全文获取类型
收费全文 | 122685篇 |
免费 | 7811篇 |
国内免费 | 515篇 |
专业分类
耳鼻咽喉 | 1414篇 |
儿科学 | 3107篇 |
妇产科学 | 2446篇 |
基础医学 | 16065篇 |
口腔科学 | 2063篇 |
临床医学 | 12751篇 |
内科学 | 24500篇 |
皮肤病学 | 1922篇 |
神经病学 | 12307篇 |
特种医学 | 5059篇 |
外国民族医学 | 11篇 |
外科学 | 19509篇 |
综合类 | 1253篇 |
一般理论 | 142篇 |
预防医学 | 9712篇 |
眼科学 | 2608篇 |
药学 | 8009篇 |
中国医学 | 163篇 |
肿瘤学 | 7970篇 |
出版年
2023年 | 581篇 |
2022年 | 1060篇 |
2021年 | 2408篇 |
2020年 | 1543篇 |
2019年 | 2391篇 |
2018年 | 2922篇 |
2017年 | 2128篇 |
2016年 | 2399篇 |
2015年 | 2690篇 |
2014年 | 3953篇 |
2013年 | 5335篇 |
2012年 | 8597篇 |
2011年 | 9056篇 |
2010年 | 5158篇 |
2009年 | 4687篇 |
2008年 | 7993篇 |
2007年 | 8399篇 |
2006年 | 8150篇 |
2005年 | 7841篇 |
2004年 | 7586篇 |
2003年 | 6867篇 |
2002年 | 6508篇 |
2001年 | 1625篇 |
2000年 | 1265篇 |
1999年 | 1549篇 |
1998年 | 1487篇 |
1997年 | 1145篇 |
1996年 | 938篇 |
1995年 | 872篇 |
1994年 | 746篇 |
1993年 | 744篇 |
1992年 | 830篇 |
1991年 | 771篇 |
1990年 | 730篇 |
1989年 | 660篇 |
1988年 | 618篇 |
1987年 | 657篇 |
1986年 | 585篇 |
1985年 | 612篇 |
1984年 | 560篇 |
1983年 | 458篇 |
1982年 | 476篇 |
1981年 | 401篇 |
1980年 | 354篇 |
1979年 | 344篇 |
1978年 | 327篇 |
1977年 | 283篇 |
1974年 | 243篇 |
1973年 | 248篇 |
1972年 | 257篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
E. Heidemann J. Weber H. Schmidt U. Reichmann 《Journal of molecular medicine (Berlin, Germany)》1986,64(20):1036-1040
Summary Even though the enhancement of the lyitc capacity and the kinetics of lysis of natural killer cells (NK) by interferon has been well documented, an increase of the target-effector cell binding percentage is still disputed. We, therefore, modified the Grimm-Bonavida single-cell assay so that 400 to 600 cells per individual determination could be reliably evaluated. Using this assay, which makes possible separate determination of effector-target cell binding and target lysis, we demonstrated that, in addition to lytic capacity, target-effector cell binding is also increased by preincubating NK with 100 to 1,000 IU interferon alpha 2 per 106 cells. Our data indicate that interferon alpha 2 induces pre-NK cells to bind target cells and that it activates these pre-NK cells to kill the targets.Abbreviations NK
Natural killer cells
- LCMV
Lymphocytic choriomeningitis virus
- IFN
Interferon
- FCS
Fetal calf serum
- RPMI 1640
Culture medium
Dedicated to Prof. H.D. Waller on the occasion of his 60th birthday 相似文献
992.
An extramedullary plasmocytoma in a right inguinal lymph node was observed in a 62-year-old woman. The tumor showed monoclonal proliferation of plasma cells which revealed highly positive stainings of both IgD and lambda light chain using the PAP-technique. Monoclonal IgD-lambda was also secreted in serum and urine. Clinical data, lymphography and bone biopsy showed a tumor spreading in the right inguinal, left iliacal and lumbar regions without systemic involvement of bone. In contrast to extramedullary plasmocytomas of other immunoglobulin classes the disease progressed rapidly and the patient died 8 months after the onset. The present case is the first reported IgD-plasmocytoma in lymph nodes. 相似文献
993.
Traub RD Contreras D Cunningham MO Murray H LeBeau FE Roopun A Bibbig A Wilent WB Higley MJ Whittington MA 《Journal of neurophysiology》2005,93(4):2194-2232
To better understand population phenomena in thalamocortical neuronal ensembles, we have constructed a preliminary network model with 3,560 multicompartment neurons (containing soma, branching dendrites, and a portion of axon). Types of neurons included superficial pyramids (with regular spiking [RS] and fast rhythmic bursting [FRB] firing behaviors); RS spiny stellates; fast spiking (FS) interneurons, with basket-type and axoaxonic types of connectivity, and located in superficial and deep cortical layers; low threshold spiking (LTS) interneurons, which contacted principal cell dendrites; deep pyramids, which could have RS or intrinsic bursting (IB) firing behaviors, and endowed either with nontufted apical dendrites or with long tufted apical dendrites; thalamocortical relay (TCR) cells; and nucleus reticularis (nRT) cells. To the extent possible, both electrophysiology and synaptic connectivity were based on published data, although many arbitrary choices were necessary. In addition to synaptic connectivity (by AMPA/kainate, NMDA, and GABA(A) receptors), we also included electrical coupling between dendrites of interneurons, nRT cells, and TCR cells, and--in various combinations--electrical coupling between the proximal axons of certain cortical principal neurons. Our network model replicates several observed population phenomena, including 1) persistent gamma oscillations; 2) thalamocortical sleep spindles; 3) series of synchronized population bursts, resembling electrographic seizures; 4) isolated double population bursts with superimposed very fast oscillations (>100 Hz, "VFO"); 5) spike-wave, polyspike-wave, and fast runs (about 10 Hz). We show that epileptiform bursts, including double and multiple bursts, containing VFO occur in rat auditory cortex in vitro, in the presence of kainate, when both GABA(A) and GABA(B) receptors are blocked. Electrical coupling between axons appears necessary (as reported previously) for persistent gamma and additionally plays a role in the detailed shaping of epileptogenic events. The degree of recurrent synaptic excitation between spiny stellate cells, and their tendency to fire throughout multiple bursts, also appears critical in shaping epileptogenic events. 相似文献
994.
Swirski FK Gajewska BU Robbins CS D'Sa A Johnson JR Pouladi MA Inman MD Stämpfli MR 《European journal of immunology》2004,34(9):2375-2386
We previously showed that granulocyte-macrophage colony-stimulating factor (GM-CSF) breaks tolerance induction. The objective of this study was to determine whether GM-CSF breaks established inhalation tolerance. To induce tolerance, BALB/c mice were exposed to aerosolized ovalbumin (OVA) for 10 consecutive days. A control group was exposed to saline. Subsequently, tolerant and control animals were exposed to OVA in a GM-CSF-enriched airway microenvironment. Tolerant animals, unlike control animals, did not develop airway and peripheral blood eosinophilia, had diminished levels of OVA-specific IgE, and reduced airway hyper-responsiveness. While tolerant animals did not express IL-4, IL-5 and IL-13, levels of the regulatory cytokines IL-10, IFN-gamma and transfoming growth factor (TGF)-beta were similar between tolerant and non-tolerant animals. Lung CD4+ T cells were activated according to CD69, CD25 and T1/ST2 expression, but systemic responses characterized by splenocyte proliferation and Th2 effector function were dramatically reduced. Concurrent expression of GM-CSF and decorin, a natural inhibitor of TGF-beta, reversed eosinophilic unresponsiveness. Our study suggests that the breakdown of tolerance and, by extension, the emergence of eosinophilic inflammation, requires two signals: one that triggers sensitization and one that interferes with negative regulation. Moreover, our study shows that dysregulated expression of an extracellular matrix protein may break established tolerance and lead to eosinophilic airway inflammation. 相似文献
995.
996.
997.
Robert E. Nickel De-Ann M. Pillers Mark Merkens R. Ellen Magenis Deborah A. Driscoll Beverly S. Emanuel Jonathan Zonana 《American journal of medical genetics. Part A》1994,52(4):445-449
Approximately 5% of children with neural tube defects (NTDs) have a congenital heart defect and/or cleft lip and palate. The cause of isolated meningomyelocele, congenital heart defects, or cleft lip and palate has been largely thought to be multifactorial. However, chromosomal, teratogenic, and single gene causes of combinations of NTDs with congenital heart defects and/or cleft lip and palate have been reported. We report on 3 patients with meningomyelocele, congenital heart defects, and 22q11 deletions. Two of the children had the clinical diagnosis of velo-cardio-facial syndrome (VCFS); both also have bifid uvula. The third child had DiGeorge sequence (DGS). The association of NTDs with 22q11 deletions has not been reported previously. An accurate diagnosis of the 22q11 deletions is critical as this micro-deletion and its associated clinical problems is transmitted as an autosomal dominant trait due to the inheritance of the deletion-bearing chromosome. We recommend that all children with NTDs and congenital heart defects, with or without cleft palate, have cytogenetic and molecular studies performed to detect 22q11 deletions. © 1994 Wiley-Liss, Inc. 相似文献
998.
Harry S. Spaulding Jr. M.D.COL MC Lyndon E. Mansfield M.D.LTC MC Mark R. Stein M.D. John C. Sellner M.D. Daniel E. Gremillion M.D. 《The Journal of allergy and clinical immunology》1982,69(6):516-521
A double-blind modification of the intraesophageal acid perfusion challenge (Bernstein procedure) was performed in asthmatic subjects with and without gastroesophageal reflux, nonasthmatic subjects with reflux, and normal subjects. Conventional spirometric functions and total respiratory resistance (Rrs) were measured prior to and after the infusion. There were no changes in pulmonary functions except in the asthmatic subjects who had had a positive add challenge. The greatest changes occurred in Rrs, which increased significantly with reflux symptoms (p < 0.01) and decreased toward baseline (p < 0.05) when these symptoms were relieved with antacids. The response was even greater in asthmatic subjects who associated reflux symptoms with attacks of asthma. These results support previous findings that acid reflux symptoms could cause a bronchoconstrictive response in certain asthmatic patients. 相似文献
999.
1000.