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   17361篇
  免费   1367篇
  国内免费   42篇
耳鼻咽喉   166篇
儿科学   576篇
妇产科学   473篇
基础医学   2386篇
口腔科学   186篇
临床医学   1995篇
内科学   3433篇
皮肤病学   259篇
神经病学   2009篇
特种医学   332篇
外科学   1784篇
综合类   100篇
一般理论   18篇
预防医学   2482篇
眼科学   232篇
药学   1034篇
中国医学   9篇
肿瘤学   1296篇
  2024年   40篇
  2023年   336篇
  2022年   569篇
  2021年   1164篇
  2020年   696篇
  2019年   966篇
  2018年   1030篇
  2017年   683篇
  2016年   700篇
  2015年   758篇
  2014年   970篇
  2013年   1193篇
  2012年   1736篇
  2011年   1696篇
  2010年   784篇
  2009年   650篇
  2008年   1047篇
  2007年   898篇
  2006年   776篇
  2005年   601篇
  2004年   480篇
  2003年   403篇
  2002年   326篇
  2001年   33篇
  2000年   26篇
  1999年   30篇
  1998年   44篇
  1997年   27篇
  1996年   9篇
  1995年   15篇
  1994年   11篇
  1993年   7篇
  1992年   7篇
  1991年   5篇
  1990年   3篇
  1989年   4篇
  1988年   4篇
  1985年   4篇
  1984年   5篇
  1983年   2篇
  1982年   4篇
  1980年   4篇
  1979年   4篇
  1977年   2篇
  1975年   2篇
  1973年   3篇
  1964年   3篇
  1960年   1篇
  1959年   1篇
  1933年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Background: The Patient-Reported Outcomes Measurement Information System Upper Extremity (PROMIS UE) computer adaptive test was developed to improve precision and reduce question burden. We hypothesized that in patients with carpal tunnel syndrome (CTS): (1) PROMIS UE would correlate with established patient-reported outcome measures (PROs); (2) the time and number of questions required would be lower than current metrics; (3) there would be no floor or ceiling effects; and (4) PROMIS UE would not correlate with disease severity. Methods: Patients undergoing electrodiagnostic evaluation found to have a primary diagnosis of unilateral CTS prospectively completed PROMIS UE, Quick Disabilities of the Arm, Shoulder and Hand (qDASH), and Boston Carpal Tunnel Syndrome Questionnaire (BCTQ). Electrophysiologic and clinical severity was recorded. The relationships among PROs were described with Spearman coefficients. A floor or ceiling effect was confirmed if >15% of patients achieved the lowest or highest possible score, respectively. Results: Fifty-one patients (average, 53.9 years) were enrolled. An excellent correlation was identified between PROMIS UE and qDASH (R = −0.76, P < .001). There was a good correlation between PROMIS UE and BCTQ (R = −0.58, P < 0.001). The PROMIS UE required less time and fewer questions than qDASH and BCTQ (P = .02 and P < .001). There were no floor or ceiling effects. Neither neurophysiologic nor clinical severity correlated with PROMIS UE (R = 0.24, P > .05 and R = −0.18, P > .05). Conclusions: The PROMIS UE has an excellent correlation with qDASH and a good correlation with BCTQ in patients with CTS. Furthermore, PROMIS UE required less time and fewer questions than established PROs. Used as a single PRO, PROMIS UE represents a practical alternative to current metrics in patients with CTS.  相似文献   
993.
994.
In forensic work, the interpretation of DNA profiles becomes complicated when samples contain more than one contributor because the simultaneous amplification of individual identification markers results in mixed profiles. To overcome this problem, we present haplotype-specific extraction (HSE) as a more straightforward method to analyze a DNA mixture. HSE has been developed to clarify ambiguous HLA alleles by separating diploid samples into their haploid components to facilitate HLA typing. We have started to establish new protocols and strategies to adapt HSE for the separation of male DNA mixtures in forensic analysis. First results have shown an improved enrichment of male DNA from a single contributor. We have also evaluated a new, optimized buffer composition by testing different concentrations of its components. Improved separation of a male DNA mixture is detected using AmpF?STR(?) Yfiler short tandem repeat analysis.  相似文献   
995.
Turning plays a prominent role in daily living activities and requires the modulation of the ground reaction forces to accelerate the body's center-of-mass along the path of the turn. With the ankle plantarflexors being prominent contributors to the propulsive ground reaction forces, it is not clear how transtibial amputees perform turning tasks without these important muscles. The purpose of this study was to identify the compensatory mechanisms used by transtibial amputees during a simple turning task by analyzing the radial and anterior–posterior ground reaction impulses and sagittal, transverse and coronal joint work of the residual and intact legs. These quantities were analyzed with the residual leg on both the inside and outside of the turn and compared to non-amputees. The analysis showed that amputees and non-amputees use different joint strategies to turn. Amputees rely primarily on sagittal plane hip joint work to turn while non-amputees rely primarily on ankle work in the sagittal plane and hip joint work in the coronal plane. Differences in strategies are most likely due to the minimal power output provided by the passive prosthetic feet used by amputees and perhaps a desire to minimize the risk of falling. Understanding these differences in turning strategies will aid in developing effective rehabilitation therapies and prosthetic devices that improve amputee mobility.  相似文献   
996.

Purpose

To evaluate safety and efficacy of transarterial hepatic radioembolization treatment of patients with liver-dominant metastatic renal cell carcinoma (RCC).

Materials and Methods

From July 2010 to December 2014, 18 patients with liver-dominant metastatic RCC were treated with yttrium-90 glass microsphere radioembolization. Retrospective review of medical records and imaging studies was performed to evaluate toxicities, treatment response, and overall survival. The median follow-up period from radioembolization treatment was 17.8 months (range, 3–54.4 months).

Results

Median overall survival from RCC diagnosis was 64 months (95% confidence interval [CI], 0–144.1 months), from diagnosis of liver metastasis was 29 months (95% CI, 7.2–50.8 months), and from radioembolization treatment was 22.8 months (95% CI, 13.2–32.3 months). After treatment, 10 patients reported grade 1 clinical toxicities, and 8 patients had grade 1 or 2 biochemical toxicities. The best radiographic responses of 17 patients who underwent contrast-enhanced cross-sectional imaging showed complete response in 16 patients and partial response in 1 patient evaluated by modified Response Evaluation Criteria in Solid Tumors (mRECIST) criteria. The last available imaging of these 17 patients demonstrated complete response in 14 patients, partial response in 1 patient, and progression of disease in 2 patients. Images of a patient who underwent noncontrast CT showed stable disease as best response and stable disease on the last available imaging evaluated by RECIST.

Conclusions

Radioembolization is safe and effective and led to improved hepatic disease control and overall survival in patients with liver-dominant metastatic RCC.  相似文献   
997.
IntroductionThe αvβ3 integrin, which is expressed by angiogenic epithelium and some tumor cells, is an attractive target for the development of both imaging agents and therapeutics. While optimal implementation of αvβ3-targeted therapeutics will require a priori identification of the presence of the target, the clinical evaluation of these compounds has typically not included parallel studies with αvβ3-targeted diagnostics. This is at least partly due to the relatively limited availability of PET radiopharmaceuticals in comparison to those labeled with 99mTc. In an effort to begin to address this limitation, we evaluated the tumor uptake of 99mTc-NC100692, a cyclic RGD peptide that binds to αvβ3 with ~ 1-nM affinity, in an αvβ3-positive tumor model as well as its in vivo specificity.MethodsMicroSPECT imaging was used to assess the ability of cilengitide, a therapeutic with high affinity for αvβ3, to block and displace 99mTc-NC100692 in an orthotopic U87 glioma tumor. The specificity of 99mTc-NC100692 was quantitatively evaluated in mice bearing subcutaneous U87MG tumors, by comparison of the biodistribution of 99mTc-NC100692 with that of the non-specific structural analogue 99mTc-AH-111744 and by blocking uptake of 99mTc-NC100692 with excess unlabeled NC100692.ResultsMicroSPECT imaging studies demonstrated that uptake of 99mTc-NC100692 in the intracranial tumor model was both blocked and displaced by the αvβ3-targeted therapeutic cilengitide. Biodistribution studies provided quantitative confirmation of these imaging results. Tumor uptake of 99mTc-NC100692 at 1 h post-injection was 2.8 ± 0.7% ID/g compared to 0.38 ± 0.1% ID/g for 99mTc-AH-111744 (p < 0.001). Blocking 99mTc-NC100692 uptake by pre-injecting the mice with excess unlabeled NC100692 reduced tumor uptake by approximately five-fold, to 0.68 ± 0.3% ID/g (p = 0.01).ConclusionThese results confirm that 99mTc-NC100692 does, in fact, target the αvβ3 integrin and may, therefore, be useful in identifying patients prior to anti-αvβ3 therapy as well as monitoring the response of these patients to therapy.  相似文献   
998.
999.
1000.
The brain adapts to asynchronous audiovisual signals by reducing the subjective temporal lag between them. However, it is currently unclear which sensory signal (visual or auditory) shifts toward the other. According to the idea that the auditory system codes temporal information more precisely than the visual system, one should expect to find some temporal shift of vision toward audition (as in the temporal ventriloquism effect) as a result of adaptation to asynchronous audiovisual signals. Given that visual information gives a more exact estimate of the time of occurrence of distal events than auditory information (due to the fact that the time of arrival of visual information regarding an external event is always closer to the time at which this event occurred), the opposite result could also be expected. Here, we demonstrate that participants'' speeded reaction times (RTs) to auditory (but, critically, not visual) stimuli are altered following adaptation to asynchronous audiovisual stimuli. After receiving “baseline” exposure to synchrony, participants were exposed either to auditory-lagging asynchrony (VA group) or to auditory-leading asynchrony (AV group). The results revealed that RTs to sounds became progressively faster (in the VA group) or slower (in the AV group) as participants'' exposure to asynchrony increased, thus providing empirical evidence that speeded responses to sounds are influenced by exposure to audiovisual asynchrony.  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