全文获取类型
收费全文 | 36132篇 |
免费 | 2313篇 |
国内免费 | 99篇 |
专业分类
耳鼻咽喉 | 513篇 |
儿科学 | 880篇 |
妇产科学 | 549篇 |
基础医学 | 4535篇 |
口腔科学 | 489篇 |
临床医学 | 3946篇 |
内科学 | 7288篇 |
皮肤病学 | 481篇 |
神经病学 | 3205篇 |
特种医学 | 1470篇 |
外科学 | 5896篇 |
综合类 | 406篇 |
一般理论 | 41篇 |
预防医学 | 3211篇 |
眼科学 | 550篇 |
药学 | 2660篇 |
中国医学 | 30篇 |
肿瘤学 | 2394篇 |
出版年
2024年 | 27篇 |
2023年 | 253篇 |
2022年 | 494篇 |
2021年 | 1103篇 |
2020年 | 669篇 |
2019年 | 1005篇 |
2018年 | 1208篇 |
2017年 | 835篇 |
2016年 | 855篇 |
2015年 | 1020篇 |
2014年 | 1516篇 |
2013年 | 1999篇 |
2012年 | 2881篇 |
2011年 | 2969篇 |
2010年 | 1558篇 |
2009年 | 1438篇 |
2008年 | 2459篇 |
2007年 | 2404篇 |
2006年 | 2215篇 |
2005年 | 2247篇 |
2004年 | 2119篇 |
2003年 | 1884篇 |
2002年 | 1754篇 |
2001年 | 250篇 |
2000年 | 217篇 |
1999年 | 268篇 |
1998年 | 327篇 |
1997年 | 260篇 |
1996年 | 253篇 |
1995年 | 175篇 |
1994年 | 182篇 |
1993年 | 152篇 |
1992年 | 113篇 |
1991年 | 103篇 |
1990年 | 105篇 |
1989年 | 106篇 |
1988年 | 89篇 |
1987年 | 68篇 |
1986年 | 70篇 |
1985年 | 66篇 |
1984年 | 77篇 |
1983年 | 84篇 |
1982年 | 92篇 |
1981年 | 63篇 |
1980年 | 46篇 |
1979年 | 61篇 |
1978年 | 43篇 |
1977年 | 46篇 |
1974年 | 26篇 |
1972年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Religious orientation, aging, and blood pressure reactivity to interpersonal and cognitive stressors
Kevin S. Masters Ph.D. Robert D. Hill Ph.D. John C. Kircher Ph.D. Tera L. Lensegrav Benson M.S. Jennifer A. Fallon M.S. 《Annals of behavioral medicine》2004,28(3):171-178
Background: Research on religion and health suggests general health benefits for those who are more religiously involved. Particular
aspects of religiosity that may influence this finding, however, have not been sufficiently investigated.Purpose: This study was designed to explore the relationship between religious orientation (intrinsic, extrinsic) and blood pressure
reactivity among older (over 60 years) and younger (18–24 years) adults exposed to two qualitatively different laboratory
stressors (cognitive, interpersonal).Methods:Participants were categorized as exhibiting either a predominately intrinsic or extrinsic religious orientation based on scores
on the Religious Orientation Scale. They were subsequently exposed (in counterbalanced order) to two laboratory stressors
that varied in terms of whether an interpersonal confrontation was involved. Measures of blood pressure were obtained at baseline
and during stressor presentation.Results: Analyses indicated that older extrinsically religious individuals demonstrated exaggerated reactivity compared to younger
participants and older intrinsically religious individuals. Older intrinsically religious participants did not differ from
younger persons. Similar results were found for analysis of baseline data. Extrinsic participants had greater reactivity during
the interpersonal confrontation condition than did intrinsic individuals.Conclusions: These findings suggest that religious orientation may be an important variable to study regarding cardiovascular reactivity
in, particularly, older adults.
This research was supported in part by National Institute on Aging Grant 1 R03 AG 18554-01. A previous version of this article
was presented in August 2002 as a Citation Paper at the 110th Annual Convention of the American Psychological Association,
Chicago.
We thank Timothy W. Smith, James A. Blumenthal, Carl E. Thoresen, and Edward M. Heath for their assistance throughout this
project. We also thank Llewellyn Jones and Jodi Hildabrandt for their efforts in collecting data. 相似文献
52.
The amplitude of the respiratory sinus arrhythmia (RSA) was investigated during a reading aloud task to determine whether alterations in respiratory control during speech production affect the amplitude of RSA. Changes in RSA amplitude associated with speech were evaluated by comparing RSA amplitudes during reading aloud with those obtained during rest breathing. A third condition, silent reading, was included to control for potentially confounding effects of cardiovascular responses to cognitive processes involved in the process of reading. Calibrated respiratory kinematics, electrocardiograms (ECGs), and speech audio signals were recorded from 18 adults (9 men, 9 women) during 5-min trials of each condition. The results indicated that the increases in respiratory duration, lung volume, and inspiratory velocity associated with reading aloud were accompanied by similar increases in the amplitude of RSA. This finding provides support for the premise that sensorimotor pathways mediating metabolic respiration are actively modulated during speech production. 相似文献
53.
Limb asymmetries in landing and jumping 2 years following anterior cruciate ligament reconstruction. 总被引:1,自引:0,他引:1
Mark V Paterno Kevin R Ford Gregory D Myer Rachel Heyl Timothy E Hewett 《Clinical journal of sport medicine》2007,17(4):258-262
OBJECTIVE: Female athletes who are at increased risk for anterior cruciate ligament (ACL) injury demonstrate biomechanical differences between limbs during athletic tasks that may persist following anterior cruciate ligament reconstruction (ACLR). This may limit an athlete's potential for safe return to sports competition. The purpose of this study was to determine if female athletes demonstrate lower limb asymmetries in landing and takeoff force following ACLR and clearance for return to competitive sports participation. We hypothesized that females following ACLR would demonstrate side-to-side differences in landing and jumping kinetics after their return to sport (2+ years) that would not be observed in a group of healthy female controls. DESIGN: Case control study. SETTING: The Sports Medicine Biodynamics Center at Cincinnati Children's Hospital Medical Center. PATIENTS: Fourteen female athletes at a mean of 27 months following ACLR and 18 healthy female athletes participated in the study. ASSESSMENT: All subjects executed a drop vertical jump (DVJ) task onto 2 force plates. Vertical ground reaction force (VGRF) was measured during landing and takeoff and was used to calculate landing phase loading rates. A 2-way analysis of variance was used to determine differences between the involved, uninvolved, and control limbs. RESULTS: Females who had undergone ACLR demonstrated increased VGRF (P = 0.001) and loading rate (P < 0.001) on the uninvolved limb during landing when compared with the involved limb and the control group. During takeoff, the involved limb showed significantly less ability to generate force (P = 0.03) than the uninvolved limb and the control limbs. CONCLUSIONS: Female athletes who have undergone ACLR and returned to sport may continue to demonstrate biomechanical limb asymmetries 2 years or more after reconstruction that can be identified during landing. 相似文献
54.
The behavioral genetics of colony defense in honeybees: Genetic variability for guarding behavior 总被引:3,自引:1,他引:2
Guard honeybees stand at the entrance of colonies and facilitate the exclusion of nonnestmates from the colony. In this study, we examined the hypothesis that genetic variability among individuals in colonies might explain variability in guarding activity. To do this, we cross-fostered honey bees between colonies with high-defensive responses and colonies with low-defensive responses in alarm pheromone tests. Individuals from high-defensive colonies were more likely to guard in their own colonies (controls) than cross-fostered bees from low-defensive colonies. Cross-fostered high-defensive bees also were more likely to guard in low-defense colonies. These results support the hypothesis that interindividual differences in guarding behavior are at least partially under genetic control. A positive correlation between number of guards and response to alarm pheromone demonstrates a link between behaviorally separated components of the overall defensive response.This work was supported by NSF Grant BNS 8605604. 相似文献
55.
The Relationship Between Daily Life Stress and Gastrointestinal Symptoms in Women with Irritable Bowel Syndrome 总被引:3,自引:0,他引:3
Rona L. Levy Kevin C. Cain Monica Jarrett Margaret M. Heitkemper 《Journal of behavioral medicine》1997,20(2):177-193
Research on irritable bowel syndrome (IBS), a functional disorder of the gastrointestinal (GI) system, has linked GI symptoms to stress. This study examined the relationship between daily stress and GI symptoms across women and within woman in IBS patients (n = 26), IBS nonpatients (IBS-NP; n = 23), and controls (n = 26), controlling for menstrual cycle phase. Women (ages 20–45) completed daily health diaries for two cycles in which they monitored daily GI symptoms and stress levels. The Life Event Survey (LES) was used as a retrospective measure of self-reported stress. The across-women analyses showed higher mean GI symptoms and stress in the IBS and IBS-NP groups relative to controls but no group differences in LES scores. The within-woman analyses found a significant and positive relationship between daily stress and daily symptoms in both the IBS-NP and the IBS groups. Controlling for menstrual cycle had no substantial impact on the results. 相似文献
56.
57.
58.
Scott A. Syverud MD J. Matthew Jenkins MD Robert A. Schwab MD Michael T. Lynch MD Kevin Knoop MD Alexander Trott MD 《Academic emergency medicine》1994,1(6):509-513
Objective: Mental nerve block is frequently used to aid repair of facial lacerations; both percutaneous and intraoral approaches to blocking this nerve are used, but have never been compared. The authors compared the two techniques for pain of administration and effectiveness of anesthesia. Methods: A prospective, randomized, single-blind, crossover study was conducted using ten healthy volunteers aged 22 to 33 years. Patients having prior experience with mental nerve blocks, lidocaine allergy, active oral/facial infection, or previous facial fractures were excluded. Bilateral mental nerve blocks were done using intraoral technique on one side and percutaneous technique on the other. Both techniques were used by the same investigator and were carried out with 27-gauge needles and 2.5 mL of 2% buffered lidocaine at room temperature injected over 20 seconds. The oral mucosa was topically anesthetized with viscous lidocaine for 1 minute prior to intraoral injection. The orders of the blocks and sides of the face anesthetized were randomized. Subjective and objective pain (visual-analog scale), efficacy (anesthesia of lower lip), time to onset, and duration of anesthesia were evaluated. Results: The intraoral technique was subjectively less painful than the percutaneous approach in nine of ten subjects (p = 0.02). Scores on the visual-analog pain scale were significantly lower for the intraoral technique (p = 0.03). Intraoral injection produced lower-lip anesthesia in 10/10 subjects versus 7/10 for percutaneous (p = 0.25). Times to onset (approximately 1–2 minutes) and durations of anesthesia (approximately one hour) were similar for the two techniques. Conclusion: The intraoral approach to the mental nerve block with adjunctive topical anesthesia was subjectively and objectively less painful than the percutaneous approach without adjunctive anesthesia. While the intraoral approach had a greater efficacy of lower-lip anesthesia and a longer duration of action, these differences were not statistically significant. 相似文献
59.
60.