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   709篇
  免费   30篇
  国内免费   18篇
耳鼻咽喉   11篇
儿科学   13篇
妇产科学   11篇
基础医学   73篇
口腔科学   55篇
临床医学   43篇
内科学   140篇
皮肤病学   15篇
神经病学   91篇
特种医学   59篇
外科学   60篇
综合类   13篇
预防医学   68篇
眼科学   6篇
药学   59篇
中国医学   2篇
肿瘤学   38篇
  2023年   5篇
  2022年   16篇
  2021年   19篇
  2020年   6篇
  2019年   14篇
  2018年   17篇
  2017年   16篇
  2016年   14篇
  2015年   14篇
  2014年   31篇
  2013年   38篇
  2012年   48篇
  2011年   55篇
  2010年   25篇
  2009年   25篇
  2008年   28篇
  2007年   47篇
  2006年   26篇
  2005年   22篇
  2004年   29篇
  2003年   20篇
  2002年   13篇
  2001年   15篇
  2000年   6篇
  1999年   14篇
  1998年   16篇
  1997年   16篇
  1996年   21篇
  1995年   9篇
  1994年   14篇
  1993年   11篇
  1991年   5篇
  1990年   2篇
  1989年   9篇
  1988年   12篇
  1987年   10篇
  1986年   11篇
  1985年   13篇
  1984年   5篇
  1983年   8篇
  1982年   6篇
  1981年   2篇
  1980年   4篇
  1978年   3篇
  1977年   2篇
  1976年   4篇
  1975年   5篇
  1969年   1篇
  1967年   2篇
  1966年   1篇
排序方式: 共有757条查询结果,搜索用时 15 毫秒
21.
Polyamidoamine (PAMAM) dendrimers are used for many pharmaceutical and biomedical applications. However, the toxicological risks of several PAMAM‐based compounds are still not fully evaluated, despite evidences of PAMAM deleterious effects on biological membranes, leading to toxicity. In this report, we investigated the toxicity of generation 0 PAMAM‐coated gold nanoparticles (AuG0 NPs) in four different models to determine how different cellular systems are affected by PAMAM‐coated NPs. Toxicity was evaluated in two mammalian cell lines, Neuro 2A and Vero, in the green alga Chlamydomonas reinhardtii and the bacteria Vibrio fischeri. AuG0 NP treatments reduced cell metabolic activity in algal and bacterial cells, measured by esterase enzymatic activity (C. reinhardtii) and luminescence emission (V. fischeri). EC50 value after 30 min of treatment was similar in both organisms, with 0.114 and 0.167 mg mL?1 for C. reinhardtii and V. fischeri, respectively. On the other hand, AuG0 NPs induced no change of mitochondrial activity in mammalian cells after 24 h of treatment to up to 0.4 mg mL?1 AuG0 NPs. Change in the absorption spectra of AuG0 NP in the mammalian cell culture media may indicate an alteration of NP properties that contributed to the low toxicity of AuG0 NPs in mammalian cells. For a safe development of PAMAM‐based nanomaterials, the difference of sensitivity between mammalian and microbial cells, as well as the modulation of NPs toxicity by medium properties, should be taken into account when designing PAMAM NPs for applications that may lead to their introduction in the environment. © 2012 Wiley Periodicals, Inc. Environ Toxicol 29: 328–336, 2014.  相似文献   
22.

Introduction

Safety in conducting a clinical trial is a prerequisite for patients who will be enrolled into that study. The aim of the present study was to evaluate retrospectively if patient and graft survival were similar among patients who participated in clinical trials versus those who did not.

Patients and Methods

We evaluated pretransplant and posttransplant characteristics of 245 kidney transplant (KT) patients who were selected to participate in at least one Phase II/Phase III clinical trial. We compared them with 361 KT patients who were not enrolled or refused to participate in those clinical trials; all studies were conducted at a single transplant center. Inclusion/exclusion criteria were as noted for each individual protocol. Only studies with enrollment at time of graft implant were considered.

Results

Selection of patients participating in clinical trials in general exclude high-risk patients. In our experience, only 36% of transplanted patients were selected for a multicenter, prospective, randomized, international study that included changes to the strategies in the administration of immunosuppressive drugs already on the market or development of a new immunosuppressant. After 5 years, graft and patient survival rates were similar between those who participated and those who did not participate in a clinical study. Although our data were collected retrospectively, an alternative design to achieve these conclusions would be a noninferiority study.

Conclusions

Our results demonstrated similar rates of graft and patient survival among enrolled patients versus nonenrolled patients. Outcome surveillance offers safety in participating in clinical trials that involve changes in standard immunosuppression therapy and are part of the research necessary to develop patient-centered medical interventions.  相似文献   
23.
24.

Objective

To test the hypothesis that fluid resuscitation in the ED with plasmalyte-148 (PL) compared with 0.9% sodium chloride (SC) would result in a lower proportion of patients with diabetic ketoacidosis (DKA) requiring intensive care unit (ICU) admission.

Methods

We performed a prespecified nested cohort study at two hospitals within a cluster, crossover, open label, randomised, controlled trial comparing the effects of PL versus SC as fluid therapy for patients who presented to the ED with DKA. All patients presenting within a fixed recruitment period were included. The primary outcome was the proportion of patients admitted to ICU.

Results

Eighty-four patients were enrolled (SC n = 38, PL n = 46). The SC group had a lower median pH on admission (SC: 7.09 [interquartile range (IQR) 7.01–7.21], PL: 7.17 [IQR 6.99–7.26]). The median volume of intravenous fluids administered in ED was 2150 mL (IQR 2000–3200 mL; SC) and 2200 mL (IQR 2000–3450; PL); respectively. A higher proportion of patients in the SC group, 19 (50%), was admitted to ICU compared with PL group, 18 (39.1%); however, after adjustment for pH at presentation and diabetes type in a multivariable logistic regression model, the PL group did not have a significantly different rate of ICU admission compared with the SC group (odds ratio for ICU admission 0.73, 95% confidence interval 0.13–3.97, P = 0.71).

Conclusion

Patients with DKA treated with PL compared with SC in the EDs had similar rates of requiring ICU admission.  相似文献   
25.
26.
27.
Using the CD40 system, in vitro proliferation of hairy cell leukemia (HCL) was examined in 43 patients. In this culture system, cells were stimulated by interleukin-4 (IL-4) and anti-CD40 monoclonal antibodies (MoAbs) that were added in soluble form or were cross-linked via their Fc part using Fc gamma RII-transfected mouse fibroblast cells. Proliferation was induced and confirmed by 3H-thymidine incorporation in 14 cases and by the presence of metaphases in 42 cases. 3H-thymidine incorporation showed a heterogeneous pattern: cross-linking of anti- CD40 gave the highest proliferation in 8 cases; in 11 cases, stimulation with anti-CD40 MoAbs alone, without cross-linking also resulted in proliferation; the addition of IL-4 further enhanced 3H- thymidine incorporation in 5 cases, but suppressed this phenomenon in 5 other cases. The CD40 system proved to be very effective in obtaining cytogenetic data. With a success rate of 42 of 43 patients tested, we found clonal abnormalities in 8 cases (19%) and nonclonal abnormalities with involvement of one or two abnormal metaphases in another 7 cases. The chromosomes most frequently involved in the abnormal karyotypes, both structurally and numerically, were chromosomes 5, 7, and 14. By fluorescence-activated cell-sorting analysis of the cultured cells, and by immunophenotypic analysis of metaphase spreads, T-cell growth could be excluded and the HCL-lineage confirmed. Stimulation via the CD40 antigen is an excellent tool for growing hairy cell leukemia cells.  相似文献   
28.
A phase I clinical trial was initiated to treat patients with stage IV B-derived chronic lymphocytic leukemia (CLL) with the IgG2a murine monoclonal antibody T101. This antibody binds to a 65,000-mol wt (T65) antigen found on normal T lymphocytes, malignant T lymphocytes, and B- derived CLL cells. All of the patients had a histologically confirmed diagnosis of advanced B-derived CLL and were refractory to standard therapy, and more than 50% of their leukemia cells reacted with the T101 antibody in vitro. The patients received T101 antibody two times per week, over two to 50 hours by intravenous administration in 100 mL of normal saline containing 5% human albumin. Twelve patients were treated with a fixed dosage of 1, 10, 50, or 100 mg, and one patient was treated with 140 mg of antibody. It was demonstrated that patients given two-hour infusions of 50 mg developed pulmonary toxicity, with shortness of breath and chest tightness. This toxicity was eliminated when infusions of 50 or 100 mg of T101 were prolonged to 50 hours. All dose levels caused a rapid but transient decrease in circulating leukemia cell counts. In vivo binding to circulating and bone marrow leukemia cells was demonstrated at all dose levels with increased binding at higher dosages. Antimurine antibody responses were not demonstrated in any patients at any time during treatment. Circulating free murine antibody was demonstrated in the serum of only the two patients treated with 100 mg of antibody as a 50-hour infusion and the patient treated with 140 mg of antibody over 30 hours. Antigenic modulation was demonstrated in patients treated at all dose levels but was particularly apparent in patients treated with prolonged infusions of 50 and 100 mg of antibody. We were also able to demonstrate antigenic modulation in lymph node cells, which strongly suggests in vivo labeling of these cells. Overall, T101 antibody alone appears to have a very limited therapeutic value for patients with CLL. The observations of in vivo labeling of tumor cells, antigenic modulation, antibody pharmacokinetics, toxicity, and antimurine antibody formation may be used in the future for more effective therapy when drugs or toxins are conjugated to the antibody.  相似文献   
29.
30.

Objectives

to verify the face validity, criterion-related validity and the reliability of two distinct forms of presentation of the instrument Measurement of Adherence to Treatment, one being for ascertaining the adherence to the use of oral antidiabetics and the other for adherence to the use of insulin, as well as to assess differences in adherence between these two modes of drug therapy.

Method

a methodological study undertaken with 90 adults with Type 2 Diabetes Mellitus. The criterion-related validity was verified using the Receiver Operating Characteristic curves; and for the reliability, the researchers calculated the Cronbach alpha coefficient, the item-total correlation, and the Pearson correlation coefficient.

Results

the oral antidiabetics and the other showed sensitivity of 0.84, specificity of 0.35 and a Cronbach correlation coefficient of 0.84. For the adherence to the use of insulin, the values found were, respectively, 0.60, 0.21 and 0.68. A statistically significant difference was found between the final scores of the two forms of the instrument, indicating greater adherence to the use of insulin than to oral antidiabetics.

Conclusion

it is concluded that the two forms of the Measurement of Adherence to Treatment instrument are reliable and should be used to evaluate adherence to drug treatment among people with diabetes mellitus.  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