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   40405篇
  免费   2413篇
  国内免费   218篇
耳鼻咽喉   449篇
儿科学   1262篇
妇产科学   1086篇
基础医学   4211篇
口腔科学   1288篇
临床医学   3543篇
内科学   8716篇
皮肤病学   735篇
神经病学   2462篇
特种医学   1404篇
外国民族医学   9篇
外科学   7171篇
综合类   941篇
现状与发展   3篇
一般理论   32篇
预防医学   2773篇
眼科学   1402篇
药学   3206篇
  1篇
中国医学   285篇
肿瘤学   2057篇
  2024年   44篇
  2023年   448篇
  2022年   1127篇
  2021年   1780篇
  2020年   1065篇
  2019年   1388篇
  2018年   1737篇
  2017年   1256篇
  2016年   1333篇
  2015年   1421篇
  2014年   1845篇
  2013年   2224篇
  2012年   3344篇
  2011年   3235篇
  2010年   1830篇
  2009年   1599篇
  2008年   2382篇
  2007年   2472篇
  2006年   2171篇
  2005年   1939篇
  2004年   1761篇
  2003年   1452篇
  2002年   1281篇
  2001年   437篇
  2000年   362篇
  1999年   341篇
  1998年   213篇
  1997年   147篇
  1996年   158篇
  1995年   121篇
  1994年   108篇
  1993年   95篇
  1992年   170篇
  1991年   184篇
  1990年   149篇
  1989年   142篇
  1988年   120篇
  1987年   115篇
  1986年   107篇
  1985年   127篇
  1984年   90篇
  1983年   64篇
  1982年   74篇
  1981年   69篇
  1980年   46篇
  1979年   65篇
  1978年   46篇
  1976年   42篇
  1975年   40篇
  1974年   38篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
Mayotte is a little French island, located in the Indian ocean, between Madagascar and Mozambic. Officially, the population goes up to 150,000 inhabitants, but in fact, it probably comes up to about 200,000 people, because of a very numerous illegal immigration, especially coming from Anjouan, the nearest Comorian island. Up to now there are no data about HIV in Mayotte. There is only one adult medical unit (except intensive care). All patients detected as seropositive for HIV are sent for treatment in this unit. The only case of systematically proposed HIV serology is pregnancy, and this since 1994. 70% to 80% of women accept it. There are annually 6000 deliveries in Mayotte. When a seropositivity is detected, screening is systematically proposed to other members of the family. Epidemiology does not seem to worsen, even if detection is increasing: 8675 tests done in 1998, 9142 in 1999, 12,085 in 2000. All cases of seropositivity attended to at present time in our unit have been registered and studied, apart from patients who died before this study, and those who did not consult for more than two years. There were 8 HIV positive people who died since 1990 in Mayotte, most of them in 1991, 1992. There was no death in the last years, nor sanitary evacuation, except one. 50 people are registered: 20 males, 30 females. Average age is 34. 39 Comorian people, 10 metropolitans, and one from another origin. Contamination was heterosexual in 43 cases, intravenous drug user in 1 case, homosexual in 2 cases, professional in 1 case, unknown in 3 cases. There are 4 double contamination Ag Hbs/HIV, and 2 HCV/HIV. 39 subjects are at A stage, 5 B, 6 C. The beginning of the epidemic in Mayotte took place probably around 1990, among militaries and prostitutes. Now, transmission keeps going on, in most cases, heterosexual, as it occurs in the nearby Africa. Polygamy, official or officious, has a leading role. Females who were detected during pregnancy have obtained zidovudine, or have been able to pursue previous therapy. Medical care and therapy are free in Mayotte, but sometimes there are delays in supplying medicines or in returning results. Epidemic has not increased up to now; even though screening has. There are very few pediatric cases: only 4 cases were notified in Mayotte until now: one who died very soon, one who has gone to live in Reunion island, and two who are still in Mayotte: one is 12 years old, and another one 5 years old.  相似文献   
73.
Isolation rearing has long been suspected to alter hormonal and behavioral responses to stress. Two experiments were conducted to test the hypothesis that isolates are more timid or fearful than socially reared rats when exposed to novel test environments. In both, isolate response to 3 graded stressors was compared to that of socially-reared rats. In the first experiment, animals were handled, shocked or not treated prior to testing to produce three levels of conditioned fear. They were then tested on four paradigms previously shown sensitive to conditioned fear: open field activity, emergence latency, auditory startle, and latency to accept food from the experimenter. In the second experiment, rats were given a 0-, 5- or 20-min forced swim, then sacrificed for analysis of plasma corticosterone and pituitary and hypothalamic beta-endorphin. It was found that isolates showed little evidence of enhanced behavioral timidity, although rearing effects were seen on all 4 behavioral measures. Plasma corticosterone levels increased in a graded fashion over the course of the forced swim, but there was no effect of rearing conditions. While there were no effects of rearing or stress on hypothalamic beta-endorphin, pituitary beta-endorphin content was lower in females than in males, and isolate males had lower pituitary endorphin than social males. In summary, these experiments provide no evidence that isolation rearing produces a primary, global increase in fearfulness, but identify several behavioral and hormonal differences associated with differential housing in rats.  相似文献   
74.
75.
Recent studies have provided evidence that macrophages from Th1-prone mouse strains respond with an M1 profile, and macrophages from Th2-prone mouse strains respond with an M2 profile, characterized by the dominant production of NO or TGF-beta 1, respectively. We have shown that peritoneal macrophages from IL-12p40 gene knockout mice have a bias toward the M2 profile, spontaneously secreting large amounts of TGF-beta 1 and responding to rIFN-gamma with weak NO production. Moreover, IL-12p40KO macrophages are more permissive to Trypanosoma cruzi replication than their wild-type littermate cells. Prolonged incubation with rIL-12 fails to reverse the M2 polarization of IL-12p40KO macrophages. However, TGF-beta 1 is directly implicated in sustaining the M2 profile because its inhibition increases NO release from IL-12p40KO macrophages. IFN-gamma deficiency is apparently not the reason for TGF-beta 1 up-regulation, because rIFN-gamma KO macrophages produce normal amounts of this cytokine. These findings raise the possibility that IL-12 has a central role in driving macrophage polarization, regulating their intrinsic ability to respond against intracellular parasites.  相似文献   
76.
This study was designed to analyze cytokine levels in bronchoalveolar lavage (BAL) fluid of patients with pulmonary fibrosis (PF) and was performed at a University hospital. Nineteen veterans had mustard gas-induced PF, and 19 normal veterans were used as a control group. Chest roentgenograms, pulmonary function tests (PFTs), the percentage diffusing capacity of carbon monoxide (D(LCO)), high-resolution CT scans of the chest, and analyses of BAL fluids for five cytokines interleukin-8 (IL-8), IL-1beta, IL-6, tumor necrosis factor-alpha (TNF-alpha), IL-12, and the growth factors transforming growth factor-beta (TGF-beta), insulin-like growth factor-1 (IGF-1), and epidermal growth factor (EGF) were performed in all cases. A transbronchial lung biopsy was done in all patients. There were significant differences in cytokine (IL-8, IL-1beta, IL-6, TNF-alpha, IL-12) levels of BAL fluid between patients with PF and healthy controls. TGF-beta, EGF, and IGF-1 levels were also significantly increased in patients with PF compared with controls. A significant negative correlation was observed between the percentage of D(LCO) and IL-8 levels in BAL fluid in patients with PF (r = -0.47, p = 0.04). A significant negative correlation was also seen between the percentage of D(LCO) and TGF-beta (r = 0.53, p = 0.02) in these patients. Except for the percentage and the absolute number of the BAL fluid neutrophils (r = 0.70, p = 0.001 and r = -0.62, p = 0.005, respectively), no correlation was found between D(LCO)% and the other BAL cells. Of all measured cytokines and growth factors, only IL-8 and TGF-beta showed a significant correlation with the degree of fibrosis (p = 0.004, p = 0.04). The increased levels of cytokines and growth factors in the BAL fluid suggest the possible causative mechanism in the lung in sulfur mustard gas-induced PF by recruitment of neutrophils and eosinophils into the lung.  相似文献   
77.
78.
Casonis skin test and indirect haemagglutination test (IHA) are still used in Turkey. The preoperative IHA test or Casonis skin test results of 120 patients with surgically confirmed hydatidosis were retrospectively studied during 1997–2004. At the same period, 306 patients with non-hydatid disease had serologic results for echinococcosis. The sensitivity of immediate intradermal reaction, delayed intradermal reaction, and IHA were 70, 62, and 56%, respectively. Casonis skin test components had higher sensitivity than IHA (P<0.01). The specificity of immediate intradermal reaction, delayed intradermal reaction, and IHA were 87, 85, and 84%, respectively. Cystic lesions in non-hydatid patients were localised commonly in the lungs. The occurrence of hydatid disease for pulmonary, hepatic, and renal cysts was 19, 54, and 5%, respectively. An immediate skin reaction to crude hydatid antigens is more useful than IHA.  相似文献   
79.
Psychopharmacological studies usually attempt to eliminate "nonspecific" influences on outcome by double-blind designs. In a randomized, double-blind comparison of alprazolam, imipramine, and placebo, the great majority of panic disorder patients (N = 59) and their physicians were able to rate accurately whether active drug or placebo had been given. Moreover, physicians could distinguish between the two types of active drugs. Inasmuch as correct rating was possible halfway through treatment, concerns about the internal validity of the double-blind strategy arise.  相似文献   
80.
BACKGROUND: Very few studies have reported cancer outcomes of patients referred through different routes, despite the prominence of current UK cancer urgent referral guidance. AIM: This study aimed to compare outcomes of cancer patients referred through the urgent referral guidance with those who were not, with respect to stage at diagnosis, survival, and delays in diagnosis. Design of study: Analysis of hospital records. SETTING: One hospital trust in England. METHOD: The records of 889 patients diagnosed in 2000-2001 with one of four types of cancer were analysed: 409 with lung cancer; 239 with colorectal cancer; 146 with prostate cancer; and 95 with ovarian cancer. Outcome measures were diagnostic stage, survival, referral and secondary care delays. RESULTS: For lung cancer, urgent referrals had more advanced TNM (tumor, node, metastasis) stage than patients diagnosed through other routes (P = 0.035) and poorer survival (P = 0.020). There was no difference in stage or survival for the other cancers. For each cancer, a higher proportion of urgent referrals was seen within 2 weeks. Secondary care delays for lung and colorectal cancer were shorter for inter-specialty referrals. CONCLUSION: For patients with lung cancer, the guidance appears to be prioritising those in the more advanced stages of disease. This was not the case for the other three cancers. Referral delays were shorter for patients urgently referred, as is the intention of the guidance. The avoidance of delays in outpatient diagnostics probably accounts for shorter secondary care delays for inter-specialty referrals.  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