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   705篇
  免费   33篇
  国内免费   2篇
耳鼻咽喉   2篇
儿科学   36篇
妇产科学   12篇
基础医学   62篇
口腔科学   6篇
临床医学   56篇
内科学   93篇
皮肤病学   1篇
神经病学   120篇
特种医学   63篇
外科学   71篇
综合类   8篇
预防医学   82篇
眼科学   7篇
药学   38篇
中国医学   2篇
肿瘤学   81篇
  2022年   3篇
  2021年   4篇
  2020年   5篇
  2019年   7篇
  2018年   9篇
  2017年   7篇
  2016年   12篇
  2015年   13篇
  2014年   14篇
  2013年   16篇
  2012年   36篇
  2011年   36篇
  2010年   16篇
  2009年   37篇
  2008年   25篇
  2007年   40篇
  2006年   35篇
  2005年   29篇
  2004年   37篇
  2003年   25篇
  2002年   22篇
  2001年   21篇
  2000年   28篇
  1999年   25篇
  1998年   6篇
  1997年   5篇
  1996年   5篇
  1995年   3篇
  1994年   4篇
  1993年   3篇
  1992年   21篇
  1991年   19篇
  1990年   21篇
  1989年   19篇
  1988年   19篇
  1987年   13篇
  1986年   16篇
  1985年   15篇
  1984年   8篇
  1983年   4篇
  1982年   7篇
  1981年   6篇
  1979年   7篇
  1978年   3篇
  1977年   3篇
  1974年   4篇
  1973年   3篇
  1972年   4篇
  1970年   4篇
  1965年   2篇
排序方式: 共有740条查询结果,搜索用时 46 毫秒
1.
A reduction of natural killer (NK) cell activity has been found in hospitalized patients with major depressive disorder. To examine whether a reduction of NK activity is found in other psychiatric patients or related to the nonspecific effects of hospitalization, NK cell cytotoxicity was compared in hospitalized depressed patients, schizophrenic inpatients, and two groups of controls separately age matched to each patient group. NK activity was significantly (p less than 0.01) lower in depressed inpatients than control subjects. However, in the hospitalized schizophrenic patients values of natural cytotoxicity did not differ from controls. These findings suggest that reduced NK cytotoxicity in depression is independent of the effects of hospitalization.  相似文献   
2.
An institution-wide program for residents impaired by alcohol, other drugs, or emotional problems was established in 1983 at the Medical College of Wisconsin Affiliated Hospitals. The goal of the program was to help impaired house staff members to continue their training in a nonpunitive environment. An approach to reviewing allegations of impairment and a legal agreement between the hospital and the recovering resident were implemented. Because no residents were reported for impairment during its first two years, the program's emphasis was shifted from an investigative to an educational, assistive role. Major problems in carrying out the program have been the program's lack of authority to ensure cooperation by program directors and by impaired residents; a widespread unfamiliarity with intervention procedures despite efforts to inform residents, their spouses, faculty members, and administrators about the program; and misconceptions that the program is punitive. Further impediments are lack of a budget to provide educational activities, inadequate socializing between the faculty and the house staff that would enable faculty members to recognize early signs of impairment; and inadequate health insurance coverage for long-term treatment.  相似文献   
3.
It has been known for some time that patients with Parkinson's disease (PD) have difficulty executing simultaneous motor acts, yet the pathophysiology underlying this impairment remains uncertain. We examined the possibility that these dual-task deficits stem from defective sensorimotor mechanisms producing interference between the motor programs underlying the two tasks. Patients with PD and normal control subjects were tested on their ability to maintain steady-state force with one hand while performing a force-reaction time task with the other hand. Although performance was worse on the dual-task than on the single-task condition for both subject groups, only the patients with PD demonstrated significant interference between the two tasks. The interference across tasks improved in 87% of the patients with PD when tested after treatment with carbidopa/levodopa (Sinemet). These findings support the contention that, in patients with PD, disturbances in the execution of simultaneous motor performance may be due to sensorimotor disinhibition.  相似文献   
4.
BACKGROUND: During the last 2 decades, cytokines such as interferons (IFN) have been used to modulate tumor response in radiotherapy. Initially, the focus was on antiviral and radiosensitizing effects of interferons but increasingly, the function of interferons and interleukins (IL) within the immune response to tumor cells is becoming important. METHOD: The cellular immune response toward tumor cells is reviewed. The role of cytokines in antigen presentation and activation of effector cells and their interactions with radiation are described. Preclinical strategies of the antitumor action of cytokines are presented and discussed based on the induction of IFN-gamma by IL-12. RESULTS: Recent advances in immunology have demonstrated the importance of local interactions between antigen-presenting cells (APC) and effector cells such as natural killer (NK) cells and T-lymphocytes for an effective immune reaction against tumors. Interferons stimulate such interactions, while IL-2 plays a central role in the activation of NK cells and T-lymphocytes. The interactions between APC and effector cells are suppressed by many tumors but can be stimulated by irradiation. Since systemic application of interferons is quite toxic, present strategies aim at local expression, e. g., the induction of IFN-gamma expression in Th1 cells by IL-12. CONCLUSION: The improved understanding of immunologic mechanisms has emphasized the role of the cytokine network in the interaction between tumor cells and effector cells such as NK cells and T-lymphocytes. This opens new possibilities for the application of cytokines as biological response modifiers, which may eventually help widening the therapeutic window in radiotherapy.  相似文献   
5.
Eleven "pure" borderlines, ten borderlines with depression, 16 "pure" depressives, and 31 normal subjects were compared on a number of standardized inventories of anxiety. While patient groups experienced more anxiety of all types than did normals, borderlines did not emerge as more anxious than other patient groups. Qualitative differences in the anxiety experienced by borderlines and nonborderlines are discussed.  相似文献   
6.
Differences among hospitals in Medicare patient mortality.   总被引:8,自引:3,他引:5       下载免费PDF全文
Using hospital discharge abstract data for fiscal year 1984 for all acute care hospitals treating Medicare patients (age greater than or equal to 65), we measured four mortality rates: inpatient deaths, deaths within 30 days after discharge, and deaths within two fixed periods following admission (30 days, and the 95th percentile length of stay for each condition). The metric of interest was the probability that a hospital would have as many deaths as it did (taking age, race, and sex into account). Differences among hospitals in inpatient death rates were large and significant (p less than .05) for 22 of 48 specific conditions studied and for all conditions together; among these 22 "high-variation" conditions, medical conditions accounted for far more deaths than did surgical conditions. We compared pairs of conditions in terms of hospital rankings by probability of observed numbers of inpatient deaths; we found relatively low correlations (Spearman correlation coefficients of 0.3 or lower) for most comparisons except between a few surgical conditions. When we compared different pairs of the four death measures on their rankings of hospitals by probabilities of the observed numbers of deaths, the correlations were moderate to high (Spearman correlation coefficients of 0.54 to 0.99). Hospitals with low probabilities of the number of observed deaths were not distributed randomly geographically; a small number of states had significantly more than their share of these hospitals (p less than .01). Information from hospital discharge abstract data is insufficient to determine the extent to which differences in severity of illness or quality of care account for this marked variability, so data on hospital death rates cannot now be used to draw inferences about quality of care. The magnitude of variability in death rates and the geographic clustering of facilities with low probabilities, however, both argue for further study of hospital death rates. These data may prove most useful as a screening mechanism to identify patterns of potentially poor quality of care. Careful choice of the mortality measure used is needed, however, to maximize the probability of identifying those hospitals, and only those hospitals, warranting more in-depth review.  相似文献   
7.
Drs. Jackson and Lohr review such skeletal injuries as fractures, dislocations and subluxations, cervical disk herniation, degenerative disks, and "stingers." Cervical strains and sprains are also discussed, and evaluation of cervical injuries and immobilization and transportation of the injured player are other topics covered.  相似文献   
8.
The mutation in the hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene has been determined in two brothers affected with Lesch-Nyhan syndrome. Female members of the family who are at risk for being heterozygous carriers of the HPRT mutation were also studied to determine whether they carry the mutation. DNA sequencing revealed that the boys' mother is heterozygous for the mutation in her somatic cells, but that three maternal aunts are not heterozygous. Such carrier information is important for the future pregnancy plans of at-risk females. The mutation, an A-->T transversion at cDNA base 590 (590A-->T), results in an amino acid change of glutamic acid to valine at codon 197, and has not been reported previously in a Lesch-Nyhan syndrome male. This mutation is designated HPRTBrasil.  相似文献   
9.
The giant glial cell in the central nervous system of the leech Hirudo medicinalis has been the subject of a series of studies trying to link its physiological properties with its role in neuron-glia interactions. Isolated ventral cord ganglia of this annelid offer several advantages for these studies. First, single giant glial cells can easily be identified and are quite accessible to electrophysiological and microfluorometric studies. Second, only two giant macroglial cells are located in the neuropil of each ganglion, rendering them well suited for studying neuron-glia interactions. Third, many neurons can be identified and are well known with respect to their physiology and their roles in controlling simple behaviors in the leech. This review briefly outlines the major recent findings gained by studying this preparation and its contributions to our knowledge of the functional role of glia in nervous systems. Emphasis is directed to glial responses during neuronal activity and to the analysis of intracellular Ca(2+) and H(+) transients mediated by neurotransmitter receptors and ion-driven carriers. Among its numerous properties, the leech giant glial cell prominently expresses a large K(+) conductance, voltage-dependent Ca(2+) channels, ionotropic non-NMDA glutamate receptors, and an electrogenic, reversible Na(+)-HCO(3)(-) cotransporter.  相似文献   
10.
OBJECTIVE: The study compared the demographic and diagnostic characteristics of clients and the outcomes of treatment in five short-term acute residential treatment programs and two acute hospital-based psychiatric programs. METHODS: A total of 368 clients in the short-term acute residential treatment programs and 186 clients in the psychiatric hospital programs participated in an observational study. The study used a repeated-measures design and assessed participants on multiple standardized measures of symptoms and functioning at admission, discharge, and four-month follow-up. Comparisons between the two groups were conducted separately by diagnostic category. Measures included the Brief Symptom Inventory, the Behavior and Symptom Identification Scale-32, the Medical Outcomes Short-Form-36, and the Client Satisfaction Questionnaire-8. RESULTS: The two types of programs admit persons with similar levels of acute distress who have comparable levels of improvement at discharge and an equivalent degree of short-term stability of treatment gains. Costs of treatment episodes were considerably lower for the short-term residential programs, and client satisfaction with the two types of programs was comparable. CONCLUSIONS: Short-term acute residential treatment is a less costly yet similarly effective alternative to psychiatric hospitalization for many voluntary adult patients.  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