全文获取类型
收费全文 | 5268篇 |
免费 | 359篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 171篇 |
儿科学 | 89篇 |
妇产科学 | 92篇 |
基础医学 | 731篇 |
口腔科学 | 246篇 |
临床医学 | 489篇 |
内科学 | 1012篇 |
皮肤病学 | 75篇 |
神经病学 | 535篇 |
特种医学 | 210篇 |
外科学 | 703篇 |
综合类 | 21篇 |
一般理论 | 3篇 |
预防医学 | 442篇 |
眼科学 | 175篇 |
药学 | 280篇 |
中国医学 | 7篇 |
肿瘤学 | 352篇 |
出版年
2023年 | 51篇 |
2022年 | 39篇 |
2021年 | 77篇 |
2020年 | 74篇 |
2019年 | 118篇 |
2018年 | 114篇 |
2017年 | 102篇 |
2016年 | 85篇 |
2015年 | 93篇 |
2014年 | 115篇 |
2013年 | 185篇 |
2012年 | 267篇 |
2011年 | 255篇 |
2010年 | 145篇 |
2009年 | 152篇 |
2008年 | 256篇 |
2007年 | 234篇 |
2006年 | 213篇 |
2005年 | 230篇 |
2004年 | 208篇 |
2003年 | 170篇 |
2002年 | 162篇 |
2001年 | 182篇 |
2000年 | 163篇 |
1999年 | 125篇 |
1998年 | 58篇 |
1997年 | 42篇 |
1996年 | 51篇 |
1995年 | 43篇 |
1994年 | 38篇 |
1993年 | 38篇 |
1992年 | 93篇 |
1991年 | 103篇 |
1990年 | 121篇 |
1989年 | 104篇 |
1988年 | 70篇 |
1987年 | 91篇 |
1986年 | 81篇 |
1985年 | 66篇 |
1984年 | 67篇 |
1983年 | 48篇 |
1982年 | 43篇 |
1980年 | 35篇 |
1979年 | 64篇 |
1978年 | 42篇 |
1977年 | 33篇 |
1975年 | 39篇 |
1974年 | 39篇 |
1973年 | 35篇 |
1970年 | 38篇 |
排序方式: 共有5633条查询结果,搜索用时 15 毫秒
81.
Tanvir S Sian Ushnah S. U. Din Colleen S. Deane Ken Smith Amanda Gates Jonathan N. Lund John P. Williams Ricardo Rueda Suzette L. Pereira Bethan E. Phillips Philip J. Atherton 《Nutrients》2021,13(5)
Ageing is associated with postprandial muscle vascular and metabolic dysfunction, suggesting vascular modifying interventions may be of benefit. Reflecting this, we investigated the impact of acute cocoa flavanol (450–500 mg) intake (versus placebo control) on vascular (via ultrasound) and glucose/insulin metabolic responses (via arterialised/venous blood samples and ELISA) to an oral nutritional supplement (ONS) in twelve healthy older adults (50% male, 72 ± 4 years), in a crossover design study. The cocoa condition displayed significant increases in m. vastus lateralis microvascular blood volume (MBV) in response to feeding at 180 and 240-min after ONS consumption (baseline: 1.00 vs. 180 min: 1.09 ± 0.03, p = 0.05; 240 min: 1.13 ± 0.04, p = 0.002), with MBV at these timepoints significantly higher than in the control condition (p < 0.05). In addition, there was a trend (p = 0.058) for MBV in m. tibialis anterior to increase in response to ONS in the cocoa condition only. Leg blood flow and vascular conductance increased, and vascular resistance decreased in response to ONS (p < 0.05), but these responses were not different between conditions (p > 0.05). Similarly, glucose uptake and insulin increased in response to ONS (p < 0.05) comparably between conditions (p > 0.05). Thus, acute cocoa flavanol supplementation can potentiate oral feeding-induced increases in MBV in older adults, but this improvement does not relay to muscle glucose uptake. 相似文献
82.
83.
Nathan Perlis Antonio Finelli Mike Lovas Alejandro Berlin Janet Papadakos Sangeet Ghai Vasiliki Bakas Shabbir Alibhai Odelia Lee Adam Badzynski David Wiljer Alexis Lund Amelia Di Meo Joseph Cafazzo Masoom Haider 《Canadian Urological Association journal》2021,15(4):108
IntroductionAs we progress to an era when patient autonomy and shared decision-making are highly valued, there is a need to also have effective patient-centered communication tools. Radiology reports are designed for clinicians and can be very technical and difficult for patients to understand. It is important for patients to understand their magnetic resonance imaging (MRI) report in order to make an informed treatment decision with their physician. Therefore, we aimed to create a patient-centered prostate MRI report to give our patients a better understanding of their clinical condition.MethodsA prototype patient-centered radiology report (PACERR) was created by identifying items to include based on opinions sought from a group of patients undergoing prostate MRI and medical experts. Data was collected in semi-structured interviews using a salient belief question. A prototype PACERR was created in collaboration with human factors engineering and design, medical imaging, biomedical informatics, and cancer patient education groups.ResultsFifteen patients and eight experts from urology, radiation oncology, radiology, and nursing participated in this study. Patients were particularly interested to have a report with laymen terms, concise language, contextualization of values, definitions of medical terms, and next course of action. Everyone believed the report should include the risk of MRI findings actually being cancer in the subsequent biopsy.ConclusionsA prostate MRI PACERR has been developed to communicate the most important findings relevant to decision-making in prostate cancer using patient-oriented design principles. The ability of this tool to improve patient knowledge and communication will be explored. 相似文献
84.
Devices for the diagnosis and treatment of temporomandibular disorders. Part I: Introduction, scientific evidence, and jaw tracking 总被引:2,自引:0,他引:2
This three-part series of articles summarizes the uses of several devices or groups of devices intended for the diagnosis or treatment of temporomandibular disorders (TMD) and compares their claimed clinical usefulness with the present scientific evidence. Part I of this review defines TMD; discusses the principal criteria for evaluating published scientific clinical evidence such as reliability, validity, sensitivity, and specificity; gives a rationale for the clinical "gold standard" against which diagnostic and therapeutic devices must be compared; and evaluates the status of jaw tracking for the diagnosis of TMD. This review and evaluation led to the conclusion that, at the present time, the claim that jaw-tracking devices have a diagnostic value for TMD is not well supported by the scientific evidence. 相似文献
85.
Comparison of Intrinsic Connectivity in Different Areas of Macaque Monkey Cerebral Cortex 总被引:18,自引:13,他引:5
Lund Jennifer S.; Yoshioka Takashi; Levitt Jonathan B. 《Cerebral cortex (New York, N.Y. : 1991)》1993,3(2):148-162
We have used small injections of biocytin to label and comparepatterns of intreareal, laterally spreading projections of pyramidalneurons in a number of areas of macaque monkey cerebral cortex.In visual areas (V1, V2, and V4), somatosensory areas (3b, 1,and 2), and motor area 4, a punctate discontinuous pattern ofconnections is made from 200-µm-diameter biocytin injectionsin the superficial layers. In prefrontal cortex (areas 9 and46), stripe-like connectivity patterns are observed. In allareas of cortex examined, the width of the terminal-free gapsis closely scaled to the average diameter of terminal patches,or width of terminal stripes. In addition, both patch and gapdimensions match the average lateral spread of the dendriticfield of single pyramidal neurons in the superficial layersof the same cortical region. These architectural features ofthe connectional mosaics are constant despite a twofold differencein scale across cortical areas and different species. They thereforeappear to be fundamental features of cortical organization.A model is offered in which local circuit inhibitory "basket"interneurons, activated at the same time as excitatory pyramidalneurons, could veto pyramidal neuron connections within eithercircular or stripe-like domains; this could lead to the formationof the pattern of lateral connections observed in this study,and provides a framework for further theoretical studies ofcerebral cortex function. 相似文献
86.
S. Gundersen S. Kvinnsland S. Lundgren O. Klepp E. Lund O. Børmer H. Høst 《Breast cancer research and treatment》1990,17(1):45-50
Summary One-hundred and seventy patients with estrogen receptor positive (10 pmol/g protein) advanced breast cancer have been treated in a prospective randomized study either with continuous tamoxifen 30 mg × 1 daily (TAM), or with TAM 30 mg × 1 daily for 8 weeks alternating with medroxyprogesterone acetate 500 mg × 2 daily for 8 weeks (TAM/HD-MPA). The response rate was 62% in the group treated with cyclic TAM/HD-MPA versus 41% in the TAM alone group (p = 0.02). There was no significant difference in duration of remissions or survival. 相似文献
87.
A retrospective clinicopathological study of 37 patients with chordoma: a danish national series 总被引:1,自引:0,他引:1 下载免费PDF全文
Purpose. There are, in general, few published series on chordoma. It is a rare disease and further data are still needed.Patients/methods. The data of 37 patients with chordoma were retrospectively analyzed. Treatment was surgical excision in 11, radical radiotherapy in 9 and a combination of the two in 16 cases. The male to female ratio was 2.7 : 1. Median age was 59 years (range 1-89 years).Results. The most common symptoms at diagnosis were pain (98%), neurological disturbances (42%) and incontinence (33%). The tumours were located in the sacro-coccygeal region in 68%, the spheno-occipital region in 16% and the vertebrae in 16% of the patients. Median tumour.size was 7 cm (range 1-30 cm). Local recurrence occurred in 21/36 treated cases and distant metastases developed in eight patients (23%). The median time to recurrence/progression after primary treatment was 2 years (range 1-10 years). The actuarial 5-year rates of overall, progression-free and symptom-free survival were 40%, 31% and 20%, respectively. The corresponding 10-year rates were 26%, 21% and 14%, respectively. At the time of analysis, seven patients were alive, six without evidence of disease. Four of the six patients without active disease were symptom free. A univariate analysis showed that age, sex, tumour size, histopathology, surgical safety margin, treatment modality and radiation dose did not significantly affect overall, progression-free or symptom-free survival. Only turnout site had a prognostic value with turnouts in the spheno-occipital region carrying the worst prognosis.Discussion. We conclude that effective treatment against chordomas is still lacking and a prospective multi-institutional registration study may provide more information on the optimal work-up and treatment of this rare disease. 相似文献
88.
The effects of caffeine on cytoplasmic Ca2+ oscillations induced by carbachol and guanosine 5-O-(3-thiotriphosphate) (GTP--S) were studied in individual mouse pancreatic ß-cells clamped at a hyperpolarized potential. Addition of 10 mM caffeine did not affect the cytoplasmic Ca2+ concentration ([Ca2+]1) in ß-cells exposed to 20 mM glucose and hyperpolarized with diazoxide. Under similar conditions 100 M carbachol induced a typical response with a marked [Ca2+]i peak followed by a lower sustained elevation. Irrespective of whether 10 mM caffeine was present, there were [Ca2+]i transients with frequencies of 1–5/min superimposed on the sustained phase in 50–60% of the cells. In previously non-exposed cells the introduction of 10 mM caffeine caused temporary lowering of the sustained phase with disappearance of the transients. Subsequent omission of caffeine in the continued presence of carbachol caused a marked [Ca2+]i peak followed by reappearance of the [Ca2+]i, transients. However, in cells oscillating in the presence of caffeine its omission caused disappearance of the transients. In this case reintroduction of caffeine restored the transients.In cells kept at –70 mV by a patch pipette containing 100 M GTP--S and 3 mM Mg-ATP there were [Ca2+]i transients with frequencies of 0.5–2.5/min. These transients were sufficiently pronounced to activate repetitively a K+ current. Addition of 10 mM caffeine caused disappearance of the [Ca2+]i transients or reduction of their amplitudes and frequencies.The results indicate that caffeine does not activate Ca2+-induced Ca2+ release in hyperpolarized ß-cells but inhibits the Ca2+-mobilizing effect of inositol 1,4,5-trisphosphate.
Correspondence to: E. Gylfe at the above address 相似文献
89.
90.
Barton JK Hammer DX Pfefer TJ Lund DJ Stuck BE Welch AJ 《Lasers in surgery and medicine》1999,24(3):236-243
BACKGROUND AND OBJECTIVE: Simultaneous irradiation and viewing of 10-120 microm cutaneous blood vessels were performed to investigate the effects of 2-micros 577-nm dye laser pulses. STUDY DESIGN/MATERIALS AND METHODS: A modified scanning laser confocal microscope recorded vessel response to different radiant exposures (J/cm2). Probit analysis determined the 50% probability ("threshold") radiant exposure necessary to cause embolized or partly occluding coagula, coagula causing complete blood flow stoppage, and hemorrhage. RESULTS: A statistically significant difference in the threshold radiant exposure existed for each damage category for blood vessels 10-30 microm in diameter, but not for larger vessels. For vessels over 60 microm, complete flow stoppage was unattainable; increasing laser pulse energy produced hemorrhage. In larger vessels, coagula often were attached to the superficial vessel wall while blood flowed underneath. Monte Carlo optical and finite difference thermal modeling confirmed experimental results. CONCLUSION: These results provide insight into the role of pulse duration and vessel diameter in the outcome of pulsed dye laser irradiation. 相似文献