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   46799篇
  免费   3689篇
  国内免费   1264篇
耳鼻咽喉   151篇
儿科学   1684篇
妇产科学   460篇
基础医学   3997篇
口腔科学   290篇
临床医学   4994篇
内科学   6262篇
皮肤病学   481篇
神经病学   898篇
特种医学   1807篇
外国民族医学   16篇
外科学   13707篇
综合类   6566篇
现状与发展   6篇
一般理论   1篇
预防医学   1436篇
眼科学   159篇
药学   3599篇
  27篇
中国医学   1497篇
肿瘤学   3714篇
  2024年   62篇
  2023年   668篇
  2022年   1117篇
  2021年   1730篇
  2020年   1698篇
  2019年   1561篇
  2018年   1576篇
  2017年   1460篇
  2016年   1733篇
  2015年   1764篇
  2014年   2903篇
  2013年   3636篇
  2012年   2292篇
  2011年   2486篇
  2010年   2146篇
  2009年   2201篇
  2008年   2191篇
  2007年   2292篇
  2006年   2131篇
  2005年   1974篇
  2004年   1760篇
  2003年   1437篇
  2002年   1290篇
  2001年   1094篇
  2000年   852篇
  1999年   733篇
  1998年   666篇
  1997年   650篇
  1996年   635篇
  1995年   586篇
  1994年   535篇
  1993年   459篇
  1992年   408篇
  1991年   375篇
  1990年   320篇
  1989年   296篇
  1988年   241篇
  1987年   220篇
  1986年   164篇
  1985年   246篇
  1984年   200篇
  1983年   123篇
  1982年   127篇
  1981年   133篇
  1980年   106篇
  1979年   90篇
  1978年   98篇
  1977年   69篇
  1976年   66篇
  1975年   43篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
911.
《Renal failure》2013,35(4):385-392
Acute renal failure (ARF) usually develops in 5% to 30% of patients undergoing heart surgery and is associated with a more complicated clinical evolution course and with an excessive mortality of up to 80%. The objective of this study was to verify the frequency of ARF in postoperative coronary artery bypass surgery with and without cardiopulmonary bypass, by the evaluation of renal function markers' performance [ plasma creatinine, plasma urea, urinalysis, fractional excretion of sodium, creatinine clearance and Alpha‐glutathione S‐transferase (α‐GST)], besides to verify possible relations between clinical variables involved in postoperative heart surgery and the occurrence of renal insufficiency.  相似文献   
912.
913.
914.
The incidence of renal cell carcinoma is increasing all over the world. The molecular mechanisms for tumorigenesis, progression and prognosis are still unknown. The erythropoietin‐producing hepatoma amplified sequence (Eph) receptors have been reported to be expressed aberrantly in many types of human cancers and in particular EphA5 may play a role in certain human cancers. In this study, a set of clear cell renal cell carcinoma (ccRCC) tissues were subjected to immunohistochemistry. The relationship between EphA5 protein expression and clinicopathological parameters was statistically analysed. Our data show that EphA5 protein was negatively (0) or weakly (1+) expressed in 48 of 78 (61.5%), moderately (2+) expressed in 15 of 78 (19.2%) and strongly (3+) expressed in 15 of 78 (19.2%) tumour samples of ccRCC. Decreased expression of EphA5 was detected more often in females than in males (P = 0.017, r= ?0.267). Expression of EphA5 was related negatively to Fuhrman grade (P = 0.013, r= ?0.279) and pathological tumour stage pT (P = 0.003, r= ?0.334). No relation between the expression of EphA5 and age of patients was found (P = 0.107, r= 0.184). Fuhrman grade and pT stage are the most important factors used in prognosis of ccRCC. Hence this study may provide a new and useful prognostic marker in the clinical practice of ccRCC.  相似文献   
915.
916.
《Renal failure》2013,35(1):87-97
A Multivariate analysis was done in all patients who developed post operative ARF, during the period 1990–1995 to determine the etiological spectrum and to identify various variables affecting the outcome. Of 140 patients (110 operated at SGPGI and 30 operated outside) 116 underwent elective surgery. The different types of surgery leading to ARF were urosurgery (3.5%), open heart surgery (32.9%), gastrosurgery (16.4%), pancreatic surgery (9.3%), obstetrical surgery (3.6%) and others (2.8%). The incidence of ARF in SGPGI patients was highest in pancreatic surgery group (8.2%) followed by open heart surgery (3%). The different etiological factors responsible for ARF were perioperative hypotension (67.1%), sepsis (63.6%) and exposure to nephrotoxic drugs (29.3%). Sixty-four patients (45.7%) required dialysis. The overall mortality was 45% The mortality was highest in patients who underwent open heart surgery (89.1%) followed by pancreatic surgery (84.6%). The factors associated with high mortality, other than the type of surgery, were preoperative hypotension (p <0.05), oliguria (p <0.01), need for dialysis (p <0.05) and multiorgan failure (p <0.001). AM following emergency surgery had poor outcome, though not statistically significant. Perioperative sepsis (p <0.05) and preoperative use of aminoglycoside (p <0.05) were significantly higher in patients operated outside SGPGI. This was associated with higher incidence of ARF. Thus we conclude that presence of multiorgan failure, oligoanuria, preoperative hypotension and need far dialysis are poor prognostic markers in ARF following surgery.  相似文献   
917.
Introduction. This study was designed to investigate whether 3-amino benzamide (3-AB), a poly (ADP-ribose) polymerase (PARP) inhibitor, has a protective effect on kidney injury induced by renal ischemia/reperfusion (I/R) by decreasing oxidative and nitrosative stress on renal dysfunction and injury. Materials and Methods. Thirty-two male Sprague-Dawley rats were divided into four groups: sham-operated, sham-operated + 3-AB, I/R, I/R + 3-AB. Rats were given 3-AB (100 mg/kg/day ip) 14 days prior to I/R. I/R and I/R + 3-AB groups underwent 60 min of bilateral renal ischemia followed by 6 h of reperfusion. After reperfusion, kidneys and blood were obtained for evaluation. Superoxide dismutase, glutathione peroxidase, malondialdehide, protein carbonyl content, and nitrite/nitrate level (NOx) were determined in the renal tissue. Serum creatinine (SCr), blood urea nitrogen (BUN), and aspartate aminotransferase (AST) were determined in the blood. Additionally, renal sections were used for histological grade of renal injury. Results. 3-AB significantly reduced the I/R-induced increases in SCr, BUN, and AST. In addition, 3-AB markedly reduced elevated oxidative stress product, restored decreased antioxidant enzymes, and attenuated histological alterations. Moreover, 3-AB attenuated the tissue NOx levels, indicating reduced NO production. Conclusions. 3-AB has beneficial effect on renal glomerular and tubular dysfunction in rats' kidneys subjected to I/R injury. Moreover, 3-AB has ameliorating effect on both oxidative stress and nitrosative stress of the kidneys, which correlated with histopathological evaluation.  相似文献   
918.
《Renal failure》2013,35(5):469-475
The effect of ticlopidine on rats with adriamycin nephropathy was observed during 26 weeks. In the ticlopidine-treated nephrotic animals (TNG), proteinuria was less than in the untreated nephrotic animals (NG), but this difference was significant only at week 6 (TNG = 47.27 ± 16.52 versus NG = 100.08 ± 13.83 mg/24h, p < 0.01) and week 26 (TNG =157.00 ± 28.73 versus NG = 217.00 ± 21.73 mg/24h, p < 0.01) after ADR injection. NG presented severe tubulointerstitial abnormalities with a tubulointerstitial lesion index of 3+. No diffience in glomerular lesions was observed among the groups (NG median = 6%. TNG median = 4% and TCG median = 2%). The tubulointerstitial lesion index of TNG was less intense (median = 2+) but not different from those of the control groups (CG median = 1+; TCG median = 0+) nor NG (median = 3+). We concluded that the treatment with ticlopidine produced some partially beneficial effects but did not prevent the devdopment of adriamycin-induced nephropathy.  相似文献   
919.
The discovery of molecular mechanisms driving the progression of renal cell carcinoma (RCC) has led to the development of drugs that target RCC at the molecular level. Inhibition of VEGF-targeting pathways is successful as a front-line treatment in patients with metastatic RCC. In addition, bevacizumab/IFN-α, sunitinib and pazopanib are recommended for first-line use in good- or intermediate-risk patients, whereas temsirolimus is approved for poor-risk patients. Second-line options are valuable as these patients eventually progress. The present review addresses which drug is best in this second-line setting. Options for sequential therapy include tyrosine kinase inhibitor (TKI)–mTOR inhibitor or TKI–TKI sequences. We also address the question of whether sequential therapy with TKIs or the combination of VEGF followed by mTOR inhibition is the best choice for specific patients, and which sequence of TKIs is most beneficial.  相似文献   
920.
目的 探讨心理干预对首次血液透析患者心理焦虑及透析不良反应的影响.方法 选择2010年1月~2011年5月在我院进行首次透析的患者80例,随机分为实验组和对照组,每组40例.对照组采用常规护理方法,实验组在常规护理的基础上予以针对性的心理干预.结果 两组透析前均存在明显焦虑,心理干预后实验组焦虑水平显著低于对照组,且透析不良反应明显少于对照组(P<0.01,P<0.05).结论 对首次血液透析患者进行心理干预能明显降低患者的焦虑程度,同时可有效减轻透析过程中的不良反应,使患者以积极的心态接受治疗.  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