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   657篇
  免费   77篇
耳鼻咽喉   2篇
儿科学   53篇
妇产科学   9篇
基础医学   96篇
口腔科学   9篇
临床医学   70篇
内科学   229篇
皮肤病学   1篇
神经病学   18篇
特种医学   6篇
外科学   89篇
综合类   7篇
预防医学   27篇
眼科学   7篇
药学   34篇
肿瘤学   77篇
  2023年   6篇
  2022年   12篇
  2021年   12篇
  2020年   16篇
  2019年   19篇
  2018年   27篇
  2017年   14篇
  2016年   21篇
  2015年   28篇
  2014年   28篇
  2013年   27篇
  2012年   23篇
  2011年   30篇
  2010年   28篇
  2009年   14篇
  2008年   30篇
  2007年   30篇
  2006年   33篇
  2005年   20篇
  2004年   29篇
  2003年   18篇
  2002年   31篇
  2001年   27篇
  2000年   21篇
  1999年   23篇
  1998年   9篇
  1997年   5篇
  1996年   8篇
  1995年   6篇
  1994年   8篇
  1993年   12篇
  1992年   16篇
  1991年   10篇
  1990年   6篇
  1989年   8篇
  1988年   5篇
  1987年   6篇
  1986年   6篇
  1985年   6篇
  1984年   5篇
  1983年   5篇
  1982年   2篇
  1980年   5篇
  1969年   2篇
  1939年   3篇
  1938年   2篇
  1932年   2篇
  1913年   2篇
  1912年   2篇
  1898年   2篇
排序方式: 共有734条查询结果,搜索用时 15 毫秒
91.
The effect of granulocyte-macrophage colony-stimulating factor (GM-CSF) on the serological response at influenza vaccination was studied in 117 patients who had undergone stem cell transplantation (SCT). The vaccine response was evaluated as significant increases in levels of influenza hemagglutination-inhibition (HAI) antibodies and of IgG antibodies measured by enzyme-linked immunosorbent assay (ELISA). There was no difference in antibody response to either influenza A or B in 64 patients who received GM-CSF at vaccination, compared with the 53 who did not. In the subgroup of allogeneic SCT patients, HAI showed that the response rate to the influenza B vaccine was significantly higher in the treatment group (P<.05). ELISA showed that autologous SCT patients with breast cancer who received GM-CSF had a better response to influenza A (P<.05) and B (P<.01). At early vaccination, 4-12 months after stem cell transplantation, these responses were more pronounced. GM-CSF appears to improve the response to influenza vaccination in some groups of SCT patients, but only to a limited extent.  相似文献   
92.
The immunostimulatory activity of viridans streptococcal strains isolated from neutropenic patients with severe sepsis (n=9) or uncomplicated bacteraemia (n=10) was compared. Peripheral blood mononuclear cells from healthy individuals were stimulated with heat-killed bacteria or culture supernatants, and cytokine production assessed. All strains were potent inducers of IL1beta, IL8, and TNFalpha production. Heat-killed bacteria induced consistently higher IL1beta and TNFalpha production than did the cell-free bacterial supernatants (P<0.01). The strains did not induce any proliferative response, nor any significant TNFbeta or IFNgamma production. No difference in cytokine-inducing capacity could be detected between the cohorts of severe and nonsevere isolates. Comparison of strains causing severe and nonsevere episodes in the same patient (n=2) revealed a significantly higher induction of IL1beta by the severe episodes associated isolates as compared to the nonsevere (P<0.04). The study underscores the importance of the host-pathogen interplay in determining the level of inflammation, and hence the severity of disease.  相似文献   
93.
Revaccination with poliovirus after allogeneic stem cell transplant (SCT) is usually effective, but the longevity of this immunity is unknown. Therefore, poliovirus immunity was studied in 134 patients having survived at least 5 years after vaccination. The median follow-up from vaccination was 8 years (1-19 years). In all, 21 (15.6%) patients had become seronegative to at least one of the poliovirus serotypes during follow-up. The estimated probabilities of remaining immune to poliovirus at 5 and 10 years after vaccination were 94 and 94% for subtype 1, 98 and 94% for subtype 2, and 93 and 90% for subtype 3, respectively. In multivariate analysis, the only risk factor for loss of immunity was younger patient age (P < 0.01), and there was a strong trend for patients with chronic GVHD to lose immunity more rapidly (P = 0.07). A total of 14 patients received a booster dose of an inactivated poliovirus vaccine and all responded. We conclude that poliovirus immunity is retained long term after revaccination in most patients after allogeneic SCT.  相似文献   
94.
We studied the clinical course of 130 chronic myeloid leukemia (CML) patients (89 males and 41 females) in the European Bone Marrow Transplantation Group (EBMT) registry who received transplants before January 1, 1988 and who subsequently had evidence of recurrent leukemia. All patients had received a pretransplant conditioning regimen including total body irradiation (TBI). The first evidence of relapse was cytogenetic only in 74 (57%) patients and hematologic in 56 (43%). The overall actuarial survival from relapse was 36% at 6 years, with a significantly higher proportion of survivors among female patients (53% v 30%; P < .002). In univariate analysis, the 6-year probability of survival was 52% for patients with cytogenetic relapse and 30% for patients relapsing in chronic phase (CP), while no patient who relapsed in advanced phase (AP or BC) survived more than 3.5 years from relapse (P < .0001). The actuarial survival of patients relapsing before 6 months, between 6 and 12 months, and later than 12 months after transplant was 27%, 26%, and 45%, respectively (P < .002). Among patients with cytogenetic relapse, partial or complete disappearance of Ph-positive cells occurred in 40% of untreated patients and in 42% of those treated with interferon (IFN). However, IFN therapy significantly delayed progression toward hematologic disease. Cytogenetic responses were observed in 25% of patients who received IFN for relapse into CP, while only one minor cytogenetic response was reported in patients on conventional chemotherapy. For patients presenting with cytogenetic relapse as well as for those in hematologic relapse, IFN therapy significantly improved the 2-year probability of survival. However, long-term survival for IFN-treated patients in either group was not different from long-term survival in comparable patients not receiving IFN therapy. Twenty-nine patients of this series underwent a second bone marrow transplant (BMT) and the projected survival at 4 years after the second transplant is 28%. In multivariate Cox regression analysis, four factors remained significantly associated with survival: disease phase at relapse (P < .0001), duration of time interval from BMT to relapse (P = .0001), interferon therapy at relapse (P = .0024), and patient sex (P = .0032). This retrospective study provides evidence that some patients who relapse after BMT may benefit from treatment with IFN; a second BMT may offer the chance of cure. Data from this analysis may be useful in designing future prospective trials on posttransplant CML relapse.  相似文献   
95.
Summary This study was designed to determine the incidence of relapse and factors predictive for relapse in 719 patients with severe aplastic anaemia (SAA) after immunosuppressive treatment (IS). Patients developing myelodysplasia or acute leukaemia after IS, and patients receiving a transplant, were excluded from this analysis. Response was defined as reaching complete independence from transfusions, relapse was defined as becoming again transfusion dependent. This criteria was validated by similar figures when using other ‘relapse criteria’ such as drop in neutrophil or platelet counts. Of 358 patients responding to IS, 74 patients relapsed after a mean time of 778 d after treatment. The actuarial incidence of relapse is 35.2% at 14 years after IS. The risk for relapse was higher in patients responding within 120 d from IS (48%) compared to patients responding between 120 and 360 d (40%) and only 20% for slow responders (>360d from IS) (P<0.00001). In multivariate analysis this factor still proved significant (P<0.0001). The mean time between diagnosis and treatment was significantly longer in patients relapsing compared to patients who did not relapse (260 v 134 d, P=0.037). Relapse was not predicted by the severity of the disease, age, and sex. In 39 of the 74 relapsing patients a second response could be achieved. Responses after relapse were associated in univariate analysis with early response to previous IS and early occurrence of relapse. The actuarial survival of patients not relapsing is significantly better than survival of patients relapsing (79.8%v 67.1%, P = 0.0024). However, the actuarial survival of 39 relapsing patients who responded again to IS was similar to patients not relapsing (86%) and significantly better than in 35 patients not reaching a second response after relapse (49.3%, P=0.0015). This study indicates that relapse is a relevant problem in the treatment of aplastic anaemia, and does have an impact on overall survival. Prospective studies of immunosuppressive regimens, looking at responses, should also address this problem in the future.  相似文献   
96.
To identify risk factors for lower limb loss after arterial embolectomy a cohort of 1189 patients was studied. Detailed data were obtained for 165 patients who underwent a major amputation within 30 days of embolectomy and for 165 matched controls. The amputation risk was increased in patients with two or more myocardial infarctions (odds ratio (OR) 3.1, 95 per cent confidence interval (CI) 0.8-11.2), chronic ischaemia (OR 2.1, CI 0.9-4.9), long duration of symptoms (OR 4.3, CI 1.9-9.6, for greater than or equal to 25 h versus less than or equal to 6 h) or postoperative heart failure (OR 3.4, CI 1.8-6.5). Reduced risks were found in association with acute myocardial infarction (OR 0.3, CI 0.1-0.9) and postoperative anticoagulation treatment with warfarin (OR 0.3, CI 0.1-0.9). The independent prognostic value of chronic ischaemia and symptom duration, and the beneficial effect of postoperative anticoagulation gained additional support in multivariate analysis. We conclude that the risk of early amputation after arterial embolectomy or thrombectomy can be predicted by several clinical characteristics.  相似文献   
97.
98.
Cadmium has been determined in 26 brands of cigarettes purchased in eight different countries throughout the world and in 16 different samples of cigarettes produced in Sweden between 1918 and 1968. In addition the amount of cadmium released from smoking one cigarette to the particulate phase collected from a smoking simulation machine, corresponding to the amount actually inhaled by a smoker, has been determined. The cadmium concentration in different brands of cigarettes ranged from 0.19 to 3.0 micrograms Cd/g dry wt, with a general tendency toward lower values in cigarettes from developing countries. No systematic change in the cadmium concentration of cigarettes with time could be revealed. The amount of cadmium inhaled from smoking one cigarette containing about 1.7 microgram Cd was estimated to be 0.14 to 0.19 microgram, corresponding to about 10% of the total cadmium content in the cigarette.  相似文献   
99.
Between October 1988 and December 1992, 167 patients with leukemia receiving marrow transplants from HLA-identical donors and conditioned with cyclophosphamide (120 mg/kg) were randomized to additional treatment with either busulfan (16 mg/kg, n = 88) or total body irradiation (TBI; n = 79). The busulfan-treated patients had an increased cumulative incidence of veno-occlusive disease of the liver, ie, 12% compared with 1% in the TBI group (P = .009). Furthermore, hemorrhagic cystitis occurred in 24% of the busulfan patients versus 8% in the TBI patients (P = .003). In patients with advanced disease beyond first remission or first chronic phase, transplantation-related mortality was 62% among the busulfan-treated patients compared with 12% among the TBI recipients (P = .002). These differences between the two groups were statistically significant in multivariate analysis. Seizures were seen in 6% of the busulfan-treated patients and were absent in the TBI group (P = .03). Grade II-IV of acute graft-versus- host disease (GVHD) was similar in the two groups, but grade III-IV and chronic disease was more common in the busulfan-treated group (P = .04). Death associated with GVHD occurred in 17% of the busulfan- treated group and 2% of the TBI group (P = .003). Patients treated with busulfan had a 3-year actuarial survival of 62%, which was worse than the 76% among those treated with TBI (P < .03). In multivariate analysis, poor survival was associated with advanced disease (P < .0001), no posttransplant septicemia (P = .0006), grade II-IV GVHD (P = .006), and busulfan treatment (P < .02). The incidence of relapse did not differ between the two groups. Relapse-free survival was also similar in the two treatment groups on analysis of data from all patients, children, patients with early disease, and those with acute myeloid leukemia, acute lymphoblastic leukemia, and chronic myeloid leukemia. However, in adults (P = .05) and patients with advanced disease (P = .005), leukemia-free survival was significantly better in those treated with TBI. We conclude that patients treated with busulfan have more early toxicity and an increased transplant-related mortality in patients with advanced disease. TBI is therefore the treatment of choice, especially in adults and patients with advanced disease. However, busulfan is an acceptable alternative for patients with early disease and for those in whom TBI is not feasible.  相似文献   
100.
In order to investigate the potential role of atrial natriuretic peptide (ANP) in mild to moderate essential hypertension, a study was conducted in groups of normotensive and hypertensive middle-aged men born in 1926 and 1927. Venous plasma concentrations of immunoreactive ANP (irANP) were studied in relation to measurements of cardiac structure and function, urinary electrolytes as well as some cardiovascular hormones. Plasma irANP did not differ between normotensive controls (31 +/- 14 pmol l-1) and borderline or untreated hypertensive patients. However, irANP concentrations were slightly but significantly (P less than 0.05) lower in the borderline (26 +/- 8 pmol l-1) compared to the untreated established hypertensives (35 +/- 14 pmol l-1). No relationships were found between irANP and blood pressure, indices of left ventricular structure and function or hormone parameters in subgroups or the whole study group. Our data do not support the view that plasma irANP is increased in uncomplicated essential hypertension, since our groups of borderline or established hypertensive middle-aged men without major cardiac involvement did not differ in irANP concentrations compared to normotensive controls. Thus, during the development or in the early stages of essential hypertension, ANP secretion does not seem to be abnormal.  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