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   1145301篇
  免费   72196篇
  国内免费   1793篇
耳鼻咽喉   15221篇
儿科学   37789篇
妇产科学   29686篇
基础医学   178404篇
口腔科学   32645篇
临床医学   100560篇
内科学   214271篇
皮肤病学   26642篇
神经病学   81540篇
特种医学   41399篇
外国民族医学   136篇
外科学   170039篇
综合类   22421篇
现状与发展   2篇
一般理论   268篇
预防医学   84717篇
眼科学   26907篇
药学   87616篇
  17篇
中国医学   3212篇
肿瘤学   65798篇
  2018年   12000篇
  2017年   9148篇
  2016年   10204篇
  2015年   11266篇
  2014年   15398篇
  2013年   23534篇
  2012年   31349篇
  2011年   33423篇
  2010年   19760篇
  2009年   18553篇
  2008年   31545篇
  2007年   33816篇
  2006年   34389篇
  2005年   32425篇
  2004年   31777篇
  2003年   30187篇
  2002年   29667篇
  2001年   56395篇
  2000年   57864篇
  1999年   47657篇
  1998年   12495篇
  1997年   10688篇
  1996年   11303篇
  1995年   10586篇
  1994年   9763篇
  1993年   9137篇
  1992年   36238篇
  1991年   36389篇
  1990年   35728篇
  1989年   34995篇
  1988年   31936篇
  1987年   31332篇
  1986年   29628篇
  1985年   28086篇
  1984年   20708篇
  1983年   17627篇
  1982年   9793篇
  1979年   19430篇
  1978年   13891篇
  1977年   11727篇
  1976年   11261篇
  1975年   12605篇
  1974年   14928篇
  1973年   14220篇
  1972年   13569篇
  1971年   12862篇
  1970年   12195篇
  1969年   11389篇
  1968年   10608篇
  1967年   9513篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
72.
73.
74.

Objective

To assess the incidence of pertussis (whooping cough) in subjects aged 50 years and older in France.

Methods

Participating family physicians (FPs) using the patient record management software AxiSanté® included patients aged 50 years and older, who had signed an informed consent form, presenting with persistent cough for 7 to 21 days. Bordetella genetic material was detected by polymerase chain reaction (PCR) on nasopharyngeal samples collected at the FP's discretion.

Results

A total of 42 FPs included 129 patients from June 2013 to August 2014 (large cities: 38; medium-sized cities: 57; rural areas: 34); 106 samples were analyzed. Overall, 30 pertussis cases were diagnosed: 10 cases confirmed by PCR, 18 purely clinical cases, and two direct epidemiological cases. The crude incidence rate per 100,000 patients aged  50 years was 103.6 (95% CI: 69.9–47.9): 77.1 in large cities, 103.1 in medium-sized cities, and 143.9 in rural areas. The extrapolated incidence rate per 100,000 persons aged  50 years was 187.1 (95% CI: 126.2–67.1): 131.1 in large cities, 256.1 in medium-sized cities, and 242.2 in rural areas.

Conclusion

The population aged 50 years and older can serve as a reservoir. Its role in Bordetella pertussis circulation should be taken into account for pertussis booster vaccination programs.  相似文献   
75.

Background

In order to contribute to the fight against the pediatric HIV infection, we have assessed, through a study in which we have systematically proposed to carry out children's testing, the rate of acceptability and the feasibility of children's HIV testing during the routine activities of the department. We have also analyzed the reasons for the acceptability or the refusal of the child's HIV testing by the accompanying person.

Methods

The study took place from May to September 2015 including all the parents/legal guardians of any child aged 0 to 14 years coming for a consultation or who was hospitalized in the Pediatric Department of Souro Sanou Teaching Hospital. Counseling sessions conducted by community health workers focused on informing and proposing the principle of child testing. After obtaining the verbal and informed consent of the accompanying person, the first test was performed with Determine® by a hospital health worker. A second SD Bioline®/ImmunoCombII® test was performed if the first test was positive. With children aged less than 18 months, after a positive antibody test, we resorted to PCR for confirmation.

Results

A total of 848 accompanying persons, 568 of whom were female, underwent a pre-test interview during which the HIV test was offered to them. The mean age of accompanying persons was 30 (25.5 to 38) years; 747 accompanying persons (88.1%) accepted the testing of their child. We have found an influence of the accompanying person's religion (P = 0.02) and the type of accompanying person on the acceptability of children's testing. Mothers were more willing to accept the test compared to other accompanying persons (P = 0.002). The main reason for refusing the child's testing was the absence of one of the child's parents, mainly the father whose opinion was needed. The test was positive for HIV1 in 10 children.

Conclusion

In health centers, getting the informed consent from parents to test their children is a big challenge. However, our study shows that this is possible, through the high rate of acceptability obtained.  相似文献   
76.
77.
Iron-oxide nanoparticles (NPs) generated by environmental events are likely to represent health problems. α-Fe2O3 NPs were synthesized, characterized and tested in a model for toxicity utilizing human whole blood without added anticoagulant. MALDI-TOF of the corona was performed and activation markers for plasma cascade systems (complement, contact and coagulation systems), platelet consumption and release of growth factors, MPO, and chemokine/cytokines from blood cells were analyzed. The coronas formed on the pristine α-Fe2O3 NPs contained contact system proteins and they induced massive activation of the contact (kinin/kallikrein) system, as well as thrombin generation, platelet activation, and release of two pro-angiogeneic growth factors: platelet-derived growth factor and vascular endothelial growth factor, whereas complement activation was unaffected. The α-Fe2O3 NPs exhibited a noticeable toxicity, with kinin/kallikrein activation, which may be associated with hypotension and long-term angiogenesis in vivo, with implications for cancer, arteriosclerosis and pulmonary disease.  相似文献   
78.
79.
According to the National Center of Health Statistics, cancer was the culprit of nearly 600,000 deaths in 2016 in the USA. It is by far one of the most heterogeneous diseases to treat. Treatment for metastasized cancers remains a challenge despite modern diagnostics and treatment regimens. For this reason, alternative approaches are needed. Chemoprevention using dietary phytochemicals such as triterpenoids, isothiocyanates, and curcumin in the prevention of initiation and/or progression of cancer poses a promising alternative strategy. However, significant challenges exist in the extrapolation of in vitro cell culture data to in vivo efficacy in animal models and to humans. In this review, the dose at which these phytochemicals elicit a response in vitro and in vivo of a multitude of cellular signaling pathways will be reviewed highlighting Nrf2-mediated antioxidative stress, anti-inflammation, epigenetics, cytoprotection, differentiation, and growth inhibition. The in vitro-in vivo dose response of phytochemicals can vary due, in part, to the cell line/animal model used, the assay system of the biomarker used for the readout, chemical structure of the functional analog of the phytochemical, and the source of compounds used for the treatment study. While the dose response varies across different experimental designs, the chemopreventive efficacy appears to remain and demonstrate the therapeutic potential of triterpenoids, isothiocyanates, and curcumin in cancer prevention and in health in general.  相似文献   
80.
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