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   2007篇
  免费   136篇
  国内免费   15篇
耳鼻咽喉   12篇
儿科学   84篇
妇产科学   27篇
基础医学   320篇
口腔科学   54篇
临床医学   153篇
内科学   481篇
皮肤病学   41篇
神经病学   320篇
特种医学   56篇
外科学   160篇
综合类   4篇
预防医学   117篇
眼科学   56篇
药学   105篇
中国医学   14篇
肿瘤学   154篇
  2024年   6篇
  2023年   26篇
  2022年   53篇
  2021年   81篇
  2020年   46篇
  2019年   59篇
  2018年   64篇
  2017年   80篇
  2016年   72篇
  2015年   87篇
  2014年   95篇
  2013年   101篇
  2012年   166篇
  2011年   175篇
  2010年   93篇
  2009年   74篇
  2008年   118篇
  2007年   102篇
  2006年   122篇
  2005年   90篇
  2004年   80篇
  2003年   72篇
  2002年   69篇
  2001年   13篇
  2000年   7篇
  1999年   25篇
  1998年   21篇
  1997年   14篇
  1996年   16篇
  1995年   13篇
  1994年   10篇
  1993年   8篇
  1992年   9篇
  1991年   6篇
  1990年   10篇
  1989年   6篇
  1988年   5篇
  1986年   4篇
  1985年   6篇
  1984年   6篇
  1983年   6篇
  1982年   8篇
  1981年   5篇
  1979年   3篇
  1978年   2篇
  1977年   4篇
  1976年   2篇
  1973年   4篇
  1971年   3篇
  1969年   2篇
排序方式: 共有2158条查询结果,搜索用时 15 毫秒
1.
2.
3.

Background  

Long-term morphofunctional outcome may vary widely in surgical anterior left ventricular wall restoration, suggesting variability in post-surgical remodeling similar to that observed following acute myocardial infarction. The aim of this pilot study was to demonstrate that surgical restoration obtained with a particular shape of endoventricular patch leads to steady morphofunctional ventricular improvement when geometry, volume and residual akinesia can be restored as normal as possible.  相似文献   
4.
5.
The pharmacokinetics and metabolism of 4-demethoxydaunorubicin (idarubicin, IDA) were studied in 21 patients with advanced cancer after i.v. (12 mg/m2) and oral (30-35 mg/m2) treatment according to a balanced crossover design. Patients were divided into four groups: subjects who showed normal liver and kidney function (group N), those who presented with normal kidney function and liver metastases (group L), those with kidney dysfunction (creatinine clearance, less than or equal to 60 l/h; group R), and those with both liver and kidney dysfunction (group LR). Five patients showed variations in liver or kidney function after the first treatment and were considered to be nonevaluable for the crossover study but evaluable for the liver/kidney function study; some of them appeared in different groups for the i.v. as opposed to p.o. treatments. After i.v. administration, IDA plasma levels followed a triphasic decay pattern. The main metabolite observed in all patients was the 13C-reduced compound (IDAol), which attained plasma levels 2-12 times higher than those of the parent compound. IDA pharmacokinetics was not dependent on the presence of liver metastases but was related to the integrity of kidney function. Analysis of variance indicated a significant correlation between IDA plasma clearance and creatinine clearance; it was also found that IDA plasma clearance was lower in patients whose creatinine clearance was less than 60 ml/min [group N, 122.8 +/- 44.0 l/h; group L, 104.4 +/- 27.7 l/h (P = 0.58) vs group R, 83.4 +/- 18.3 l/h (P = 0.037)]. The IDAol terminal half-life and mean residence time (MRT) were significantly increased in patients with impaired kidney function [MRT: group N, 63.6 +/- 10.8 h; group L, 69.9 +/- 10.2 h (P = 0.27) vs group R, 83.2 +/- 10.9 h (P = 0.025) and t1/2 gamma: group N, 41.3 +/- 10.1 h; group L, 47.0 +/- 7.4 h (P = 0.31) vs group R, 55.8 +/- 8.2 h (P = 0.025)]. After oral treatment, drug absorption occurred during in the first 2-4 h after IDA administration; a biphasic decay pattern was observed thereafter. The main metabolite observed in all patients was again IDAol. The AUC of IDAol was greater after oral administration than after i.v. treatment in proportion to the AUC of IDA (i.v.: AUC-IDAol/AUC-IDA, 2.4-18.9; p.o.: AUC-IDAol/AUC-IDA, 4.1-21.4). Following oral dosing, a substantial amount of 4-demethoxydaunomycinone (AG1) was found in 11/21 patients.(ABSTRACT TRUNCATED AT 400 WORDS)  相似文献   
6.
Because of reported synergism between 5-fluorouracil (5-FU) and cisplatin (CDDP) in L1210 leukemic mice and activity of this combination in clinical studies, a trial was initiated in previously untreated patients with advanced colorectal carcinoma. Cisplatin at 20 mg/m2 and 5-FU as a continuous infusion at 1000 mg/m2 were both administered for 5 consecutive days every 4 weeks. Forty-one patients were treated at Memorial Sloan-Kettering Cancer Center (MSKCC) and 46 were treated by the Community Clinical Oncology Program (CCOP) physicians. A 50% reduction in measurable disease was seen in 12 of 35 (34%) MSKCC patients and in nine of 41 (22%) of the CCOP patients with 95% confidence intervals of 0.18 to 0.50 and 0.10 to 0.35 in the two groups, respectively. The predominant toxicities were as follows: nausea and vomiting, 32%; mucositis, 26%; leukocyte counts less than 2000 cells/mm3, 17%; platelet counts less than 25,000 cells/mm3, 8%; and severe neurotoxicity, 5%. Dose attenuation was similar in the two groups. The median survival was 16.4 months for the MSKCC group and 9.6 months for the CCOP group (P = 0.0003). Although the baseline characteristics (age, sex, performance status, and baseline lactic dehydrogenase [LDH] and alkaline phosphatase) were similar, on further examination differences between the two groups were evident. In the MSKCC group, 14% of patients with liver metastases had greater than 50% of their liver involved with tumor whereas this occurred in 41% of the CCOP group (P = 0.03). The LDH values greater than 500 U/l were observed in 10% of patients in the MSKCC group and in 37% of the patients in the CCOP group (P = 0.007). Characteristics which reflect the bulk of disease, such as the percent of liver involvement, need to be analyzed in order to evaluate purported survival differences in randomized and nonrandomized trials of colorectal carcinoma.  相似文献   
7.
The aim of this study was to evaluate the occurrence of deep venous thrombosis (DVT) and superficial vein thrombosis (SVT) and its prophylaxis with an oral anti-edema and antithrombotic agent (Pycnogenol, Horphag, Research Management SA, Geneva, Switzerland) in long-haul flights, in subjects at moderate to high-risk of DVT and SVT. The study pre-included 244 pre-selected subjects; 211 were included (33 were excluded for several reasons due to logistic problems) and 198 completed the study; 13 subjects were lost for follow-up at the end of the flight, all for non-medical problems (i.e., for difficult connections). All subjects were scanned within 90 minutes before the flight and within 2 hours after disembarking. Subjects were supplemented with 100 mg Pycnogenol per capsule. Treatment subjects received two capsules between 2 and 3 hours before flights with 250 mL of water; two capsules were taken 6 hours later with 250 mL of water and one capsule the next day. The control group received comparable placebo at the same intervals. The flight duration was on average 8 hours and 15 minutes (SD 55 min) (range, 7.45-12.33). In the control group there were five thrombotic events (one DVT and four superficial thromboses) while only nonthrombotic, localized phlebitis was observed in the Pycnogenol group (5.15% vs. no events; p<0.025). The ITT (intention to treat) analysis detects 13 failures in the control group (eight lost to follow up + five thrombotic events) of 105 subjects (12.4%) vs. five failures (4.7%; all lost, no thrombotic events) in the treatment group (p<0.025). No unwanted effects were observed. In conclusion, this study indicates that Pycnogenol treatment was effective in decreasing the number of thrombotic events (DVT and SVT) in moderate-to-high risk subjects, during long-haul flights.  相似文献   
8.
This randomized phase II study was designed to evaluate the activity of intravenous 6-thioguanine (6-TG) as a single agent and the combination of cisplatin and 5-fluorouracil (5-Fu) modulated by oral leucovorin (PFL) in patients with advanced non-small cell lung cancer (NSCLC). Eligible patients had measurable or evaluable stage III B or IV NSCLC, had no received prior chemotherapy and had a performance status of 0-2. Patients were randomized to treatment with intravenous 6-TG at 55 mg/m2 administered over 30 minutes for 5 consecutive days and repeated every 35 days, or PFL chemotherapy with cisplatin 100 mg/m2 on day 1, 5-FU 800 mg/m2/day as a continuous intravenous infusion over 5 days and oral leucovorin administered at 100 mg every 4 hours during the entire duration of the cisplatin and 5-FU infusions. PFL was repeated every three weeks. Ninety-five eligible patients were randomized, 46 to 6-TG and 49 to PFL. Response rates were 4% for 6-TG (95% confidence interval 0.5%-14.8%, 1 partial, and 1 complete response) and 29% (16.6%-43.3%) for PFL (all partial). The median time to treatment failure was 2 and 4 months, respectively, and the median survival times were 6 and 10 months, respectively. Toxicities with 6-TG were, generally, mild to moderate but severe or life-threatening granulocytopenia was observed in 21% of patients. With PFL, mucositis was dose-limiting, and 78% of patients had severe or life-threatening mucositis. This led to dose reduction of 5-FU and leucovorin during subsequent cycles or treatment termination in 82% of patients.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
9.
Recent observations suggest that some patients with congenital myasthenic syndromes respond favorably to ephedrine, pseudoephedrine, or albuterol. Conventional microelectrode studies, however, provide no clear explanation for a beneficial effect of ephedrine in endplate diseases. To gain further insight into how these drugs affect neuromuscular transmission, we investigated their effects on the kinetic properties of the acetylcholine (ACh) receptor. Single channel currents were recorded from rat lumbrical muscles endplates using low concentrations of ACh and 2.5–100 μM of drugs. Between 10–100 μM, each drug progressively increased the rate of channel closure in a concentration dependent manner, consistent with an open-channel block. Albuterol acted as a sequential fast-acting channel blocker, increasing the mean burst duration in a concentration dependent manner without altering the total open time per burst or the duration of intraburst blockages. Increasing concentrations of ephedrine and pseudoephedrine also increased the number of intraburst closures but decreased the total open time per burst. None of the drugs altered single channel conductance. The channel blocking effects of ephedrine and pseudoephedrine might reduce the synaptic overactivity that occurs in the slow-channel myasthenic syndromes or in endplate ACh esterase deficiency, but these effects occur at concentrations not attainable in clinical practice.  相似文献   
10.
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