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   761篇
  免费   57篇
  国内免费   2篇
耳鼻咽喉   5篇
儿科学   21篇
妇产科学   11篇
基础医学   137篇
口腔科学   14篇
临床医学   69篇
内科学   153篇
皮肤病学   51篇
神经病学   70篇
特种医学   11篇
外科学   128篇
综合类   9篇
一般理论   1篇
预防医学   27篇
眼科学   10篇
药学   60篇
中国医学   5篇
肿瘤学   38篇
  2023年   5篇
  2021年   10篇
  2020年   7篇
  2019年   13篇
  2018年   11篇
  2017年   5篇
  2016年   9篇
  2015年   12篇
  2014年   15篇
  2013年   19篇
  2012年   34篇
  2011年   37篇
  2010年   21篇
  2009年   19篇
  2008年   39篇
  2007年   35篇
  2006年   34篇
  2005年   27篇
  2004年   27篇
  2003年   33篇
  2002年   48篇
  2001年   30篇
  2000年   39篇
  1999年   39篇
  1998年   13篇
  1997年   9篇
  1996年   10篇
  1995年   4篇
  1994年   8篇
  1993年   8篇
  1992年   27篇
  1991年   22篇
  1990年   23篇
  1989年   18篇
  1988年   8篇
  1987年   14篇
  1986年   15篇
  1985年   18篇
  1984年   6篇
  1983年   9篇
  1982年   3篇
  1981年   2篇
  1980年   2篇
  1979年   8篇
  1978年   4篇
  1977年   3篇
  1976年   2篇
  1974年   4篇
  1973年   2篇
  1972年   6篇
排序方式: 共有820条查询结果,搜索用时 62 毫秒
1.
Daily exposure to sunlight is known to affect the structure and function of the epidermal basement membrane (BM), as well as epidermal differentiation and epidermal barrier function. The aim of this study is to clarify whether the inhibition of BM‐degrading enzymes such as heparanase and matrix metalloproteinase 9 (MMP‐9) can improve the epidermal barrier function of facial skin, which is exposed to the sun on a daily basis. 1‐(2‐hydroxyethyl)‐2‐imidazolidinone (HEI) was synthesized as an inhibitor of both heparanase and MMP‐9. HEI inhibited not only the BM damage at the DEJ but also epidermal proliferation, differentiation, water contents and transepidermal water loss abnormalities resulting from ultraviolet B (UVB). This was determined in this study by the use of UVB‐induced human cultured skins as compared with the control without HEI. Moreover, topical application of HEI improved epidermal barrier function by increasing water content and decreasing transepidermal water loss in daily sun‐exposed facial skin as compared with non‐treated skins. These results suggest that the inhibition of both heparanase and MMP‐9 is an effective way to care for regularly sun‐exposed facial skin by protecting the BM from damage.  相似文献   
2.
3.
Abstract Uro-neurological assessment was performed in four patients with small-fiber neuropathy due to amyloidosis (2 transthyretin-type/2 immunoglobulin light-chain-type). Voiding difficulties were due to detrusor weakness and impaired bladder sensation. In two patients cholinesterase inhibition treatment caused urge incontinence, indicating detrusor denervation supersensitivity. The underlying mechanisms of urinary dysfunction seem to involve postganglionic cholinergic and afferent somatic nerves.  相似文献   
4.
5.
B-1 virus belonging to the hantavirus group was serially passaged in the brains of newborn mice. Inactivated vaccine was prepared from the brains after inactivation with formalin and then purification by ultracentrifugation. The antigenic potency of this vaccine in vitro was determined by antibody-bound enzyme-linked immunosorbent assay (ELISA) and serial diluted vaccine bound to an aluminium hydroxide gel was inoculated into Balb/c mice to test immunogenicity. After two injections of this vaccine preparation, antibodies were detected in the mice by immunofluorescent, neutralizing and haemagglutination inhibition antibody tests. When mice immunized with this vaccine were challenged with B-1 virus and Hantaan virus (KHF-83-61BL strain), the virus titres in their lungs and spleens were significantly less than those in non-immunized mice. These results suggest that inactivated B-1 virus vaccine is effective against virus challenge by homotypic (B-1 virus) and heterotypic (Hantaan virus) viruses.  相似文献   
6.
A system composed of a functional continuous magnetic stimulator (FCMS) and a saddle-type coil has been developed for non-invasive treatment of urinary incontinence, especially stress incontinence and urge incontinence. The FCMS conditions were as follows: 2 kW maximum electrical power consumption, 800 V maximum capacitor voltage, 720 μs pulsewidth (180 μs rise time), and 5–30 Hz frequency. A frequency between 5 and 10 Hz is used to treat urge incontinence and a frequency between 25 Hz and 30 Hz is used to treat urge incontinence. The coil (120 mm long, 90 mm wide and 50 mm thick) fits the most suitable region for this treatment, the region from the anus to the perineum. The coil is cooled to maintain a coil temperature between 20 and 25°C so that it can be used efficiently and safely. In experiments with anaesthetised dogs, it was confirmed that the urethral pressure increased when the circumference of the perineum received continuous magnetic stimulation of 720 μs pulsewidth (180 μs rise time), 10Hz frequency and about 520 V capacitor voltage. This result suggests that magnetic stimulation can be effective as a urinary incontinence therapy.  相似文献   
7.
Acyclovir (9-/2-hydroxyethoxymethyl/guanine) enhanced the plaque formation of HSV and VZV at subinhibitory dose and inhibited at higher concentration but not in thymidine kinase deficient viruses. The enhancement was neutralized by thymidine. Induction of viral thymidine kinase activity was not affected with ACV. These results suggest that the enhancement may be mediated by viral thymidine kinase.  相似文献   
8.
Summary Azathioprine (Aza) was found to have anti-human cytomegalovirus (HCMV) activity in vitro at concentrations used for immunosuppression therapy. The dose of Aza for 50% plaque reduction was 0.592µg/ml for HCMV in human embryonic lung (HEL) cells, but those of Aza for 50% plaque reduction for herpes simplex virus (HSV) and varicella-zoster virus were more than 20µg/ml. The dose of Aza for 50% reduction of the HCMV yield in infected cells was 0.25µg/ml, while that for 50% reduction of the HSV yield in infected cells was more than 50µg/ml. The dose of Aza for 50% growth inhibition of HEL cells was 30µg/ml, and 50.7 and 120 times greater than the doses for 50% reduction of the plaque formation and the yield of HCMV, respectively. Thus Aza was found to have a strong anti-HCMV activity at concentrations used for immunosuppression. When HCMV infected cells were treated with cyclosporine (CsA: 0.2µg/ml) and prednisolone (Pred: 0.3µg/ml) simultaneously with Aza, the doses of Aza for 50% reduction of plaque formation and the yield of HCMV were 0.73 and 0.32µg/ml, respectively. Thus an inhibitory effect of Aza was also observed in HCMV-infected cells treated with CsA and Pred at their concentrations used for immunosuppression. Maintenance of an anti-HCMV dose of Aza in combination with CsA and Pred might establish not only satisfactory immunosuppression but also suppression of HCMV infection in transplant recipients.  相似文献   
9.
To study cow’s milk allergy at the cellular level, we assessed the reactivity of peripheral blood mononuclear cells from patients allergic to cow’s milk to αs1-casein, which is one of the major allergens in cow’s milk. Proliferation of the cells to αs1-casein activation showed a rather weak response. Therefore to understand T-cell reactivity to αs1-casein in more detail, we prepared αs1-casein–specific T-cell lines from patients allergic to cow’s milk and established 26 T-cell lines. These T-cell lines could be classified into three groups by analyzing their surface marker expression: those containing predominantly CD4+CD8- T cells, those containing both CD4+CD8- and CD4-CD8+ T cells, and those containing predominantly CD4-CD8+ T cells. The CD8+ T cells were obtained at an unexpectedly higher frequency from the patients. These T-cell lines produced interferon-γ and IL-4. These results suggest that CD8+ T cells specific for αs1-casein and CD4+ T cells were primed by the stimulation with αs1-casein in patients allergic to milk and that both T cells may play a key role in the onset, progression of, or recovery from cow’s milk allergy. (J ALLERGY CLIN IMMUNOL 1996;97:1342-9.)  相似文献   
10.
HL-60 cells can be induced to differentiate into macrophage-like cells by treatment with 12-O-tetra-decanoylphorbol-13-acetate (TPA). The relationship between virus replication and cell differentiation was investigated using HL-60 cells that had been induced to differentiate by TPA (dHL-60 cells) and undifferentiated cells (udHL-60 cells). On infection of these cells with cell-free varicella-zoster virus (VZV), virus antigens were detected in dHL-60 cells but not in udHL-60 cells, and the percentage of antigen-positive dHL-60 cells increased during incubation. Similar results were obtained by infectious center assay, and the percentage of antigen-positive cells correlated with the stage of cell differentiation. No significant difference was found in the binding of VZV to dHL-60 cells and udHL-60 cells. Furthermore, trypsin treatment after adsorption suggested that VZV penetrated into udHL-60 cells. These findings indicate that VZV may be able to replicate in mature monocytes but may be harbored in immature monocytes in vivo.  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