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   16007篇
  免费   1421篇
  国内免费   32篇
耳鼻咽喉   212篇
儿科学   633篇
妇产科学   443篇
基础医学   1995篇
口腔科学   140篇
临床医学   1849篇
内科学   2899篇
皮肤病学   288篇
神经病学   1780篇
特种医学   324篇
外科学   1799篇
综合类   122篇
一般理论   21篇
预防医学   2392篇
眼科学   345篇
药学   1034篇
  1篇
中国医学   18篇
肿瘤学   1165篇
  2024年   49篇
  2023年   328篇
  2022年   485篇
  2021年   970篇
  2020年   571篇
  2019年   822篇
  2018年   903篇
  2017年   612篇
  2016年   627篇
  2015年   624篇
  2014年   787篇
  2013年   949篇
  2012年   1409篇
  2011年   1372篇
  2010年   689篇
  2009年   541篇
  2008年   882篇
  2007年   848篇
  2006年   660篇
  2005年   626篇
  2004年   497篇
  2003年   440篇
  2002年   353篇
  2001年   108篇
  2000年   101篇
  1999年   114篇
  1998年   71篇
  1997年   51篇
  1996年   49篇
  1995年   38篇
  1994年   37篇
  1993年   43篇
  1992年   63篇
  1991年   58篇
  1990年   65篇
  1989年   55篇
  1988年   44篇
  1987年   44篇
  1986年   36篇
  1985年   39篇
  1984年   25篇
  1983年   22篇
  1982年   20篇
  1981年   25篇
  1979年   31篇
  1978年   24篇
  1974年   22篇
  1973年   20篇
  1970年   19篇
  1968年   17篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
51.
52.
53.
Although breast milk is recommended as the optimal source of infant nutrition, breastfeeding initiation is below recommended levels, especially among teenage mothers. Breastfeeding initiation rates among Michigan (US) teenage mothers (12-19 y) were compared by demographics and health behaviors. Multivariate analyses determined which factors were significant independent predictors of breastfeeding initiation among teenage mothers enrolled prenatally in the Michigan Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) program in 1995. Significant predictors independently associated with breastfeeding initiation were race/ethnicity, education, marital status, postpartum anemia status, parity, prenatal trimester of WIC enrollment, and smoking. The strongest predictor of breastfeeding initiation differed for white mothers (positive predictor: education beyond high school [OR = 3.13]) and black mothers (negative predictor: multiparous [OR = 0.25]). Initiation rates for this population of teenage mothers fall below the national average for mothers of all ages and the US Healthy People 2010 goals. Research is needed concerning how breastfeeding support and education can be improved to reach the US national health goals.  相似文献   
54.
Chronic rejection is the major hurdle to long-term survival after lung transplantation. Endobronchial infection with Pseudomonas aeruginosa is common in patients with chronic rejection and this may further contribute to deterioration of the allograft. Inhaled tobramycin is commonly used to treat P aeruginosa airways infection in patients with cystic fibrosis. The safety of inhaled tobramycin in transplant recipients, however, has not been established. We describe the first report of a lung transplant recipient who developed renal failure and vestibular injury after receiving inhaled tobramycin. We review the literature regarding the safety of inhaled tobramycin and discuss potential mechanisms that may promote systemic toxicity in transplant recipients.  相似文献   
55.
Dapsone, used for prevention of Pneumocystis jirovecii infections, has been reported to cause hemolytic anemia and methemoglobinemia; its tolerability in solid organ transplant recipients is not well described. We investigated dapsone-related adverse events in patients undergoing solid organ transplantation from 1999 to 2004. Transplant providers identified patients for the investigators who then reviewed the patients' hospital and outpatient records. Sixteen solid organ transplant recipients fit case definitions for dapsone-related hemolytic anemia (n = 11) or methemoglobinemia (n = 5). Median time from event to dapsone discontinuation was 15 days; all patients improved after drug discontinuation. G6PD enzyme activity was normal in all patients whose test results were available. Dapsone may be associated with hemolytic anemia or methemoglobinemia, even with normal G6PD levels. These events are often not promptly recognized, and drug discontinuation is delayed. Dapsone-related hemolytic anemia or methemoglobinemia should be considered in solid organ transplant recipients with unexplained anemia or hypoxia.  相似文献   
56.
K B Saunders  S S Fernando  H R Dalton    A Joseph 《Thorax》1994,49(7):725-727
A 37 year old patient with chronic active hepatitis progressing to cirrhosis presented with increasing breathlessness and was found to be hypoxic with finger clubbing. A progressive exercise study with measurement of oxygen saturation (SaO2) showed abnormally high ventilation and desaturation to 81% at 100 W. Serial studies over nearly two years showed, first, deterioration, then improvement with lower ventilation and higher saturation levels at all work loads. This could not be correlated with any change in treatment with azathioprine, prednisolone, or propranolol.  相似文献   
57.
58.
Two enzyme immunoassays (EIAs) detecting Chlamydia trachomatis from endocervical swabs, Syva MicroTrak (MT) and Abbott Chlamydiazyme (CZ), were compared with a tissue culture (TC) standard. Initially, 8% (100 of 1250) of specimens were TC positive, yielding sensitivities of 94% (94 of 100) for MT and 79% (79 of 100) for CZ with identical 98% specificities (1129 of 1150 for MT and 1130 of 1150 for CZ). Discrepant specimens were retested by both EIAs and assayed for elementary bodies (EBs) by a fluorescent antibody test. After discrepancy analysis, 9.5% (118) of 1240 patients were either TC or EB positive, yielding sensitivities of 94.1% for MT (111 of 118) and 79.7% for CZ (94 of 118) with identical specificities of 100% (1122 of 1122). These results indicate that the MT is significantly more sensitive (p less than 0.05, McNemar test) than CZ in detecting C. trachomatis from endocervical swabs.  相似文献   
59.
Using radio-biotelemetry, the timecourse of recovery and sensitivity to ambient temperature (Ta) of the thermogenic response of methylenedioxymethamphetamine (MDMA or “Ecstasy”) was examined. Ambient temperatures of 17 and 22°C produced very different response profiles, with the lower temperature producing a hypothermic response to 10 and 15 mg/kg doses of MDMA, and the higher temperature producing a profound hyperthermia to the same doses. Although the peak responses to the drug had subsided within 5 h of administration, residual effects, in the form of an elevation of body temperature during the “low” phase of the diurnal cycle, were present for a further 48 h. Long-lasting disruption of the thermoregulatory system following a short series of MDMA administrations (10 mg/kg once per day for 4 days) was shown by exposing the rats in the undrugged state to a thermoregulatory challenge, consisting of 60-min exposure to a Ta of 30°C, at 1 week before, and at 4 weeks and 14 weeks after the drug administration. MDMA-treated rats showed a prolonged hyperthermic response to the challenge at both post-drug intervals compared with fenfluramine-treated rats and saline-treated controls. Thus, the results indicate both that MDMA’s thermogenic effects are more sensitive to Ta than previously demonstrated, and that the serotonergic neurotoxicity of the drug may produce long-lasting changes in thermoregulatory mechanisms. Received: 7 December 1997/Final version: 23 January 1998  相似文献   
60.
Exposure to low levels of cadmium reduces fertility. In male mice spermatogenesis is highly sensitive to cadmium, whereas in females the peri-implantation period of pregnancy is sensitive. To examine the potential roles of the cadmium-binding protein, metallothionein (MT), in the reproductive toxicology of cadmium, we examined a transgenic mouse strain that overexpresses metallothionein-I (MT-I). These mice had dramatically increased steady-state levels of MT-I mRNA and MT in the testes and in the female reproductive tract during the peri-implantation period of pregnancy, and this overexpression occurred in a cell-specific and temporally regulated manner similar to that of the endogenous MT-I gene. Transgenic and control males were injected with cadmium, and the histology of the testes was examined. An injection of 7.5 mumol Cd/kg had no effect on histology of the testes in either transgenic or control mice. In contrast, an injection of 10 mumol Cd/kg caused rapid changes in the histology of the testes and resulted in pronounced testicular necrosis in both control and transgenic mice. Female transgenic and control mice were mated and then injected with cadmium (30-45 mumol Cd/kg) on the day of blastocyst implantation (day 4). In both of these groups, injection of cadmium reduced pregnancy rate, and no dramatic protection was afforded by maternal and/or embryonic overexpression of MT. Thus, overexpression of MT-I does not significantly protect against either of these cadmium-induced effects on fertility.  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