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   20912篇
  免费   1542篇
  国内免费   86篇
耳鼻咽喉   204篇
儿科学   793篇
妇产科学   487篇
基础医学   2644篇
口腔科学   271篇
临床医学   2760篇
内科学   4068篇
皮肤病学   507篇
神经病学   2031篇
特种医学   532篇
外科学   2377篇
综合类   436篇
一般理论   13篇
预防医学   2105篇
眼科学   362篇
药学   1183篇
中国医学   15篇
肿瘤学   1752篇
  2022年   124篇
  2021年   238篇
  2020年   178篇
  2019年   284篇
  2018年   333篇
  2017年   272篇
  2016年   282篇
  2015年   321篇
  2014年   462篇
  2013年   729篇
  2012年   1012篇
  2011年   1101篇
  2010年   602篇
  2009年   583篇
  2008年   1045篇
  2007年   1098篇
  2006年   1080篇
  2005年   1122篇
  2004年   1001篇
  2003年   1029篇
  2002年   988篇
  2001年   539篇
  2000年   569篇
  1999年   496篇
  1998年   269篇
  1997年   233篇
  1996年   174篇
  1995年   179篇
  1994年   165篇
  1993年   142篇
  1992年   391篇
  1991年   393篇
  1990年   395篇
  1989年   381篇
  1988年   297篇
  1987年   328篇
  1986年   323篇
  1985年   326篇
  1984年   233篇
  1983年   261篇
  1982年   147篇
  1980年   121篇
  1979年   217篇
  1978年   157篇
  1977年   139篇
  1976年   159篇
  1975年   141篇
  1974年   152篇
  1973年   148篇
  1970年   124篇
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
81.
An HIV-1/hepatitis C virus (HCV) co-infected patient with haemophilia received a 48-week course of pegylated interferon-alpha-2b and ribavirin therapy for genotype 5a HCV infection. Virological response was achieved at week 24. At the end of treatment, HCV RNA in serum was detected and identified to belong to genotype 2b, rather than genotype 5a. A sensitive method for identifying minority HCV genotypes in pre-treatment serum showed genotype 2b HCV carriage prior to treatment. Sequencing the interferon sensitivity-determining region of the HCV NS5A gene obtained from pre-, intra- and post-treatment sera revealed emergence of quasispecies bearing R-->K and M-->A/T mutations at codons 2222 and 2223, respectively. Occult presence of minority HCV subpopulations and their acquisition of mutations following therapy can result in poor treatment outcome.  相似文献   
82.
The purpose of this pilot study was to determine the effects of the addition of coping skills training for obese multiethnic parents whose overweight children were attending a weight management program. At 6 months, parents in the experimental group had significantly lower body mass index (BMI) and body fat percentage (BFP) and higher numbers of pedometer steps compared with those in the control group. Parents in the experimental group also demonstrated significant improvement in interpersonal relationships, behavior control, and stress management compared with those in the control group. Children in the experimental group demonstrated trends toward decreased BMI and BFP and increased pedometer steps.  相似文献   
83.
84.
The aim of this study was to determine whether there are quantitative changes in the innervation of the anterior cruciate ligament in osteoarthritis. Eleven whole anterior cruciate ligaments were obtained at autopsy from cadavera of individuals with advanced osteoarthritis; five healthy ligaments were used as controls. The ligaments were transected and stained with hematoxylin and eosin, oil red O for fat, and a modification of Gairn's gold chloride method. The latter stain permits visualization of axons, mechanoreceptors, and free nerve endings that are not apparent on routine stains. The ratio of nerve tissue to periligamentous synovial tissue was determined histomorphometrically by the point-counting method. The nerve tissue was located almost exclusively in the periligamentous synovial tissue. There was a statistically significantly greater area of nerve tissue (as a percentage of the total area) around the anterior cruciate ligaments in the osteoarthritic group than around the ligaments in the control group (p < 0.02). The nerve tissue was distributed evenly throughout the periligamentous synovial tissue in the specimens in both groups. A neurological role has been proposed for the anterior cruciate ligament in osteoarthritis. This study provides morphological evidence for neural pathology of the anterior cruciate ligament in subjects with osteoarthritis.  相似文献   
85.
Latent inhibition (LI) of a conditioned emotional response (CER) has been proposed as a quantitative measure of selective attention. We have assessed the parallels of the pharmacology of LI in rats with the clinical pharmacology of schizophrenia. Drug and vehicle treated rats were divided into groups and preexposed 20 times to cage illumination as a CS, or not preexposed. All groups were conditioned with 2 CS-footshock pairings. The following day CER, as measured by interruption of drinking in response to CS presentation, was recorded. LI was observed as a decreased CER in preexposed relative to non-preexposed animals. LI was enhanced by haloperidol 0.3 mg/kg after 7 or 14 daily treatments, but not after a single acute dose. Haloperidol doses of 0.3 and 0.03 mg/kg enhanced LI, while doses of 0.003 and 3.0 mg/kg had no effect. Haloperidol enhancement of LI was unaffected by the coadministration of the anticholinergic agent trihexyphenidyl. Enhancement of LI is exhibited by the antipsychotic drugs fluphenazine, chlorpromazine, thiothixene, thioridazine, mesoridazine, and metoclopramide but not clozapine. The non-antipsychotic drugs pentobarbital, imipramine, chlordiazepoxide, trihexyphenidyl, and promethazine failed to enhance LI. LI exhibits striking parallels to the clinical pharmacology of schizophrenia.Preliminary data were presented in part at the Society for Neuroscience Annual Meeting, Phoenix, AZ, 1989  相似文献   
86.
87.
This study examined comorbid psychiatric disorders in adolescents with bipolar disorder. Hospitalized bipolar adolescents (N=10) were compared to hospitalized adolescents with unipolar depression (N=33), and to adolescents with nonaffective psychiatric disorders (N=11). Results showed conduct disorder, attention-deficit hyperactivity disorder, psychosis, and having any DSM-III-R psychoactive substance use disorder were all significantly more common in the bipolar group than the unipolar depressed group. Comorbid anxiety disorder was present in 40–45% of the subjects in the unipolar and bipolar groups, but in none of the control group subjects. This study is supported in part by a grant to Dr. Borchardt from the University of Minnesota Graduate School.  相似文献   
88.
OBJECTIVE: The aim of the study was to measure the use and estimate the cost of HIV service provision in England. DESIGN AND SETTING: Standardised activity and case-severity data were collected prospectively in 10 English HIV clinics (5 London and 5 non-London sites) for the periods 1 January 1996 to 30 June 1996 and 1 July 1996 to 31 December 1996 and linked to unit cost data. In total, 5440 patients with HIV infection attended during the first 6 months and 5708 during the second 6 months in 1996. MAIN OUTCOME MEASURES AND RESULTS: The mean number of inpatient days per patient-year for patients with AIDS was 19.7 [95% confidence interval (CI): 13.7 to 25.7] for January to June and 20.8 (95% CI: 15.3 to 26.4) for July to December 1996. The mean number of outpatient visits for asymptomatic patients with HIV infection was 14.8 (95% CI: 11.9 to 17.6) and 13.3 (95% CI: 10.8 to 15.7) for the respective periods and 16.1 (95% CI: 13.21 to 18.97) and 15.7 (95% CI: 11.2 to 20.2), respectively, for patients with symptomatic non-AIDS (i.e. symptomatic patients with HIV infection but without AIDS-defining conditions). Substantial centre-to-centre variation was observed, suggesting that many clinics can continue the shift from an inpatient- to an outpatient-based service. Cost estimates per patient-year for HIV service provision for 1996 varied from 4695 Pounds (95% CI: 3769 Pounds to 5648 Pounds) for asymptomatic patients, to 7605 Pounds (95% CI: 6273 Pounds to 8909 Pounds) for symptomatic non-AIDS patients to 20,358 Pounds (95% CI: 17,681 Pounds to 23,206 Pounds) for patients with AIDS. CONCLUSIONS: Different combinations of antiretroviral therapy affect the cost estimates of HIV service provision differently. Anticipated reduction in inpatient-related activity through the increased use of combination antiretroviral therapy will further shift service provision from an inpatient- to outpatient-based service and reduce costs per patient-year. The extent and duration of such effects are currently unknown. The long term effects of combination treatment on the morbidity and mortality patterns of individuals infected with HIV are also currently unknown, as are their implications on the use and cost of HIV service provision. Multicentre databases like the National Prospective Monitoring System (NPMS) will provide healthcare professionals with information to improve existing services and anticipate the impact of new developments.  相似文献   
89.
In the past 32 years, lasers have progressed from interesting curiosities to important instruments in medicine and surgery, with a wide variety of wavelengths and medical-surgical applications. Today's physician is faced with a bewildering array of laser types, each touted by its manufacturer as the ultimate surgical tool. This article sets forth in simple, understandable prose, the basic principles of the interaction of laser light with living tissue, so that the physician can decide which type of laser is best suited to a given application, without relying on the manufacturer's sales literature. The topics discussed are the nature of light; reflection, absorption, scattering, and attenuation in living tissue; physical processes by which laser light destroys tissue; relative importance of the three unique properties of laser light in surgery and therapy; temporal modes of lasers; means of delivering laser beams to their targets; and considerations in the selection of laser systems.  相似文献   
90.
We studied 32 coronary bypass patients to examine the effect of hypnosis on recovery from surgery. The patients were assessed for hypnotizability with the Hypnotic Induction Profile (HIP) and assigned to experimental groups with a random stratification procedure to equate for differences in hypnotizability, age, and severity of illness. We taught patients in groups one and two formal hypnosis with different treatment strategies; patients in group three were not taught formal hypnosis or a treatment strategy. Scores on the HIP were significant predictors of recovery, independent of experimental treatment with formal hypnosis. Patients who scored "Midrange" stabilized more quickly in the intensive care unit (ICU) than those who scored "High" or "Low" (p = < .05). Patients who scored "High" had more labile blood pressure in the ICU compared to the "Midrange" and "Lows" (p = < .05). Measured hypnotizability was associated with the recovery sequence from surgery.  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