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   3171篇
  免费   197篇
  国内免费   37篇
耳鼻咽喉   39篇
儿科学   114篇
妇产科学   145篇
基础医学   309篇
口腔科学   129篇
临床医学   271篇
内科学   535篇
皮肤病学   84篇
神经病学   144篇
特种医学   117篇
外国民族医学   2篇
外科学   593篇
综合类   71篇
一般理论   3篇
预防医学   219篇
眼科学   94篇
药学   326篇
中国医学   21篇
肿瘤学   189篇
  2023年   42篇
  2022年   123篇
  2021年   163篇
  2020年   116篇
  2019年   157篇
  2018年   183篇
  2017年   102篇
  2016年   124篇
  2015年   115篇
  2014年   136篇
  2013年   214篇
  2012年   251篇
  2011年   289篇
  2010年   152篇
  2009年   104篇
  2008年   171篇
  2007年   136篇
  2006年   137篇
  2005年   103篇
  2004年   114篇
  2003年   81篇
  2002年   68篇
  2001年   33篇
  2000年   15篇
  1999年   18篇
  1998年   22篇
  1997年   12篇
  1996年   12篇
  1995年   7篇
  1994年   13篇
  1993年   8篇
  1992年   12篇
  1991年   21篇
  1990年   15篇
  1989年   8篇
  1988年   6篇
  1987年   11篇
  1985年   9篇
  1984年   16篇
  1983年   6篇
  1982年   9篇
  1981年   6篇
  1980年   4篇
  1979年   4篇
  1978年   5篇
  1976年   9篇
  1974年   4篇
  1973年   4篇
  1972年   5篇
  1966年   5篇
排序方式: 共有3405条查询结果,搜索用时 0 毫秒
81.
82.
Radioembolization with radioactive microspheres has been an effective method for the treatment of liver lesions. The aim of this study was to prepare carrier‐free 188Re loaded poly (L‐lactic acid) (PLLA) microspheres through 188Re sulfide colloidal nanoparticles (188Re‐SC nanoparticles). The formation of 188Re‐SC nanoparticles was confirmed by ultraviolet‐visible spectrophotometry. The labeling yield of 188Re‐SC nanoparticles was verified using the RTLC method. Effects of synthesis parameters on morphology and size of prepared 188Re‐sulfide colloidal‐PLLA microspheres (188Re‐SC‐PLLA microspheres) were studied by scanning electron microscopy. In vitro stability of 188Re‐SC‐PLLA microspheres was investigated in normal saline at room temperature and in human serum at 37°C. In vivo distribution studies and gamma camera imaging were performed in healthy BALB / c mice. The microspheres could be prepared with sizes between 13 and 48 μm (modal value 29 μm) and radiolabeling efficiency >99%. After incubation, the microspheres were found stable in vitro up to 72 hours. The biodistribution after intravenous injection in healthy BALB / c mice showed high accumulation in lung as a first capture pathway organ for microsphere followed by great retention over 48 hours for these microspheres. These data show that 188Re‐SC‐PLLA microspheres are suitable candidate for clinical studies.  相似文献   
83.

Background

Hydroxychloroquine (HCQ) is a widely prescribed medication to patients with systemic lupus erythematosus (SLE), with potential anti-inflammatory effects. This study was performed to investigate the efficacy of HCQ therapy by serial assessment of disease activity and serum levels of proinflammatory cytokines in SLE patients.

Methods

In this prospective cohort study, 41 newly diagnosed SLE patients receiving 400 mg HCQ per day were included. Patients requiring statins and immunosuppressive drugs except prednisolone at doses lower than 10 mg/day were excluded. Outcome measures were assessed before commencement of HCQ therapy (baseline visit) as well as in two follow-up visits (1 and 2 months after beginning the HCQ therapy). Serum samples of 41 age-matched healthy donors were used as controls.

Results

Median levels of IL-1β (p?<?0.001), IL-6 (p?=?0.001), and TNF-α (p?<?0.001) were significantly higher, whereas, median CH50 level was significantly lower (p?<?0.001) in SLE patients compared with controls. Two-month treatment with HCQ resulted in significant decrease in SLEDAI-2K (p?<?0.001), anti-dsDNA (p?<?0.001), IL-1β (p?=?0.003), IL-6 (p?<?0.001) and TNF-α (p?<?0.001) and a significant increase in CH50 levels (p?=?0.012). The reductions in SLEDAI-2K and serum levels of IL-1β and TNF-α were significantly greater in the first month compared with the reductions in the second month.

Conclusion

HCQ therapy is effective on clinical improvement of SLE patients through interfering with inflammatory signaling pathways, reducing anti-DNA autoantibodies and normalizing the complement activity.
  相似文献   
84.
Accurate measurement of structural features represented in medical images is important in clinical trials and patient diagnosis. A key factor for precision is spatial resolution, which in ultrasonic imaging is limited by transducer array arrangements, transmitting frequency, and data acquisition firmware. In this paper, a variation of pixel compounding is proposed to enhance ultrasound resolution using acquired cine loops. The technique operates on a sequence of ultrasound B-scan images acquired with random motion. Subpixel registration is estimated and a maximum a posteriori (MAP) approach with the shift information is used to reconstruct a high-resolution single image. A nonhomogeneous anisotropic diffusion algorithm follows from the estimation process and is implemented to enhance the high-resolution edges. Preliminary tests using simulations and phantom studies show promising results. Pixel compounding can be a powerful preprocessing tool to assure accurate segmentation, measurement, and analysis of ultrasound images.  相似文献   
85.
Background Cisplatin-induced nephrotoxicity still occurs despite the intensive hydration approach adapted to prevent its occurrence. Objective Evaluation of the effect of acetazolamide (ACTZ) on minimizing cisplatin-induced nephrotoxicity compared to mannitol when added to hydration regimen. Setting Nasser Institute Cancer Center (NICC), Cairo, Egypt. Method A total of 35 patients planned to receive cisplatin were divided into two groups: 20 patients received mannitol and 15 patients received ACTZ. Both groups received standard hydration measures as well for prevention of cisplatin-induced nephrotoxicity. Main outcome measure Patients’ kidney function was assessed using serum creatinine, creatinine clearance and blood urea nitrogen. Kidney injury was assessed using RIFLE criteria. Patients’ liver function tests and hematological parameters were also monitored. Results Patients in the mannitol group showed higher risk of developing kidney injury (30%) whereas those in the ACTZ group showed lower risk (8.9%), relative risk (RR) 0.269, 95% CI 0.108–0.815. No statistically significant difference occurred between the two groups concerning liver function tests or hematological parameters. Conclusion Use of ACTZ in addition to intensive hydration may have more beneficial effect on minimizing cisplatin-induced nephrotoxicity compared to mannitol plus intensive hydration approach. A large multicenter randomized clinical trials is recommended to confirm study results and to assess effect of ACTZ on tumor response.  相似文献   
86.
International Urology and Nephrology - Saffron (Crocus sativus L.) has been proposed as a potential agent to improve renal function in animal studies. But, due to insufficient evidence in human...  相似文献   
87.
International Urology and Nephrology - Vesicoureteral reflux (VUR) is the most common congenital urinary tract abnormality in children. The objective of this study was to evaluate the diagnostic...  相似文献   
88.
The current study aimed to investigate the protective potential of Chlorella Vulgaris (CV) extract against the reproductive dysfunction induced by sodium nitrite toxicity. Forty-five male Wistar albino rats were assigned into five groups (n = 9). Control group received normal saline orally for 3 months, CV-treated: administered CV extract (70 mg/kg.BW) orally for 3 months, sodium nitrite-treated: received sodium nitrite (80 mg/kg.BW) orally for 3 months, co-treated: simultaneously received CV along with sodium nitrite treatment, orally, daily for 3 months, and CV-pre-treated: pre-treated with CV extract for 4 weeks followed by simultaneous treatment with sodium nitrite and CV extract for additional 8 weeks. Treatment with sodium nitrite significantly decreased serum testosterone and follicle-stimulating hormone concentrations, sperm count, motility, and viability. Besides, it decreased testicular superoxide dismutase and glutathione peroxidase activities while increased malondialdehyde concentration. This effect of sodium nitrite was associated with degenerative, necrotic, vascular, and inflammatory changes in testicular tissues. Treatment of sodium nitrite-intoxicated rats with CV in co-treated and pre-treated groups significantly prevented sodium nitrite-induced alterations of sperm parameters, hormonal concentrations, testicular oxidative–antioxidant status, and histological architecture. This study indicates that CV extract ameliorates the reproductive dysfunction induced by sodium nitrite toxicity via improving reproductive hormonal levels and testicular antioxidant activities.  相似文献   
89.
Background contextNKCC1 regulates neuronal homeostasis of chloride ions and mediates GABAergic activities in nociceptive processing. WNK1 is an upstream regulator of NKCC1 and acts via SPAK (STE20/SPS1-related proline/alanine-rich kinase) and oxidative stress-responsive kinase 1. NKCC1 activity has been shown to be important in edema formation and nociception following spinal cord injury (SCI).PurposeTo determine the role of NKCC1 and WNK1 in spinal cord tissues in the acute and chronic phases following contusional SCI.Study designAn experimental study investigating the phosphorylation profile of an important Cl-regulatory protein Na+-K+-Cl? cotransporter 1 (NKCC1) and its regulatory-kinase WNK1 (kinase with-no-lysine).MethodsSprague-Dawley rats underwent a contusive SCI at T9. The epicenter spinal cord tissues were harvested at Days 1, 3, and 7 for acute phase of injury or Days 35 and 42 in the chronic phase of injury. Western blot was used to compare phosphorylated levels of both NKCC1 and WNK1 in injured tissues compared with those of sham.ResultsA sustained increase in phosphorylation of NKCC1 and WNK1 was detected in the lesion epicenter in spinal cord during both acute and chronic phases following SCI.ConclusionsThese results suggest that persistent activation of NKCC1 and WNK1 may play an important role in SCI.  相似文献   
90.
Background and aimsThe association of water intake with type 2 diabetes mellitus (T2DM) is still unclear. Therefore, the aim of this systematic review and meta-analysis was to synthesize the knowledge about the relationship between water intake and the risk of T2DM.MethodsWe conducted a systematic search in PubMed and Scopus up to June 2018 for observational studies. Risk ratios (RR)s and 95% confidence intervals (95% CI)s were calculated and fixed effects models were used.ResultsOverall, 6 studies were included in the meta-analyses. There was an inverse relationship between water intake and risk of T2DM (RR: 0.94; 95% CI: 0.91–0.97, P < 0.001) with low heterogeneity (I2 = 24%, P = 0.24).ConclusionOur findings indicated that the intake of water was correlated with reduced risk of type 2 diabetes in women and men. These results support the current recommendations of water intake as an inseparable part of a diet with the lowest risk of diabetes mellitus.  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