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   19229篇
  免费   1359篇
  国内免费   71篇
耳鼻咽喉   342篇
儿科学   516篇
妇产科学   341篇
基础医学   2280篇
口腔科学   243篇
临床医学   1933篇
内科学   4360篇
皮肤病学   468篇
神经病学   1671篇
特种医学   676篇
外科学   2865篇
综合类   229篇
现状与发展   1篇
一般理论   18篇
预防医学   1755篇
眼科学   498篇
药学   1254篇
中国医学   25篇
肿瘤学   1184篇
  2023年   95篇
  2022年   164篇
  2021年   444篇
  2020年   270篇
  2019年   414篇
  2018年   529篇
  2017年   357篇
  2016年   419篇
  2015年   463篇
  2014年   674篇
  2013年   944篇
  2012年   1368篇
  2011年   1445篇
  2010年   793篇
  2009年   749篇
  2008年   1213篇
  2007年   1318篇
  2006年   1274篇
  2005年   1247篇
  2004年   1252篇
  2003年   1088篇
  2002年   958篇
  2001年   175篇
  2000年   158篇
  1999年   197篇
  1998年   244篇
  1997年   167篇
  1996年   143篇
  1995年   144篇
  1994年   130篇
  1993年   112篇
  1992年   111篇
  1991年   93篇
  1990年   70篇
  1989年   86篇
  1988年   77篇
  1987年   78篇
  1986年   81篇
  1985年   84篇
  1984年   89篇
  1983年   66篇
  1982年   93篇
  1981年   100篇
  1980年   84篇
  1979年   71篇
  1978年   56篇
  1977年   72篇
  1976年   44篇
  1975年   44篇
  1974年   45篇
排序方式: 共有10000条查询结果,搜索用时 208 毫秒
51.
Alex  Neil 《JAMA》2004,291(24):3017
  相似文献   
52.
The dbl oncogene was initially isolated from a human diffuse B-cell lymphoma. Antisera from mice bearing tumors induced by this oncogene specifically detected a protein of about 66 kDa (p66) in dbl transformants. dbl cDNA-selected poly(A)+ RNA isolated from a transfectant clone expressing p66 directed the in vitro synthesis of this protein, establishing that it is encoded by dbl. Subcellular localization studies revealed that p66 is a cytoplasmic protein distributed between cytosol and crude membrane fractions. Moreover, p66 was shown to be a phosphoprotein, with phosphorylation specific to serine residues. Our characterization of the dbl-encoded protein appears to distinguish this transforming gene product from those of other known oncogenes.  相似文献   
53.
54.
BACKGROUND: Pravastatin and simvastatin prolong survival and reduce transplant-related coronary vasculopathy, although low-density lipoprotein (LDL) lowering with these agents is only modest. The objective of this study was to assess the safety of moderate dose atorvastatin and its efficacy when prior treatment with another statin had failed to lower LDL to < 100 mg/dl. METHODS: Data from 185 patients were retrospectively evaluated for adverse events, duration of exposure (person-days), and the mean atorvastatin dose exposure. Changes in lipid parameters, and prednisone and cyclosporine doses were determined. RESULTS: Safety: 48 patients received atorvastatin for 24,240 person-days at a mean dose exposure of 21 +/- 10 mg. Rhabdomyolysis, myositis, myalgias, and hepatotoxicity occurred in 0, 2, 2, and 0 patients, respectively. All events occurred at the 10-mg dose, within the first 3 months, and were rapidly reversible with atorvastatin discontinuation. Efficacy: Thirty-four patients evaluable for efficacy analyses had a pre-atorvastatin LDL of 145 +/- 38 mg/dl on the following statins: pravastatin (n = 30, 40 +/- 0mg), fluvastatin (n = 3, 33 +/- 12 mg), simvastatin (n = 1, 40 mg). After atorvastatin (21 +/- 9 mg/day) for 133 +/- 67 days, LDL was reduced to 97 +/- 24 mg/dl (relative reduction 31 +/- 20%, p < 0.0001). At the end of the observation period (418 +/- 229 days, atorvastatin final dose 24 +/- 14 mg/day), LDL was further decreased to 88 +/- 23 mg (relative reduction 37 +/- 17%, p < 0.0001). CONCLUSION: Atorvastatin, when used at moderate doses and with close biochemical and clinical monitoring, appears to be safe and is effective in aggressively lowering LDL in heart transplant recipients when treatment with other statins has failed to achieve LDL goals.  相似文献   
55.
Pregnant mice were exposed to one of five regimens at 9.5 days of gestation: no treatment (group 1), intraperitoneal injection of normal saline (group 2), intraperitoneal injection of gadopentetate dimeglumine (group 3), intraperitoneal injection of gadopentetate dimeglumine and magnetic resonance (MR) exposure (group 4), and MR exposure alone (group 5). At 18 days of gestation, the mice were sacrifice and fetuses were removed and examined for the following end points: litter size, number alive or dead, fetal weight, extremity morphology, eye and ear development, and appearance of the head. A total of 739 fetuses were analyzed: group 1 (n = 161), group 2 (n = 149), group 3 (n = 142), group 4 (n = 136), and group 5 (n = 151). The only statistically significant difference was a lower mean fetal weight in the saline-injection group compared with the control group. The results show that MR exposure with and without gadopentetate dimeglumine had no adverse effect on the end points analyzed.  相似文献   
56.
Objectives: To evaluate a group intervention to help individuals with psychiatric disorder stop smoking.
Method: A waitlist-treatment crossover design. Outcome measures included smoking cessation, motivation to stop, the Fagerstrom Test for Nicotine Dependence (FTND), urinary cotinine and psychiatric symptoms on the General Health Questionnaire.
Results: 38 subjects participated, of whom 19 completed the waitlist and intervention phases. There were no significant differences between subjects and dropouts. During the waitlist period there were no significant changes in tobacco use. At the end of the intervention, almost a quarter had stopped smoking, ( z = -2.24, p =0.02). Subjects also showed significant improvements on state of change, FTND score and urinary cotinine levels. These improvements were maintained at three-month follow-up (n=10). Psychiatric morbidity showed no change.
Conclusions: It is possible to reduce smoking in individuals with psychiatric disorder.
Implications: Larger randomised controlled trials are indicated to determine the relative contributions of nicotine replacement, bupropion and group interventions to smoking cessation in this population.  相似文献   
57.
58.

Background and Purpose:   

Management of rib fractures constitutes a major part of the trauma workload of any unit. Rib fractures result in disrupted chest wall mechanics and ventilatory insufficiency. The ability of a lung injury scoring system to predict the degree of respiratory dysfunction after rib fractures was evaluated.  相似文献   
59.
BACKGROUND: Interdialytic weight gain (IDWG) can be reduced by lowering the dialysate sodium concentration ([Na]) in haemodialysis patients. It has been assumed that this is because thirst is reduced, although this has been difficult to prove. We compared thirst patterns in stable haemodialysis patients with high and low IDWG using a novel technique and compared the effect of low sodium dialysis (LSD) with normal sodium dialysis (NSD). METHODS: Eight patients with initial high IDWG and seven with low IDWG completed hourly visual analogue ratings of thirst using a modified palmtop computer during the dialysis day and the interdialytic day. The dialysate [Na] was progressively reduced by up to 5 mmol/l over five treatments. Dialysis continued at the lowest attained [Na] for 2 weeks and the measurements were repeated. The dialysate [Na] then returned to baseline and the process was repeated. RESULTS: Baseline interdialytic day mean thirst was higher than the dialysis day mean for the high IDWG group (49.9+/-14.0 vs 36.2+/-16.6) and higher than the low weight gain group (49.9+/-14.0 vs 34.1+/-14.6). This trend persisted on LSD, but there was a pronounced increase in post-dialysis thirst scores for both groups (high IDWG: 46+/-13 vs 30+/-21; low IDWG: 48+/-24 vs 33+/-18). The high IDWG group demonstrated lower IDWG during LSD than NSD (2.23+/-0.98 vs 2.86+/-0.38 kg; P<0.05). CONCLUSIONS: Our results indicate that patients with high IDWG experience more intense feelings of thirst on the interdialytic day. LSD reduces their IDWG, but paradoxically increases thirst in the immediate post-dialysis period.  相似文献   
60.
With the exception of post-exposure prophylaxis for reported rape, no preventive strategy addresses the choice disabled – those who might like to benefit from AIDS prevention but who are unable to do so because they do not have the power to make and to act on prevention decisions. In southern African countries, where one in every three has been forced to have sex by the age of 18 years, a very large proportion of the population is choice disabled. This group is at higher risk of HIV infection and unable to respond to AIDS prevention programmes; they represent a reservoir of infection. Reduction of sexual violence would probably decrease HIV transmission directly, but also indirectly as more people can respond to existing AIDS prevention programmes.  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