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   310篇
  免费   20篇
  国内免费   6篇
耳鼻咽喉   1篇
儿科学   16篇
妇产科学   5篇
基础医学   55篇
口腔科学   1篇
临床医学   31篇
内科学   82篇
皮肤病学   4篇
神经病学   13篇
特种医学   19篇
外科学   25篇
综合类   19篇
预防医学   42篇
眼科学   5篇
药学   9篇
中国医学   5篇
肿瘤学   4篇
  2024年   2篇
  2023年   4篇
  2022年   4篇
  2021年   5篇
  2020年   5篇
  2019年   5篇
  2018年   9篇
  2017年   3篇
  2016年   6篇
  2015年   8篇
  2014年   11篇
  2013年   12篇
  2012年   20篇
  2011年   12篇
  2010年   15篇
  2009年   13篇
  2008年   19篇
  2007年   21篇
  2006年   22篇
  2005年   9篇
  2004年   17篇
  2003年   9篇
  2002年   9篇
  2001年   8篇
  2000年   5篇
  1999年   7篇
  1998年   4篇
  1997年   9篇
  1996年   6篇
  1995年   3篇
  1994年   9篇
  1993年   7篇
  1992年   3篇
  1991年   5篇
  1990年   2篇
  1988年   4篇
  1987年   7篇
  1986年   1篇
  1985年   2篇
  1983年   2篇
  1982年   2篇
  1981年   3篇
  1980年   1篇
  1978年   1篇
  1976年   1篇
  1975年   1篇
  1974年   2篇
  1968年   1篇
排序方式: 共有336条查询结果,搜索用时 15 毫秒
1.
2.
Paediatric dacryocystorhinostomy   总被引:1,自引:0,他引:1  
Of 258 cases of dacryocystorhinostomy performed on children in the period September 1981 to September 1991, 130 were for simple, unresolved congenital nasolacrimal duct obstruction. Other indications for surgery included punctal agenesis, lacrimal fistula, post-traumatic and post-inflammatory canalicular obstruction. Of 177 children without canalicular pathology, 171 (96%) were relieved of symptoms with one operation, without canalicular intubation. Of 81 cases with canalicular disease, 55 of 70 (79%) who underwent DCR plus canalicular intubation, and 10 of 11 who underwent DCR plus Lester-Jones tube, were substantially improved with one operation. No child required peroperative or postoperative blood transfusion. Dacryocystorhinostomy in childhood, in experienced surgical hands, is a safe procedure, achieving relief of symptoms in most cases, particularly in the absence of canalicular disease.  相似文献   
3.
In this century, the use of pesticides and fertilizers (agrochemicals) is indispensable because they are seen as a panacea for protecting crops from insects and diseases. However, the manner in which these agrochemicals are handled poses significant health risks to manufacturers, transporters, vendors and farmers. In Kenya, for example, coffee factory workers (specifically storekeepers) apportion the agrochemicals and sell them to the coffee farmers. The process of apportioning and other factors expose these workers to health risks. In order to evaluate the extent of the problem, a pilot study was undertaken in the Githuguri location. The results showed that lack of use of protective clothing, poor handling of agrochemicals and poorly designed storage facilities were very common. As a result, 95% of the workers interviewed reported a variety of agrochemical health related problems. In conclusion, the government and the public role regarding possible preventive measures were proposed.  相似文献   
4.
5.
Previous studies have demonstrated the development of an age-dependent resistance to reinfection after chemotherapeutic cure of the helminthic parasite Schistosoma mansoni. Here we report on a longitudinal investigation of cell-mediated responses in infected individuals before and after treatment which was designed to outline those parameters important in mediating a protective response. A well-defined study group of 89 individuals with an age range of 9 to 35 years was selected from an area of high S. mansoni transmission in the Machakos district of Kenya. Peripheral blood mononuclear cell proliferation and cytokine production (interleukin-2 [IL-2], gamma interferon IL-5, IL-4, and tumor necrosis factor) in response to different crude life cycle-stage antigens of S. mansoni were assessed longitudinally in vitro before, 3 months after, and 1 year after treatment. Detailed statistical analyses of the results from this study have indicated a clear negative association between the proliferative responses to adult- and schistosomulum-stage antigens and subsequent reinfection intensity in older individuals (14 to 35 years) which was not present in the younger individuals (9 to 13 years). This association was significant even after the effects of age, sex, and exposure had been accounted for in multiple regression analyses. Cytokines were detected predominantly in response to adult worm and egg antigen extracts. An inverse association between the two cytokines gamma interferon and IL-5 was detected in response to all antigens at the three time points investigated, indicating cross-regulation in the production of these two mediators. Differences in antigen-specific cytokine levels between the two age groups were detected, with significantly higher IL-5 levels detected in the older (more resistant) age group. An inverse correlation between this cytokine and reinfection was detected but could not be dissociated from the effects of age and exposure in multiple regression analysis.  相似文献   
6.
7.
恶性肿瘤患者血清与尿液中一氧化氮含量测定   总被引:1,自引:1,他引:0  
0 引言一氧化氮(Nitric oxide,NO)是一种具有活跃生物化学性质的无机小分子. NO对许多肿瘤细胞和微生物有细胞毒性[1],为探讨NO与肿瘤的关系,我们检测了119例恶性肿瘤患者血清及尿液中的NO.  相似文献   
8.
Khat products and chewing practices are common in East Africa, Middle East for centuries with concomitant socio-economic and public health repercussions. We assessed memory deficits associated with khat use in rodents. Young male CBA mice, 5–7 weeks old (n?=?20), weighing 25–35 g were used. Mice were treated with either 40, 120 or 360 mg/kg body weight (bw) methanolic khat extract, or 0.5 ml saline for 10 days. Spatial acquisition, reversal and reference memory were assessed using modified Morris Water maze (MMWM). Mice treated with 40 mg/kg khat extract had longer (t4?=?4.12 p?=?0.015) and t4?=?2.28 p?=?0.065) escape latency on first and second day during reversal relative to the baseline. Under 120 mg/kg khat dose, the escape latency was shorter (t4?=??2.49 p?=?0.05) vs (t3?=??2.5 p?=?0.05) on third and fourth day. Further, treatment with 360 mg/kg khat extract resulted in significantly longer time (49.13, 33.5, 40.2 and 35.75) vs. (23.5 s), compared to baseline. Mice treated with khat or control preferred the target quadrant post acquisition while differential pattern was seen during reversal phase. Mice treated with 40 or 120 mg/kg khat showed significant preference for target quadrant. Substantial time (19.9) was spent in the old target compared to the new (16.9 s) by animals treated with highest dose however, the difference was not significant. There is a biological plausibility that chronic khat use may induce memory deficits and impair cognitive flexibility. The differential patterns of memory deficits may reflect the differences in dose effect as well as time dependent impairment.  相似文献   
9.
In Kenya, the median incubation time to AIDS in seroconverting sex workers is 4 years; this incubation time is specific to female sex workers. We studied the influence of acute sexually transmitted infections (STIs) on several immunologic parameters in 32 human immunodeficiency virus type 1 (HIV-1)-positive and 10 HIV-1-negative women sex workers who were followed for 1-5 months. Plasma cytokines, soluble cytokine receptors, CD4 and CD8 T cell counts, and HIV-1 plasma viremia were quantitated before, during, and after episodes of STI. Increases in interleukin (IL)-4, IL-6, IL-10, soluble tumor necrosis factor (TNF)-alpha, and viremia and a decline in CD4(+) T cell counts occurred during gonococcal cervicitis and returned to baseline after treatment. Increases in viremia correlated with increased IL-4 and decreased IL-6 concentrations. Similar changes were seen among women with acute pelvic inflammatory disease. Acute bacterial STI resulted in increased HIV-1 viremia. This may be mediated through increased inflammatory cytokines or through modulation of immune responses that control HIV-1 viremia.  相似文献   
10.
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