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   1970篇
  免费   117篇
  国内免费   38篇
耳鼻咽喉   7篇
儿科学   63篇
妇产科学   35篇
基础医学   239篇
口腔科学   62篇
临床医学   164篇
内科学   363篇
皮肤病学   40篇
神经病学   77篇
特种医学   191篇
外科学   216篇
综合类   179篇
一般理论   2篇
预防医学   194篇
眼科学   43篇
药学   138篇
  1篇
中国医学   15篇
肿瘤学   96篇
  2023年   36篇
  2022年   76篇
  2021年   116篇
  2020年   63篇
  2019年   56篇
  2018年   87篇
  2017年   52篇
  2016年   54篇
  2015年   59篇
  2014年   64篇
  2013年   90篇
  2012年   121篇
  2011年   136篇
  2010年   88篇
  2009年   84篇
  2008年   83篇
  2007年   101篇
  2006年   67篇
  2005年   55篇
  2004年   56篇
  2003年   39篇
  2002年   40篇
  2001年   16篇
  2000年   19篇
  1999年   22篇
  1998年   46篇
  1997年   38篇
  1996年   43篇
  1995年   28篇
  1994年   22篇
  1993年   25篇
  1992年   13篇
  1991年   8篇
  1990年   9篇
  1989年   25篇
  1988年   24篇
  1987年   19篇
  1986年   24篇
  1985年   21篇
  1984年   6篇
  1983年   5篇
  1982年   18篇
  1981年   9篇
  1980年   13篇
  1979年   3篇
  1978年   6篇
  1977年   9篇
  1976年   9篇
  1975年   7篇
  1953年   2篇
排序方式: 共有2125条查询结果,搜索用时 15 毫秒
41.
42.
Apart from its classical function in bone and calcium metabolism, vitamin D is also involved in immune regulation and has been linked to various cancers, immune disorders and allergic diseases. Within the innate and adaptive immune systems, the vitamin D receptor and enzymes in monocytes, dendritic cells, epithelial cells, T lymphocytes and B lymphocytes mediate the immune modulatory actions of vitamin D. Vitamin D insufficiency/deficiency early in life has been identified as one of the risk factors for food allergy. Several studies have observed an association between increasing latitude and food allergy prevalence, plausibly linked to lower ultraviolet radiation (UVR) exposure and vitamin D synthesis in the skin. Along with mounting epidemiological evidence of a link between vitamin D status and food allergy, mice and human studies have shed light on the modulatory properties of vitamin D on the innate and adaptive immune systems. This review will summarize the literature on the metabolism and immune modulatory properties of vitamin D, with particular reference to food allergy.  相似文献   
43.
While Pakistan has made progress toward achieving Millennium Development Goal 5 for maternal health, it is unlikely to achieve the target; further, it is also not on track for Millennium Development Goal 4 regarding child health. Two low-cost, temperature stable and life-saving drugs, misoprostol and chlorhexidine, can respectively avert maternal and newborn deaths, and are particularly pertinent for poor and marginalized areas which bear the brunt of maternal and newborn deaths in Pakistan. In response, Mercy Corps led focused advocacy efforts to promote changes in policies, protocols, and regulatory environments for misoprostol (2012–2014) and for chlorhexidine (2014). These short-duration advocacy projects facilitated significant policy gains, such as inclusion of misoprostol and chlorhexidine into province-specific essential drug lists, development and endorsement of clinical protocols for the two drugs by provincial health departments, inclusion of misoprostol into pre-service training curriculum for several health cadres, and application for registration of chlorhexidine (at the concentration required for newborn care) by two pharmaceutical companies. These results were achieved by a consultative and evidence-based process which generated feedback from community members, program implementers, and policymakers, and ultimately put the government in the driver’s seat to facilitate change. Community Action Dialogue forums were linked with provincial-level Technical Working Groups and Provincial Steering Committees, who passed on endorsed recommendations to the Health Secretary. The key factors which facilitated change were the identification of champions within the provincial health departments, prioritization of relationship building and follow-up, focus on concrete advocacy aims rather than broad objectives, and the use of multi-stakeholder forums to secure an enabling environment for the policy changes to take root. While these advocacy initiatives resulted in significant policy changes in Pakistan’s devolved health system, to ensure these policy changes have an impact on health outcomes, Pakistan should focus on the scale-up of appropriate use of chlorhexidine and misoprostol. Further, future policy initiatives in Pakistan should make use of similar multi-stakeholder policy forums, while ensuring a third party to facilitate the process so that civil society and community voices are not lost in the policy development discussion.  相似文献   
44.
Clinical Rheumatology - To investigate the characteristics, evolution, and visual outcome of non-infectious uveitis. Records of 201 patients with non-infectious uveitis (136 (67.7%) males and 84...  相似文献   
45.
BACKGROUND: We have previously reported that chronic treatment with certain 'beta-blockers' reduces airway hyperresponsiveness (AHR) to methacholine in a murine model of asthma. METHODS: Airway resistance was measured using the forced oscillation technique in ovalbulmin-sensitized and ovalbulmin-challenged mice treated with several beta-adrenoceptor (beta-AR) ligands. We used the selective beta 2-AR ligand ICI 118,551 and the preferential beta 1-AR ligand metoprolol to investigate the receptor subtype mediating the beneficial effect. Expression of beta-ARs was evaluated using immunofluorescence. We evaluated several signaling proteins by western blot using lung homogenates, and measured the relaxation of the isolated trachea produced by EP2 and IP receptor agonists. RESULTS: Four findings were associated with the decreased AHR after chronic beta-blocker treatment: (1) the highly selective beta 2-AR antagonist/inverse agonist, ICI 118,551 produced the bronchoprotective effect; (2) beta 2-AR up-regulation resulted from chronic 'beta-blocker' treatment; (3) reduced expression of certain proteins involved in regulating bronchial tone, namely, Gi, phosphodiesterase 4D and phospholipase C-beta 1; and (4) an enhanced bronchodilatory response to prostanoid agonists for the IP and EP2 receptors. CONCLUSIONS: These data suggest that in the murine model of asthma, several compensatory changes associated with either increased bronchodilator signaling or decreased bronchoconstrictive signaling, result from the chronic administration of certain 'beta-blockers'.  相似文献   
46.
GH has been proposed as a therapy for patients with HIV-associated fat accumulation, but the pharmacological doses (6 mg/d) used have been associated with impaired fasting glucose and hyperglycemia. In contrast, physiologic doses of GH ( approximately 1 mg/d) in HIV-negative men reduced visceral adiposity and eventually improved insulin sensitivity, despite initially causing insulin resistance. We conducted an open-label study to evaluate the effects of a lower pharmacologic dose of GH (3 mg/d) in eight men with HIV-associated fat accumulation. Oral glucose tolerance, insulin sensitivity, and body composition were measured at baseline, and 1 and 6 months. Six patients completed 1 month and 5, 6 months of GH therapy. IGF-I levels increased 4-fold within 1 month of GH treatment. Over 6 months, GH reduced buffalo hump size and excess visceral adipose tissue. Total body fat decreased (17.9 +/- 10.9 to 13.5 +/- 8.4 kg, P = 0.05), primarily in the trunk region. Lean body mass increased (62.9 +/- 6.4 to 68.3 +/- 9.1 kg, P = 0.03). Insulin-mediated glucose disposal, measured by a euglycemic hyperinsulinemic clamp, declined at month 1 (49.7 +/- 27.5 to 25.6 +/- 6.6 nmol/kg(LBM).min/pmol(INSULIN)/liter, P = 0.04); values improved at month 6 (49.2 +/- 22.6, P = 0.03, compared with month 1) and did not differ significantly from baseline. Similarly, the integrated response to an oral glucose load worsened at month 1 (glucose area under the curve 20.1 +/- 2.3 to 24.6 +/- 3.7 mmol.h/liter, P < 0.01), whereas values improved at month 6 (22.1 +/- 1.5, P = 0.02, compared with month 1) and did not differ significantly from baseline. One patient developed symptomatic hyperglycemia within 2 wk of GH initiation; baseline oral glucose tolerance testing revealed preexisting diabetes despite normal fasting glucose. In conclusion, GH at 3 mg/d resulted in a decrease in total body fat and an increase in lean body mass in this open-label trial. While insulin sensitivity and glucose tolerance initially worsened, they subsequently improved toward baseline. However, the dose of GH used in this trial was supraphysiologic and led to an increase in IGF-I levels up to three times the upper normal range. Because there are known adverse effects of long-term GH excess, the effectiveness of lower doses of GH should be studied. We also recommend a screening oral glucose tolerance test be performed to exclude subjects at risk for GH-induced hyperglycemia.  相似文献   
47.
48.
49.
Objective:Spectral detector CT (SDCT) has many applications in advanced liver imaging. If appropriately utilized, this technology has the potential to improve image quality, provide new diagnostic information, and allow for decreased radiation dose. The purpose of this review is to familiarize radiologists with the uses of SDCT in liver imaging.Conclusion:SDCT has a variety of post-processing techniques, which can be used in advanced liver imaging and can significantly add value in clinical practice.  相似文献   
50.
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