全文获取类型
收费全文 | 79523篇 |
免费 | 5855篇 |
国内免费 | 256篇 |
专业分类
耳鼻咽喉 | 911篇 |
儿科学 | 2048篇 |
妇产科学 | 1083篇 |
基础医学 | 10768篇 |
口腔科学 | 843篇 |
临床医学 | 8411篇 |
内科学 | 17066篇 |
皮肤病学 | 884篇 |
神经病学 | 7747篇 |
特种医学 | 3061篇 |
外科学 | 12818篇 |
综合类 | 888篇 |
一般理论 | 91篇 |
预防医学 | 5962篇 |
眼科学 | 1964篇 |
药学 | 5365篇 |
中国医学 | 94篇 |
肿瘤学 | 5630篇 |
出版年
2024年 | 55篇 |
2023年 | 667篇 |
2022年 | 1039篇 |
2021年 | 2412篇 |
2020年 | 1358篇 |
2019年 | 2206篇 |
2018年 | 2527篇 |
2017年 | 1801篇 |
2016年 | 1894篇 |
2015年 | 2216篇 |
2014年 | 3210篇 |
2013年 | 4060篇 |
2012年 | 6510篇 |
2011年 | 6753篇 |
2010年 | 3693篇 |
2009年 | 3236篇 |
2008年 | 5394篇 |
2007年 | 5589篇 |
2006年 | 5180篇 |
2005年 | 5137篇 |
2004年 | 4635篇 |
2003年 | 4251篇 |
2002年 | 3852篇 |
2001年 | 597篇 |
2000年 | 399篇 |
1999年 | 570篇 |
1998年 | 786篇 |
1997年 | 590篇 |
1996年 | 477篇 |
1995年 | 425篇 |
1994年 | 399篇 |
1993年 | 395篇 |
1992年 | 251篇 |
1991年 | 197篇 |
1990年 | 179篇 |
1989年 | 162篇 |
1988年 | 157篇 |
1987年 | 129篇 |
1986年 | 132篇 |
1985年 | 144篇 |
1984年 | 181篇 |
1983年 | 150篇 |
1982年 | 236篇 |
1981年 | 232篇 |
1980年 | 164篇 |
1979年 | 94篇 |
1978年 | 114篇 |
1977年 | 99篇 |
1976年 | 69篇 |
1975年 | 59篇 |
排序方式: 共有10000条查询结果,搜索用时 19 毫秒
11.
Andrew Kramar Sophie Gourgou-Bourgade Marc Ychou 《Journal of clinical oncology》2005,23(3):650; author reply 650-650; author reply 651
12.
G Anita Heeren John B Jemmott Andrew Mandeya Joanne C Tyler 《AIDS education and prevention》2007,19(1):1-12
This study compared the predictive value of the theory of planned behavior in university students in South Africa (N = 251) and the United States (N = 160) who completed an anonymous self-administered questionnaire. Multiple regression analyses revealed that condom use and intention were significantly predicted by positive condom attitude, subjective norm, self-efficacy, and attending university in South Africa. Significant interactions between country and predictors indicated that subjective norm predicted condom use and intention more strongly in the American sample than in the South African sample; attitude predicted intention more strongly in the American sample than in the South African sample; but self-efficacy predicted intention more strongly in the South African sample than in the American sample. The theory of planned behavior may provide a useful framework for interventions to reduce South African students' risk of HIV/and sexuality transmitted diseases. Such interventions should especially focus on building self-efficacy to use condoms. 相似文献
13.
14.
15.
Andrew F Shorr William L Jackson Brendan M Weiss Lisa K Moores 《Blood coagulation & fibrinolysis》2007,18(4):309-316
Multiple options exist for the prevention of deep vein thrombosis (DVT) in medical inpatients. We sought to determine the cost-effectiveness of low-molecular-weight heparin (LMWH) relative to unfractionated heparin (UFH) for DVT prevention in this setting. We conducted a cost-effectiveness analysis from the perspective of a third-party payer employing a decision model and literature-based estimates for inputs. In the base-case analysis, LMWH had little impact on the rate of DVT. Despite higher acquisition costs, however, LMWHs resulted in net savings. Routine use of LMWH saves approximately US$89 per patient. The lower rate of heparin-induced thrombocytopenia (HIT) with LMWH accounted for this differential. Univariate sensitivity analysis revealed the model was moderately sensitive to the odds ratio of HIT with LMWH and the cost of HIT. Multivariate sensitivity analysis confirmed the LMWH approach dominated financially. 'Worst-case' scenario modeling, where LMWH actually increased the risk for DVT, had little effect on the rate of HIT, and was substantially more costly than UFH, still demonstrated that LMWHs were economically superior. Monte-Carlo simulation indicated the 95% confidence interval around the estimate for savings with LMWH ranged from US$7 to US$373. We conclude that, despite their higher cost, LMWHs for thromboprophylaxis in medical patients result in savings. 相似文献
16.
17.
18.
Keith J Murphy Andrew G Foley Alan W O'connell Ciaran M Regan 《Neuropsychopharmacology》2006,31(1):90-100
Recent data suggest that Alzheimer's patients who discontinue treatment with cholinesterase inhibitors have a significantly delayed cognitive decline as compared to patients receiving placebo. Such observations suggest cholinesterase inhibitors to provide a disease-modifying effect as well as symptomatic relief and, moreover, that this benefit remains after drug withdrawal. Consistent with this suggestion, we now demonstrate that chronic administration of tacrine, nefiracetam, and deprenyl, drugs that augment cholinergic function, increases the basal frequency of dentate polysialylated neurons in a manner similar to the enhanced neuroplasticity achieved through complex environment rearing. While both drug-treated and complex environment reared animals continue to exhibit memory-associated activation of hippocampal polysialylated neurons, the magnitude is significantly reduced suggesting that such interventions induce a more robust memory pathway that can acquire and consolidate new information more efficiently. This hypothesis is supported by our findings of improved learning behavior and enhanced resistance to cholinergic deficits seen following either intervention. Furthermore, the level of enhancement of basal neuroplastic status achieved by either drug or environmental intervention correlates directly with improved spatial learning ability. As a combination of both interventions failed to further increase basal polysialylated cell frequency, complex environment rearing and chronic drug regimens most likely enhanced cognitive performance by the same mechanism(s). These findings suggest that improved memory-associated synaptic plasticity may be the fundamental mechanism underlying the disease modifying action of drugs such as cholinesterase inhibitors. Moreover, the molecular and cellular events underpinning neuroplastic responses are identified as novel targets in the search for interventive drug strategies for the treatment of neurodegenerative and neuropsychiatric disorders. 相似文献
19.
Nicholas L. Shortt Gary F. Keenan Andrew Y. Muir Prof. Dr. A. Hamish R. W. Simpson 《Operative Orthopadie und Traumatologie》2006,18(4):364-376
OBJECTIVE: Avoidance of potential iatrogenic nerve injury during insertion of Ilizarov fine wires into areas of high anatomic risk by using a modified nerve stimulation technique. INDICATIONS: Application of the Ilizarov ring fixator to areas of high anatomic hazard, in situations where anatomic topography may be distorted by previous surgery, trauma, or congenital anomalies. CONTRAINDICATIONS: Use of systemic muscle relaxants. Caution in patient with cardiac pacemaker. SURGICAL TECHNIQUE: Preliminary experiments showed that a standard nerve-stimulating device can deliver a negatively charged, monophasic square pulse of current through Ilizarov wires. During the application of an Ilizarov frame to potentially hazardous anatomic regions, providing no systemic muscle relaxants are used, a voltage field sufficient to cause nerves in close proximity to the Ilizarov wire to depolarize is produced. Identification of a distal muscle twitch provoked by the stimulation may indicate a potential for iatrogenic nerve injury. RESULTS: Results show that with the nerve stimulator set at 2.5 mA (pulsed at a frequency of 2 Hz), peripheral nerves are stimulated if they lie within 5 mm of the wires. Should a distal muscle twitch occur, wires should be repositioned so that equivalent stimulation produces no twitch. The technique was used during Ilizarov frame application in ten patients, with only a single occurrence of distal muscle twitches in a lower-leg frame. Following repositioning of the Ilizarov wire in this case, no further twitches were observed, indicating that no Ilizarov wire was inserted close to peripheral nerves. No neurologic impairment was present postoperatively. 相似文献
20.
OBJECTIVE: To establish if there is a role for gabapentin or nortriptyline in the treatment of chronic orchialgia. METHODS: Twenty-six consecutive patients with chronic orchialgia were seen in the chronic pain clinic by a multidisciplinary team. A pain questionnaire was completed prior to commencing either gabapentin or nortriptyline. They were reviewed at 3 months and a repeat questionnaire completed. A 50% improvement in pain was considered successful. RESULTS: Complete data was available for 19 patients. Overall, 61.5% of patients commenced on gabapentin and 66.6% of patients commenced on nortriptyline had a greater than 50% improvement in pain. Patients with post-vasectomy testicular pain were considered as a subgroup. None of these patients had a greater than 50% improvement in pain. However, 80% of patients in the subgroup with idiopathic chronic orchialgia had a greater than 50% improvement in pain. CONCLUSION: Although this is a small study, it appears that gabapentin and nortriptyline are effective in the treatment of idiopathic chronic orchialgia but not post-vasectomy pain. 相似文献