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   7541篇
  免费   563篇
  国内免费   57篇
耳鼻咽喉   25篇
儿科学   207篇
妇产科学   81篇
基础医学   1088篇
口腔科学   256篇
临床医学   722篇
内科学   1741篇
皮肤病学   283篇
神经病学   496篇
特种医学   365篇
外科学   1042篇
综合类   139篇
一般理论   3篇
预防医学   631篇
眼科学   254篇
药学   349篇
  1篇
中国医学   1篇
肿瘤学   477篇
  2021年   62篇
  2019年   68篇
  2018年   73篇
  2015年   64篇
  2014年   107篇
  2013年   192篇
  2012年   229篇
  2011年   268篇
  2010年   158篇
  2009年   158篇
  2008年   306篇
  2007年   338篇
  2006年   284篇
  2005年   277篇
  2004年   266篇
  2003年   235篇
  2002年   205篇
  2001年   269篇
  2000年   214篇
  1999年   204篇
  1998年   110篇
  1997年   94篇
  1996年   76篇
  1995年   73篇
  1993年   68篇
  1992年   227篇
  1991年   195篇
  1990年   212篇
  1989年   205篇
  1988年   184篇
  1987年   210篇
  1986年   185篇
  1985年   193篇
  1984年   133篇
  1983年   110篇
  1982年   75篇
  1981年   84篇
  1980年   71篇
  1979年   124篇
  1978年   89篇
  1977年   89篇
  1976年   71篇
  1975年   87篇
  1974年   91篇
  1973年   104篇
  1972年   81篇
  1971年   74篇
  1970年   80篇
  1969年   88篇
  1968年   75篇
排序方式: 共有8161条查询结果,搜索用时 36 毫秒
1.
A 24-year-old man presented with acute pancreatitis. Serial ultrasonographic examination showed the development of bright echoes within the pancreatic parenchyma compatible with gas formation. This was confirmed on subsequent computed tomography and at laparotomy. The value of serial ultrasonographic examinations in pancreatitis is emphasized.  相似文献   
2.
Three children with malignant primary CNS tumors treated with craniospinal radiotherapy developed intraparenchymal hemorrhages a median of 5 years following therapy in sites distant from the primary tumor. Radical surgical procedures disclosed fresh and old hematoma, gliosis, and necrosis in all 3 patients and an aggregation of abnormal microscopic blood vessels in two. No tumor was found. All 3 patients remain in long-term (greater than 10 years) continuous remission.  相似文献   
3.
4.
5.
6.
The magnitude and dynamics of lung cancer incidence in Jews and Arabs in Israel between the years 1962 and 1982 were studied. In general, age-standardized incidence rates increased consistently between the years 1962 and 1976 among Jewish (24% increase) and Arab (39%) males, and to a lesser degree among Jewish females (15%). Arab females had the highest (77%) increase. From 1977 to 1982 a general decrease in incidence rates, which was largest among Arab males (19%) and females (15%), was noted. Rates among Jewish males are currently 26% higher than among Arab males, and are 162% higher among Jewish females than in Arab females. Lung cancer rates in both males and females in Istrael (Jews and Arabs) are lower than in most developed countries in the world. Among the possible reasons are differences in the population risk factors profile, availability of health care and the level of diagnosis and ascertainment of cases.  相似文献   
7.
Current knowledge about alcohol and marital functioning is limited by restrictive sample selection, inattention to the literature on individual-based alcoholic subtypes, and lack of research linking individual differences among alcoholics to marital functioning. The present study was designed to study marital functioning of alcoholics in light of current alcohol typologies. Subjects were part of a larger study on conjoint treatment of alcoholic males and their female partners. Four typologies—including Type 1/2, In-Home/Out-of-home, SteadyIEpisodic, and EarlyILate Onset—were tested for replicability and discriminant validity before linking them to marital functioning. Discriminant validity was found only for the Early (59%)-versus Late (41 %)-Onset typology; thus, further analyses linked only this typology with marital functioning. At baseline, Early-Onset couples reported more marital instability, and the females in these couples were more distressed. During treatment, Early-Onset couples reported higher daily marital satisfaction than Late-Onset couples. Regardless of age of onset, males reported higher marital satisfaction than their spouses during treatment, but their satisfaction did not increase during treatment. Female partners' marital satisfaction increased during treatment. Female partners of Late-Onset males reported particularly low marital satisfaction during treatment. Parsing the sample according to the early-/late-onset typology yielded different predictors of marital satisfaction for males and females within each subtype. For female partners of Early-Onset alcoholics, psychological distress unrelated to her pattner's drinking severity was most associated with her own marital satisfaction, whereas marital adjustment of female partners of Late-Onset alcoholics was most associated with the male's level of perceptual accuracy regarding her needs. This pattern was reversed for the males; marital adjustment of Early-Onset alcoholics was most associated with his partner's perceptual accuracy of his needs, whereas marital functioning of Late-Onset alcoholics was best accounted for by his own psychological distress.  相似文献   
8.
9.
Abstract Human immunodeficiency virus (HIV)-l neuropathogenesis can be divided into three important components: (i) virus entry into the nervous system; (ii) the role of viral proteins and/or cellular products in neural tissue damage; and (iii) the mechanisms of neuronal injury/death. Both blood derived macrophages or trafficking HIV-1 infected T-lymphocytes have been implicated in viral entry to the central nervous system (CNS). The major cell type harboring productive HIV-1 infection in the nervous system is the perivascular macrophage/ microglia. The HIV-1 infection of brain astrocytes, restricted to the expression of regulatory gene products, may cause astrocyte dysfunction and contribute to neuronal injury or to disruption of the blood-brain barrier (BBB). Studies of cerebrospinal fluid and postmortem tissues reveal chronic inflammation/immune activation in the nervous system during the later stages of HIV-1 infection associated with disruption of BBB integrity. Blood-brain barrier damage may underlie the white matter pallor described in HIV-1 infection and could result in further entry into the CNS of toxic viral or cellular products, or additional HIV-1 infected cells. The HIV infected and activated macrophages/microglia produce excessive amounts of pro-inflammatory cytokines, including tumor necrosis factor alpha, and platelet activating factor. These products are directly toxic to human neurons in vitro. The HIV-1 envelope glycoprotein, gp 120 may stimulate the release of toxic factors from brain macrophages. Blocking N-methyl-D-aspartate (NMDA; or AMPA) glutamate receptors can antagonize candidate toxins of both viral and cellular origin. It has been postulated that (weak) excitotoxicity leads to oxidative stress in neurons and ultimately to apoptosis. Neuronal apoptosis occurs in the brains of both children and adults with HIV-1 infection. This understanding of HIV neuropathogenesis implies that therapeutic strategies should include: (i) anti-retroviral medications to decrease systemic and CNS virus load, and possibly to prevent perinatal transmission of HIV; (ii) anti-inflammatory compounds to decrease the chronic immune activation in microglia and allow the restoration of BBB integrity; and (iii) neuroprotective compounds to reduce neuronal injury and apoptotic death.  相似文献   
10.
OBJECTIVE: To describe the course of rheumatoid arthritis over 5 years in adults and to evaluate the effect of parenterally administered gold salts on that course. DESIGN: A prospective observational study of adults with rheumatoid arthritis. Data derived from annual interviews with patients from 1983 to 1988 and from physician surveys in 1983 and 1987. SETTING: Rheumatology practices in the community. PATIENTS: The study began in 1982 with 822 adults who had rheumatoid arthritis and were under the care of rheumatologists. INTERVENTIONS: Those selected by rheumatologists in the management of their patients. MEASUREMENTS: Information describing sociodemographic and clinical characteristics, course, and therapy was collected from patients and verified by physician reports. Functional status, measured by the Health Assessment Questionnaire, and the number of painful joints were used as outcome variables. Outcome variables were adjusted for age, sex, disease duration, baseline values of the outcome variable, and the use of four disease-remittive agents other than gold. MAIN RESULTS: Multivariate repeated-measures analysis of variance showed no change in the course of rheumatoid arthritis over 5 years. The use of parenteral gold for at least 2 consecutive years at the start of the observation period produced, on average, no change in the course over 5 years in the two outcome variables. CONCLUSION: In our study of a community-based population of adults with rheumatoid arthritis who were under the care of community rheumatologists, we found that there was, on average, no statistically significant change in function or number of painful joints between 1983 and 1988. Patients receiving parenteral gold therapy for at least 2 consecutive years did not show a statistically significant difference in outcome when compared with those not receiving such therapy.  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