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   4921篇
  免费   392篇
  国内免费   20篇
耳鼻咽喉   28篇
儿科学   96篇
妇产科学   127篇
基础医学   569篇
口腔科学   78篇
临床医学   559篇
内科学   1119篇
皮肤病学   67篇
神经病学   315篇
特种医学   151篇
外国民族医学   1篇
外科学   1035篇
综合类   94篇
一般理论   2篇
预防医学   294篇
眼科学   137篇
药学   292篇
中国医学   13篇
肿瘤学   356篇
  2023年   44篇
  2022年   109篇
  2021年   195篇
  2020年   96篇
  2019年   158篇
  2018年   174篇
  2017年   154篇
  2016年   142篇
  2015年   163篇
  2014年   227篇
  2013年   251篇
  2012年   426篇
  2011年   401篇
  2010年   207篇
  2009年   177篇
  2008年   273篇
  2007年   262篇
  2006年   273篇
  2005年   256篇
  2004年   214篇
  2003年   227篇
  2002年   185篇
  2001年   65篇
  2000年   58篇
  1999年   48篇
  1998年   36篇
  1997年   22篇
  1996年   20篇
  1995年   19篇
  1994年   12篇
  1993年   14篇
  1992年   33篇
  1991年   31篇
  1990年   28篇
  1989年   25篇
  1988年   21篇
  1987年   19篇
  1986年   16篇
  1985年   12篇
  1984年   18篇
  1983年   14篇
  1982年   13篇
  1980年   11篇
  1979年   12篇
  1978年   11篇
  1977年   12篇
  1976年   17篇
  1973年   13篇
  1972年   23篇
  1971年   21篇
排序方式: 共有5333条查询结果,搜索用时 15 毫秒
991.

Background

The combination of everolimus and the imidazoquinoline derivative, BEZ235 (dactolisib), a dual PI3K/mTOR inhibitor, demonstrated synergy in a preclinical model.

Objective

To establish clinical feasibility, a phase Ib dose-escalation trial investigating safety and pharmacokinetics of this combination in patients with advanced tumors was performed.

Patients and Methods

BEZ235 was orally administered daily in escalating doses of 200, 400, and 800 mg along with everolimus at 2.5 mg daily in 28-day cycles. Nineteen patients were enrolled. Adverse events and tumor responses were evaluated using CTCAE v4.0 and RECIST 1.1, respectively. Pharmacokinetic analyses were performed.

Results

Common toxicities observed included fatigue, diarrhea, nausea, mucositis, and elevated liver enzymes. No confirmed responses were observed. BEZ235 pharmacokinetics exhibited dose-proportional increases in Cmax and AUC0-24 over the three doses, with high inter-individual variability. Non-compartmental and population pharmacokinetic-based simulations indicated significant increases in everolimus Cmax and AUC0-24 on day 28 and decreased clearance to 13.41 L/hr.

Conclusions

The combination of BEZ235 and everolimus demonstrated limited efficacy and tolerance. BEZ235 systemic exposure increased in a dose-proportional manner while oral bioavailability was quite low, which may be related to gastrointestinal-specific toxicity. The changes in steady-state pharmacokinetics of everolimus with BEZ235 highlight potential drug–drug interactions when these two drugs are administered together.
Clinicaltrials.gov: NCT01508104
  相似文献   
992.
993.
994.
OBJECTIVE: The aims of this study were to investigate absolute assessment of aortic valve area (AVA), before surgery for aortic stenosis, using cardiovascular magnetic resonance (CMR) in comparison with transesophageal echocardiography (TEE) and with effective AVA indirectly obtained by routine techniques i.e. transthoracic echocardiography (TTE) and cardiac catheterisation. MATERIALS AND METHODS: Absolute AVA planimetry was performed by TEE and CMR steady state free precession sequences obtained through the aortic valvular plane. Effective AVA was calculated by the continuity equation in TTE and by cardiac catheterisation (Gorlin formula). RESULTS: Thirty-nine patients with aortic valve stenosis, mean age 71.7 +/- 7.6 years, with a mean AVA of 0.93 +/- 0.31 cm2 as measured by TEE, were enrolled in the study. Mean differences were: between CMR and TEE planimetry: d = 0.01 +/- 0.14 cm2, between CMR and cardiac catheterisation: d = 0.05 +/- 0.13 cm2, between CMR and TTE: d = 0.10 +/- 0.17 cm2, between TTE and TEE: d = 0.10 +/- 0.18 cm2, between TTE and cardiac catheterisation: d = 0.06 +/- 0.16 cm2, and between TEE and cardiac catheterisation: d = 0.07 +/- 0.13 cm2. Mean intraobserver and interobserver differences of CMR planimetry were d = 0.02 +/- 0.07 cm2 and d = 0.03 +/- 0.14 cm2, respectively. CONCLUSION: CMR planimetry of the AVA is a noninvasive and reproducible technique to evaluate stenotic aortic valves and can be used as an alternative to echocardiography or cardiac catheterisation.  相似文献   
995.
996.

Background

Comprehensive preoperative appraisal of potential living renal donors is the key for selecting a proper donor and a suitable kidney.

Objective

To prospectively assess the diagnostic value of 16-slice multidetector computed tomography (MDCT) in preoperative appraisal of vascular anatomy in potential living renal donors.

Materials and methods

Preoperative angiography using a 16-slice MDCT scanner was performed in 68 consecutive potential living renal donors. The MDCT angiography included unenhanced and contrast-enhanced multiphasic scans. The MDCT images were reviewed for the number and branching pattern of the renal arteries and for the number and presence of major or minor variants of the renal veins. The results were compared with the actual anatomy at the open donor nephrectomy as the diagnostic standard of reference.

Results

The sensitivity and the specificity of MDCT angiography for the detection of various anatomic variants of renal arteries as well as renal venous anomalies were 100%. The anatomic variants of renal arteries included accessory arteries (n = 7) and early arterial branching (n = 10). Whereas, the detected venous anomalies were of major category of the circumaortic left renal vein anomaly (n = 2). No minor renal venous anomaly was identified in any subject.

Conclusion

16-Slice MDCT angiography is highly accurate for preoperative assessment of diverse anomalies of the renal vascular anatomy in potential living renal donors; in consequence, it markedly affects the surgical planning.  相似文献   
997.
998.

Purpose

LY2334737 is an oral gemcitabine prodrug. This Phase I study assessed the safety and tolerability of LY2334737 in Japanese patients with solid tumors and evaluated pharmacokinetics (PK), pharmacodynamics, and antitumor activity.

Methods

Patients with advanced/metastatic solid tumors received escalating doses of LY2334737 once daily for 14 days, followed by a 7-day drug-free period. Cycles were repeated until discontinuation criteria were met.

Results

Of 13 patients treated, 3 received 20 mg/day, 6 received 30 mg/day, 4 received 40 mg/day. On the 40 mg dose, 3 patients experienced dose-limiting toxicities (DLTs): hepatic toxicities (e.g., Grade [G]3/4 transaminase and G1–3 bilirubin elevation) and G4 thrombocytopenia; all 3 showed features of disseminated intravascular coagulation. One additional DLT occurred on the 30 mg dose (G3 transaminase elevation). Exploratory pharmacogenetic analyses identified a genetic variation in the CES2 gene potentially associated with these DLTs. PK data showed no clear relationship between the AUC of gemcitabine and its incorporation into leukocyte DNA; 2 of the 3 DLT patients had high incorporation. Two patients (30 mg/day) achieved stable disease with progression-free survival lasting 135 and 155 days.

Conclusions

LY2334737 was tolerated by Japanese patients up to 30 mg/day. The toxicities observed at the 40 mg dose may require the development of alternative dosing schedules.  相似文献   
999.
Perioperative nutrition with supplements containing l-arginine, ω3-polyunsaturated fatty acids, and nucleotides could boost liver function recovery, immune response, and resistance to infection after hepatic resection. We conducted a placebo-controlled, randomized, double-blind study to assess the effect of a perioperative nutritional supplementation with Oral Impact® in patients undergoing hepatic surgery for liver cancer. Treatment was given three times daily for 7 days before and 3 days after surgery. Primary outcome was factor V, 3 days after surgery. Thirty-five patients (placebo: 17; Oral Impact: 18) were included. Five patients (placebo: three; Oral Impact: two) were not operated and five (placebo: two; Oral Impact: three) did not undergo hepatic resection. Factor V (mean ± SD) was 70 ± 27% and 79 ± 25% (P = 0.409) 3 days after surgery and 90 ± 30% and 106 ± 16% (P = 0.066) 5 days after surgery, in placebo and Oral Impact groups, respectively. There were no significant differences between groups on other outcomes assessing liver function recovery (bile production, γ-glutamyl transferase, α-fetoprotein), immune response (CD3, CD4, CD8 cells, CD4/CD8 ratio, natural killer cells, B lymphocytes), number of infections, and tolerance. A 10-day perioperative nutritional supplementation with Oral Impact does not improve hepatic function, immune response, and resistance to infection in patients undergoing hepatic surgery for liver cancer.  相似文献   
1000.
Disease prioritarianism is a principle that is often implicitly or explicitly employed in the realm of healthcare prioritization. This principle states that the healthcare system ought to prioritize the treatment of disease before any other problem. This article argues that disease prioritarianism ought to be rejected. Instead, we should adopt ‘the problem-oriented heuristic’ when making prioritizations in the healthcare system. According to this idea, we ought to focus on specific problems and whether or not it is possible and efficient to address them with medical means. This has radical implications for the extension of the healthcare system. First, getting rid of the binary disease/no-disease dichotomy implicit in disease prioritarianism would improve the ability of the healthcare system to address chronic conditions and disabilities that often defy easy classification. Second, the problem-oriented heuristic could empower medical practitioners to address social problems without the need to pathologize these conditions. Third, the problem-oriented heuristic clearly states that what we choose to treat is a normative consideration. Under this assumption, we can engage in a discussion on de-medicalization without distorting preconceptions. Fourth, this pragmatic and de-compartmentalizing approach should allow us to reconsider the term ‘efficiency’.  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