收费全文 | 6421篇 |
免费 | 454篇 |
国内免费 | 27篇 |
耳鼻咽喉 | 38篇 |
儿科学 | 234篇 |
妇产科学 | 114篇 |
基础医学 | 780篇 |
口腔科学 | 169篇 |
临床医学 | 481篇 |
内科学 | 1564篇 |
皮肤病学 | 79篇 |
神经病学 | 241篇 |
特种医学 | 241篇 |
外国民族医学 | 2篇 |
外科学 | 634篇 |
综合类 | 408篇 |
一般理论 | 2篇 |
预防医学 | 783篇 |
眼科学 | 144篇 |
药学 | 553篇 |
中国医学 | 69篇 |
肿瘤学 | 366篇 |
2023年 | 46篇 |
2022年 | 131篇 |
2021年 | 275篇 |
2020年 | 139篇 |
2019年 | 190篇 |
2018年 | 174篇 |
2017年 | 153篇 |
2016年 | 168篇 |
2015年 | 181篇 |
2014年 | 228篇 |
2013年 | 299篇 |
2012年 | 524篇 |
2011年 | 452篇 |
2010年 | 282篇 |
2009年 | 250篇 |
2008年 | 343篇 |
2007年 | 328篇 |
2006年 | 305篇 |
2005年 | 301篇 |
2004年 | 241篇 |
2003年 | 232篇 |
2002年 | 177篇 |
2001年 | 142篇 |
2000年 | 127篇 |
1999年 | 120篇 |
1998年 | 79篇 |
1997年 | 69篇 |
1996年 | 70篇 |
1995年 | 64篇 |
1994年 | 38篇 |
1993年 | 42篇 |
1992年 | 67篇 |
1991年 | 54篇 |
1990年 | 45篇 |
1989年 | 68篇 |
1988年 | 47篇 |
1987年 | 35篇 |
1986年 | 51篇 |
1985年 | 44篇 |
1984年 | 38篇 |
1983年 | 33篇 |
1982年 | 27篇 |
1981年 | 25篇 |
1980年 | 26篇 |
1979年 | 26篇 |
1978年 | 19篇 |
1977年 | 13篇 |
1975年 | 18篇 |
1973年 | 16篇 |
1972年 | 12篇 |
This study aimed to determine the seroprevalence and determinants of hepatitis B virus (HBV) infection among university students in Bangladesh. This cross-sectional study was conducted among 614 students from five universities in central Bangladesh. Data were collected on demographic information, immunization history, medical and blood transfusion history through the face-to-face interview. Blood samples were collected and screened for anti-HBsAg using ELISA, HBsAg Rapid Test-cassette, and immune chromatographic test. The overall seroprevalence of HBV infection was 5.0%, and vaccination coverage was 19.2% among the participants. Students having a history of surgery (OR 11.004, 95% CI 3.211–37.707), blood transfusion (OR 5.651, 95% CI 0.965–33.068), being married (OR 4.776, 95% CI 1.508–15.127), and not being vaccinated (OR 9.825, 95% CI 1.130–85.367) were at higher risk of being infected by HBV. This study showed the endemicity of HBV infection among the Bangladeshi population. Marriage, surgical or blood transfusion history, not being vaccinated were the determinants of HBV infection within the study population. Public health initiatives for preventing HBV infection at the university levels should be envisaged.
相似文献Exceptional precautionary measures have been adopted to stop the transmission and control of COVID-19 through the world and Pakistan is facing lockdown in this scenario. Public loyalty to precautionary measures is affected by their knowledge, attitude, risk factors and practices (KAP) towards COVID-19. The present study was conducted among the Pakistani residents to observe the knowledge, attitude, practices and risk factors towards COVID-19 outbreak in Pakistan. A questionnaire was designed, and a cross-sectional survey was conducted among participants of the study area. Participants were asked the questions regarding knowledge, attitude, practices and risk factors towards COVID-19. Data were analyzed by SPSS and t/F test and correlation was applied among the knowledge, attitude, risk factors and practices. A total of 1060 questionnaires were received. 1004 were included while 56 were excluded. The highest representation was from Punjab province (65.6%), female (63%) and age group of 21–30 years (62.1%). Most participants were single (85%), Muslim (99.4%), Urdu speaking (45.6%) and were graduates (51.5%). Most of the participants were students (52.9%) and were from economically middle-class families (40.8%). The knowledge was positively correlated with attitude and practices whereas negatively correlated with risk factors (P?<?0.05). The attitude was negatively correlated with risk factor and positively correlated with practices. The risk factors and practices were positively correlated with each other. Health education program to improve the COVID-19 knowledge, attitude, practices and risk factors should be initiated to combat current health challenge.
相似文献Methods. Twenty neonatal piglets underwent 60 minutes of ventilator hypoxia (FiO2 8% to 10%) followed by 20 minutes of normothermic ischemia on cardiopulmonary bypass (hypoxic-ischemic stress). They then underwent 70 minutes of multidose blood cardioplegic arrest. Five (Group 1), received a hypocalcemic (Ca+2 0.2 to 0.4 mM/L) cardiologic solution without magnesium, whereas in 10, magnesium was added at either a low dose (5 to 6 mEq/L, Group 2) or high dose (10 to 12 mEq/L, Group 3). In the last 5 (Group 4), magnesium (10 to 12 mEq/L) was added to a normocalcemic cardioplegic solution. Function was assessed using pressure volume loops and expressed as percentage of control.
Results. Compared to hypocalcemia cardioplegic solution without magnesium (Group 1), both high- and low-dose magnesium enrichment (Groups 2 and 3) improved myocardial protection resulting in complete return of systolic (40% vs 101% vs 102%) (p < 0.001 vs Groups 2 and 3) and global myocardial function (39% vs 102% vs 101%) (p < 0.001 vs Groups 2 and 3), and reduced diastolic stiffness (267% vs 158% vs 154%) (p < 0.001 vs Groups 2 and 3). Conversely, even high-dose magnesium supplementation could not offset the detrimental effects of normocalcemic cardioplegia resulting in depressed systolic (End Systolic Elastance [EES] 41% ± 1%) (p < 0.001 vs Groups 2 and 3) and global myocardial function (40% ± 1%) (p < 0.001 vs Groups 2 and 3), and a marked rise in diastolic stiffness (258% ± 5%) (p < 0.001 vs Groups 2 and 3). Hypocalcemic magnesium cardioplegia has now been used successfully in 247 adult and pediatric patients.
Conclusions. Magnesium enrichment of hypocalcemic cardioplegic solutions improves myocardial protection resulting in complete functional preservation. However, magnesium cannot prevent the detrimental effects of normocalcemic cardioplegia when the heart is severely stressed. This study, therefore, strongly supports using both a hypocalcemic cardioplegic solution and magnesium supplementation as their benefits are additive. 相似文献