全文获取类型
收费全文 | 2374篇 |
免费 | 129篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 31篇 |
儿科学 | 106篇 |
妇产科学 | 35篇 |
基础医学 | 300篇 |
口腔科学 | 144篇 |
临床医学 | 189篇 |
内科学 | 471篇 |
皮肤病学 | 30篇 |
神经病学 | 222篇 |
特种医学 | 46篇 |
外科学 | 452篇 |
综合类 | 43篇 |
一般理论 | 1篇 |
预防医学 | 75篇 |
眼科学 | 32篇 |
药学 | 161篇 |
中国医学 | 15篇 |
肿瘤学 | 156篇 |
出版年
2023年 | 14篇 |
2022年 | 19篇 |
2021年 | 78篇 |
2020年 | 41篇 |
2019年 | 76篇 |
2018年 | 83篇 |
2017年 | 53篇 |
2016年 | 41篇 |
2015年 | 55篇 |
2014年 | 79篇 |
2013年 | 110篇 |
2012年 | 192篇 |
2011年 | 165篇 |
2010年 | 101篇 |
2009年 | 93篇 |
2008年 | 162篇 |
2007年 | 136篇 |
2006年 | 129篇 |
2005年 | 131篇 |
2004年 | 112篇 |
2003年 | 92篇 |
2002年 | 83篇 |
2001年 | 33篇 |
2000年 | 37篇 |
1999年 | 34篇 |
1998年 | 22篇 |
1997年 | 16篇 |
1996年 | 10篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 9篇 |
1992年 | 12篇 |
1991年 | 27篇 |
1990年 | 19篇 |
1989年 | 17篇 |
1988年 | 17篇 |
1987年 | 21篇 |
1986年 | 15篇 |
1985年 | 15篇 |
1984年 | 11篇 |
1983年 | 16篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 7篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1972年 | 10篇 |
1971年 | 7篇 |
1970年 | 7篇 |
排序方式: 共有2509条查询结果,搜索用时 187 毫秒
21.
The traditional association of psammoma bodies with some malignancies of the gynecologic tract raises potentially significant management difficulties when such bodies are identified on routine cervicovaginal smears. This review summarizes the reported cases of psammoma bodies identified on cervicovaginal smears in the world literature (a total of 140 cases, 113 (81%) of which had sufficient clinicopathologic information). Our conclusions are as follows: (1) The finding of psammoma bodies in this setting is distinctly unusual with an incidence of less than 0.001% on consecutively screened smears. (2) On consecutively screened smears, patients with psammoma bodies have an associated malignancy or ovarian borderline tumor 0-22.7% of the time, depending on the series; this figure climbs to 38% when all the case reports and small series in the literature are included. (3) The most reliable predictor of a malignancy in these patients is the finding of cells on the smear that by themselves are diagnostic of malignancy on cytologic grounds. (4) Other factors that, on a purely statistical basis, appear to increase the likelihood of a synchronous or metachronous malignancy or borderline tumor include an older age at diagnosis and/or clinical presentations such as postmenopausal bleeding. (5) When 1 or more psammoma bodies are identified on a cervicovaginal smear, this finding should not be ignored and should generate some clinical investigation to identify its source. 相似文献
22.
N. Forss R. Hari R. Salmelin A. Ahonen M. Hämäläinen M. Kajola J. Knuutila J. Simola 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1994,99(2):309-315
We recorded somatosensory evoked magnetic fields from ten healthy, right-handed subjects with a 122-channel whole-scalp SQUID magnetometer. The stimuli, exceeding the motor threshold, were delivered alternately to the left and right median nerves at the wrists, with interstimulus intervals of 1, 3, and 5 s. The first responses, peaking around 20 and 35 ms, were explained by activation of the contralateral primary somatosensory cortex (SI) hand area. All subjects showed additional deflections which peaked after 85 ms; the source locations agreed with the sites of the secondary somatosensory cortices (SII) in both hemispheres. The SII responses were typically stronger in the left than the right hemisphere. All subjects had an additional source, not previously reported in human evoked response data, in the contralateral parietal cortex. This source was posterior and medial to the SI hand area, and evidently in the wall of the postcentral sulcus. It was most active at 70–110 ms. 相似文献
23.
Malignancies in the acquired immunodeficiency syndrome 总被引:1,自引:0,他引:1
Alexandra M. Levine M.D. Parkash S. Gill M.D. Franco Muggia M.D. 《Current problems in cancer》1987,11(4):209-255
Aside from opportunistic infections, several neoplasms have been identified as part of the spectrum of acquired immunodeficiency syndrome (AIDS) as defined by the Centers for Disease Control. Kaposi's sarcoma (KS) was the first such neoplasm to be recognized within the spectrum of AIDS. Although the classic form of Kaposi's sarcoma had been well recognized prior to the epidemic of AIDS, it was quite distinct from the illness that was seen in its "epidemic" form in young homosexual males. In this setting, Kaposi's sarcoma is an aggressive disease, with extensive involvement of skin and mucous membranes, early dissemination to lymph nodes, impressive development of extreme lymphedema, even in the absence of bulky adenopathy, and rapid spread to visceral organs, including lungs and gastrointestinal tract, among others. Although rapid clinical progression and short median survival have been the rule, a spectrum of disease has been seen such that some patients have survived for many years with disease limited to the skin. Certain clinical and laboratory features, such as presence of unexplained fever, night sweats, weight loss ("B" symptoms), or significant T-4-lymphocytopenia, have been identified as indicators of poor prognosis. Various therapeutic interventions have been employed in epidemic KS, and although partial and complete remissions have occurred, no regimen yet reported has significantly improved the survival of treated patients. High-dose recombinant alpha interferon has produced response rates in approximately 30% of treated patients, although toxicity has been observed in approximately 30% as well. Likewise, vinblastine has produced similar response rates with no evidence of long-term efficacy or "cure." Aside from Kaposi's sarcoma, lymphoma primary to the central nervous system was recognized early in the AIDS epidemic as a criterion for inclusion within AIDS in patients less than sixty years of age. Several years after the initial reports of disease, it became apparent that specific types of systemic lymphoma were also quite extraordinary, and the definition of AIDS was amended in June 1985 to include high-grade B-cell lymphomas in individuals who had positive serology or virology for the human immunodeficiency virus (HIV). The AIDS-related lymphomas are characteristic, both pathologically and clinically. The vast majority of these cases have been high-grade B-lymphoid tumors of either immunoblastic or small-non-cleaved type (also known as "undifferentiated," Burkitt, or Burkitt-like).(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
24.
Danka Peričié Hari Manev Sonja Levanat Branimi Jernej Dunja Vujić Nebojša Djordjević 《Psychopharmacology》1986,90(1):112-118
Acute (50.0 mg/kg) and repeated (0.1–10.0 mg/kg) administration of dihydroergosine (DHESN) to rats over 5 days lowered the concentration of 5-HIAA in the brain. DHESN given acutely increased the brain 5-HT in p-CPA-treated animals and diminished the probenecid-induced increase in brain 5-HIAA. In pargyline-treated rats DHESN enhanced the 5-HT/5-HIAA ratio. DHESN administered to rats repeatedly over 5 days decreased the level of 5-HT in blood platelets, and in vitro at concentrations of 10-4 M and 10-3 M inhibited the uptake of [14C]-5-HT in platelets. DHESN (10.0–100.0 mg/kg) potentiated the 5-HT syndrome produced in rats by pargyline and 5-HTP. This potentiation was blocked with cyproheptadine but not with haloperidol. DHESN (1.0 and 10.0 mg/kg) lowered the locomotor activity of rats and 10.0 mg/kg DHESN also reduced the duration of immobility in rats forced to swim in a restricted space. The results indicate that DHESN, like antidepressants, decreases the turnover of serotonin in the brain and potentiates the 5-HT-mediated behaviour. This might suggest that the drug should be further investigated for its potential antidepressive properties. 相似文献
25.
Matthew S. Austin Blair S. Ashley Nicholas A. Bedard Hari P. Bezwada Charles P. Hannon Yale A. Fillingham Yogesh V. Kolwadkar Harold W. Rees Matthew J. Grosso Erik N. Zeegen 《The Journal of arthroplasty》2021,36(8):2665-2673.e8
BackgroundThe prevalence of total joint arthroplasty (TJA) in the United States has drawn the attention of health care stakeholders. The payers have also used a variety of strategies to regulate the medical necessity of these procedures. The purpose of this study was to examine the level of evidence of the coverage policies being used by commercial payers in the United States.MethodsThe references of the coverage policies of four commercial insurance companies were reviewed for type of document, level of evidence, applicability to a TJA population, and success of nonoperative treatment in patients with severe degenerative joint disease.Results282 documents were reviewed. 45.8% were primary journal articles, 14.2% were level I or II, 41.2% were applicable to patients who were candidates for TJA, and 9.9% discussed the success of nonoperative treatment in patients who would be candidates for TJA.ConclusionMost of the references cited by commercial payers are of a lower level of scientific evidence and not applicable to patients considered to be candidates for TJA. This is relatively uniform across the reviewed payers. The dearth of high-quality literature cited by commercial payers reflects the lack of evidence and difficulty in conducting high level studies on the outcomes of nonoperative versus operative treatment for patients with severe, symptomatic osteoarthritis. Patients, surgeons, and payers would all benefit from such studies and we encourage professional societies to strive toward that end through multicenter collaboration. 相似文献
26.
27.
Camille G. Apple Elizabeth S. Miller Kolenkode B. Kannan Julie A. Stortz Tyler J. Loftus Maria Cecilia Lopez Hari K. Parvataneni Matthew Patrick Jennifer E. Hagen Henry V. Baker Philip A. Efron Alicia M. Mohr 《Surgery》2021,169(5):1206-1212
BackgroundPrevious data has shown that severe traumatic injury is associated with bone marrow dysfunction, which manifests as persistent injury-associated anemia. This study sought to identify whether the expression of erythropoiesis-related microRNAs were altered in the bone marrow of trauma patients to determine if these microRNAs play a role in persistent injury-associated anemia.MethodsBone marrow was collected from severely injured trauma patients who underwent fracture fixation as well as patients who underwent elective hip replacement. There were 27 trauma patients and 10 controls analyzed. Total RNA and microRNA were isolated from CD34-positive cells using the RNeasy Plus Mini kit, and genome-wide microRNA expression patterns were assayed. Genes with significant expression differences were found using BRB-ArrayTools with a significance of P < .01.ResultsThere were marked differences in expression of 108 microRNAs in the trauma group when compared with hip replacement patients. Four of these microRNAs play a role in regulating erythropoiesis: microRNA-150, microRNA-223, microRNA15a, and microRNA-24. These microRNAs were all upregulated significantly, with trauma/hip replacement fold changes of 1.7, 1.8, 1.2, and 1.2 respectively, and all act to suppress or regulate erythropoiesis.ConclusionAssessment of the bone marrow microRNA profile in trauma patients compared to those undergoing elective hip replacement revealed the differential expression of microRNA-150, microRNA-223, microRNA-15a, and microRNA-24. These microRNAs all play a role in decreased erythroid progenitor cell growth and provide important insight to the erythropoietic dysfunction seen after trauma. 相似文献
28.
Recent non-invasive human studies show that rhythmic oscillatory activity of the motor cortex and the firing of motor units of the muscle are coherent during isometric contraction, with peak frequencies around 20 Hz or 40 Hz, depending on the contraction strength. The cortical signals precede the motor unit firing and appear to reflect modulation of the common central drive to the spinal motoneuron pool. The rhythmic modulation may form a tool for efficient driving of motor units but we express some reservations about the assumed binding and attention-related roles of the rolandic brain rhythms. The cortex-muscle coherence is of interest for understanding of cortical control of voluntary movements and the pathophysiology of various motor disorders, as well as for unravelling the functional significance of cortical rhythms. 相似文献
29.
Sari Levänen Riitta Hari Linda McEvoy Mikko Sams 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1993,97(1):177-183
Neuromagnetic responses were recorded with a 24 SQUID magnetometer in two oddball experiments to determine whether mismatch responses to changes in single stimulus features are additive. In experiment 1, the one feature deviants differed from standards in interstimulus interval (ISI) or frequency, and the two feature deviants in both ISI and frequence. In experiment 2, deviants differed in duration, frequency, or both. All deviants evoked a mismatch field (MMF) with sources close to each other in the supratemporal auditory cortex. Except for the ISI deviants, the MMF sources were about 1 cm anterior to the source of the 100ms response, N100m, to the standards. In the two experiments, MMFs obtained in response to the two feature deviants resembled closely the sum of MMFs in response to one feature deviants. The results suggest that the standards leave a multiple neuronal representation in the human auditory cortex. The particular neuronal traces of the representation react independently to changes in different features of sound stimuli. 相似文献
30.
Kamel Sadat M.D. Hari Prakash Diddi M.B.B.S. Berthold Klas B.S. Ayman Haj Asaad M.D. Elif İjlal Çekirdekçi M.D. Aylin Sungur M.D. Selvin Sudhakar M.D. Matthew Cain M.D. Arshad Kamal M.D. Navin C. Nanda M.D. 《Echocardiography (Mount Kisco, N.Y.)》2013,30(10):1227-1231
Hypertrophic cardiomyopathy (HCM) is the most common genetically transmitted cardiomyopathy. In patients resistant to medical management, myectomy is the surgical procedure of choice to reduce the symptoms of left ventricular outflow obstruction. Two‐dimensional transesophageal echocardiography (2DTEE) has become part of the operative procedure by decreasing the incidence of postoperative complications. However, because of the three‐dimensional geometry of left ventricular outflow tract, it is unable to comprehensively assess the location and severity of the obstruction and to provide accurate guidance during myectomy. In this study, 10 patients with HCM underwent live/real time three‐dimensional transesophageal echocardiography (3DTEE) intra‐operatively to measure the volume of the resected septum. This volume correlated well with the volume of the resected septal muscle directly obtained using a graduating cylinder containing water (r = 0.9, P < 0.000). 3DTEE may be potentially used as an adjunct to guide the surgeon in performing an adequate myectomy with a lower incidence of residual obstruction and complications such as an iatrogenic ventricular septal defect. 相似文献