全文获取类型
收费全文 | 236169篇 |
免费 | 5894篇 |
国内免费 | 138篇 |
专业分类
耳鼻咽喉 | 1743篇 |
儿科学 | 8839篇 |
妇产科学 | 5044篇 |
基础医学 | 24269篇 |
口腔科学 | 2339篇 |
临床医学 | 22710篇 |
内科学 | 42113篇 |
皮肤病学 | 1567篇 |
神经病学 | 21584篇 |
特种医学 | 10131篇 |
外国民族医学 | 33篇 |
外科学 | 34560篇 |
综合类 | 3206篇 |
一般理论 | 91篇 |
预防医学 | 26258篇 |
眼科学 | 3404篇 |
药学 | 13215篇 |
1篇 | |
中国医学 | 716篇 |
肿瘤学 | 20378篇 |
出版年
2023年 | 348篇 |
2022年 | 527篇 |
2021年 | 1169篇 |
2020年 | 775篇 |
2019年 | 1264篇 |
2018年 | 23173篇 |
2017年 | 18238篇 |
2016年 | 20484篇 |
2015年 | 2108篇 |
2014年 | 2454篇 |
2013年 | 3519篇 |
2012年 | 10836篇 |
2011年 | 25027篇 |
2010年 | 20858篇 |
2009年 | 13514篇 |
2008年 | 23008篇 |
2007年 | 25735篇 |
2006年 | 4530篇 |
2005年 | 6067篇 |
2004年 | 7141篇 |
2003年 | 7981篇 |
2002年 | 5888篇 |
2001年 | 1101篇 |
2000年 | 1185篇 |
1999年 | 991篇 |
1998年 | 1010篇 |
1997年 | 878篇 |
1996年 | 669篇 |
1995年 | 609篇 |
1994年 | 592篇 |
1993年 | 537篇 |
1992年 | 642篇 |
1991年 | 642篇 |
1990年 | 667篇 |
1989年 | 574篇 |
1988年 | 502篇 |
1987年 | 499篇 |
1986年 | 430篇 |
1985年 | 472篇 |
1984年 | 402篇 |
1983年 | 380篇 |
1982年 | 411篇 |
1981年 | 343篇 |
1980年 | 329篇 |
1979年 | 339篇 |
1978年 | 258篇 |
1977年 | 239篇 |
1976年 | 219篇 |
1975年 | 189篇 |
1974年 | 210篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Statutory reimbursement agencies as well as private insurers throughout member states of the Organization for Economic Cooperation and Development (OECD) reimburse the cost of medicines on the basis of criteria that include robust clinical evidence, budget impact analysis, and incremental cost effectiveness. The Centers for Medicare and Medicaid Services (CMS) in the US are no exception to this rule and are, in principle, seeking to maximize benefit for their Medicare enrollees, whilst ensuring reasonable drug outlays for the small number of drugs that they reimburse. This paper provides a retrospective analysis of the way two functionally equivalent drugs are treated for reimbursement purposes by the CMS; the period under consideration was 2001–3. The two drugs, epoetin-α and darbepoetin-α, are used for the treatment of anemia in renal failure and in patients receiving chemotherapy. By reviewing the publicly available pharmacological and clinical data of epoetin-α and darbepoetin-α, the paper confirms the two drugs’ functional equivalence, despite their structural differences. The implications of dose conversion ratios and costs to Medicare are subsequently explored. It is argued that the issue of dose equivalence between epoetin-α and darbepoetin-α has significant implications for patients, practitioners, and payors. A payor’s perspective is adopted in this respect, whereby clinical evidence and pricing data are used simultaneously. Based on the clinical evidence, a dose conversion ratio for epoetin-α:darbepoetin-α is established, which achieves a comparable clinical effect for the two drugs and this is set to be <254IU:1μg. The incremental costs to Medicare are calculated subsequently. The Average Wholesale Price and the Outpatient Prospective Payment System rule that Medicare uses to reimburse providers are used and suggest that treatment of cancer patients with chemotherapy-related anemia with epoetin-α would save Medicare an estimated $US600 million each year. Patients would also benefit significantly in terms of lower co-payments for epoetin-α. The evidence is supportive of the decision made by the CMS to reimburse the two drugs at the rate reflecting the achievement of comparable clinical effects and therefore reducing the pass-through payments for darbepoetin-α to zero for the 2002–3 fiscal year. 相似文献
92.
Objective: To study the diagnostic value of T2^*-weighted first-pass perfusion imaging in breast tumors. Methods: We analyzed the magnetic resonance imaging (MRI) information along with the pathological and immunohistochemistry results. Magnetic resonance imaging was performed in 28 patients with breast tumor. The time to signal intensity curves were generated according to the T2^*-weighted first-pass perfusion imaging. The curve's maximal signal intensity drop rate and maximal signal intensity decrease time were analyzed and compared with the pathological diagnoses after surgery. Results: Malignant breast lesions showed higher maximal signal intensity drop rate (44.69% ± 17.07 vs. 17.22% ±7.49, P 〈 0.001) than benign lesions, but there was no significant difference of maximal signal decrease time between those two lesions (23.94 s ± 4.92 vs. 20.02 s ± 6.83, P 〉 0.05). Conclusion: The T2^*-weighted first-pass perfusion imaging has enough sensitivity and specificity in breast tumor diagnosis. 相似文献
93.
94.
Kevin Gruffydd-Jones Sandra Hollinghurst Sabbi Ward Gordon Taylor 《The British journal of general practice》2005,55(521):918-923
BACKGROUND: There is a high non-attendance rate for traditional clinic-based routine asthma care in general practice. Alternative methods of providing routine asthma care need to be examined. AIM: To examine the cost and effectiveness of targeted routine asthma care in general practice using telephone triage, compared to usual clinic care. DESIGN OF STUDY: An open randomised controlled trial. SETTING: A single semi-rural practice in the southwest of England. METHOD: Adult patients with asthma were randomised to receive either their routine asthma care in the surgery or care by telephone triage. Asthma control parameters, health status and NHS resource utilisation were measured over the 12-month study period. RESULTS: One hundred and ninety-four patients were randomised and 35% per cent more patients (n = 84 versus n = 62) received more than one consultation in the telephone group. Asthma control as measured by the asthma control questionnaire (ACQ) was similar in the clinic and telephone groups: mean change in ACQ = -0.11 (95% CI = -0.32 to 0.11) versus -0.18 (95% CI = -0.38 to 0.02). Mean NHS costs were 210 pounds sterling per patient per year in the telephone group compared to 334 pounds sterling in the clinic group (P-value of bootstrapped difference = 0.071). CONCLUSION: Targeted routine asthma care by telephone triage of adult asthmatics can lead to more asthma patients being reviewed, at less cost per patient and without loss of asthma control compared to usual routine care in the surgery. 相似文献
95.
David M Raffel Robert A Koeppe Roderick Little Chia-Ning Wang Suyu Liu Larry Junck Mary Heumann Sid Gilman 《Journal of nuclear medicine》2006,47(11):1769-1777
Scintigraphic imaging with (123)I-metaiodobenzylguanidine ((123)I-MIBG) has demonstrated extensive losses of cardiac sympathetic neurons in idiopathic Parkinson's disease (IPD). In contrast, normal cardiac innervation has been observed in (123)I-MIBG studies of multiple-system atrophy (MSA) and progressive supranuclear palsy (PSP). Consequently, it has been hypothesized that cardiac denervation can be used to differentiate IPD from MSA and PSP. We sought to test this hypothesis by mapping the distribution of cardiac sympathetic neurons in patients with IPD, MSA, and PSP by using PET and (11)C-meta-hydroxyephedrine ((11)C-HED). Also, the relationship between cardiac denervation and nigrostriatal denervation was investigated by measuring striatal presynaptic monoaminergic nerve density with PET and (11)C-dihydrotetrabenazine ((11)C-DTBZ). METHODS: (11)C-HED and (11)C-DTBZ scans were obtained for patients with IPD (n = 9), MSA (n = 10), and PSP (n = 8) and for age-matched control subjects (n = 10). Global and regional measurements of (11)C-HED retention were obtained to assess the extent of cardiac sympathetic denervation. (11)C-DTBZ binding was measured in the caudate nucleus, anterior putamen, and posterior putamen. RESULTS: As expected, extensive cardiac denervation was observed in several of the patients with IPD. However, substantial cardiac denervation was also seen in some patients with MSA and PSP. (11)C-DTBZ studies demonstrated striatal denervation in all patients with IPD and in most patients with MSA and PSP. No correlation was found between cardiac (11)C-HED retention and striatal (11)C-DTBZ binding. CONCLUSION: Cardiac sympathetic denervation was found to occur not only in IPD but also in other movement disorders, such as MSA and PSP. This finding implies that scintigraphic detection of cardiac sympathetic denervation cannot be used independently to discriminate IPD from other movement disorders, such as MSA and PSP. Cardiac sympathetic denervation was not correlated with striatal denervation, suggesting that the pathophysiologic processes underlying cardiac denervation and striatal denervation occur independently in patients with parkinsonian syndromes. These findings provide novel information about central and peripheral denervation in patients with neurodegenerative disorders. 相似文献
96.
97.
Hand preferences and whole (Galago senegalensis) 总被引:1,自引:0,他引:1
The hand preferences in prey capture and whole-body turning biases after prey capture were assessed in 10 lesser bushbabies (Galago senegalensis) in 8 conditions designed to manipulate posture, visibility of prey and angle of reaching. Each subject received 60 trials in each test condition for a total of 480 trials. Seven subjects had a left-hand preference in food reaching, three right and none were ambipreferent. Eight subjects had a left whole-body turning bias, one right and one had no bias. No correlation was found between reach preference and turning bias. Bipedal posture facilitated the use of the dominant hand, whereas other manipulated conditions did not have a significant effect on hand use. A neuraxial arousal system is postulated as mediator of the bipedal effect on hand use. 相似文献
98.
99.
A model is described for obtaining long-term and stable discriminative conditioning-related slow-potential and single-unit responses from the frontal cortex of urethane-anesthetized rats. Responses were recorded and analyzed to reinforced (rewarding medial forebrain bundle stimulation) and non-reinforced tone cues. In the present study, cortical event-related slow potentials provided an adequate index of the level of discriminative conditioning. Single-unit response patterns are described for 57 neurons which demonstrated a discriminative response to either the reinforced or non-reinforced tone cue. 相似文献
100.