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   1921939篇
  免费   134391篇
  国内免费   3779篇
耳鼻咽喉   26292篇
儿科学   63744篇
妇产科学   53236篇
基础医学   275093篇
口腔科学   53798篇
临床医学   172573篇
内科学   366379篇
皮肤病学   44010篇
神经病学   148766篇
特种医学   75151篇
外国民族医学   497篇
外科学   290380篇
综合类   42305篇
现状与发展   1篇
一般理论   620篇
预防医学   142497篇
眼科学   44382篇
药学   146587篇
  9篇
中国医学   4357篇
肿瘤学   109432篇
  2018年   20029篇
  2017年   15622篇
  2016年   17833篇
  2015年   19970篇
  2014年   27310篇
  2013年   40804篇
  2012年   54917篇
  2011年   58326篇
  2010年   34661篇
  2009年   32515篇
  2008年   54309篇
  2007年   57915篇
  2006年   58875篇
  2005年   56330篇
  2004年   54470篇
  2003年   52297篇
  2002年   50473篇
  2001年   96757篇
  2000年   99296篇
  1999年   83008篇
  1998年   21955篇
  1997年   19452篇
  1996年   19459篇
  1995年   18487篇
  1994年   16990篇
  1993年   15989篇
  1992年   64349篇
  1991年   62294篇
  1990年   61485篇
  1989年   59270篇
  1988年   53648篇
  1987年   53090篇
  1986年   49744篇
  1985年   47454篇
  1984年   35021篇
  1983年   29542篇
  1982年   16944篇
  1981年   15043篇
  1979年   31776篇
  1978年   22099篇
  1977年   19348篇
  1976年   17512篇
  1975年   19067篇
  1974年   22604篇
  1973年   21878篇
  1972年   20506篇
  1971年   19169篇
  1970年   17679篇
  1969年   16840篇
  1968年   15300篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Although surgical lung resection could improve prognosis in some patients with multidrug-resistant tuberculosis (MDR-TB), there are no reports on the optimal candidates for this surgery. The aim of the present study was to elucidate the prognostic factors for surgery in patients with MDR-TB. Patients who underwent lung resection for the treatment of MDR-TB between March 1993 and December 2004 were included in the present study. Treatment failure was defined as greater than or equal to two of the five cultures recorded in the final 12 months of treatment being positive, any one of the final three cultures being positive, or the patient having died during treatment. The variables that affected treatment outcomes were identified through univariate and multivariate logistic regression analysis. In total, 79 patients with MDR-TB were included in the present study. The treatment outcomes of 22 (27.8%) patients were classified as failure. A body mass index <18.5 kg x m(-2), primary resistance, resistance to ofloxacin and the presence of a cavitary lesion beyond the range of the surgical resection were associated with treatment failure. Low body mass index, primary resistance, resistance to ofloxacin and cavitary lesions beyond the range of resection are possible poor prognostic factors for surgical lung resection in multidrug-resistant tuberculosis patients.  相似文献   
92.
The increased number of lymphocytes in airways during an asthmatic response is believed to be the result of increased recruitment of these cells. However, it is possible that a decreased apoptotic rate could also contribute to the increased number. The aim of the present study was to investigate whether allergen airway provocation influences the apoptotic phenotype of lung and peripheral blood lymphocytes (PBL) in subjects with atopic asthma. Bronchoalveolar lavage (BAL) lymphocytes and PBL from 12 asthmatic subjects previously challenged with allergen (n = 7) or saline (n = 5) were exposed to the apoptotic stimulus tributyltin (TBT) in vitro and assayed for apoptosis. Airway allergen provocation resulted in decreased sensitivity of BAL lymphocytes to TBT-induced apoptosis, with 42.2% (range 33.9-62.5%) apoptotic cells before challenge versus 23.5% (range 15.3-42.4%) after challenge, while PBL were unaffected. The increased apoptosis resistance correlated with higher numbers of Bcl-2-expressing lymphocytes. Interestingly, baseline caspase-3-like activity was significantly elevated in viable BAL lymphocytes compared with viable PBL, and was unaltered by allergen exposure. In conclusion, allergen inhalation renders bronchoalveolar lavage lymphocytes more resistant to apoptosis while peripheral blood lymphocytes were not influenced at all, indicating that the apoptotic phenotype of airway lymphocytes may play a role in asthmatic inflammation.  相似文献   
93.
Pancreatic panniculitis is an uncommon condition that can occur in association with pancreatic disease. We present a case of pancreatic panniculitis in a female pancreas-kidney transplant recipient 5 months post-transplant. The patient was on standard immunosuppressive medications and had acute rejection of her renal allograft. The diagnosis of allograft pancreatitis and rejection presenting with pancreatic panniculitis was supported clinically, histopathologically and by laboratory and imaging data. This is the fourth case of pancreatic panniculitis occurring in a transplant recipient and the first in a simultaneous pancreas-kidney transplant recipient. It is also the first case associated with allograft rejection. Clinicians should be aware that pancreatic panniculitis may be a manifestation of underlying allograft pancreatic disease.  相似文献   
94.
The clinical outcome and appropriate management for patients showing 'borderline changes' on allograft biopsy after renal transplantation is still controversial. In an attempt to identify predictive factors of clinical outcome of patients with such lesions, we reviewed the clinical course of 91 patients with borderline changes. Multivariate analysis revealed significant and independent effects of histological stage (i + t < or = or > 2) and time to borderline changes (< or = or > 3 months after transplant) on serum creatinine levels at 1 year from borderline changes episodes (respectively, p = 0.04 and p = 0.02) and only a significant effect of time to borderline changes on serum creatinine levels at 2 years (p = 0.005). Renal function at 1 year and 2 years as 5- and 8-year graft survival were not significantly different in the group of patients treated with antirejection therapy (T group, n = 49) compared with the untreated group (UT group, n = 42). This study strongly suggests that borderline changes with histological score (i + t) > 2 and late episodes of borderline changes should be considered to be of poor prognosis.  相似文献   
95.
In floating hip injuries, the priority of the steps in fixation has not been well described. We have treated these patients in accordance with the following protocols. In patients with pelvic ring fractures, the external fixation should be performed first, and in patients with acetabular fractures, the femoral fractures should be internally fixated first. The purpose of the present study was to review our experience with these fracture treatments to evaluate our strategy. For 8 years, 31 patients with femoral fractures associated with ipsilateral fractures: 26 unstable pelvic ring fractures and 7 unstable acetabular fractures were surgically treated at our level 1 trauma center. We reviewed the admission, operation, and follow-up records retrospectively and evaluated the order of the fixation and the complications. Two patients with acetabular fractures failed to follow our protocol outlined at the preoperative planning stage. There were no surgical difficulties other than two patients with the hemipelvis dislocated proximally who required traction of the fixated femur. The complications that were thought to be related to our protocol were one fat embolism syndrome and one pubic fracture displacement. One heterotopic ossification seemed to occur due to using a single approach for both fractures. We believe our protocol to be generally effective, however, in patients with acetabular and vertical shear type pelvic ring fractures, the internal or external fixation of the femur should be performed before the internal fixation of the pelvis.  相似文献   
96.
97.
98.
99.
PURPOSE: In children with locally advanced or recurrent malignant tumours, prognosis can be improved by regional deep hyperthermia (RHT) in combination with platin-based chemotherapy. However, because of the increasing number of patients that achieve long-time remission with this therapy, it is necessary to evaluate long-term sequelae of thermochemotherapy. During the years 1993-2004 one has observed avascular osteonecrosis (AON) of the femoral head after RHT in seven children with pelvic germ cell tumours or rhabdomyosarcomas. METHODS: Although AON may develop in patients with malignancies treated with chemo- or radiotherapy alone, RHT might nevertheless contribute to the occurrence of AON. In order to determine potential risk factors for AON after RHT, this study analysed the relationship of AON to the patient's age, medical history and treatment parameters such as thermal dose equivalent and power output. RESULTS AND CONCLUSIONS: In the present study AON was associated with young age as well as intensity of hyperthermia indicated by high power levels that exceed 20 W per kg body weight and/or application of eight or more heat sessions as well as additional radiotherapy. Based on this observation, it was assumed that an optimized three dimensional thermal field modelling may be helpful to avoid hazardous temperatures in the femoral heads during RHT treatment and to reduce AON of the femoral heads.  相似文献   
100.
A 17-year-old man presented with signs of peritonitis. Laparotomy revealed gangrene of the stomach without obvious cause. The patient underwent total gastrectomy with esophago-jejunal anastomosis with formation of jejunal pouch. Bacterial culture of the peritoneal fluid grew Strept. pyogenes and E. coli. The patient was discharged on day 21 after a stormy postoperative course.  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