全文获取类型
收费全文 | 78269篇 |
免费 | 4941篇 |
国内免费 | 319篇 |
专业分类
耳鼻咽喉 | 969篇 |
儿科学 | 2103篇 |
妇产科学 | 1293篇 |
基础医学 | 9809篇 |
口腔科学 | 1569篇 |
临床医学 | 8081篇 |
内科学 | 16701篇 |
皮肤病学 | 1286篇 |
神经病学 | 8048篇 |
特种医学 | 2459篇 |
外国民族医学 | 3篇 |
外科学 | 12384篇 |
综合类 | 830篇 |
一般理论 | 77篇 |
预防医学 | 5579篇 |
眼科学 | 1925篇 |
药学 | 4473篇 |
3篇 | |
中国医学 | 73篇 |
肿瘤学 | 5864篇 |
出版年
2023年 | 352篇 |
2022年 | 578篇 |
2021年 | 1368篇 |
2020年 | 806篇 |
2019年 | 1416篇 |
2018年 | 1688篇 |
2017年 | 1301篇 |
2016年 | 1484篇 |
2015年 | 1632篇 |
2014年 | 2315篇 |
2013年 | 3266篇 |
2012年 | 5096篇 |
2011年 | 5580篇 |
2010年 | 3031篇 |
2009年 | 2836篇 |
2008年 | 4852篇 |
2007年 | 5151篇 |
2006年 | 5067篇 |
2005年 | 5040篇 |
2004年 | 4815篇 |
2003年 | 4526篇 |
2002年 | 4296篇 |
2001年 | 1036篇 |
2000年 | 975篇 |
1999年 | 1005篇 |
1998年 | 912篇 |
1997年 | 755篇 |
1996年 | 670篇 |
1995年 | 683篇 |
1994年 | 568篇 |
1993年 | 496篇 |
1992年 | 721篇 |
1991年 | 636篇 |
1990年 | 622篇 |
1989年 | 519篇 |
1988年 | 561篇 |
1987年 | 511篇 |
1986年 | 528篇 |
1985年 | 498篇 |
1984年 | 480篇 |
1983年 | 461篇 |
1982年 | 484篇 |
1981年 | 447篇 |
1980年 | 358篇 |
1979年 | 315篇 |
1978年 | 315篇 |
1977年 | 248篇 |
1976年 | 207篇 |
1974年 | 220篇 |
1973年 | 215篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
31.
32.
Steven J Lavine 《Journal of the American Society of Echocardiography》2005,18(2):133-141
BACKGROUND: The index of myocardial performance (IMP) has been used as a prognostic systolic-diastolic index for patients with dilated cardiomyopathy and postmyocardial infarction. To date, systematic evaluation of the effect of heart rate and preload alteration on IMP has not been performed with normal or reduced left ventricular (LV) function. METHODS: We studied 14 mongrel dogs at baseline, after the induction of acute ischemic LV dysfunction, and with chronic LV dysfunction. Heart rate was altered by atrial pacing 10 and 20 beats above baseline, and volume loading was accomplished with 10 mL/kg of saline at a paced rate. Hemodynamics, and transmitral and transaortic pulsed Doppler, were obtained. RESULTS: With normal LV function, there were no changes in IMP with pacing. With acute LV dysfunction, IMP was also unchanged with pacing, although both LV ejection time (ET) (192 +/- 23 vs 208 +/- 25 milliseconds, P < .05) and isovolumic contraction time (58 +/- 25 vs 72 +/- 31 milliseconds, P < .05) declined. With chronic LV dysfunction, IMP was unchanged although LV ET declined (188 +/- 15 vs 204 +/- 18 milliseconds, P < .01). Volume loading did not alter the IMP with normal LV function although LV ET increased (208 +/- 25 vs 220 +/- 20 milliseconds, P < .001). With acute LV dysfunction, IMP decreased (0.66 +/- 0.11 vs 0.82 +/- 0.20, P < .05) because of a decrease in isovolumic relaxation time (63 +/- 33 vs 76 +/- 38 milliseconds, P < .05). With chronic LV dysfunction, IMP also declined with volume loading (0.59 +/- 0.29 vs 0.73 +/- 0.28, P < .01) because of an increase in LV ET (224 +/- 30 vs 198 +/- 22 milliseconds, P < .0001). CONCLUSION: Heart rate incrementation does not change IMP. However, volume loading reduces IMP primarily as a result of LV ET lengthening with chronic LV dysfunction. Further systematic evaluation of IMP is needed if this index is to be useful as a prognostic indicator. 相似文献
33.
Trawat Attarbaschi Julia Sacher Thomas Geiss-Granadia Nikolas Klein Nilufar Mossaheb Rupert Lanzenberger Susanne Asenbaum Robert Dudczak Siegfried Kasper Johannes Tauscher 《European neuropsychopharmacology》2007,17(2):102-107
We explored the relationship between striatal dopamine-2 (D(2)) receptor occupancy and extra-pyramidal symptoms (EPS) in bipolar patients receiving olanzapine. Seventeen patients with a DSM-IV diagnosis of bipolar disorder were treated with 5-45 mg/day olanzapine for at least 14 days. After that period, D(2) receptor occupancy was determined using Iodobenzamide (IBZM) and SPECT. EPS were assessed by the Simpson-Angus Scale (SAS) and Barnes-Akathisia Scale (BAS). We found a dose-dependent increase in occupancy: 5 mg led to 28-50%, 10 mg to 40-68%, 15 mg to 69%, 20 mg to 57-66%, 30 mg to 66% and 45 mg to 80% D(2) receptor occupancy; and a significant correlation between plasma levels and occupancy (R(2)=.55, P=.001). Similar to schizophrenic patients, bipolar patients did not exhibit EPS at D(2) occupancy levels of 28 to 80%. Although we did not find an increased vulnerability for acute EPS in bipolar patients receiving olanzapine at clinical relevant doses, this needs to be replicated with larger sample sizes. 相似文献
34.
Marcel J. Kooy Wouter S. Dessing Esther F. Kroodsma Steven R. J. G. Smits Esther H. Fietje Martine Kruijtbosch Peter A. G. M. De Smet 《Pharmacy World & Science》2007,29(2):81-89
OBJECTIVE: According to a report published by the federation of Dutch patients' associations, patients would like to see a pharmacist, who acts more as a personal adviser. This raised the question, how often Dutch community pharmacists have personal consultations with their patients in daily practice, on which factors this depends, and what kind of topics are discussed during these meetings. SETTING: Community pharmacies in the Netherlands. METHOD: A questionnaire was distributed among 800 randomly selected pharmacies. Questions were restricted to consultations characterized by one-to-one contact, drug therapy related content, and adequate privacy. These consultations were labelled as pharmaceutical consultations in private to distinguish them from other contacts between pharmacists and patients. MAIN OUTCOME MEASURE: Number, content, and character of consultations. RESULTS: 198 (24.8%) community pharmacies responded. The pharmacists provide an average of roughly 1.2 consultations in private per working day. The vast majority of respondents provided face-to-face and telephone consultations (94.4 and 91.9%, respectively), only a minority gave consultations by e-mail (30.8%). These consultations primarily dealt with topics related to medication safety. The mean overall time spent was 290 min per month. A relatively high frequency of personal consultations was significantly associated with the absolute number of full-time equivalent pharmacists in the pharmacy. CONCLUSION: The frequency of pharmaceutical consultations in private is low, but may be improved by reorganisation of the pharmacist's activities. The possibility of personal consultations by e-mail is not yet well-developed. Further research is needed to assess the patient's view of pharmaceutical consultations in private. 相似文献
35.
Leonard A. Jason PhD Steven B. Pokorny PhD Monica Adams MPH Annie Topliff MA Courtney Harris BA Yvonne Hunt PhD 《The American journal on addictions / American Academy of Psychiatrists in Alcoholism and Addictions》2009,18(5):367-374
This study evaluated the effects of tobacco Purchase, Use and Possession (PUP) laws on student perceptions of adolescent tobacco use within towns and schools. Twenty‐four towns were randomly assigned into two conditions, the experimental condition (E PUP) involved efforts to increase both PUP law enforcement and reduce minors' access to commercial sources of tobacco, whereas the control condition (C) focused only on efforts to reduce minors' access to commercial sources of tobacco. A hierarchical linear modeling analytical approach was selected due to the multilevel data and nested design. The present study found that over time, youth in the experimental PUP condition observed less youth tobacco usage at school and in their town, and perceived lower rates of tobacco among their peers at school and among friends than youth in the control condition. The findings suggest that PUP law enforcement might be used to strengthen community norms against youth tobacco use. 相似文献
36.
37.
38.
39.
40.
Oren N Gottfried Steven Chin H Christian Davidson William T Couldwell 《Skull base》2007,17(5):317-324
The authors present a case of amyloid infiltration involving the trigeminal nerve that mimicked a malignant cavernous sinus tumor with perineural tumor infiltration. A 64-year-old man presented with trigeminal nerve numbness. Imaging revealed a plaque-like enhancing lesion along the right lateral cavernous sinus extending anteriorly into Meckel's cave and involving the proximal V2 and V3 branches of the trigeminal nerve. The patient underwent an extradural frontotemporal craniotomy with middle fossa exposure of the cavernous sinus to diagnose and treat the presumed malignant cavernous sinus tumor. A reddish mass involving the lateral dural wall of the cavernous sinus was resected. The gasserian ganglion, V2, and V3, the latter of which was biopsied, were enlarged. Permanent histopathological studies showed microscopic eosinophilic, amorphous material, which stained positive for Congo red, and an absence of neoplastic cells. The final diagnosis was amyloidoma. Thus, amyloidomas can involve the trigeminal nerve or ganglia and should be considered in the differential diagnosis of a cavernous sinus lesion mimicking a tumor. Patients may have symptomatic improvement of trigeminal neuropathy with resection of the amyloidoma outside the nerve capsule that is compressing the nerve, while resection of the lesion from within the capsule may result in permanent trigeminal nerve dysfunction. 相似文献