全文获取类型
收费全文 | 47036篇 |
免费 | 3792篇 |
国内免费 | 111篇 |
专业分类
耳鼻咽喉 | 376篇 |
儿科学 | 1904篇 |
妇产科学 | 1293篇 |
基础医学 | 6745篇 |
口腔科学 | 971篇 |
临床医学 | 6480篇 |
内科学 | 9129篇 |
皮肤病学 | 894篇 |
神经病学 | 4802篇 |
特种医学 | 1074篇 |
外科学 | 4105篇 |
综合类 | 406篇 |
一般理论 | 62篇 |
预防医学 | 5767篇 |
眼科学 | 671篇 |
药学 | 2638篇 |
2篇 | |
中国医学 | 55篇 |
肿瘤学 | 3565篇 |
出版年
2024年 | 60篇 |
2023年 | 422篇 |
2022年 | 583篇 |
2021年 | 1264篇 |
2020年 | 938篇 |
2019年 | 1396篇 |
2018年 | 1531篇 |
2017年 | 1202篇 |
2016年 | 1329篇 |
2015年 | 1398篇 |
2014年 | 1782篇 |
2013年 | 2619篇 |
2012年 | 3654篇 |
2011年 | 3769篇 |
2010年 | 2068篇 |
2009年 | 1831篇 |
2008年 | 3048篇 |
2007年 | 3134篇 |
2006年 | 3081篇 |
2005年 | 2898篇 |
2004年 | 2808篇 |
2003年 | 2575篇 |
2002年 | 2316篇 |
2001年 | 363篇 |
2000年 | 261篇 |
1999年 | 313篇 |
1998年 | 522篇 |
1997年 | 391篇 |
1996年 | 347篇 |
1995年 | 338篇 |
1994年 | 267篇 |
1993年 | 265篇 |
1992年 | 184篇 |
1991年 | 158篇 |
1990年 | 143篇 |
1989年 | 112篇 |
1988年 | 123篇 |
1987年 | 87篇 |
1986年 | 93篇 |
1985年 | 97篇 |
1984年 | 100篇 |
1983年 | 100篇 |
1982年 | 127篇 |
1981年 | 123篇 |
1980年 | 103篇 |
1979年 | 62篇 |
1978年 | 66篇 |
1977年 | 49篇 |
1976年 | 45篇 |
1972年 | 35篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Nhân Pham-Thi Pierre Scheinmann Riad Fadel Anne Combebias Claude Andre the Study Group 《Pediatric allergy and immunology》2007,18(1):47-57
Although several studies have demonstrated the efficacy of subcutaneous immunotherapy in allergic asthma, few have shown the same benefit using sublingual immunotherapy (SLIT) in asthmatic patients. This study was conducted to assess the efficacy of house dust mite (HDM) SLIT in addition to allergen avoidance and standard pharmacologic treatment. A double-blind, placebo-controlled trial was performed in 111 children (aged 5-15 yr) with HDM-induced mild-to-moderate asthma. After a 4-week baseline phase, patients were randomly assigned to receive SLIT with tablets of HDM extract (n = 55) or placebo (n = 56) for 18 months. Pharmacologic treatment was adjusted every 3 months following a step-down approach. Asthma symptom scores, reduction in use of inhaled corticosteroids and inhaled beta(2)-agonists, rhinitis symptoms, lung function tests, skin sensitivity to HDM, dust mite-specific immunoglobulin (Ig) E and IgG(4), and quality of life (QoL) were assessed during the study. After 18 months of treatment, diurnal and nocturnal asthma symptoms scores did not show significant differences between SLIT and placebo groups. Inhaled corticosteroids and inhaled beta(2)-agonists use was reduced in both groups without significant differences between groups. There were no significant differences in lung function (forced expiratory volume in 1 s and peak flow rate variations) between groups. Rhinitis symptom score decreased in both groups, with no difference between the two groups. The severity dimension of QoL was significantly improved in the SLIT group (age 6-12 yr). SLIT induced a significant reduction of skin sensitivity to HDM (p < 0.01) and a significant increase in HDM-specific IgE and IgG(4) antibodies (p < 0.001) in the SLIT group compared with the placebo group. SLIT was well tolerated with mild/moderate local adverse events. No severe systemic reactions were reported. This study indicates that, when mild-moderate asthmatic children are optimally controlled by pharmacologic treatment and HDM avoidance, SLIT does not provide additional benefit, despite a significant reduction in allergic response to HDM. Under such conditions, only a complete, but ethically unfeasible, discontinuation of inhaled corticosteroid would have demonstrated a possible benefit of SLIT. 相似文献
22.
Marilyn Anne Murphy M.S. 《Journal of medical systems》1986,10(2):109-120
This paper identifies the need for more specific guidelines in preparing faculty to use and develop computer-based instructional materials. Cory's model for faculty development is described and planning considerations are outlined. Finally, components of this multifaceted approach to faculty development—identifying available resources, emphasizing the current uses of computers, providing computer literacy/faculty awareness sessions, focusing on the instructional use of microcomputers, collaboration, and communication—are discussed. 相似文献
23.
Legionnaire's disease was first identified and described in January 1977. Even today, it is often regarded as an unusual or exotic disease, when in fact it is a very common form of community and nosocomial acquired pneumonia. The major roles of the acute care nurse, including patient health education; psychosocial needs of the patient; and strategies for disease prevention and control, are discussed. 相似文献
24.
25.
Nancy S Krieger Kevin K Frick Kelly LaPlante Strutz Anne Michalenka David A Bushinsky 《Journal of bone and mineral research》2007,22(6):907-917
Chronic metabolic acidosis induces net Ca efflux from bone; this osteoclastic bone resorption is mediated by increased osteoblastic prostaglandin synthesis. Cyclooxygenase, the rate-limiting enzyme in prostaglandin synthesis, is present in both constitutive (COX-1) and inducible (COX-2) forms. We report here that acidosis increases both osteoblastic RNA and protein levels for COX-2 and that genetic deficiency or pharmacologic inhibition of COX-2 significantly reduces acid-induced Ca efflux from bone. INTRODUCTION: Incubation of neonatal mouse calvariae in medium simulating physiologic metabolic acidosis induces an increase in osteoblastic prostaglandin E2 (PGE2) release and net calcium (Ca) efflux from bone. Increased PGE2 is necessary for acid-induced bone resorption, because inhibition of cyclooxygenase activity with indomethacin significantly decreases not only PGE2 production but also Ca release. Cyclooxygenase is present in both constitutive (COX-1) and inducible (COX-2) forms. Because COX-2 activity has been implicated in several forms of pathological bone resorption, we tested the hypothesis that COX-2 is critical for acid-induced, cell-mediated bone Ca efflux. MATERIALS AND METHODS: To determine the effect of metabolic acidosis on COX-2 RNA and protein, primary cells isolated from neonatal CD-1 mouse calvariae were cultured in neutral (Ntl) or physiologically acidic medium (Met). RNA levels for COX-2 and COX-1 were measured by quantitative real-time PCR. Levels of COX-2 and COX-1 protein were measured by immunoblot analysis. To determine the effect of acidosis on bone Ca efflux in genetically deficient COX-2 mice, mice heterozygous for the COX-2 knockout (strain B6;129S7-Ptgs2(tm1Jed)/J) were used as breeders, and neonatal calvariae were cultured in Ntl or Met. To determine the effects of the specific COX-2 inhibitor, NS398, on acid-induced bone resorption, CD-1 calvariae were incubated in Ntl or Met with or without NS398 (1 microM). Medium PGE2 was assayed by ELISA. RESULTS: Incubation of mouse calvarial cells in Met significantly increased COX-2 RNA and protein levels without a change in COX-1. Increased COX-2 protein levels in response to Met were also observed in cultured calvariae. Acid-induced, cell-mediated Ca efflux from B6;129S7-Ptgs2(tm1Jed)/J calvariae was dependent on genotype. From 0 to 24 h, when physicochemical Ca efflux predominates, Met significantly increased net Ca efflux in all genotypes. After 24 h, when cell-mediated Ca efflux predominates, Met induced greater Ca efflux from (+/+) than from (+/-), and there was no increase from (-/-). In calvariae from CD-1 mice, NS398 significantly inhibited both the acid-induced increase in PGE2 and Ca release. CONCLUSIONS: The specific acid-induced increase in COX-2 RNA and protein levels and the dependency of the increased Ca efflux on COX-2 activity, as determined by both genetic deficiency and pharmacologic inhibition, show that COX-2 is critical for acid-induced, cell-mediated bone resorption. 相似文献
26.
ABSTRACT:Background: In 1996 a new model of maternity care characterized by continuity of midwifery care from early pregnancy through the postpartum period was implemented for women attending Monash Medical Centre, a tertiary level obstetric service, in Melbourne, Australia. This study's purpose was to assess the impact of this model on women's views and experiences of care during the antenatal, intrapartum, and postpartum periods compared with views of women receiving standard maternity care. Methods: One thousand low‐ and high‐risk women who booked at the antenatal clinic and met the eligibility criteria were randomly allocated to continuity of midwifery care from a group of seven midwives in collaboration with medical staff, or to standard care from a variety of midwives and medical staff. Women's views of care were measured by means of a postal questionnaire at four months after the birth. Results: Team midwifery care was associated with increased satisfaction with antenatal, intrapartum, and some aspects of postpartum care. The differences were most obvious for antenatal care. Conclusions: Continuity of midwifery care is realistically achievable in a tertiary obstetric referral service and is associated with increased satisfaction. (BIRTH 30:1 March 2003) 相似文献
27.
28.
Joseph Cofrancesco Nina Shah Khalil G Ghanem Adrian S Dobs Robert S Klein Kenneth Mayer Paula Schuman David Vlahov Anne M Rompalo 《Gynecological endocrinology》2006,22(5):244-251
Drug use and HIV infection may affect sex hormone levels in women. One hundred and ninety-six women with and without a history of illicit drug use (50 HIV-negative and 148 HIV-infected), with regular menses, who never used antiretrovirals, were evaluated. Luteinizing hormone levels were significantly higher in women with a CD4 cell count <200/microl (p < 0.002). Current methadone use was associated with lower levels of total testosterone (p = 0.03) and higher levels of prolactin (p = 0.002); mean estradiol levels were 43% lower in women who used intravenous drugs (p < 0.001). Alcohol and crack cocaine use was not associated with sex hormone levels. Age, race, body mass index and degree of HIV immunosuppression were also associated with differences in sex hormone levels. 相似文献
29.
30.
In this study, ethnographic interviews were used to identify first-time fathers' experiences of the birth of their first child. Fourteen fathers were interviewed, and prenatal expectations of the experience are compared with the fathers' perceptions after the birth. Although the fathers expected to be treated as part of a laboring couple, they found that they were relegated to a supporting role. Initially the fathers were confident of their ability to support their wives, but they found that labor was more work than they had anticipated. They became fearful of the outcome, but hid these fears from their partners. Later, they found that their focus moved from their wives to their babies at the time of birth. The men all completed the experience with an enhanced respect for their wives. Fathers should be included in labor management plans and need support for their role as coach, particularly when their wives experience pain. They also need to be encouraged to eat and take a break from their wives' labor when appropriate. 相似文献