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   4886822篇
  免费   387962篇
  国内免费   16329篇
耳鼻咽喉   69395篇
儿科学   153794篇
妇产科学   130291篇
基础医学   732987篇
口腔科学   137105篇
临床医学   446310篇
内科学   891396篇
皮肤病学   115006篇
神经病学   413828篇
特种医学   192384篇
外国民族医学   1213篇
外科学   734817篇
综合类   143649篇
现状与发展   24篇
一般理论   2821篇
预防医学   413955篇
眼科学   116343篇
药学   345949篇
  24篇
中国医学   13102篇
肿瘤学   236720篇
  2021年   56521篇
  2019年   59193篇
  2018年   75315篇
  2017年   57716篇
  2016年   64317篇
  2015年   76883篇
  2014年   111806篇
  2013年   177314篇
  2012年   138788篇
  2011年   145406篇
  2010年   129160篇
  2009年   130342篇
  2008年   131506篇
  2007年   140764篇
  2006年   148776篇
  2005年   143688篇
  2004年   143856篇
  2003年   133787篇
  2002年   123575篇
  2001年   188153篇
  2000年   185711篇
  1999年   167451篇
  1998年   75692篇
  1997年   70843篇
  1996年   68745篇
  1995年   64466篇
  1994年   58386篇
  1993年   54125篇
  1992年   124170篇
  1991年   118727篇
  1990年   113192篇
  1989年   109974篇
  1988年   102001篇
  1987年   100317篇
  1986年   94779篇
  1985年   92502篇
  1984年   76396篇
  1983年   67467篇
  1982年   51785篇
  1981年   47929篇
  1980年   44991篇
  1979年   67802篇
  1978年   53479篇
  1977年   46668篇
  1976年   43522篇
  1975年   43276篇
  1974年   49413篇
  1973年   47552篇
  1972年   44644篇
  1971年   41044篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
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   
992.
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   
993.
994.
Background Familial partial lipodystrophy (FPLD) is a monogenic form of diabetes characterised by a dominantly inherited disorder of adipose tissue associated with the loss of subcutaneous fat from the limbs and trunk, with excess fat deposited around the face and neck. The lipodystrophy causes severe insulin resistance, resulting in acanthosis nigricans, diabetes, dyslipidaemia, and increased risk of cardiovascular disease. Preliminary results from animals and man suggest that increasing subcutaneous fat by treatment with thiazolidinediones should improve insulin resistance and the associated features of this syndrome. Case report We report a 24-year-old patient with FPLD caused by a mutation in the LMNA gene (R482W) treated with 12 months of rosiglitazone. Subcutaneous fat increased following rosiglitazone treatment as demonstrated by a 29% generalised increase in skin-fold thickness. Leptin levels increased from 5.8 to 11.2 ng/ml. Compared with treatment on Metformin, there was an increase in insulin sensitivity (HOMA S% 17.2–31.6) but no change in glycaemic control. The lipid profile worsened during the follow-up period. Conclusion This initial case suggests that, for modification of cardiovascular risk factors, there are no clear advantages in treating patients with FPLD with rosiglitazone despite increases in subcutaneous adipose tissue. Larger series will be needed to identify moderate beneficial effects and treatment may be more effective in patients with generalised forms of lipodystrophy.  相似文献   
995.
996.
997.
肱骨骨不连的手术治疗   总被引:4,自引:0,他引:4  
目的探讨肱骨骨不连的手术治疗方法及疗效。方法1998年12月~2005年5月共收治肱骨骨不连患者25例,均为肱骨骨折内固定术后发生骨不连,其中3例并发骨髓炎,6例合并不同程度肱骨骨缺损,骨缺损长度为3~6cm。骨不连病程8个月~5年。15例行吻合血管游离腓骨移植,10例采用加压交锁髓内针进行肱骨固定并辅以自体骨植骨。结果术后25例均得到随访,时间6个月~6年2个月。吻合血管游离腓骨移植组中移植的腓骨段均与肱骨干形成骨性愈合,平均骨性愈合时间为3.1个月;交锁髓内针组平均骨愈合时间为3.8个月。按Crates和Whittle肩肘关节功能评价标准,腓骨移植组:优9例,良4例,差2例;交锁髓内针组:优5例,良3例,差2例。结论应用加压交锁髓内针辅以自体骨移植对硬化性肱骨骨不连是一种有效的外科治疗方法;对合并骨髓炎、大段骨缺损及严重骨质疏松的肱骨骨不连,采用吻合血管游离腓骨移植可一期进行修复与重建。  相似文献   
998.
999.
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   
1000.
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   
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