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   1504篇
  免费   46篇
  国内免费   5篇
耳鼻咽喉   9篇
儿科学   19篇
妇产科学   60篇
基础医学   210篇
口腔科学   9篇
临床医学   103篇
内科学   360篇
皮肤病学   37篇
神经病学   112篇
特种医学   36篇
外科学   114篇
综合类   9篇
预防医学   83篇
眼科学   11篇
药学   158篇
中国医学   19篇
肿瘤学   206篇
  2022年   25篇
  2021年   50篇
  2020年   22篇
  2019年   19篇
  2018年   15篇
  2017年   14篇
  2016年   16篇
  2015年   34篇
  2014年   27篇
  2013年   56篇
  2012年   88篇
  2011年   87篇
  2010年   61篇
  2009年   46篇
  2008年   87篇
  2007年   110篇
  2006年   117篇
  2005年   135篇
  2004年   125篇
  2003年   105篇
  2002年   109篇
  2001年   13篇
  2000年   6篇
  1999年   11篇
  1998年   12篇
  1997年   6篇
  1996年   7篇
  1995年   5篇
  1994年   8篇
  1993年   5篇
  1992年   15篇
  1991年   6篇
  1988年   3篇
  1987年   6篇
  1986年   5篇
  1985年   6篇
  1984年   4篇
  1983年   3篇
  1982年   6篇
  1981年   4篇
  1979年   4篇
  1978年   6篇
  1977年   6篇
  1976年   3篇
  1975年   3篇
  1974年   4篇
  1973年   3篇
  1971年   7篇
  1966年   3篇
  1964年   3篇
排序方式: 共有1555条查询结果,搜索用时 78 毫秒
91.
We attempted to identify deleted segments in two model tumor suppressor gene loci on chromosomes 13q14 and 17p13 that were associated with clonal expansion of in situ bladder preneoplasia using single nucleotide polymorphisms (SNPs)-based whole-organ histologic and genetic mapping. For mapping with SNPs, the sequence-based maps spanning approximately 27 and 5 Mb centered around RB1 and p53, respectively, were assembled. The integrated gene and SNP maps of the regions were used to select 661 and 960 SNPs, which were genotyped by pyrosequencing. Genotyping of SNPs was performed on DNA samples corresponding to histologic maps of the entire bladder mucosa in human cystectomy specimens with invasive urothelial carcinoma. By using this approach, we have identified deleted regions associated with clonal expansion of intraurothelial neoplasia; which ranged from 0.001 to 4.3 Mb (average 0.67 Mb) and formed clusters of discontinuous deleted segments. The high resolution of such maps is a prerequisite for future positional targeting of genes involved in early phases of bladder neoplasia. This approach also permits analysis of the overall genomic landscape of the involved region and discloses that a unique composition of noncoding DNA characterized by a high concentration of repetitive sequences may predispose to deletions.  相似文献   
92.
93.
Background. The following study is an attempt to draw the readers' attention to the issue of the multifariousness of the intervertebral discs' destructive processes resulting in the neuro-vertebral syndrome. The professional literature mentioned here gives a prominence to the thread of immunological phenomena accompanying disc diseases and their treatment.
Material and methods. Selected groups of patients with a high probability of the coexistence of immunological processes were analyzed in terms of pain patterns and topographic cross-sections of the intervertebral discs. They were then treated transdermically with butapirazole and levamisole hydrochloride under the control of Lasegu's bioengineer test, electro-sensory tests and CIC level tests.
Results. A Lasegu's test, an electro-sensory (I) test and a survey showed that the groups of patients treated locally 15 times with Butapirazole showed an almost complete recovery of the symmetry with no effect on the CIC level and the localized pain intensity (II). The majority of the patients experienced a regression of ailments within 3 months. As far as the group of patients treated with Levamisole is concerned both root (I) and localized pains (II) subsided rapidly as confirmed by a survey and a Lasegu's test as well as the electro-sensory tests (I), (II). A high decrease of the level of immunological complexes was noticed after only 15 Levamisole infusions. This correct level was maintained 3 months later, which was shown by further tests.
Conclusions. This seems to be the premise confirming the effect of a localized inflammatory point on the level of immunological complexes present in blood (CIC).  相似文献   
94.
95.
Adenosine is an endogenous agent exerting potent action on the immune system including regulation of lymphocyte functioning. Impaired T lymphocyte functioning is a common feature of diabetes. The aims of this study were to examine the effects of glucose and insulin on nucleoside transporters (NT) expression level and adenosine (Ado) transport in rat T lymphocytes cultured under the defined concentrations of glucose and insulin. Performed experiments revealed that rat T lymphocytes expressed the equilibrative nucleoside transporter type 1 and 2 (rENT1, rENT2) and concentrative nucleoside transporter type 2 (rCNT2). The mRNA levels of rENT2 and rCNT2 were highly dependent on insulin but were not affected by changes in extracellular glucose concentration. Exposition of T cells to 10nM insulin resulted in 73% increase in rENT2 mRNA and 50% decrease in the rCNT2 mRNA level. The level of rENT1 mRNA was sensitive to extracellular glucose concentration but not to insulin. The highest differences among cells cultured in high (20mM) and low (5mM) glucose were observed in equilibrative nitrobenzylthioinosine sensitive adenosine transport, which was lowered by 65% in cells cultured at high glucose. Alterations in adenosine transport were accompanied by changes in adenosine accumulation in the cell. These results indicate that adenosine transport in rat T lymphocytes is independently and differentially regulated by glucose and insulin by means of changes in the nucleoside transporters expression level. Altered adenosine transport has a great impact on its intracellular level. This suggests that under diabetic conditions adenosine action on T lymphocytes might be altered.  相似文献   
96.
Recent preclinical and clinical data indicate beneficial role of zinc in the antidepressant treatment. To evaluate the mechanism of interaction between zinc and antidepressants, in the present study we examined the brain zinc, imipramine and desipramine concentrations in mice treated with combinations of zinc and imipramine and subjected to the forced swim test. We have chosen doses of zinc (10 mg/kg) and imipramine (15 mg/kg) which we have previously found to be ineffective in the forced swim test when given alone. However, when administered jointly, a significant reduction in the immobility time in this test was demonstrated. In the present study, we demonstrated a significant ca. 60% reduction in the brain desipramine and non-significant reduction (ca. 40%) in brain imipramine concentrations in the group of animals treated with zinc plus imipramine compared with animals treated with imipramine alone. The brain zinc concentration in the zinc plus imipramine group was reduced when compared with the group treated with zinc or imipramine alone. Since there was no increase in brain imipramine/desipramine or zinc brain concentration after combined zinc and imipramine treatment, the data suggest that pharmacodynamic rather than pharmacokinetic interaction between zinc and imipramine is responsible for behavioral effect in the forced swim test.  相似文献   
97.
David John Faulkner, one of the pioneers of marine natural products chemistry and the 2003 recipient of the ASP Research Achievement Award, passed away on November 23, 2002. John was very pleased to learn that he'd been named as the award recipient and was intending to present the ASP Research Achievement Award Address at the annual meeting in July 2003, Chapel Hill, North Carolina. John's untimely death left an unprecedented event in the history of the ASP-a posthumous Research Achievement Award to a deserving individual and an untimely loss for us all. We are bereft of a colleague, a friend, and a mentor, and the opportunity to hear John's words on the occasion of his own award. In tribute to John, we have assembled a retrospective of John's work that is not meant to be a comprehensive review (this would take considerably more space) but a selection of highlights and personal vignettes from some of those that trained in marine natural products under his mentorship. This paper is a written account of the symposium presented by the authors at the ASP Annual Meeting in Chapel Hill, North Carolina, on July 16, 2003.  相似文献   
98.
A new antifungal agent, (2S,3R)-2-aminododecan-3-ol (1), has been isolated from the ascidian Clavelina oblonga collected in Brazil. The structure of 1 was established by analysis of spectroscopic data, including absolute stereochemistry determined by circular dichroism analysis of the dibenzoyl derivative 2. Compound 1 displayed antifungal activity against Candida albicans ATCC 10231 with a MIC of 0.7 mug/mL and against Candida glabrata with a MIC of 30 microg/mL.  相似文献   
99.
100.
The purpose of the study was to determine some apoptotic events in mononuclear cells obtained from peripheral blood of patients with B-cell chronic lymphocytic leukemia (B-CLL) during and after therapy with 2-chlorodeoxyadenosine (2-CdA; C), and the combination of 2-CdA with cyclophosphamide (CC), or 2-CdA with mitoxantrone and cyclophosphamide (CMC). Western blot technique was performed to estimate expression/proteolytic degradation of generally accepted apoptotic markers, i.e., Bcl-2 protein, lamin B, PARP-1, and caspase-3 in leukemic cells isolated from blood samples of patients before treatment and subjected to drug(s) administration. The decrease of antiapoptotic protein Bcl-2 expression and proteolytic cleavage of nuclear proteins--lamin B and PARP-1 were observed in leukemic cells of patients treated according to the above therapy protocols, however, each to a different level among the studied groups. The obtained results indicated also that procaspase-3 was cleaved and activated in leukemic cells of three drug(s) treated groups. However, the cleavage of procaspase-3 and the generation of fragments with mol. mass of 17/20 kDa occurred especially effectively among patients treated according to CMC regimen. The changes in expression/proteolytic degradation of the above selected apoptotic markers, are accompanied by the appearance of apoptotic morphology in leukemic cells originated from blood of patients treated with the above drug(s) in comparison to untreated ones.  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