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   6031篇
  免费   384篇
  国内免费   30篇
耳鼻咽喉   62篇
儿科学   137篇
妇产科学   190篇
基础医学   710篇
口腔科学   237篇
临床医学   516篇
内科学   1348篇
皮肤病学   135篇
神经病学   290篇
特种医学   196篇
外国民族医学   4篇
外科学   1005篇
综合类   105篇
现状与发展   2篇
一般理论   2篇
预防医学   306篇
眼科学   159篇
药学   653篇
中国医学   41篇
肿瘤学   347篇
  2023年   81篇
  2022年   227篇
  2021年   348篇
  2020年   220篇
  2019年   286篇
  2018年   370篇
  2017年   234篇
  2016年   226篇
  2015年   227篇
  2014年   263篇
  2013年   342篇
  2012年   469篇
  2011年   414篇
  2010年   255篇
  2009年   194篇
  2008年   279篇
  2007年   261篇
  2006年   238篇
  2005年   291篇
  2004年   218篇
  2003年   211篇
  2002年   180篇
  2001年   48篇
  2000年   31篇
  1999年   47篇
  1998年   35篇
  1997年   28篇
  1996年   29篇
  1995年   23篇
  1994年   13篇
  1993年   20篇
  1992年   24篇
  1991年   19篇
  1990年   16篇
  1989年   23篇
  1988年   21篇
  1987年   21篇
  1986年   21篇
  1985年   29篇
  1984年   13篇
  1983年   20篇
  1982年   10篇
  1981年   14篇
  1980年   15篇
  1979年   18篇
  1977年   10篇
  1976年   12篇
  1975年   13篇
  1974年   6篇
  1972年   8篇
排序方式: 共有6445条查询结果,搜索用时 15 毫秒
71.
72.
73.
Renal cell carcinoma (RCC) is the most common renal malignancy in adults and exhibits highly intrinsic and acquired resistance to standard therapeutic strategies. We sought to determine the anti-cancer activity of hydroalcoholic extract of Nigella sativa seeds (NSE) and thymoquinone (TQ). Human renal cell carcinoma (ACHN) and fibroblast L929 cell lines were treated with NSE and TQ, and cytotoxicity was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium (MTT) assay. Cell death pattern was determined by annexin V and propidium iodine (PI)-staining methods. Exposure to NSE, TQ and cisplatin significantly inhibited the growth of ACHN cells and showed significant increase of early apoptotic cells. Normal cells were more resistant to NSE and TQ-induced effects. The present study demonstrates that N. sativa and TQ exert anti-proliferative and pro-apoptotic effects on ACHN cells in a concentration and time-dependent manner, which suggests their potential to be used as a new therapeutic strategy for renal cancers.  相似文献   
74.
The aim of this study was to evaluate the use of different fixatives on the reliability of histopathological changes in a rabbit model of proliferative vitreoretinopathy (PVR). Twenty eyes from 10 rabbits were divided into four groups. The right eyes were used in two experimental groups (each n = 5), and the left, in two control groups (each n = 5). Using a newly developed scleral incision marker, an oblique scleral incision was standardized in the experimental groups, followed by intravitreal injection of 0.4 ml autologous blood and the left for wound repair for four weeks. Eyes were enucleated at four weeks. The groups differed in the type of used fixative solution (formaldehyde 4% vs. 1% buffered formaldehyde and 1.25% glutaraldehyde). The eyes were evaluated for the development of fibrosis, retinal detachment (RD), and processed for histopathology. Fibrous ingrowth of a variable degree was present in the experimental groups originating from the trauma site. Experimental eyes fixed with formaldehyde 4% had RD extension that was greater than that fixed in formaldehyde/glutaraldehyde mixture; however, the difference did not reach statistical significance (P = 0.15). This difference was not fully explained by the fibrosis which developed. In addition, in control groups, formaldehyde 4% induced a fixative-dependent retinal separation that was absent in eyes fixed with formaldehyde/glutaraldehyde mixture (P = 0.03). In conclusion, a mixture of buffered formaldehyde 1% and glutaraldehyde 1.25% combined with standardized scleral incision resulted in consistent pathological changes. A reliable PVR model is a condition sine qua non to evaluate antifibrotic treatment strategies.  相似文献   
75.
Background The impact of isolated diastolic dysfunction (IDD) and systolic dysfunction (SD) on health-related quality of life (HRQOL) is unknown. Methods and Results To evaluate HRQOL in patients with IDD and SD under treatment, information on outpatients aged 60-84 years was extracted from the records of 4,500 consecutive individuals who underwent echocardiographic examination at Sado General Hospital. The medical records of these patients were reviewed and a questionnaire, including the Medical Outcome Study Short Form 36, was mailed to 71 IDD and 99 SD patients; answers were obtained from 66 and 91 patients, respectively. The HRQOL of patients with cardiac dysfunction was impaired even when echocardiographic parameters improved with treatment. Patients with IDD showed an impairment of HRQOL similar to those with SD. Compared with males, female patients had a larger and more significant reduction in the physical and mental components of the HRQOL score. These scores correlated positively with exercise capacity in patients with IDD or SD. Conclusions Impaired HRQOL, in both its mental and physical components, is a serious problem for IDD and SD patients under treatment. Because exercise intolerance may underlie the reduced HRQOL, improving exercise capacity could be an important target for managing outpatients with heart failure. (Circ J 2008; 72: 1436 - 1442).  相似文献   
76.
BACKGROUND: The future burden of heart failure in Japan was projected to 2055 in order to prospectively estimate of the number of these patients. METHODS AND RESULTS: The statistics are based on prevalence data of left ventricular dysfunction (LVD) in Sado City using the Sado Heart Failure Study (2003) and population estimates from the Japanese National Institute of Population and Social Security Research Report (2006). The number of Japanese outpatients with LVD was 979,000 in 2005, and is predicted to increase gradually as the population ages, reaching 1.3 million by 2030. CONCLUSION: LVD is expected to precipitate a future epidemic of heart failure in Japan.  相似文献   
77.
Antigenicity of xenogeneic tissues is the major obstacle to increased use of these materials in clinical medicine. Residual xenoantigens in decellularized tissue elicit the immune response after implantation, causing graft failure. With this in mind, the potential use is proposed of three protein solubilization‐based protocols for porcine aortic valve leaflets decellularization. It was demonstrated that hydrophile solubilization alone achieved incomplete decellularization; lipophile solubilization alone (LSA) completely removed all cells and two most critical xenoantigens – galactose‐α(1,3)‐galactose (α‐Gal) and major histocompatibility complex I (MHC I) – but caused severe alterations of the structure and mechanical properties; sequential hydrophile and lipophile solubilization (SHLS) resulted in a complete removal of cells, α‐Gal and MHC I, and good preservation of the structure and mechanical properties. In contrast, a previously reported method using Triton X‐100, sodium deoxycholate and IGEPAL CA‐630 resulted in a complete removal of all cells and MHC I, but with remaining α‐Gal epitope. LSA‐ and SHLS‐treated leaflets showed significantly reduced leucocyte activation (polymorphonuclear elastase) upon interaction with human blood in vitro. When implanted subdermally in rats for 6 weeks, LSA‐ or SHLS‐treated leaflets were presented with more biocompatible implants and all four decellularized leaflets were highly resistant to calcification. These findings illustrate that the SHLS protocol could be considered as a promising decellularization method for the decellularization of xenogeneic tissues in tissue engineering and regenerative medicine. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
78.

Background and Purpose

Cyclosporine (CSA) and non-steroidal anti-inflammatory drugs (NSAIDs) are co-prescribed for some arthritic conditions. We tested the hypothesis that this combined regimen elicits exaggerated nephrotoxicity in rats via the up-regulation of endothelin (ET) receptor signalling.

Experimental Approach

The effects of a 10 day treatment with CSA (20 mg·kg−1·day−1), indomethacin (5 mg·kg−1·day−1) or their combination on renal biochemical, inflammatory, oxidative and structural profiles were assessed. The roles of ETA receptor and COX-2 pathways in the interaction were evaluated.

Key Results

Oral treatment with CSA or indomethacin elevated serum urea and creatinine, caused renal tubular atrophy and interstitial fibrosis, increased renal TGF-β1, and reduced immunohistochemical expressions of ETA receptors and COX-2. CSA, but not indomethacin, increased renal ET-1, the lipid peroxidation product malondialdehyde (MDA) and GSH activity. Compared with individual treatments, simultaneous CSA/indomethacin exposure caused: (i) greater elevations in serum creatinine and renal MDA; (ii) loss of the compensatory increase in GSH; (iii) renal infiltration of inflammatory cells and worsening of fibrotic and necrotic profiles; and (iv) increased renal ET-1 and decreased ETA receptor and COX-2 expressions. Blockade of ETA receptors by atrasentan ameliorated the biochemical, structural, inflammatory and oxidative abnormalities caused by the CSA/indomethacin regimen. Furthermore, atrasentan partly reversed the CSA/indomethacin-evoked reductions in the expression of ETA receptor and COX-2 protein.

Conclusions and Implications

The exaggerated oxidative insult and associated dysregulation of the ETA receptor/COX-2/TGF-β1 signalling might account for the aggravated nephrotoxicity caused by the CSA/indomethacin regimen. The potential renoprotective effect of ETA receptor antagonism might be exploited therapeutically.Tables of Links
TARGETS
GPCRsa2001Enzymesb2001
ETA receptorCOX-2
Open in a separate window
LIGANDS
CyclosporineIndomethacin
ET-1TGF-β1
GSHUrea
Open in a separate windowThese Tables list key protein targets and ligands in this article which are hyperlinked to corresponding entries in http://www.guidetopharmacology.org, the common portal for data from the IUPHAR/BPS Guide to PHARMACOLOGY (Pawson et al., 2014) and are permanently archived in the Concise Guide to PHARMACOLOGY 2013/14a,bAlexander et al., 2013a,b).  相似文献   
79.
80.
This study was designed to highlight the relation of tumor necrosis factor- (TNF-) to neuropsychiatric lupus (NPLE) manifestations. The relation of TNF- to the type of single photon emission computed tomography (SPECT) findings in this context was also studied. Twenty-one systemic lupus erythematosus (SLE) females, mean age 27.57 ± 9.89 years, and twenty age-matched normal females (controls), were subjected to TNF- assessment. Different clinical and neuropsychiatric manifestations were evaluated. SPECT was carried out for all patients. The results showed that the mean TNF- level (pg/ml) was significantly raised in patients compared with controls (167.8 ± 102.5 versus 64 ± 50.2, respectively, P 0.005). Thirteen patients (69.1%) had NPLE manifestations. NPLE patients had a significantly higher mean TNF- than patients without NPLE (203 ± 102.8 versus 109 ± 47.3, respectively, P 0.03). Positive SPECT findings were found in 18 lupus patients (85.7%), including all 13 patients with NPLE (100% sensitivity), with a multiple focal pattern of hypoperfusion being the most frequent type (9/13), followed by diffuse (3/13), and then single focal pattern (1/13). The mean TNF- was significantly higher in patients with multiple focal pattern (P 0.001). In conclusion, results of this work support the hypothesis that TNF- could be involved in the pathogenesis of NPLE, and hence, it could be speculated that the evolving anti-TNF therapy can play a potential role in the management of this disease.  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