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   26724篇
  免费   1426篇
  国内免费   99篇
耳鼻咽喉   438篇
儿科学   513篇
妇产科学   327篇
基础医学   3712篇
口腔科学   674篇
临床医学   1852篇
内科学   6613篇
皮肤病学   658篇
神经病学   1819篇
特种医学   1060篇
外国民族医学   1篇
外科学   4420篇
综合类   143篇
一般理论   2篇
预防医学   703篇
眼科学   335篇
药学   2012篇
中国医学   77篇
肿瘤学   2890篇
  2022年   279篇
  2021年   454篇
  2020年   278篇
  2019年   347篇
  2018年   441篇
  2017年   354篇
  2016年   440篇
  2015年   422篇
  2014年   626篇
  2013年   720篇
  2012年   1168篇
  2011年   1261篇
  2010年   695篇
  2009年   690篇
  2008年   1109篇
  2007年   1288篇
  2006年   1195篇
  2005年   1268篇
  2004年   1212篇
  2003年   1067篇
  2002年   1063篇
  2001年   1025篇
  2000年   962篇
  1999年   902篇
  1998年   319篇
  1997年   219篇
  1996年   243篇
  1995年   193篇
  1994年   163篇
  1993年   193篇
  1992年   636篇
  1991年   548篇
  1990年   536篇
  1989年   529篇
  1988年   514篇
  1987年   484篇
  1986年   459篇
  1985年   427篇
  1984年   311篇
  1983年   257篇
  1982年   160篇
  1979年   247篇
  1978年   157篇
  1977年   184篇
  1973年   177篇
  1972年   186篇
  1971年   190篇
  1970年   172篇
  1969年   186篇
  1968年   170篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.

Background

Renal inulin clearance is the gold standard for evaluation of kidney function, but is compromised by problems of collecting urine samples in children, especially those <6 years or with a bladder dysfunction. Therefore, we should utilize the serum cystatin C (cysC)-based estimated glomerular filtration rate (eGFR) for measuring serum cysC. The purpose of the present study is to determine the applicability of the new serum cysC-based eGFR in Japanese children and adolescents, including infants with chronic kidney disease (CKD), for evaluation of renal function.

Methods

Inulin clearance and standardized serum cysC level determined by the colloidal gold immunoassay were measured in 135 pediatric CKD patients between the ages of 1 month and 18 years with no underlying disease that affects renal function except CKD, to determine serum cysC-based eGFR in Japanese children and adolescents.

Results

We showed the inulin clearance by expression of 1/serum cysC in pediatric CKD patients, which resulted in the equation: inulin GFR (mL/min/1.73 m2) = 104.1 × 1/serum cysC (mg/L) ? 7.80. We also validated the cysC-based eGFR formula for Japanese adults. eGFR values obtained with the adult formula significantly underestimated GFR by approximately 8 % in children with CKD.

Conclusion

We determined the new cysC-based eGFR formula is useful for clinical screening of renal function in Japanese children and adolescents, including infants.  相似文献   
992.

Rationale

Phosphodiesterases (PDEs) play an important role in the regulation of intracellular signaling mediated by cyclic adenosine monophosphate (cAMP). Recently, several PDE inhibitors were assessed for their possible cognitive enhancing properties. However, little is known about the effect of PDE3 inhibitors on memory function.

Objectives

We examined how the PDE3 inhibitor cilostazol affects C57BL/6 J mice as they perform various behavioral tasks. After behavioral assessment, brains of the mice were analyzed immunohistochemically to quantify the phosphorylation of cAMP-responsive element binding protein (CREB), a downstream component of the cAMP pathway.

Results

Oral administration of cilostazol significantly enhanced recollection of the exact platform location in the Morris water maze probe test. Cilostazol also improved context-dependent long-term fear memory, without affecting short-term memory. No apparent effect was observed in cue-dependent fear memory. The results suggest that cilostazol selectively improves hippocampus-dependent long-term memory in these tasks. Cilostazol also significantly increased the number of phosphorylated-CREB-positive cells in hippocampal dentate gyrus.

Conclusions

These results suggest that cilostazol may exert its beneficial effects on learning and memory by enhancing the cAMP system in hippocampus, where it increases intracellular cAMP activity.  相似文献   
993.
The safety, pharmacokinetics, and antitumor activity of the multikinase inhibitor regorafenib in Japanese patients was assessed in this multicenter, single-arm, phase I trial. Fifteen patients with treatment-refractory advanced solid tumors received regorafenib 160 mg once daily for the first 3 weeks of each 4-week cycle until disease progression, unacceptable toxicity, or investigator or patient decision to stop. The median duration of treatment was 2.1 months (range, 0.9–20.1 months). At data cutoff, one patient was still receiving regorafenib in cycle 21. Reasons for treatment discontinuation were disease progression (n?=?12) and adverse events (liver enzyme elevation n?=?1; anemia n?=?1). Adverse events necessitated dose reduction in six patients, interruption of daily treatment in seven patients, and cycle delay in four patients. All patients experienced at least one drug-related adverse event, particularly gastrointestinal (87 %), dermatologic (73 %), or hematologic (67 %) events. There was no significant change in time to maximum concentration or terminal half-life of regorafenib and its active metabolites M2 and M5 between single dosing and 21-day continuous dosing. The area under the concentration–time curve was 2.1-fold higher for regorafenib, 5.2-fold higher for M2, and 37.3-fold higher for M5, and the maximum concentration was 2.0-fold, 4.8-fold, and 36.0-fold higher, respectively, after continuous dosing than after single dosing. One patient had a partial response (duration 10.5 months) and seven patients had stable disease. This study indicates that regorafenib 160 mg orally once daily (21 days on/7 days off treatment) can be given to Japanese patients who have solid tumors, without undue toxicity.  相似文献   
994.
Adsorption parameters such as the distribution coefficient are required to predict the release behavior of contaminants using advection-dispersion models. However, for potentially contaminant-releasing materials (PCMs) such as dredged sludge and coal ash, these parameters cannot be obtained by conventional adsorption tests. This study developed a method to determine adsorption parameters for PCMs from a set of batch tests conducted in parallel as a function of the liquid-solid ratio (LS-parallel test). This LS-parallel test was performed on sandy soil derived from marine sediment using liquid-solid ratios from 1 to 300 L/kg. The water-contact time was also changed from 10 min to 28 d to elucidate the kinetics or equilibrium of contaminants released from the sample. Adsorption parameters were successfully obtained if the substance was under adsorption control. A column percolation test was performed to confirm the effectiveness of the obtained parameters. Good agreements were observed for SO42− and B, but discrepancies remained for other substances such as F and As suggesting that improvements are necessary in both the LS-parallel test procedure and the advection-dispersion model.  相似文献   
995.
Aims/IntroductionSodium–glucose cotransporter 2 inhibitors (SGLT2i) improve renal outcome in patients with type 2 diabetes mellitus, but the mechanism is not fully understood. The aim of this retrospective study was to assess the association of achieved blood pressure with renal outcomes in Japanese type 2 diabetes mellitus patients with chronic kidney disease.Materials and MethodsWe assessed 624 Japanese type 2 diabetes mellitus patients with chronic kidney disease taking SGLT2i for >1 year. The patients were classified as those with post‐treatment mean arterial pressure (MAP) of ≥92 mmHg (n = 344) and those with MAP of <92 mmHg (n = 280) for propensity score matching (1:1 nearest neighbor match with 0.04 of caliper value and no replacement). The end‐point was a composite of progression of albuminuria or a decrease in the estimated glomerular filtration rate by ≥15% per year.ResultsBy propensity score matching, a matched cohort model was constructed, including 201 patients in each group. The incidence of renal composite outcome was significantly lower among patients with MAP of <92 mmHg than among patients with MAP of ≥92 mmHg (n = 11 [6%] vs n = 26 [13%], respectively, P = 0.001). The change in estimated glomerular filtration rate was similar in the two groups; however, the change in the albumin‐to‐creatinine ratio was significantly larger in patients with MAP of <92 mmHg.ConclusionsIn Japanese type 2 diabetes mellitus patients with chronic kidney disease, blood pressure after SGLT2i administration influences the renal composite outcome. Blood pressure management is important, even during treatment with SGLT2i.  相似文献   
996.
Esophagus - Endoscopic diagnosis of the invasion depth of superficial esophageal squamous cell carcinoma (ESCC) is an important determinant of the treatment strategy. The three endoscopic imaging...  相似文献   
997.
Heart Failure Reviews - Current echocardiography techniques have allowed more precise assessment of cardiac structure and function of the several types of cardiomyopathies. Parameters derived from...  相似文献   
998.
999.
1000.
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