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   903篇
  免费   32篇
  国内免费   4篇
耳鼻咽喉   23篇
儿科学   31篇
妇产科学   39篇
基础医学   104篇
口腔科学   12篇
临床医学   44篇
内科学   242篇
皮肤病学   23篇
神经病学   41篇
特种医学   7篇
外科学   165篇
综合类   9篇
预防医学   12篇
眼科学   2篇
药学   69篇
中国医学   7篇
肿瘤学   109篇
  2023年   5篇
  2022年   9篇
  2021年   23篇
  2020年   13篇
  2019年   10篇
  2018年   18篇
  2017年   8篇
  2016年   20篇
  2015年   13篇
  2014年   34篇
  2013年   19篇
  2012年   33篇
  2011年   29篇
  2010年   21篇
  2009年   28篇
  2008年   32篇
  2007年   42篇
  2006年   27篇
  2005年   31篇
  2004年   53篇
  2003年   49篇
  2002年   44篇
  2001年   31篇
  2000年   41篇
  1999年   42篇
  1998年   20篇
  1997年   12篇
  1996年   12篇
  1995年   9篇
  1994年   4篇
  1993年   4篇
  1992年   15篇
  1991年   16篇
  1990年   12篇
  1989年   17篇
  1988年   12篇
  1987年   13篇
  1986年   19篇
  1985年   24篇
  1984年   18篇
  1983年   9篇
  1982年   7篇
  1981年   6篇
  1980年   5篇
  1979年   4篇
  1978年   5篇
  1977年   5篇
  1974年   2篇
  1973年   5篇
  1972年   2篇
排序方式: 共有939条查询结果,搜索用时 0 毫秒
11.

Background/purpose

To clarify the role of interval appendectomy (IA) in pediatric patients with acute appendicitis with an appendiceal inflammatory mass or abscess, we histologically analyzed the appendices removed during IA.

Patients and methods

We treated 355 consecutive pediatric patients with acute appendicitis and reviewed the admission charts of patients who started conservative management (CM). The histology of the appendix removed during IA was also examined. The relationships among the clinical features, appendicolith formation at the time of IA and histological findings were analyzed by stepwise regression analyses.

Results

(1) CM was started in 48 patients (13.5 %). Recurrence or a remaining abscess was observed in nine patients (18.8 %). (2) Histopathological changes, particularly foreign body reaction with fibrosis and infiltration of inflammatory cells, were observed in about half of the specimens. (3) In a stepwise regression analysis, the presence of an appendicolith at IA was correlated with an appendicolith at diagnosis, foreign body reaction in the appendix and a decrease in the inflammatory reaction at diagnosis.

Conclusion

More than half the patients had strong histopathological changes in the appendix, suggesting a high possibility of recurrence. The presence of appendicolith formation at IA, which is a risk factor for recurrence, was influenced by the presence of an appendicolith at diagnosis, foreign body reaction in the appendix and the inflammatory status of patients at diagnosis. These clinical findings are indications for IA.  相似文献   
12.
OBJECTIVE: Ultrasound (US) has been used as a tool to determine the indication for surgery for neonatal ovarian cysts. The purpose of this study was to investigate whether magnetic resonance imaging (MRI) contributes to optimal management. METHODS: Between 1993 and 2001, US and MRI studies were simultaneously performed on 13 consecutive infants younger than 2 months of age with ovarian cysts. The US Patterns were classified as complex or simple. Signal intensity (SI) of the cysts on MRI was compared with that of the liver on T1-weighted images (T1WI) and with urine on T2-weighted images (T2WI). We assumed that high SI on T1WI and iso or low SI on T2WI indicated complications. RESULTS: There were 10 complex and three simple cysts on US. Of the 10 complex cysts, two had no complications at surgery or resolved spontaneously. These two cysts showed low SI on T1WI. Eight complex cysts showed high SI on T1WI and all were haemorrhagic. The US diagnosis corresponded to the MRI findings in three simple cysts. The sensitivity of US for haemorrhage was 80%, and that of MRI was 100%. CONCLUSIONS: We found that MRI was a more reliable diagnostic modality than US for diagnosing neonatal ovarian cysts.  相似文献   
13.
14.
Purpose: The purpose of this paper is to describe the ultrasonographic findings of the patent processus vaginalis (PPV) in neonates.Methods: The patency of the processus vaginalis was examined by ultrasonography in 117 neonates. The ultrasonographic findings, with increment and decrement of the intraabdominal pressure, were categorized into 6 types as follows: type I, the intraabdominal organ is observed; type II, cystic PPV; type III, the PPV is widened with abdominal pressure increment, the length is ≥20 mm; type IV, the PPV contains moving fluid without PPV widening; type V, the PPV is widened with abdominal pressure increment, the length is less than 20 mm; type VI, others. The authors we regarded types I to IV as PPV with inguinal hernia.Results: Twenty-two of 40 neonates with a birth weight under 2,500 g had PPV, including 8 with type I. Twenty of 37 premature neonates 22 to 37 gestational weeks had PPV, including 8 with type I. Eighty-one percent (13 of 16) of PPV in low-birth-weight neonates and 91% (10 of 11) in premature neonates closed spontaneously. The median ages at the time of spontaneous regression of PPV were 242 days in low birth weight neonates and 262 days in premature neonates.Conclusions: Most premature or low-birth-weight neonates with PPV regress spontaneously. The inguinal hernia in neonates (especially in premature or low-birth-weight neonates) should be observed until at least 9 months of age without attempting hernia repair.  相似文献   
15.
Background/Purpose: Sertoli cell cytoskeletons play an important role in the process of spermatogenesis. The authors investigated the effects of cryptorchidism in immature rats on the distribution of Sertoli cell cytoskeletons and the incidence of testis germ cell apoptosis. Methods: Immature 3-week-old rats were made cryptorchid unilaterally, and the distribution of Sertoli cell cytoskeletons by immunohistochemistry and germ cell apoptosis by TUNEL technique were evaluated at different day intervals. Results: Immunohistochemical staining from control rats showed that the distribution of vimentin in Sertoli cells changes in developing rats. Basally, it is localized in the perinuclear region of the cell as well as in filament networks that project into the apical Sertoli cell cytoplasm in a [ldquo ]spokelike[rdquo ] pattern. In cryptorchidism, there was an intense vimentin immunoreactivity surrounding Sertoli cell nuclei along with the collapse of the apical extensions. This became significantly evident by 7 days. Microtubules occur in Sertoli cell cytoplasm apical to the nucleus. Cryptorchidism did not alter their distribution. Spontaneous apoptosis of germ cells occurs in the control testis, and a markedly increased incidence of apoptosis was observed in cryptorchidism by 7 days with decreased testis weight. Conclusions: Taken together, the authors propose that Sertoli cells are affected in cryptorchidism, and altered distribution of Sertoli cells vimentin filaments correlates with the increased germ cell apoptosis. Sertoli cell vimentin filaments are important for maintaining the structural integrity of the seminiferous epithelium.  相似文献   
16.
Background: The incidence of intrahepatic cholelithiasis and cholangitis has not yet been well studied postoperatively in patients with choledochal cysts. Methods: One hundred three patients with choledochal cysts had operative cholangiography, underwent standard excision of a choledochal cyst with Roux-en-Y hepatico-jejunal anastomosis, and were at a mean follow-up of 12[frac12] years. The incidence of intrahepatic bile duct stones was analyzed according to the 3 morphologic types of intrahepatic bile duct observed at initial operative cholangiography: type 1, no dilatation of the intrahepatic bile ducts; type 2, dilatation of the intrahepatic bile ducts but without any downstream stenosis; and type 3, dilatation of the intrahepatic bile ducts associated with downstream stenosis. Initially, there was no evidence of intrahepatic bile duct stones in any of the 103 patients. Results: Among 50 type 1 patients, intrahepatic cholelithiasis developed in only 1 patient (2%). Among 43 type 2 patients, 1 patient (2%) had intrahepatic cholelithiasis, and 2 (5%) had postoperative cholangitis. Among 10 type 3 patients, 4 (40%) had intrahepatic cholelithiasis (P [lt ] .01), and 3 (30%) had postoperative cholangitis. Time intervals between the initial surgery and the first identification of intrahepatic stones ranged from 3 to 22 years. Conclusions: One of the major causes of formation of intrahepatic cholelithiasis has been clarified; patients with intrahepatic biliary dilatation with downstream stenosis can get intrahepatic bile duct stones long after excision of a choledochal cyst.  相似文献   
17.
Abstract: A total of 9000 urine samples from 69 kidney transplant recipients were studied for differential diagnoses of transplant rejection and cyclosporin/tacrolimus toxicity. New–Sternheimer and Papanicolaou staining were used to differentiate cells in urine. We also employed an immunocytochemical technique for further identification of exfoliated cells. With New–Sternheimer and Papanicolaou staining, the predominance of proximal tubular cells was useful to differentiate cyclosporin/tacrolimus toxicity from acute rejection in cases of increased serum creatinine level. During rejection episodes, an increased number of mononuclear cells and renal epithelial cells were found. Immunocytochemical analysis showed a significant increase of CD2-, CD4- CD8-, CD25- and HLA-DR-positive cells with rejection. However, there was no relationship between Banff criteria rejection grade and the increase of mononuclear cells.  相似文献   
18.
Anti-CD20 antibody (rituximab) is recently being used as a B cell-depleting agent in renal transplantation (RTx). However, the incidence of infectious complications associated with rituximab therapy remains uncertain. We evaluated the incidence of cytomegalovirus (CMV) infection associated with rituximab therapy in RTx. A total of 83 patients were enrolled. The immunosuppressive regimen consisted of tacrolimus or cyclosporin, mycophenolate mofetil, methylprednisolone and basiliximab. In 54 patients, only one dose of rituximab (200 or 500 mg/kg body weight) was given before RTx. A total of 25 of 43 (58.1%) recipients who were CMV seropositive prior to RTx and who received rituximab induction therapy developed CMV infection, compared to 18 of 24 (75%) CMV seropositive recipients who did not receive rituximab therapy ( P  = 0.1676). A total of 8 of 11 patients who were CMV seronegative prior to RTx and who received rituximab developed CMV infection. However, CMV seroconversion was seen in all 8 of these infected patients. Low-dose rituximab induction therapy in renal transplant recipients appears to have no influence on the incidence of CMV infection and CMV seroconversion. However, we have to consider anti-CMV prophylaxis therapy, because of high incidents of CMV infection, especially for CMV seronegative recipients who received rituximab.  相似文献   
19.

Purpose

We attempted to identify the exact point of tumor eruption of a solitary fibrous tumor of the pleura (SFTP).

Methods

We morphologically classified 36 SFTPs into 5 categories. Type A showed a connection that included a bloodstream with the pleura on both sides. Type B only showed a connection that included a bloodstream with the visceral pleura, and had a non-bloodstream connection with the parietal pleura. Type C only showed a connection that included a bloodstream with the visceral pleura, and had no connection with the parietal pleura. Type D showed a non-bloodstream connection with the visceral pleura, and only showed a connection that included a bloodstream with the parietal pleura. Finally, type E had no connection with the visceral pleura, and only showed a connection that included a bloodstream with the parietal pleura. The clinicopathological profiles of the tumors were investigated according to their type.

Results

The distribution of the 36 SFTPs was as follows: A (19 %), B (6 %), C (67 %), D (0 %) and E (8 %). The tumors categorized as type A tended to be large in size.

Conclusions

SFTPs commonly arise from the visceral pleura and in accordance with tumor progression they will form a non-bloodstream connection with the parietal pleura. Finally, a vascular pedicle will arise with the parietal pleura.
  相似文献   
20.
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