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   6392篇
  免费   398篇
  国内免费   76篇
耳鼻咽喉   15篇
儿科学   340篇
妇产科学   90篇
基础医学   668篇
口腔科学   184篇
临床医学   613篇
内科学   1679篇
皮肤病学   231篇
神经病学   540篇
特种医学   766篇
外国民族医学   1篇
外科学   564篇
综合类   116篇
一般理论   1篇
预防医学   387篇
眼科学   51篇
药学   232篇
  2篇
中国医学   1篇
肿瘤学   385篇
  2021年   50篇
  2019年   58篇
  2018年   71篇
  2017年   67篇
  2016年   63篇
  2015年   82篇
  2014年   131篇
  2013年   151篇
  2012年   190篇
  2011年   202篇
  2010年   201篇
  2009年   165篇
  2008年   225篇
  2007年   291篇
  2006年   213篇
  2005年   220篇
  2004年   207篇
  2003年   185篇
  2002年   175篇
  2001年   183篇
  2000年   199篇
  1999年   155篇
  1998年   166篇
  1997年   199篇
  1996年   165篇
  1995年   144篇
  1994年   152篇
  1993年   136篇
  1992年   151篇
  1991年   167篇
  1990年   135篇
  1989年   179篇
  1988年   146篇
  1987年   151篇
  1986年   148篇
  1985年   138篇
  1984年   99篇
  1983年   82篇
  1982年   66篇
  1981年   73篇
  1980年   69篇
  1979年   81篇
  1978年   71篇
  1977年   65篇
  1976年   60篇
  1975年   49篇
  1974年   56篇
  1973年   50篇
  1971年   43篇
  1970年   47篇
排序方式: 共有6866条查询结果,搜索用时 31 毫秒
1.
Cutaneous plasmacytosis is a rare disorder characterized by a benign proliferation of mature plasma cells that appears as multiple dark-brown to purplish skin lesions, often associated with polyclonal hypergammaglobulinaemia. We present the case of a 55-year-old Caucasian man who suffered from a cutaneous plasmacytosis associated with two different carcinomas. Cutaneous plasmacytosis seems to be a reactive process because most cases reported are not associated with any apparent underlying disease. Nevertheless, because few reported cases were associated with malignancies, screening of additional neoplasms would be justified.  相似文献   
2.
3.
4.
Although an uncommon cause of sexual dysfunction, hyperprolactinaemia is almost invariably associated with loss of libido and impotence in men. The finding of hyperprolactinaemia should prompt a systematic search for an underlying cause, particularly prolactin-secreting pituitary adenomas; in this condition, sexual dysfunction may antedate other complications of the pituitary tumour by many years.  相似文献   
5.
While extensive evidence suggests that adrenoceptors play an important role in the control of growth hormone in the rat, there are few studies involving the direct measurement of growth hormone-releasing hormone (GHRH). We have therefore developed a radioimmunoassay for rat GHRH, and used it to investigate the modulation of GHRH release by noradrenaline from incubated rat hypothalamus in vitro. The GHRH radioimmunoassay had no significant cross-reactivity with other hypothalamic or GHRH-related peptides, and was sensitive to 4 pg/tube; intra- and interassay coefficients of variation were 6% and 12% respectively. Single incubated rat hypothalami produced a stable and readily measurable output of GHRH in successive 20 min incubations after an initial 60 min preincubation; the release of GHRH was increased in the presence of 56 mM KCI, but did not respond to KCI-depolarization when calcium was excluded from the medium. Stimulated GHRH release was identical to synthetic rat GHRH(1–43) on high-performance liquid chromatography and Sephadex G-75 chromatography.
Noradrenaline stimulated GHRH secretion in a dose-dependent manner in the concentration range 10−10— 10−6M, with a plateau in response at 10−7M. Stimulation with noradrenaline 10−7M was blocked by idazoxan 10−5M and attenuated by thymoxamine 10−5M, but was unaffected by timolol 10−5M. Both the α2-adrenoceptor agonist guanfacine, and the α1-adrenoceptor agonist methoxamine, specifically stimulated GHRH secretion.
It is concluded that noradrenaline stimulates the release of GHRH at both α1 and α2-adrenoceptors.  相似文献   
6.
Although iophendylate (Pantopaque) has been largely replaced by water soluble agents for myelography, retained intracranial or intraspinal Pantopaque remains a common occurrence. Pantopaque has signal characteristics similar to fat with both short T1 and T2 relaxation times. In vitro measurements revealed T1 = 170 ms and T2 = 27 ms. Spine radiography is recommended in patients with a history of previous myelography and magnetic resonance abnormalities similar to fat.  相似文献   
7.
Neoplastic meningitis.   总被引:1,自引:0,他引:1  
Neoplastic meningitis appears to be increasing in frequency with improvements in the treatment of many cancers. It is most often recognized in patients with leukemia, breast cancer, lymphomas, and small-cell cancer of the lung, although it may be seen with virtually any malignancy. Treatment should include intrathecal chemotherapy, radiation therapy to symptomatic areas of the CNS, and optimal therapy of the systemic cancer. New efforts are underway to decrease the toxicity and improve the efficacy of antineoplastic therapy for this devastating complication of cancer.  相似文献   
8.
The identification of clinically relevant, active immunomodulatory agents is important for developing immunotherapeutic approaches to chronic lymphocytic leukemia (CLL) and other B-cell lymphomas that are not curable with conventional chemotherapy. In this investigation, the imidazoquinoline Toll-like receptor (TLR)-7/8 agonist, imiquimod, was found to mediate the clearance of a lymphomatous skin lesion in a CLL patient. Imidazoquinolines also activated TLR-7/8 signaling pathways, resulting in increased expression of costimulatory molecules on circulating tumor cells. These observations extend the therapeutic spectrum of imiquimod to cutaneous B-cell lymphomas and suggest the use of TLR-7/8 agonists in CLL immunotherapy.  相似文献   
9.
The aim of this study was to evaluate the cerebral synthesis of eicosanoids in the asphyctic newborn and to investigate the relation between the prostanoid profiles in cerebrospinal fluid (CSF) and the appearance and severity of hypoxic-ischaemic encephalopathy (HIE). Levels of 6-keto-PGF 1-α, TXB2, PGE2 and PGF2-α in CSF were measured in 40 full term newborns during the first day of life. Thirty of these newborns had birth asphyxia and were divided into three groups: 10 without HIE, 12 with mild HIE and 8 with moderate-severe HIE. They were compared to a control group of 10 non-hypoxic newborns. Determinations of the metabolites in CSF were performed by RIA and expressed as pg/ml (mean ± SD). The CSF TXB2 (thromboxane A2 metabolite) in asphyxiated newborns was always higher than in the control group (28.12 ± 10.6), and related to the severity of HIE ( p = 0:005): without HIE (50.84 ± 16.4; p = 0:02), mild HIE (80.65 ± 12.64; p ± 0:01) and moderate-severe HIE (178.14 ± 20.5; p < 0:01). The CSF 6-keto-PGF 1-α (prostacyclin metabolite) in asphyxiated newborns was always higher than in the control group (80.55 ± 12.56), but indirectly related to the severity of HIE: without HIE (240.95 ± 28.12; p < 0:01), mild HIE (183.65 ± 30.1; p < 0:01) and moderate-severe HIE (140.55 ± 25.12; p < 0:01). In the moderate-severe HIE group, the increase in TXB2 was higher than the rise in 6-keto-PGF 1-α.  相似文献   
10.
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