms of enhanced bone resorption by PTH remain to be elucidated. Although PTH has been shown to increase the expression level of osteoblastic matrix metalloproteinase (MMP)-13 in vitro, only limited results are available regarding the in vivo regulation of MMP expression. In the present study, we have examined expression levels of MMPs in PTH-infused rats. Infusion of 1.5 or 2.0 nmol/kg/day rat PTH(1–34) for 3 days resulted in a dose-dependent increase in serum Ca. PTH infusion also decreased serum phosphate levels and increased urinary excretion of Ca and phosphate. Infusion of PTH for 7 days resulted in less severe hypercalcemia and hypophosphatemia. Urinary Ca and phosphate excretion in rats infused for 7 days was less than that in rats infused for 3 days. Northern blot analysis showed that PTH infusion increased the expression level of MMP-13 in calvaria, although it did not affect MMP-2 expression. Furthermore, the time-course and severity of hypercalcemia and hypercalciuria correlated with the expression level of MMP-13. In situ hybridization also showed that PTH infusion increased the expression level of MMP-13 in femora. These results indicate that PTH enhances MMP-13 expression in vivo and suggest that PTH stimulates bone resorption at least partly by enhancing MMP-13 expression. Received: June 5, 2000 / Accepted: January 12, 2001  相似文献   
36.
We report a 71-year-old man who had undergone pylorus-preserving pancreatoduodenectomy (PPPD) using PPPD-IV reconstruction for cholangiocarcinoma. For 6 years thereafter, he had suffered recurrent cholangitis, and also a right liver abscess (S5/8), which required percutaneous drainage at 9 years after PPPD. At 16 years after PPPD, he had been admitted to the other hospital because of acute purulent cholangitis. Although medical treatment resolved the cholangitis, the patient was referred to our hospital because of dilatation of the intrahepatic biliary duct (B2). Peroral double-balloon enteroscopy revealed that the diameter of the hepaticojejunostomy anastomosis was 12 mm, and cholangiography detected intrahepatic stones. Lithotripsy was performed using a basket catheter. At 1 year after lithotripsy procedure, the patient is doing well. Hepatobiliary scintigraphy at 60 minutes after intravenous injection demonstrated that deposit of the tracer still remained in the upper afferent loop jejunum. Therefore, we considered that the recurrent cholangitis, liver abscess, and intrahepatic lithiasis have been caused by biliary stasis due to nonobstructive afferent loop syndrome. Biliary retention due to nonobstructive afferent loop syndrome may cause recurrent cholangitis or liver abscess after hepaticojejunostomy, and double-balloon enteroscopy and hepatobiliary scintigraphy are useful for the diagnosis of nonobstructive afferent loop syndrome.Key words: Nonobstructive afferent loop syndrome, Biliary stasis, Hepaticojejunostomy, Hepatobiliary scintigraphy, Double-balloon enteroscopyIt has been reported that cholangitis occurs in between 6.7% and 14.3% of postoperative pancreatoduodenectomy (PD).1 Most cases of cholangitis originate due to biliary stasis, which is broadly caused by either anastomotic or nonanastomotic stenosis. In many cases, anastomotic stenosis is accompanied by intrahepatic biliary duct dilatation and obstructive jaundice, making early diagnosis and treatment possible.23 On the other hand, nonanastomotic stenosis, including those of afferent loop syndrome, is performed as a conservative treatment for unexplained fever and cholangitis. However, in many cases, the cause remains unidentified, thereby causing this condition to repeat itself. Since cholangitis can at times be fatal, it is therefore important to identify the cause.It has been reported that afferent loop syndrome occurs in around 13% of postoperative PD patients.4 Afferent loop syndrome is generally caused by mechanical occlusion due to the recurrence or metastasis of cancer,46 adhesion,78 torsion,9 internal hernia,10 enterolithiasis,1112 etc., and thereafter, leads to a syndrome associated with acute abdominal symptom or acute cholangitis. On the other hand, nonobstructive afferent loop syndrome may also be caused by biliary stasis due to jejunal motility failure or the length of the blind end or jejunum, and thereafter, leads to acute cholangitis, liver abscess, and the formation of enterolithiasis and intrahepatic stones. Nonobstructive afferent loop syndrome occurs in around 37% of all of the afferent loop syndrome,1213 but few cases have actually been reported.We herein report a rare case in which the patient experienced recurrent cholangitis and liver abscess by biliary stasis due to nonobstructive afferent loop syndrome after pylorus-preserving pancreatoduodenectomy (PPPD) for cholangiocarcinoma.  相似文献   
37.
BACKGROUND: Concerning the relationship between morphology and clinical outcome, there have been many reports using computed tomography/myelography but not so many using axial magnetic resonance imaging (MRI) of the spinal cord. This is the first report to correlate axial cord image, intensity changes in MRI, and cord expansion pattern using intraoperative ultrasonography. OBJECTIVE: The objectives were to correlate MRI studies, axial cord images/expansion, and changes in MRI intensity to see if there is a direct prognostic significance to these changes and to determine whether preoperative axial MRI images of the spinal cord predict recovery from compressive myelopathy. METHODS: Posterior cervical decompressions with laminoplasty were performed in 44 patients with cervical myelopathy due to ossification of the posterior longitudinal ligament. On T2-weighted MR images, the cross-sectional shape of the cord at the level of maximal compression was categorized as boomerang, teardrop, or triangle. Additionally, with use of intraoperative ultrasonography, the expansion pattern of the cord that occurred intraoperatively was contrasted with that seen on postoperative MR images. RESULTS: Clinical recovery rates were the worst for those with triangular, intermediate for those with boomerang, and the best for those with teardrop shape. Preoperative low T1 and high T2 signals were found in most cases with triangular cord configurations. Triangular cord configurations showed the least expansion among the three categorized spinal cords. CONCLUSION: Patients with triangular deformity of the cord have atrophy as confirmed on MR studies where there is a low T1 and high T2 signal in the cord. Poor postoperative clinical recovery correlates with the lack of postoperative cord expansion on either MR or ultrasound evaluations. Those with either teardrop or boomerang deformities demonstrate a relatively good recovery rate.  相似文献   
38.

Background  

Most elderly patients have cardiopulmonary diseases anamnesis and a perceived risk of perioperative complications. The responsible lesion may be located more cranially in elderly patients with cervical spondylotic myelopathy (CSM) compared with that in younger patients. The study aimed at evaluating cardiopulmonary dysfunction of CSM and effects of surgery on cardiopulmonary function and perioperative complications.  相似文献   
39.
Surgery combined with radiosurgery of large acoustic neuromas   总被引:6,自引:0,他引:6  
Iwai Y  Yamanaka K  Ishiguro T 《Surgical neurology》2003,59(4):283-9; discussion 289-91
The treatment of acoustic neuromas has been improved by advancements in microsurgical techniques and in radiosurgery. To further elucidate the degree of clinical improvement, we evaluated the treatment results of a combination of surgery and radiosurgery for large acoustic neuromas. METHODS: From January 1994 through December 2000, we treated 14 patients with large acoustic neuromas using a combination of surgery and radiosurgery. Of these, 8 were male and 6 were female patients, with an average age of 47 years (range, 18-64). The average maximum diameter of the tumor was 42 mm (range, 30-58 mm). All patients underwent operations using the retrosigmoid approach, and one patient was retreated using the transpetrosal transtentorial approach. The tumors were removed subtotally in thirteen patients and partially in one who had a very large hypervascular acoustic neuroma. There were no mortality and no surgical complications, such as hemorrhage or CSF leakage. Postoperative facial palsy was avoided in 10 patients (71%). Radiosurgery was performed 1 to 6 months (mean, 2.9 months) after surgery. At the time of radiosurgery, the treatment size (mean diameter) became 19.2 mm (range, 9.8-36.1 mm). The average tumor marginal dose was 12.1Gy (range, from 10-14 Gy). The mean follow-up period was 32 months after radiosurgery. RESULTS: The tumor size decreased in 6 patients, unchanged in 5 patients, and increased in 3 patients. Only 1 patient (7%) with extra large tumor needed surgical resection 1 year after radiosurgery. Excellent facial nerve function (House & Brackmann Grade I or II) was preserved in 12 patients (85.7%) in the final follow-up. CONCLUSIONS: In the case of large acoustic neuromas, subtotal removal and subsequent radiosurgery is one option for maintaining cranial nerve function and long-term tumor growth control.  相似文献   
40.
BACKGROUND: Cytokeratin immunostaining is the most common method used to identify micrometastatic cancer cells from the lymph nodes. However, contamination with hyalinized cytokeratin particles, frequently observed in the lymph nodes of esophageal cancer patients, can lead to misinterpretation of cytokeratin immunostaining. MATERIALS AND METHODS: Cytokeratin immunostaining (AE1/AE3) of surgically removed lymph nodes was performed for 41 cases of node-negative, but locally advanced (T3, T4), esophageal cancer patients. Cytokeratin immunoreactivity (CK) was classified as micrometastasis (MM) or cytokeratin deposit (CD) by the presence or absence of tumor nuclei in serial sections given hematoxylin-eosin staining. RESULTS: CK (+) was observed in 18 patients (44%), including 11 with MM (+) (27%) and 10 with CD (+) (24%). There was no correlation between MM and CD, and neither was associated with clinicopathological factors, except for a high incidence of preoperative chemotherapy in CD (+) patients. The presence of CK did not affect postoperative survival of esophageal cancer patients at this limited stage, showing a 5-year survival rate of 57% for CK (+) and 64% for CK (-) (P = 0.6064). Interestingly, patients with MM (+) showed poorer prognosis than MM (-) (5-year survival: 28% vs 79%, P = 0.0188), while CD (+) patients tended to display better prognosis than CD (-) ones (5-year survival: 78% vs 56%, P = 0.1860). CONCLUSIONS: Evaluation by cytokeratin immunostaining of lymph nodes requires careful discrimination of CD from MM, in order to allow MM to be used as a prognostic factor for esophageal cancer patients.  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