全文获取类型
收费全文 | 12539篇 |
免费 | 1031篇 |
国内免费 | 33篇 |
专业分类
耳鼻咽喉 | 106篇 |
儿科学 | 519篇 |
妇产科学 | 385篇 |
基础医学 | 1909篇 |
口腔科学 | 342篇 |
临床医学 | 1249篇 |
内科学 | 2631篇 |
皮肤病学 | 123篇 |
神经病学 | 1295篇 |
特种医学 | 846篇 |
外科学 | 1228篇 |
综合类 | 159篇 |
一般理论 | 7篇 |
预防医学 | 1107篇 |
眼科学 | 194篇 |
药学 | 834篇 |
中国医学 | 18篇 |
肿瘤学 | 651篇 |
出版年
2022年 | 98篇 |
2021年 | 163篇 |
2020年 | 121篇 |
2019年 | 183篇 |
2018年 | 219篇 |
2017年 | 192篇 |
2016年 | 211篇 |
2015年 | 224篇 |
2014年 | 274篇 |
2013年 | 441篇 |
2012年 | 596篇 |
2011年 | 693篇 |
2010年 | 349篇 |
2009年 | 351篇 |
2008年 | 577篇 |
2007年 | 534篇 |
2006年 | 535篇 |
2005年 | 519篇 |
2004年 | 489篇 |
2003年 | 448篇 |
2002年 | 416篇 |
2001年 | 427篇 |
2000年 | 409篇 |
1999年 | 403篇 |
1998年 | 205篇 |
1997年 | 178篇 |
1996年 | 173篇 |
1995年 | 171篇 |
1994年 | 171篇 |
1993年 | 151篇 |
1992年 | 272篇 |
1991年 | 287篇 |
1990年 | 233篇 |
1989年 | 265篇 |
1988年 | 258篇 |
1987年 | 206篇 |
1986年 | 191篇 |
1985年 | 191篇 |
1984年 | 157篇 |
1983年 | 136篇 |
1982年 | 90篇 |
1981年 | 105篇 |
1980年 | 66篇 |
1979年 | 92篇 |
1978年 | 77篇 |
1977年 | 108篇 |
1976年 | 80篇 |
1975年 | 94篇 |
1974年 | 91篇 |
1971年 | 71篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
William T Mahle Robert N Vincent Alexandria M Berg Kirk R Kanter 《The Journal of heart and lung transplantation》2005,24(1):63-66
BACKGROUND: Hydroxymethylglutaryl CoA reductase inhibitors (statins) have been demonstrated to reduce the risk of developing coronary allograft vasculopathy (CAV) following heart transplantation in adults and are used routinely in many centers. CAV and lipid abnormalities have been reported to be less prevalent in pediatric heart transplant recipients. It is not known whether statins reduce the risk of CAV in this population METHODS: A retrospective review was performed to analyze the risk factors for developing CAV following pediatric heart transplantation with particular attention to the impact of pravastatin therapy. The study population was comprised of 129 pediatric patients who underwent 142 heart transplants at our institution from 1988 to 2003. The outcome variable was freedom from CAV, CAV being determined by coronary angiography or autopsy. RESULTS: CAV was identified in 25 recipients at a median of 3.7 years after transplantation. There were 331 patient-years of pravastatin therapy. Pravastatin therapy resulted in a reduction in total cholesterol levels, 162 +/- 29 to 137 +/- 20 mg/dl, p = 0.01. In multivariate analysis the use of pravastatin was associated with a lower incidence of CAV (p = 0.03), whereas an increased frequency of late rejection (p = 0.003) and earlier year of transplantation (p = 0.04) were associated with increased risk of CAV. CONCLUSIONS: The routine use of pravastatin was associated with a lower risk following pediatric heart transplantation. Further studies into the relationship between lipid abnormalities, inflammation and rejection, and the development of CAV in children are warranted. 相似文献
72.
The direct reporting of adverse drug reactions by patients is becoming an increasingly important topic for discussion in the world of pharmacovigilance. At this time, few countries accept consumer reports. We present an overview of experiences with consumer reporting in various countries of the world. The potential contribution of patient reports of adverse drug reactions is discussed, both in terms of their qualitative and quantitative contribution. The crucial question is one of whether patient reports will increase the number and quality of the reports submitted and/or lead to a more timely detection of signals of possible adverse reactions, thus contributing to an enhancement of the existing methods of drug safety monitoring. To date, the data available are insufficient to establish such added value. 相似文献
73.
Missense mutation in exon 7 of the common gamma chain gene causes a moderate form of X-linked combined immunodeficiency. 总被引:6,自引:2,他引:4 下载免费PDF全文
F C Schmalstieg W J Leonard M Noguchi M Berg H E Rudloff R M Denney S K Dave E G Brooks A S Goldman 《The Journal of clinical investigation》1995,95(3):1169-1173
Clinical and immunologic features of a recently recognized X-linked combined immunodeficiency disease (XCID) suggested that XCID and X-linked severe combined immunodeficiency (XSCID) might arise from different genetic defects. The recent discovery of mutations in the common gamma chain (gamma c) gene, a constituent of several cytokine receptors, in XSCID provided an opportunity to test directly whether a previously unrecognized mutation in this same gene was responsible for XCID. The status of X chromosome inactivation in blood leukocytes from obligate carriers of XCID was determined from the polymorphic, short tandem repeats (CAG), in the androgen receptor gene, which also contains a methylation-sensitive HpaII site. As in XSCID, X-chromosome inactivation in obligate carriers of XCID was nonrandom in T and B lymphocytes. In addition, X chromosome inactivation in PMNs was variable. Findings from this analysis prompted sequencing of the gamma c gene in this pedigree. A missense mutation in the region coding for the cytoplasmic portion of the gamma c gene was found in three affected males but not in a normal brother. Therefore, this point mutation in the gamma c gene leads to a less severe degree of deficiency in cellular and humoral immunity than that seen in XSCID. 相似文献
74.
Steenbergen EJ; Verhagen OJ; van Leeuwen EF; van den Berg H; von dem Borne AE; van der Schoot CE 《Blood》1995,86(2):692-702
Crosslineage T-cell receptor delta (TCR delta) rearrangements are widely used as tumor markers for the follow up of minimal residual disease in childhood B-precursor acute lymphoblastic leukemia (ALL) by polymerase chain reaction (PCR). The major drawback of this approach is the risk of false-negative results due to clonal evolution. We investigated the stability of V delta 2D delta 3 rearrangements in a group of 56 childhood B-precursor ALL patients by PCR and Southern blot analysis. At the PCR level, V delta 2D delta 3-to-J alpha rearranged subclones (one pathway for secondary TCR delta recombination) were demonstrated in 85.2% of V delta 2D delta 3-positive patients tested, which showed that small subclones are present in the large majority of patients despite apparently monoclonal TCR delta Southern blot patterns. Sequence analysis of V delta 2D delta 3J alpha rearrangements showed a biased J alpha gene usage, with HAPO5 and J alpha F in 26 of 32 and 6 of 32 clones, respectively. Comparison of V delta 2D delta 3 rearrangement status between diagnosis and first relapse showed differences in seven of eight patients studied. In contrast, from first relapse onward, no clonal changes were observed in six patients studied. To investigate the occurrence of crosslineage TCR delta rearrangements in normal B and T cells, fluorescence-activated cell sorter-sorted peripheral blood CD19+/CD3- and CD19-/CD3+ cell populations from three healthy donors were analyzed. V delta 2D delta 3 rearrangements were detected at low frequencies in both B and T cells, which suggests that V delta 2-to-D delta 3 joining also occurs during normal B-cell differentiation. A model for crosslineage TCR delta rearrangements in B-precursor ALL is deduced that explains the observed clonal changes between diagnosis and relapse and is compatible with multistep leukemogenesis of B-precursor ALL. 相似文献
75.
A randomized controlled trial of electromagnetic therapy in the primary care management of venous leg ulceration 总被引:1,自引:1,他引:0
OBJECTIVE: The aim was to establish the potential efficacy, tolerabilityand side-effect profile of electromagnetic therapy as an adjunctto conventional dressings in the treatment of venous leg ulcers. METHOD: A prospective, randomized, double blind controlled clinicaltrial was carried out in a dedicated leg ulcer clinic basedin one urban general practice. Nineteen patients with leg ulcersof confirmed venous aetiology were assessed. The main outcomemeasures were rate and scale of venous leg ulcer healing, changesin patient-reported pain levels, quality of life, degree ofmobility, side effect profile and acceptability to patientsand staff. RESULTS: Sixty-eight per cent of patients attending this dedicated clinicachieved improvements in the size of their ulcer (4, 21%, healedfully) and in reduced pain levels (P < 0.05) during the trial,despite the chronicity of ulcer histories. Patients treatedwith electromagnetic therapy at 800 Hz were found at day 50to have significantly greater healing (P < 0.05) and paincontrol (P < 0.05) than placebo therapy or treatment with600 Hz. All patients reported improved mobility at the end ofthe study. The electromagnetic therapy was well tolerated bypatients, with no differences between groups in reporting adverseevents, and proved acceptable to staff. CONCLUSION: Despite the small numbers in this pilot study, electromagnetictherapy provided significant gains in the healing of venousleg ulcers and reduction in pain. Keywords. Electromagnetic therapy, RCT, leg ulcers, primary care. 相似文献
76.
77.
M C Zillikens J W van den Berg J H Wilson G R Swart 《The American journal of clinical nutrition》1992,55(3):621-625
Bioelectrical impedance analysis (BIA) is a simple technique for determining body water and calculating body composition. It has been validated in healthy control subjects but not in patients with liver disease. We examined the ability of BIA to detect changes in total body water (TBW) due to removal of ascites. In 12 cirrhotic patients, BIA of the whole body and of body segments was performed before and after treatment of ascites with paracentesis (n = 12) and diuretics (n = 2). TBW changes predicted by BIA, by using two prediction equations, were significantly less than body weight changes (51% and 45% of the weight loss). BIA of body segments showed highly significant changes in both the trunk and the leg and small changes in the arm. These data indicate that BIA of the whole body is not a suitable technique for monitoring fluid changes in cirrhotic patients with ascites. Changes in BIA of body segments may be due to mobilization of edema after the removal of ascites. 相似文献
78.
79.
Ingalill R. Hallberg Agneta Berg Lany T. Arlehamn 《Perspectives in psychiatric care》1994,30(2):26-32
The authors analyze a male nurse's account of how he experienced his interaction with a female schizophrenic client during sessions of systematic clinical supervision. Notes taken during 15 sessions were analyzed by means of open coding. The analysis revealed the importance of being aware of the parallel process that occurs among the client, the primary nurse, and the unit staff. 相似文献
80.