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   2623篇
  免费   135篇
  国内免费   160篇
耳鼻咽喉   50篇
儿科学   69篇
妇产科学   25篇
基础医学   309篇
口腔科学   55篇
临床医学   264篇
内科学   511篇
皮肤病学   129篇
神经病学   131篇
特种医学   536篇
外科学   269篇
综合类   25篇
预防医学   85篇
眼科学   35篇
药学   260篇
  1篇
中国医学   8篇
肿瘤学   156篇
  2023年   10篇
  2022年   32篇
  2021年   76篇
  2020年   44篇
  2019年   51篇
  2018年   79篇
  2017年   47篇
  2016年   77篇
  2015年   97篇
  2014年   121篇
  2013年   106篇
  2012年   174篇
  2011年   134篇
  2010年   109篇
  2009年   103篇
  2008年   131篇
  2007年   200篇
  2006年   100篇
  2005年   95篇
  2004年   73篇
  2003年   55篇
  2002年   51篇
  2001年   60篇
  2000年   63篇
  1999年   45篇
  1998年   88篇
  1997年   79篇
  1996年   73篇
  1995年   66篇
  1994年   44篇
  1993年   52篇
  1992年   12篇
  1991年   19篇
  1990年   13篇
  1989年   53篇
  1988年   35篇
  1987年   35篇
  1986年   28篇
  1985年   23篇
  1984年   21篇
  1983年   14篇
  1982年   28篇
  1981年   14篇
  1980年   15篇
  1979年   7篇
  1978年   5篇
  1977年   16篇
  1976年   29篇
  1975年   13篇
  1969年   2篇
排序方式: 共有2918条查询结果,搜索用时 0 毫秒
71.
72.
73.
Properties of sulfatides in factor-XII-dependent contact activation   总被引:2,自引:0,他引:2  
Tans  G; Griffin  JH 《Blood》1982,59(1):69-75
Incubation of normal human plasma with low amounts of sulfatides resulted in the initiation of intrinsic coagulation and the appearance of kallikrein activity. The optimal initiation of procoagulant and kallikrein amidolytic activity was dependent on the presence of factor XII, high molecular weight kininogen, and prekallikrein. Since the activated partial thromboplastin clotting times in prekallikrein- deficient plasma approach normal values upon prolonged incubation with kaolin, this phenomenon of autocorrection was studied and found to be even more pronounced in the presence of sulfatides. Autocorrection was essentially completed in 5 min in the presence of sulfatides, whereas a preincubation of 15-20 min was required in the presence of kaolin. The limited proteolysis of 125I-factor XII in plasma during incubation with activating material or during clotting was determined. Cleavage of factor XII was more rapid and more extensive in the presence of sulfatides than in the presence of kaolin. In prekallikrein-deficient plasma, factor XII cleavage was completed within 5 min in the presence of sulfatides and within 15 min in the presence of kaolin. Thus, the appearance of factor-XII-dependent coagulant activity correlates with the limited proteolysis of factor XII when normal or prekallikrein- deficient plasma is activated by sulfatides or kaolin.  相似文献   
74.
Marrow transplantation was attempted in a 13-yr-old boy with congenital hypoplastic anemia who had never responded to corticosteroid therapy. Prior to the transplant, he had received 238 transfusions, at least 12 of which were from his father. He was prepared for grafting with antilymphocyte globulin, procarbazine, and total body irradiation (1000 rads). The patient, whose red cells were Group B, then received marrow cells from his Group O, histocompatible, sister. Thereafter, reticulocytes, Group O erythrocytes, and female leukocytes appeared in the peripheral blood. Erythroid precursors were seen in the patient's marrow for the first time in his life, and all lacked fluorescent Y chromosomes. Dividing cells were all female. After initially progressing well, the patient developed interstitial pneumonia and died 55 days after the transplant. The successful erythroid graft suggested that this patient's failure to produce red blood cells was due to a defective stem cell rather than to a humoral defect, plasma inhibitor, or abnormal marrow microenvironment. It suggested further that sibling marrow may be engrafted in patients who have received multiple transfusions, even from a parent.  相似文献   
75.
To study the effect of interleukin-1 (IL-1) beta on the proliferation of hematopoietic progenitor cells (HPC) in long-term bone marrow cultures (LTBMC), stromal cell layers were established from normal human bone marrow. Autologous cryopreserved mononuclear phagocyte- and T-lymphocyte-depleted bone marrow cells were reinoculated on the stromal layers in fresh culture medium, with or without the addition of human IL-1 beta (30 U/mL). Once a week, half of the culture supernatant was replaced with fresh culture medium with or without IL-1, and all nonadherent cells were returned to the flasks. At weekly intervals during a period of 5 weeks, one culture was sacrificed to determine the total number of cells and hematopoietic progenitor cells, present in the adherent and the nonadherent cell fractions. In IL-1-stimulated cultures, the number of cells recovered during a period of 5 weeks exceeded the number of cells in unstimulated control cultures by 1.5 times. This difference was attributed to a twofold increase in the number of adherent cells. The number of HPC recovered from IL-1- stimulated cultures was not different from that recovered from controls. The levels of colony-stimulating activity (CSA) in supernatants from IL-1-stimulated cultures were significantly higher than those in supernatants from control cultures. These results indicate that IL-1 enhances the recovery of cells in LTBMC by stimulating the proliferation of HPC with the concurrent release of CSA from stromal cells, without diminishing the number of HPC.  相似文献   
76.
Pancreatic fistulas are usually caused by the disruption of pancreatic duct. The majority of pancreatic fistulas are external fistulas and common causes of external and internal pancreatic fistulas are trauma and surgery. Internal pancreatic fistulas due to pancreatitis are rare. Internal pancreatic fistulas may communicate with peritoneal cavity, colon, small bowel, biliary system or pleural cavity. Among them, fistula between pancreatic duct and portal vein due to acute pancreatitis is rare. We report a case of 32-year-old male with fistula between pancreatic duct and portal vein as a complication of acute pancreatitis. Pancreaticoportal fistula was diagnosed by endoscopic retrograde cholangiopancreatography. He recovered after distal pancreatectomy with splenectomy and supportive care.  相似文献   
77.
Delay in hematologic recovery after bone marrow transplantation (BMT) can extend and amplify the risks of infection and hemorrhage, compromise patients' survival, and increase the duration and cost of hospitalization. Because current studies suggest that granulocyte- macrophage (GM) colony-stimulating factor (CSF) may potentiate the sensitivity of hematopoietic progenitor cells to G-CSF, we performed a prospective, randomized trial comparing GM-CSF (250 micrograms/m2/d x 14 days) versus sequential GM-CSF x 7 days followed by G-CSF (5 micrograms/kg/d x 7 days) as treatment for primary or secondary graft failure after BMT. Eligibility criteria included failure to achieve a white blood cell (WBC) count > or = 100/microL by day +21 or > or = 300/microL by day +28, no absolute neutrophil count (ANC) > or = 200/microL by day +28, or secondary sustained neutropenia after initial engraftment. Forty-seven patients were enrolled: 23 received GM-CSF (10 unrelated, 8 related allogeneic, and 5 autologous), and 24 received GM- CSF followed by G-CSF (12 unrelated, 7 related allogeneic, and 5 autologous). For patients receiving GM-CSF alone, neutrophil recovery (ANC > or = 500/microL) occurred between 2 and 61 days (median, 8 days) after therapy, while those receiving GM-CSF+G-CSF recovered at a similar rate of 1 to 36 days (median, 6 days; P = .39). Recovery to red blood cell (RBC) transfusion independence was slow, occurring 6 to 250 days (median, 35 days) after enrollment with no significant difference between the two treatment groups (GM-CSF: median, 30 days; GM-CSF+G- CSF; median, 42 days; P = .24). Similarly, platelet transfusion independence was delayed until 4 to 249 days (median, 32 days) after enrollment, with no difference between the two treatment groups (GM- CSF: median, 28 days; GM-CSF+G-CSF: median, 42 days; P = .38). Recovery times were not different between patients with unrelated donors and those with related donors or autologous transplant recipients. Survival at 100 days after enrollment was superior after treatment with GM-CSF alone. Only 1 of 23 patients treated with GM-CSF died versus 7 of 24 treated with GM-CSF+G-CSF who died 16 to 84 days (median, 38 days) after enrollment, yielding Kaplan-Meier 100-day survival estimates of 96% +/- 8% for GM-CSF versus 71% +/- 18% for GM-CSF+G-CSF (P = .026). These data suggest that sequential growth factor therapy with GM-CSF followed by G-CSF offers no advantage over GM-CSF alone in accelerating trilineage hematopoiesis or preventing lethal complications in patients with poor graft function after BMT.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
78.
BACKGROUND/AIMS: MELD-Na (model for end-stage liver disease with incorporation of serum sodium) was suggested to provide better survival prediction than MELD alone for patients with end stage liver disease. However, there is no data verifying the usefulness of MELD-Na for predicting short term mortality of cirrhotic patients in Korea. This study was aimed to determine whether MELD-Na would be more accurate in predicting short term mortality than other scoring systems such as Child-Turcotte-Pugh (CTP) or MELD. METHODS: Data from 355 patients admitted due to liver cirrhosis were retrospectively reviewed. The cumulative survival rates were obtained. Prediction of mortality rate for three months and one year were analyzed using the area under the receiver's operating characteristics curve (AUC). RESULTS: One hundred patients (28%) died during the study period. All of the three systems showed significant differences in the cumulative survival rate according to the scores on admission (p0.001). The AUC of CTP, MELD, and MELD-Na in predicting three-months mortality were 0.828, 0.845, and 0.862 (p0.05), and the AUC of each score system for death within one year were 0.792, 0.800, and 0.831, respectively (p0.05). The AUC of MELD-Na in predicting short term death were the highest, although it was not statistically significant. Multivariate analysis showed that only MELD-Na was significantly related to three-month mortality (p=0.012). CONCLUSIONS: MELD-Na is more appropriate in predicting short term mortality, but larger scale studies are needed to confirm the superiority of MELD-Na to MELD and CTP in patients with liver cirrhosis.  相似文献   
79.

Objective

Chronic pain frequently coexists with psychiatric symptoms in patients diagnosed with complex regional pain syndrome (CRPS). Previous studies have shown a relationship between CRPS and the risk of suicide. The purpose of this study was to assess risk factors for suicidal ideation in patients with CRPS.

Methods

Based on criteria established by the International Association for the Study of Pain, 39 patients diagnosed with CRPS Type 1 or Type 2 were enrolled in this study. Suicidal ideation was assessed using item 3 of the Hamilton Depression Rating Scale (HAMD), and symptoms of pain were evaluated using the short form of the McGill Pain Questionnaire (SF-MPQ). Psychiatric symptoms were assessed in using the Structured Clinical Interview for DSM-IV Disorders (SCID-I, SCID-II), the HAMD, the Hamilton Anxiety Rating Scale (HAMA), the Global Assessment of Functioning Scale (GAF), and the Pittsburgh Sleep Quality Index (PSQI).

Results

Twenty-nine patients (74.4%) were at high risk and 10 (25.6%) were at low risk for suicidal ideation. Risk factors significantly associated with suicidal ideation included depression (p=0.002), severity of pain (p=0.024), and low scores on the GAF (p=0.027). No significant correlations were found between suicidal ideation and anxiety or quality of sleep.

Conclusion

Significant risk factors for suicidal ideation in patients with CRPS include severity of pain, depressive symptoms, and decreased functioning. These results suggest that psychiatric evaluation and intervention should be included in the treatment of CRPS.  相似文献   
80.
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