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   12517篇
  免费   576篇
  国内免费   31篇
耳鼻咽喉   387篇
儿科学   1043篇
妇产科学   453篇
基础医学   791篇
口腔科学   707篇
临床医学   985篇
内科学   2052篇
皮肤病学   382篇
神经病学   898篇
特种医学   466篇
外科学   3123篇
综合类   75篇
一般理论   6篇
预防医学   341篇
眼科学   389篇
药学   677篇
中国医学   70篇
肿瘤学   279篇
  2024年   15篇
  2023年   165篇
  2022年   92篇
  2021年   203篇
  2020年   173篇
  2019年   193篇
  2018年   382篇
  2017年   324篇
  2016年   398篇
  2015年   324篇
  2014年   460篇
  2013年   684篇
  2012年   771篇
  2011年   972篇
  2010年   501篇
  2009年   286篇
  2008年   692篇
  2007年   826篇
  2006年   824篇
  2005年   936篇
  2004年   830篇
  2003年   781篇
  2002年   726篇
  2001年   371篇
  2000年   453篇
  1999年   268篇
  1998年   108篇
  1997年   72篇
  1996年   59篇
  1995年   43篇
  1994年   31篇
  1993年   18篇
  1992年   24篇
  1991年   16篇
  1990年   10篇
  1989年   8篇
  1988年   7篇
  1987年   5篇
  1986年   5篇
  1985年   6篇
  1983年   5篇
  1982年   3篇
  1981年   4篇
  1980年   4篇
  1979年   8篇
  1978年   9篇
  1977年   3篇
  1976年   6篇
  1974年   7篇
  1927年   2篇
排序方式: 共有10000条查询结果,搜索用时 302 毫秒
101.
BACKGROUND: The study was aimed to evaluate the analgesic efficacy, postoperative comfort, recovery characteristics and side effects of three different analgesic agents administered prophylactically. METHODS: Eighty patients undergoing day-case minor operative laparoscopy were randomly allocated into four groups to receive tenoxicam 20 mg i.v. (Group T), fentanyl 100 microg i.v. (Group F), 5 ml of bupivacaine 2.5 mg/ml for infiltration of trocar sites (Group B), 30, 10 and 5 min before incision respectively. Bupivacaine, 35 ml, 2.5 mg/ml was also administered into the pelvic cavity in Group B. Group P received only placebo. Postoperative pain, analgesic requirements, first response to verbal stimulus, first analgesic requirement, ability to walk without help, to drink and to void, blood pressures, SpO2 and respiration rates were recorded in the PACU. Postoperative pain was evaluated by verbal rating scale. Pain scores, analgesic requirements and side effects were evaluated by telephone calls until the 48th postoperative hour. RESULTS: Postoperative pain scores were lower and time to requirement of rescue analgesics was longer in groups F and B compared to Group P. In the PACU, analgesic requirements were lower in Group B, compared to Group P. Nausea and vomiting were increased in Group F. CONCLUSION: Tenoxicam 20 mg i.v. was found to be ineffective whereas bupivacaine was superior to other groups in reducing pain and analgesic requirements. Bupivacaine also increased time to first analgesics and obtained better recovery characteristics, underlining its value in prophylactic pain management compared to the other two agents.  相似文献   
102.
103.
PURPOSE: We evaluate the effectiveness of deep dorsal vein embolization for the treatment of venous impotence. MATERIALS AND METHODS: A total of 32 impotent patients with veno-occlusive dysfunction underwent deep dorsal vein embolization. The condition was suspected based on findings of penile Doppler ultrasonography and cavernosometry. The diagnosis was confirmed with pharmacocavernosography that appeared to delineate venous leakage. During the procedure we isolated and cannulated the deep dorsal vein through a small dorsal penile incision with the patient under local anesthesia. We used a mixture of the tissue glue, N-butyl cyanoacrylate, and lipodol for embolization, with a total volume of 5 ml. injected antegrade into the previously catheterized dorsal vein under fluoroscopic control. As soon as we observed the occluded veins we performed repeat pharmacocavernosography. At 3-month followup patients were reassessed with history and cavernosometry. Followup ranged from 12 to 36 months (median 25). RESULTS: Of 32 patients 22 (68.7%) regained sexual activity, which was confirmed by cavernosometry. The remaining 10 patients (31.3%) experienced little if any clinical response, which correlated with cavernosometry. There were no significant side effects. CONCLUSIONS: Deep dorsal vein embolization for venogenic impotence is simple, effective and safe, and appears to be cost-effective. The results obtained in this limited number of patients are promising and justify trials in larger groups.  相似文献   
104.
OBJECTIVE: Hydatid disease is a parasitosis and endemic in many sheepraising areas; it is still an important health problem in Turkey. We report our experience with childhood hydatid cyst and discuss the concepts of treatment. METHODS: The clinical courses of 128 children with thoracic and liver hydatid cyst operated on from 1994 to 2000 were reviewed. The group consisted of 71 boys and 57 girls aged from 8 months to 16 years. Intact cysts were found in 144 patients and ruptured cysts in 68. RESULTS: In the postoperative course we have encountered 20 perioperative complications in 16 patients. The most common complication was residual pleural space and delayed air leakage, which occurred in 9 patients. There was no early death. CONCLUSION: Surgery is the treatment of choice for most patients with pulmonary hydatid disease. The aim of surgery is evacuation of the cyst, removal of the endocyst, and management of the residual cavity. Conservative surgical methods that preserve lung parenchyma should be preferred.  相似文献   
105.
BACKGROUND: Coronary bypass surgery that provides good long-term graft patency can be performed on the beating heart as a viable alternative to conventional coronary artery bypass grafting (CABG). METHODS: From September 1993 to December 1996, 696 patients underwent CABG on the beating heart at the Ko?uyolu Heart and Research Hospital in Istanbul. Among them, 70 patients were chosen randomly for angiographic assessment of off-pump coronary artery bypass grafting. RESULTS: The interval from operation to angiography varied from 24 to 61 months (mean, 36.1+/-10.9 months). The patency rate of left internal mammary-left anterior descending artery anastomoses was 95.59% (patency achieved in 65 of 68 patients) and of vein grafts was 47.06% (patency achieved in 16 of 34 patients) (p < 0.0001). The patency rates of grafts anastomosed to the left anterior descending artery were significantly higher than the rates of the grafts anastomosed to the other coronary arteries (95.71% versus 45.45%, p < 0.0001). Multivariate analysis showed that graft type (p < 0.0001) and hyperlipidemia (p = 0.023) were significant predictors for graft occlusion. Left ventricular function improved significantly after CABG (p = 0.04). Reintervention (using percutaneous transluminal cardiac angioplasty) and reoperation rates were 0.97% and 1.4%, respectively. CONCLUSIONS: Off-pump coronary artery bypass grafting appears to produce midterm and long-term patency rates that are comparable to those of conventional techniques; that is especially true in cases of arterial conduits and of conduits anastomosed to the left anterior descending artery.  相似文献   
106.
To understand antioxidant activity and the role played by melatonin, we have designed and tested several new compounds. We present the results in terms of structure-activity relationships, focusing on the lack of the methoxy group and the influence of the amide side chain. Antioxidant activity of melatonin and some new melatonin analogue indole derivatives were investigated, using lipid peroxidation and superoxide anion radical scavenger activity assays, in rat liver tissue homogenate. Most of the compounds were found to be very potent inhibitors of malondialdehyde (MDA) formation at 10−3M. Inhibition rates ranged from 75-44 %. However, no significant inhibitory effect was obtained on superoxide anion formation. Consequently, it can be concluded that these compounds exhibit important LP activity compared to melatonin.  相似文献   
107.
A laryngocele is an air-filled dilation of the saccule of the larynx. An infected laryngocele is called a laryngopyocele. Our experience with a case of laryngopyocele with signs on computed tomography before and after antibiotic therapy is presented since laryngopyocele is more unusual.  相似文献   
108.
109.
Objective: Various foods play important role in the pathogenesis of gastroesophageal reflux disease (GERD). These foods are shown to increase gastroesophageal reflux symptoms via various mechanisms and majority of these foods also contain nickel. The purpose of this study is to evaluate the relationship between Nickel sensitivity and GERD.

Material and methods: Fifty-four patients diagnosed with GERD and 50 healthy volunteers who were admitted to our gastroenterology outpatient clinic were took part in the study. European standard patch test series, nickel-containing test units and corticosteroids were applied to the patient body; upper back. Evaluation was performed according to the scheme of the International Contact Dermatitis Research Group (ICDRG). The positive and negative reactions were recorded at the hours of 48, 72 and 96. Following the test implementations, 7?days later, the tests were reevaluated for late reactions. Statistics package for Social Sciences (SPSS) 17 package program was used for statistical evaluation and results of tests were compared between groups with the Chi-squared test. p?Results: Individuals in both groups were statistically similar in terms of age and gender. Nickel sensitivity was found to be positive in 48.2 and %22 of the GERD patients and control group, respectively. Difference between groups was statistically significant (p?=?0.008).

Conclusions: Nickel sensitivity was significantly higher in GERD patients compared to the control group. In addition to imbalance between defensive and aggressive forces of the esophagus, there seems to be an association between nickel sensitivity and GERD.  相似文献   
110.
A series of new compounds containing formyl and imine group were synthesized. New formyl-substituted compounds were prepared by the reaction of 1,2-bis(bromomethyl)benzene with benzaldehyde derivatives in the presence of NaOH. New bis-crown ether imine compounds were prepared by the condensation of corresponding aldehydes with 4′-aminobenzo-15-crown-5. Sodium complexes of the bis-crown ethers form crystalline 2:1 (Na+:ligand) stoichiometries were also been synthesized. The prepared compounds were structurally confirmed by analytical and spectral data and evaluated for their antibacterial and antifungal activities. The results show that the antibacterial activity of compounds including o-methoxy group was significantly higher against S. epidermis compared to the other studied antimicrobial group.  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