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   1463篇
  免费   103篇
  国内免费   1篇
耳鼻咽喉   13篇
儿科学   56篇
妇产科学   166篇
基础医学   187篇
口腔科学   13篇
临床医学   115篇
内科学   314篇
皮肤病学   27篇
神经病学   124篇
特种医学   40篇
外科学   158篇
综合类   12篇
一般理论   1篇
预防医学   115篇
眼科学   28篇
药学   69篇
中国医学   2篇
肿瘤学   127篇
  2024年   5篇
  2023年   22篇
  2022年   16篇
  2021年   34篇
  2020年   30篇
  2019年   34篇
  2018年   41篇
  2017年   25篇
  2016年   23篇
  2015年   24篇
  2014年   47篇
  2013年   39篇
  2012年   86篇
  2011年   82篇
  2010年   43篇
  2009年   35篇
  2008年   61篇
  2007年   55篇
  2006年   70篇
  2005年   70篇
  2004年   50篇
  2003年   55篇
  2002年   55篇
  2001年   28篇
  2000年   30篇
  1999年   33篇
  1998年   18篇
  1997年   13篇
  1996年   16篇
  1995年   17篇
  1994年   13篇
  1993年   16篇
  1992年   29篇
  1991年   33篇
  1990年   34篇
  1989年   30篇
  1988年   22篇
  1987年   31篇
  1986年   15篇
  1985年   33篇
  1984年   13篇
  1983年   16篇
  1982年   8篇
  1981年   13篇
  1980年   10篇
  1979年   19篇
  1977年   10篇
  1976年   7篇
  1968年   5篇
  1967年   4篇
排序方式: 共有1567条查询结果,搜索用时 33 毫秒
101.
We investigated toxicity and efficacy of in vivo T-cell depletion with anti-thymocyte globulin (ATG) as part of an intensified myeloablative conditioning regimen followed by allogeneic stem cell transplantation in patients with advanced multiple myeloma. The conditioning regimen consisted of modified total body irradiation, busulfan and cyclophosphamide (n=15) or in the case of prior dose-limiting radiotherapy of busulfan and cyclophosphamide (n=3). The median age was 44 years (range, 29-53) and the median time from diagnosis to transplant was 12 months (range, 6-144). Grade II-IV acute graft-versus-host disease (GvHD) occurred in six patients (35%). Severe grade III/IV GvHD developed in one patient (6%). Three patients died of therapy-related causes (17%). A complete remission (CR) with negative immunofixation after allogeneic transplantation was seen in eight of the evaluable patients (53%). After a median follow-up of 41 months (range, 8-84), the estimated overall survival at 6 years for all patients is 77% (CI 95%: 58-96%). The estimated progression-free survival at 6 years for all patients is 31% (CI 95%: 2-59%) and 46% (CI 95%: 9-83%) for patients with CR. In vivo T-cell depletion with ATG resulted in a low rate of severe GvHD with low treatment-related mortality, and a substantial number of long-term survivors.  相似文献   
102.
Data suggest that nutrient order during a meal significantly impacts postprandial glucose and insulin excursions in type 2 diabetes, while its effects in prediabetes have not been reported. Fifteen participants with prediabetes consumed the same meal on 3 days in random order: carbohydrate first, followed 10 minutes later by protein and vegetables (CF); protein and vegetables first, followed 10 minutes later by carbohydrate (PVF); or vegetables first followed by protein and carbohydrate (VF). Blood was sampled for glucose and insulin measurements at 0, 30, 60, 90, 120, 150 and 180 minutes. Incremental glucose peaks were similarly attenuated by >40% in the PVF and VF meal conditions compared with CF. The incremental area under the curve for glucose was 38.8% lower following the PVF meal order, compared with CF, and postprandial insulin excursions were significantly lower in the VF meal condition compared with CF. The CF meal pattern showed marked glycaemic variability whereas glucose levels were stable in the PVF and VF meal conditions. Food order presents a novel, simple behavioural strategy to reduce glycaemic excursions in prediabetes.  相似文献   
103.
BackgroundPancreatoduodenectomy (PD) or distal pancreatectomy (DP) are common procedures for patients with a pancreatic neuroendocrine tumor (pNET). Nevertheless, certain patients may benefit from a pancreas-preserving resection such as enucleation (EN). The aim of this study was to define the indications and differences in long-term outcomes among patients undergoing EN and PD/DP.MethodsPatients undergoing resection of a pNET between 1992 and 2016 were identified. Indications and outcomes were evaluated, and propensity score matching (PSM) analysis was performed to compare long-term outcomes between patients who underwent EN versus PD/DP.ResultsAmong 1034 patients, 143 (13.8%) underwent EN, 304 (29.4%) PD, and 587 (56.8%) DP. Indications for EN were small size (1.5 cm, IQR:1.0–1.9), functional tumors (58.0%) that were mainly insulinomas (51.7%). After PSM (n = 109 per group), incidence of postoperative pancreatic fistula (POPF) grade B/C was higher after EN (24.5%) compared with PD/DP (14.0%) (p = 0.049). Median recurrence-free survival (RFS) was comparable among patients who underwent EN (47 months, 95% CI:23–71) versus PD/DP (37 months, 95% CI: 33–47, p = 0.480).ConclusionComparable long-term outcomes were noted among patients who underwent EN versus PD/DP for pNET. The incidence of clinically significant POPF was higher after EN.  相似文献   
104.
OBJECTIVE: Interest has focused recently on the influences of the polypeptide factors inhibin and activin on the selective regulation of the pituitary secretion of gonadotropins. DESIGN: Measurement of the concentrations of inhibin-related proteins in relation to the changes in pituitary gonadotropin (FSH, LH) parameters, after GnRH stimulation with a bolus injection of 100 microg gonadorelin, in 19 women with ovulatory disturbances. METHODS: Serum levels of inhibin A and B, activin A, and pro alpha-C were measured using sensitive ELISA kits. RESULTS: Within 60 min after GnRH stimulation, FSH values doubled from 5 to 10 mU/ml (P < 0.001). LH increased 12-fold from 2 to 24 mU/ml (P < 0.001). Activin A showed a significant decrease from 0.47 to 0.36 ng/ml (P < 0.001), whereas pro alpha-C increased from 127 to 156 pg/ml (P = 0.039). The median inhibin A concentration did not show a significant change between baseline and the 60 min value, whereas inhibin B was characterized by a minor, but not significant, increase in the median from 168 to 179 pg/ml (P = 0.408). A significant inverse correlation (P = 0.014) with a mean coefficient of correlation of 0.5516 was found, demonstrating a strong relationship between high inhibin B baseline levels and a small increase of FSH after 60 min. CONCLUSION: Our results show an interesting correlation between the baseline inhibin B and the change in FSH before and after GnRH stimulation. A high baseline inhibin B implies only a minor increase of FSH after 60 min.  相似文献   
105.

Background

Complement C3 is an emerging risk factor for coronary heart disease (CHD) and is particularly increased in the metabolic syndrome. A direct effect of smoking on structure and function of complement C3 has been suggested.

Hypothesis

Smoking behavior may affect the cardiovascular risk that is associated with plasma complement C3.

Methods

The association between plasma C3 and CHD was studied in the CODAM (Cohort on Diabetes and Atherosclerosis Maastricht) study population (n = 562, 61% male) with examination of effect modification by smoking.

Results

The overall prevalence of CHD was 23.3%. Higher plasma C3 levels were associated with a higher CHD prevalence, and there was a significant interaction with heavy smoking (p = 0.01). In never & light smokers, the univariate OR for CHD per 1 s.d. (0.33 g/L) increase in C3 was 1.09 [95% confidence interval (CI) 0.85-1.41] (p = 0.505) whereas in heavy smokers it was 2.05 [1.43-2.93] (p < 0.001). The association in the group of heavy smokers remained significant (OR 2.38 [1.54-3.68], p < 0.001) after adjustment for traditional risk factors for cardiovascular disease and also after further adjustment for other cardiometabolic risk factors, i.e. the metabolic syndrome, CRP and insulin resistance (HOMA2IR) (OR C3 between 2.16 and 2.29, all p ≤ 0.001).

Conclusion

Human plasma complement C3 is associated with prevalent CHD, but only in heavy smokers, and this association is independent of important metabolic cardiovascular risk factors.  相似文献   
106.
This phase I/II study evaluated high-dose treosulfan in patients with high-grade lymphoma. In all, 21 patients (median age 51, 25-60 years) with primary refractory disease (n=3) or early (n=11) or late (n=7) relapse received DexaBEAM and one course etoposide for cytoreduction and PBPC mobilization. Subsequently, 16 patients received 30 g/m2 treosulfan and 140 mg/m2 melphalan, followed by autologous transplantation. Nine patients received a 2nd high-dose treatment (HDT) with 30 g/m2 treosulfan and 750 mg/m2 thiotepa. Recovery time to >1/nl leukocytes and >25/nl thrombocytes was 8.9 (range 8-11) and 11.9 (8-16) days after 1st and 9.6 (7-13) and 13 (9-19) days after 2nd HDT. Reversible grade 3 or 4 nonhematologic toxicities included mucositis (n=7), infection (n=7) and one episode of re-entry tachycardia. Two treatment-related deaths occurred after 2nd HDT. Since three dose-limiting toxicities occurred among nine patients receiving tandem HDT, 30 g/m2 of treosulfan was considered MTD in this setting. Patients with late compared to early relapse or refractory disease had a higher probability of CR (6/7 vs 3/14 patients, P=0.017) and overall survival (71 vs 21%, P<0.05, 24-49 months follow-up). In conclusion, high-dose treosulfan as major therapy component induces sustained complete remissions in relapsed high-grade lymphoma with acceptable toxicity.  相似文献   
107.
The Maillard reaction is a process in which reducing sugars react spontaneously with amino groups in proteins to advanced glycation end products (AGEs). Although an elevated level of glucose had been thought to play a primary role in the Maillard reaction, on a molecular basis, glucose is among the least reactive sugars within biological systems. The formation of AGEs is now also known to result from the action of various metabolites other than glucose, which are primarily located intracellularly and participate in the non-enzymatic glycation reaction at a much faster rate, such as fructose, trioses and dicarbonyl compounds. In this review, we considered the glycation reaction with particular attention to the potential role of fructose and fructose metabolites. The two sources for fructose are an exogenous supply from the diet and the endogenous formation from glucose through the aldose reductase pathway. Despite its approximately eightfold higher reactivity, the contribution of extracellular glycation by fructose is considerably less than that by glucose, because of the low plasma concentration of fructose (5 mmol/L glucose vs 35 micro mol/L fructose). Intracellularly, fructose is elevated in a number of tissues of diabetic patients in which the polyol pathway is active. In the cells of these tissues, the concentrations of fructose and glucose are of the same magnitude. Although direct evidence is not yet available, it is likely that the high reactivity of fructose and its metabolites may substantially contribute to the formation of intracellular AGEs and may contribute to alterations of cellular proteins, dysfunction of cells and, subsequently, to vascular complications.  相似文献   
108.
Dendritic cells (DCs) are known to induce the growth and function of natural killer (NK) cells. Here, we address the capacity of DCs to interact with NK cells in human lymphoid organs and identify the role of specific DC-derived cytokines. We demonstrate that DCs colocalize with NK cells in the T cell areas of lymph nodes. In culture, DCs from either blood or spleen primarily stimulate the CD56(bright)CD16- NK cell subset, which is enriched in secondary lymphoid tissues. Blocking of IL-12 abolished DC-induced IFN-gamma secretion by NK cells, whereas membrane-bound IL-15 on DCs was essential for NK cell proliferation and survival. Maturation by CD40 ligation promoted the highest IL-15 surface presentation on DCs and led to the strongest NK cell proliferation induced by DCs. These results identify secondary lymphoid organs as a potential DC/NK cell interaction site and identify the distinct roles for DC-derived IL-12 and IL-15 in NK cell activation.  相似文献   
109.
OBJECTIVE Circulating levels of NH(2)-terminal probrain natriuretic peptide (NT-proBNP), a marker of acute heart failure, are associated with increased risk of cardiovascular disease (CVD) in the general population. However, there is little information on the potential role of NT-proBNP as a biomarker of vascular complications in type 1 diabetic patients. We investigated whether serum NT-proBNP levels were associated with micro- and macrovascular disease in type 1 diabetic subjects. RESEARCH DESIGN AND METHODS A cross-sectional nested case-control study from the EURODIAB Prospective Complications Study of 507 type 1 diabetic patients was performed. Case subjects (n = 345) were defined as those with one or more complications of diabetes; control subjects (n = 162) were those with no evidence of any complication. We measured NT-proBNP levels by a two-site sandwich electrochemiluminescence immunoassay and investigated their associations with complications. RESULTS Mean NT-proBNP levels were significantly higher in case than in control subjects. In logistic regression analyses, NT-proBNP values >26.46 pg/mL were independently associated with a 2.56-fold increased risk of all complications. Odds ratios of CVD (3.95 [95% CI 1.26-12.35]), nephropathy (4.38 [1.30-14.76]), and distal symmetrical polyneuropathy (4.32 [1.41-13.23]) were significantly increased in patients with NT-proBNP values in the highest quartile (>84.71 pg/mL), independently of renal function and known risk factors. These associations were no longer significant after inclusion of TNF-α into the model. CONCLUSIONS In this large cohort of type 1 diabetic subjects, we found an association between NT-proBNP and diabetic micro- and macrovascular complications. Our results suggest that the inflammatory cytokine TNF-α may be involved in this association.  相似文献   
110.
Liposomal cytarabine has been proven to be useful for the prevention and intrathecal treatment of neoplastic meningitis. It has no demonstrable myelosuppressive effects and may therefore be an attractive alternative for prophylaxis and treatment of the central nervous system (CNS) relapse after allogeneic haematopoietic stem cell transplantation (HSCT). The use of liposomal cytarabine had not been reported in HSCT recipients. We retrospectively reviewed the feasibility of liposomal cytarabine in the prophylaxis (n = 2) and treatment (n = 4) of neoplastic meningitis in a cohort of patients after allogeneic HSCT. This report focusses on neurological complications after intrathecal application of liposomal cytarabine. Mild headache was the most commonly reported adverse event. Two patients experienced sacral radiculopathy with irreversible cauda equina syndrome in one patient. Another patient progressed with pre-existing leukencephalopathy. Intrathecal liposomal cytarabine should be used very cautiously in allogeneic HSCT recipients with a history of CNS complications potentially involving cerebral-spinal fluid circulation, since significant neurotoxicity was observed in patients with extensive CNS-directed pre-treatment. The feasibility and safety of liposomal cytarabine in HSCT recipients has to be evaluated in a prospective study.  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