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   2234篇
  免费   112篇
  国内免费   4篇
耳鼻咽喉   13篇
儿科学   40篇
妇产科学   71篇
基础医学   258篇
口腔科学   118篇
临床医学   218篇
内科学   531篇
皮肤病学   49篇
神经病学   172篇
特种医学   58篇
外科学   275篇
综合类   5篇
预防医学   90篇
眼科学   23篇
药学   162篇
中国医学   4篇
肿瘤学   263篇
  2023年   14篇
  2022年   19篇
  2021年   40篇
  2020年   34篇
  2019年   43篇
  2018年   51篇
  2017年   39篇
  2016年   40篇
  2015年   52篇
  2014年   74篇
  2013年   91篇
  2012年   130篇
  2011年   141篇
  2010年   59篇
  2009年   89篇
  2008年   81篇
  2007年   86篇
  2006年   110篇
  2005年   138篇
  2004年   141篇
  2003年   83篇
  2002年   67篇
  2001年   75篇
  2000年   77篇
  1999年   50篇
  1998年   25篇
  1997年   19篇
  1996年   21篇
  1995年   32篇
  1994年   11篇
  1993年   10篇
  1992年   35篇
  1991年   33篇
  1990年   50篇
  1989年   41篇
  1988年   35篇
  1987年   29篇
  1986年   26篇
  1985年   17篇
  1984年   18篇
  1983年   8篇
  1982年   8篇
  1979年   10篇
  1977年   8篇
  1974年   7篇
  1973年   8篇
  1971年   11篇
  1969年   8篇
  1968年   6篇
  1967年   6篇
排序方式: 共有2350条查询结果,搜索用时 312 毫秒
991.
Recent data from phase II trials have shown that lonidamine (LND) is effective in the treatment of tumors of various histogenesis, including gliomas. In the present work, we tested the antiproliferative effect of LND on a human glioblastoma cell line (LI) in different culture conditions. When LI are cultured in their standard conditions, a reduction of cell growth is seen after 3 days of treatment with 10(-4) M LND. It reaches 70% with respect to control after 6 days and is statistically significant. LND is ineffective at the other concentrations tested. In more stringent culture conditions, 10(-4) M LND determines a higher inhibition of cell proliferation both after 3 and 6 days of exposure, while other doses of LND are unable to affect cell growth.  相似文献   
992.
Apoptosis of natural killer (NK) cells can be induced by non-specific physical damage (UV irradiation, heat shock) or by simultaneous ligation of the CD 16 and the interleukin-2 receptor (IL-2R) molecules, but not with either anti-CD 16 or IL-2 alone. Whereas blockade of GTP-binding protein (G protein)-mediated signal transduction using ADP-ribosylating bacterial toxins or the GTPase-resistant GTP analog guanosine 5′-0-(3-thiotriphosphate (GTPγS) does not affect non-specific induction of NK cell apoptosis, such interventions do inhibit induction of apoptosis by anti-CD16/IL-2. The G proteins involved in the regulation of activation-induced NK apoptosis are sensitive to pertussis toxin (PTX) and to the non-specific GTP analog GTPγS but not to cholera toxin, Pseudomonas exotoxin A or diphtheria toxin. A pertussis toxin mutant that lacks ADP-ribosylating activity, but conserves the membrane translocating and T cell-mitogenic effects of the native molecule, fails to inhibit NK apoptosis. To exert their apoptosis-inhibitory effect, PTX and GTPγS must be employed before cells are activated. Later addition has no effect, suggesting the implication of G proteins in the transmission of apoptosis-inducing signals, but not in the effector stage of apoptosis. Pre-incubation with PTX or GTPγS does not affect the activation of NK cells by CD 16 cross-linking, IL-2 stimulation - or both, as assessed by the induction of CD69 expression, protein tyrosine phosphorylation and calcium mobilization. Moreover, neither PTX nor GTPγS compromise the effector function of NK cells or the susceptibility of target cells to NK-mediated lysis. These data suggest apoptosis as a novel mechanism by which NK responses may be controlled in vivo, as well as an experimental and therapeutical strategy to counteract endogenous down-regulation of NK responses.  相似文献   
993.
Summary In 7 patients with congestive heart failure acute oral administration of ibopamine, a new dopamine derivative, induced a significant decrease in serum prolactin and aldosterone without affecting serum growth hormone or cortisol. The Metoclopramide-induced secretion of prolactin and aldosterone was blunted in 6 patients pretreated with 200 mg ibopamine. The data are consistent with a dopaminergic effect of ibopamine due to a peripheral action, probably on D-2 receptors.  相似文献   
994.
995.
Data on adjuvant chemotherapy in early-stage uterine sarcomas are conflicting and most often based on small patient groups with relatively short duration of follow-up. Approximately 60% of patients present with stage I disease with an overall 5-year survival of 30-50% when treated with surgery alone. This study examines the efficacy and results of long-term follow-up of a multiagent chemotherapy regimen of cyclophosphamide, vincristine, doxorubicin, and dacarbazine (CYVADIC) as adjuvant treatment for patients with stage I uterine sarcoma. Between 1982 and 1999, 24 evaluable patients with completely staged uterine sarcomas received adjuvant multiagent chemotherapy with vincristine sulfate (1mg /m(2)) on days 1 and 4, doxorubicin (40 mg /m(2)) and cyclophosphamide (400 mg /m(2)) on day 2, and dacarbazine (200 mg /m(2)) on days 1 through 4 for a total of nine monthly cycles or until recurrence of disease was documented. Survival distributions were calculated by the Kaplan-Meier method, and statistical significance was determined with the log-rank test. Factors significant on univariate analysis were analyzed in a multivariate fashion using Cox proportional hazards model. The histologic distribution of patients was 46% leiomyosarcoma, 33% mixed mullerian tumors, 13% stromal sarcomas, 4% adenosarcomas, and 4% hemangiosarcoma. The patients received 206 of a planned 216 cycles of chemotherapy. The median follow-up of the patient population was 93 months (range 11-213 months). Eight patients (33%) developed recurrent disease. The median time to recurrence was 19 months (range 7-184 months). The estimated survival for the entire group was 88, 75, and 69% at 2, 5, and 15 years, respectively. Factors that did not affect survival included age, histology, and tumor grade. Four patients required dose reductions secondary to grade 2-3 toxicities (hematologic). Grade 1 neurotoxicity was observed in six patients (25%) and grade 2 neurotoxicity in one patient (4%). Adjuvant CYVADIC chemotherapy appears to be safe and well tolerated in patients with stage I uterine sarcomas. Our data provide information on the longest duration of follow-up ever reported and suggests that CYVADIC may have a potential role in the adjuvant treatment of early-stage uterine sarcoma.  相似文献   
996.
On September 22, 1986, Judge Myron Thompson issued a consent decree in the Wyatt v. Stickney litigation. The settlement occurred 14 years after Judge Frank M. Johnson, Jr. rendered his landmark decision in this case. The consent decree included termination of the court's active supervision of the state's mental health system, termination of the receivership, and termination of the court monitor's powers. The state agreed to adhere to Wyatt standards, maintain Title XIX accreditation, continue deinstitutionalization efforts, and develop an internal advocacy and quality assurance program. Mechanisms are also to be put in place to apprise the plaintiffs' attorneys of progress in these efforts.  相似文献   
997.
The effect of castration and testosterone treatment on the distribution of [3H] radioactive and endogenous bound folates in hepatic cytosolic folate binding proteins (FBP-C) has been studied in rats. The distribution of [3H] radioactive bound folates in these FBP's shows no significant difference in the three experimental group animals. On the contrary a significant decrease in the amount of endogenous bound folates is observed in castrated if compared with control rats, particularly marked for FBP-CI and FBP-CII bound folates. The testosterone treatment of castrated rats partially restores bound folate levels. The decrease of bound folates in castrated rats might be ascribable to a lower availability of longer-chain forms, almost the ones that bind to FBP's; however lower binding protein content and/or lower affinity for ligands cannot be excluded.  相似文献   
998.
We develop and apply a new method for estimating the locations of hypervariable residues in immunoglobulin-related molecules. The method differs from the standard introduced by Wu and Kabat in two essential ways: (1) we take explicit account of the type of substitution at a given position, rather than just the total number of substitutions, and (2) we use an explicit statistical decision criterion for classifying a site into either the complementarity determining or framework category. Simulations indicate that the method is reliable with relatively little data, approximately 5% of the sites being misclassified when 10 sequences are aligned. The method is applied to immunoglobulin light chains and to class 1 and class 2 products of the major histocompatibility complex.  相似文献   
999.
1000.
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