全文获取类型
收费全文 | 42584篇 |
免费 | 2637篇 |
国内免费 | 1394篇 |
专业分类
耳鼻咽喉 | 647篇 |
儿科学 | 1023篇 |
妇产科学 | 637篇 |
基础医学 | 4168篇 |
口腔科学 | 745篇 |
临床医学 | 4373篇 |
内科学 | 6355篇 |
皮肤病学 | 2037篇 |
神经病学 | 2678篇 |
特种医学 | 1077篇 |
外国民族医学 | 1篇 |
外科学 | 2253篇 |
综合类 | 6013篇 |
现状与发展 | 3篇 |
预防医学 | 4543篇 |
眼科学 | 498篇 |
药学 | 6278篇 |
31篇 | |
中国医学 | 2221篇 |
肿瘤学 | 1034篇 |
出版年
2024年 | 65篇 |
2023年 | 501篇 |
2022年 | 1059篇 |
2021年 | 1504篇 |
2020年 | 1305篇 |
2019年 | 1172篇 |
2018年 | 1229篇 |
2017年 | 1250篇 |
2016年 | 1251篇 |
2015年 | 1344篇 |
2014年 | 2521篇 |
2013年 | 2938篇 |
2012年 | 2576篇 |
2011年 | 2718篇 |
2010年 | 2219篇 |
2009年 | 2070篇 |
2008年 | 2116篇 |
2007年 | 2186篇 |
2006年 | 1815篇 |
2005年 | 1709篇 |
2004年 | 1394篇 |
2003年 | 1230篇 |
2002年 | 995篇 |
2001年 | 929篇 |
2000年 | 801篇 |
1999年 | 772篇 |
1998年 | 600篇 |
1997年 | 600篇 |
1996年 | 546篇 |
1995年 | 538篇 |
1994年 | 483篇 |
1993年 | 379篇 |
1992年 | 423篇 |
1991年 | 386篇 |
1990年 | 313篇 |
1989年 | 327篇 |
1988年 | 314篇 |
1987年 | 284篇 |
1986年 | 236篇 |
1985年 | 259篇 |
1984年 | 199篇 |
1983年 | 167篇 |
1982年 | 180篇 |
1981年 | 139篇 |
1980年 | 122篇 |
1979年 | 94篇 |
1978年 | 81篇 |
1977年 | 65篇 |
1976年 | 50篇 |
1975年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
T. J. C. Faes G. A. Yff O. De Weerdt P. Lanting J. J. Heimans F. W. Bertelsmann 《Journal of neurology》1993,240(3):156-160
To evaluate the effects of the aldose reductase inhibitor Ponalrestat (Statil) on diabetic autonomic neuropathy, a double-blind placebo controlled trial was carried out on a group of 34 diabetic patients with documented cardiac autonomic neuropathy. After a 4-week, placebo run-in period, patients were randomised for treatment with 600 mg Statil or placebo for another 24 weeks. Moreover, the reliability of the autonomic nerve function tests was investigated by comparing the results at onset and at week 4. Fifteen patients treated with Statil and 12 with placebo completed the study. Neither symptom scores nor cardiovascular reflexes, pupil reflexes and skin vasomotor reflexes improved after Statil therapy, which led us to conclude that Statil is not effective in the treatment of diabetic autonomic neuropathy. Reliability coefficients for cardiovascular reflexes and pupil reflex showed high values, ranging from 60% to 80%. Therefore these methods are recommended in future therapy trials. 相似文献
12.
13.
14.
W. N. Charman 《Ophthalmic & physiological optics》2006,26(1):5-12
In the Cardiff acuity test, simple pictures on an otherwise neutral grey card are defined by borders consisting of a relatively broad white band flanked by black bands each half the width of the white band. Higher levels of acuity correspond to the ability to detect figures defined by narrower borders, the figure size remaining constant. It is sometimes implied that the acuity limit corresponding to each card can be equated with different levels of grating resolution, the total width of the border corresponding to the overall grating period. It is shown that although the spatial frequency spectra of the Cardiff figures, like those of other vanishing optotypes, lack very low-frequency components, they have a complex two-dimensional form. The figures have wide spatial bandwidth and no well-defined discrete frequency components. As a result, the relationship between measured Cardiff and grating acuity will vary somewhat, depending upon the particular optical, neural or other deficits of the individual being tested. 相似文献
15.
Martine Hascoët Michel Bourin Jacques Bradwejn 《Progress in neuro-psychopharmacology & biological psychiatry》1991,15(6):825-840
1. The mechanism of action of drugs might change according to the test used. Several noradrenergic drugs were tested in order to understand their implication in the mobility tests.
2. It was found that clonidine, an Alpha 2 agonist, acted differently according to the tast used. It provoked sedation in spontaneous activity test, and anti-immobility effects in the other tests.
3. Tall suspension test is able to show the double acting of clonidine.
4. Idazoxan might act either as an alpha 2 antagonist or as partial alpha 2 agonist. TST shown the unexpected partial alpha agonist effect of the molecule.
5. Forced swimming test is more specific for predicting antidepressant activity than tail suspension test which is close to a spontaneous activity model. 相似文献
16.
17.
Margaret Sullivan Pepe Ziding Feng Gary Longton Joseph Koopmeiners 《Statistics in medicine》2009,28(5):762-779
Development of a disease screening biomarker involves several phases. In phase 2 its sensitivity and specificity is compared with established thresholds for minimally acceptable performance. Since we anticipate that most candidate markers will not prove to be useful and availability of specimens and funding is limited, early termination of a study is appropriate, if accumulating data indicate that the marker is inadequate. Yet, for markers that complete phase 2, we seek estimates of sensitivity and specificity to proceed with the design of subsequent phase 3 studies. We suggest early stopping criteria and estimation procedures that adjust for bias caused by the early termination option. An important aspect of our approach is to focus on properties of estimates conditional on reaching full study enrollment. We propose the conditional‐UMVUE and contrast it with other estimates, including naïve estimators, the well‐studied unconditional‐UMVUE and the mean and median Whitehead‐adjusted estimators. The conditional‐UMVUE appears to be a very good choice. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
18.
19.
S. M. Fuchs C. Heinemann S. Schliemann-Willers H. Härtl J. W. Fluhr P. Elsner 《Skin research and technology》2006,12(4):223-227
OBJECTIVE: In the present study, we evaluated the anti-inflammatory activity of Poria cocos (PoCo) on experimentally induced irritant contact dermatitis (ICD) in a repeated sodium lauryl sulphate (SLS) irritation model. METHODS: The anti-irritative effect of PoCo was evaluated with a visual score and quantified by non-invasive bioengineering methods, namely chromametry and transepidermal water loss. Three concentrations of PoCo in base cream DAC (amphiphilic emollient; German pharmacopoeia) were tested in a 4-day repetitive irritation test using SLS. RESULTS: A statistically significant anti-inflammatory activity was observed for PoCo by all three methods when applied in parallel to the induction period of ICD. Application of PoCo after induction of ICD once a day for 5 days, starting just at the end of 4 days, was without any effect. CONCLUSION: An anti-inflammatory efficacy of PoCo on the elicitation phase of the ICD induced by repeated SLS test could be observed and quantified by three independent, non-invasive biophysical assessment parameters. This effect can be explained by its influence on pro-inflammatory enzymes, namely phospholipase A2. 相似文献
20.
Yukihisa Fukuda Savio L-Y Woo John C Loh Eiichi Tsuda Peter Tang Patrick J McMahon Richard E Debski 《Journal of orthopaedic research》2003,21(6):1107-1112
The loads needed to elicit a positive pivot shift test in a knee with an anterior cruciate ligament (ACL) rupture have not been quantified. The coupled anterior tibial translation (ATT), coupled internal tibial rotation (ITR), and the in situ force in the ACL in response to a valgus torque, an inherent component of the pivot shift test, were measured in 10 human cadaveric knee specimens. Using a robotic/universal force-moment sensor testing system, valgus torques ranging from 0.0 to 10.0 Nm were applied in nine increments on the intact and ACL-deficient knee in flexion ranging from 0 degrees to 90 degrees. At 15 degrees of knee flexion, the coupled ATT and ITR were significantly increased in the ACL-deficient knee when compared to the intact knee. Coupled ATT increased a maximum of 291% (6.7 mm, p<0.05), while coupled ITR increased a maximum of 85% (5.1 degrees, p<0.05). At 30 degrees, the increases in coupled ATT and ITR were significant at valgus loads of 3.3 Nm and greater with a maximum increase in coupled ATT of 137% (6.3 mm, p<0.05) and a maximum increase in coupled ITR of 38% (3.6 degrees, p<0.05). At 45 degrees, coupled ATT increased significantly (maximum of 69%, 4.4 mm, p<0.05), but only at torques > or =6.7 Nm. The in situ force in the ACL was less than 20 N for all flexion angles when a torque between 3.3 and 5.0 Nm was applied. Low valgus torque elicited tibial subluxation in the ACL-deficient knee with low in situ ACL forces, similar to a positive pivot shift test. Thus, application of a valgus torque may be suitable to evaluate ACL-deficient and ACL-reconstructed knees, since subluxation can be achieved with minimal harm to the ACL graft. This work is important in understanding one load component needed for the pivot shift examination; further studies quantifying other load components are essential for better comprehension of the in vivo pivot shift examination. 相似文献