全文获取类型
收费全文 | 25380篇 |
免费 | 1830篇 |
国内免费 | 48篇 |
专业分类
耳鼻咽喉 | 117篇 |
儿科学 | 1036篇 |
妇产科学 | 860篇 |
基础医学 | 2925篇 |
口腔科学 | 312篇 |
临床医学 | 4141篇 |
内科学 | 4764篇 |
皮肤病学 | 444篇 |
神经病学 | 2366篇 |
特种医学 | 384篇 |
外科学 | 2040篇 |
综合类 | 349篇 |
一般理论 | 28篇 |
预防医学 | 3778篇 |
眼科学 | 365篇 |
药学 | 1570篇 |
中国医学 | 34篇 |
肿瘤学 | 1745篇 |
出版年
2023年 | 181篇 |
2022年 | 234篇 |
2021年 | 403篇 |
2020年 | 346篇 |
2019年 | 554篇 |
2018年 | 634篇 |
2017年 | 514篇 |
2016年 | 552篇 |
2015年 | 614篇 |
2014年 | 838篇 |
2013年 | 1333篇 |
2012年 | 1964篇 |
2011年 | 1929篇 |
2010年 | 1089篇 |
2009年 | 1024篇 |
2008年 | 1655篇 |
2007年 | 1819篇 |
2006年 | 1698篇 |
2005年 | 1751篇 |
2004年 | 1662篇 |
2003年 | 1502篇 |
2002年 | 1450篇 |
2001年 | 231篇 |
2000年 | 187篇 |
1999年 | 204篇 |
1998年 | 294篇 |
1997年 | 218篇 |
1996年 | 193篇 |
1995年 | 201篇 |
1994年 | 175篇 |
1993年 | 152篇 |
1992年 | 119篇 |
1991年 | 99篇 |
1990年 | 110篇 |
1989年 | 100篇 |
1988年 | 76篇 |
1987年 | 72篇 |
1986年 | 75篇 |
1985年 | 92篇 |
1984年 | 99篇 |
1983年 | 71篇 |
1982年 | 93篇 |
1981年 | 77篇 |
1980年 | 71篇 |
1979年 | 52篇 |
1978年 | 55篇 |
1977年 | 42篇 |
1975年 | 35篇 |
1973年 | 24篇 |
1972年 | 31篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Smart Robert C.; Huang Mou-Tuan; Chang Richard L.; Sayer Jane M.; Jerina Donald M.; Conney Allan H. 《Carcinogenesis》1986,7(10):1663-1667
The effect of ellagic acid and some of its more lipophilk derivativeson the mutagenicity of (? )-7ß, 8-di-hydroxy-9 10-epoxy-7,8, 910-etrahydrobenz[a]pyrene was examined in Salmonella typhimuriumTA100. Ellagic acid, 3, 3' -di-O-methylellagic add, 4, 4' -di-O-methylellagicacid and 3-O-decyiellagic acid were found to have approximatelyequal antimutagenic activity. The tissue distribution and eliminationof ellagic add, 3, 3' -di-O-methyleCagic add and 3-O-decylellagicacid were examined in CD-I mice. Little or no ellagic acid (<1 nmol/g) was found in blood, lung or liver after the oral administrationby gavage of 300 µunol of ellagic acid per kg body weightor after feeding 1% of ellagic acid in the diet for 1 week.Following the i.p. administration of 120 µmol/kg of ellagicacid, the blood and lung levels of ellagic acid were 1520nmol/g at 30 min after the dose, and the concentrations of ellagicacid decreased to 13 nmol/g at 68 h after thedose. A portion of the administered i.p. dose precipitated inthe abdominal cavity. After i.v. administration, ellagic acidwas eliminated very rapidly from blood, lung and liver, and 70% of the administered dose was recovered in the urine andfeces as free ellagic acid and its conjugates. At 2 h afteran i.v. injection of 60 µ/kg of ellagic add, 46% of thedose was recovered in the urine as ellagic acid and its conjugates.Of this amount, about half was excreted as free ellagic acidand half was excreted as conjugates. An additional 25% of thedose was recovered in the feces (mostly as free ellagic acid)after 7 h. The disposition of 3, 3' -di-O-methylelIagic acidor 3O-decyIellagic acid after i.v. administration (32µmol;sol;kg) was examined and compared to the dispositionof the same i.v. dose of ellagic acid. The concentrations ofellagic acid, 3,3' -di-O-methylellagic acid and 3-O-decytellagicadd decreased rapidly in the blood, liver and lung, but theconcentrations of 3-O-decylellagic add in the lung throughoutthe experimental period (2360 min) was on average 20-to 40-fold higher than the corresponding average concentrationsof ellagic acid or 3, 3' -di-O-methylellagic acid. 相似文献
92.
Jane F. Gibson Robert K. Poole Martin N. Hughes John F. Rees 《Archives of environmental contamination and toxicology》1986,15(5):519-523
The toxicity and possible accumulation of ruthenium nitrosyl complexes by marine bacteria and test organisms have been studied, A range of these complexes show no toxic effects towardsEscherichia coli K12 at concentrations of mM and below. Yeasts are more sensitive, showing effects on growth at 10 M. The ruthenium nitrosyl complexes tested are unable to permeate the cytoplasmic membrane ofE. coli. This may account for their lack of toxicity. However, these compounds did not have significant inhibitory effects on Mg2+-ATPase activity in cell-extracts, I50 values lying in the range 2 to 125 mol(mg protein)–1. Marine bacteria are capable of taking up ruthenium complexes from simulated effluent, but this cannot be demonstrated in the presence of sediment which competes effectively for binding of complexes. There is minimal likelihood of concentration of ruthenium compounds from effluents by marine bacteria. 相似文献
93.
Mary Jane Yagi Mohammed Zanjani James F. Holland J. George Bekesi 《Cancer chemotherapy and pharmacology》1984,12(2):70-76
Summary A new synthetic tripeptide (p-F-Phe-m-bis-(2-chloroethyl)amino-Phe-Met ethoxy HCl), PTT.119, was demonstrated to have significant cancericidal activity against seven in vitro tumor cell lines of different origins and etiologies and against primary human AMML, ALL, and hairy cell leukemias. Viabilities of each murine tumor and rabbit, marmoset, and human leukemia and lymphoma line were significantly reduced by treatment with 1–50 g PTT.119 in media containing serum. Continuous 24-h exposure or pulse treatment as short as 15 and 30 min with the tripeptide resulted in irreversible damage to the tumor cells. Under identical treatment conditions, freshly isolated human leukemic cells, particularly ALL lymphoblasts, were even more susceptible to PTT.119 than any of the tested tumor cell models.Examination of the parameters of PTT.119 activity revealed that reductions of tumor cell survival were dependent on the concentration of the tripeptide. Prolongation of PTT.119 exposure from 15 min to 24 h increased the rates of tumor cell death but did not proportionally reduce the numbers of surviving cells. Assessment of tumor cell viabilities for 5 consecutive days following pulse exposure to PTT.119 demonstrated increasing reductions in tumor cell survival, which were greatest 5 days after treatment with the tripeptide.The cancericidal activity of PTT.119 was compared with its three parental components either as individual agents or as a mixture. Both the alkylator moiety, m-sarcolysin (m.L.SL) alone or together with p-fluoro-phenylalanine and l-methionine ethoxy HCl, and l-PAM (l-phenylalanine mustard), the p-isomer of m.L.SL, were 1.5- to 3-fold less cytotoxic to L1210 leukemia and MJY-alpha mammary tumor cells than PTT.119. Covalent linkage of the amino acid residues to m.L.SL yielded a molecule with greatly augmented cancericidal activity capable of acting against a broad spectrum of tumor cells. 相似文献
94.
Jiao Boshen Hankins Jane S. Devine Beth Barton Martha Bender M. Basu Anirban 《Quality of life research》2022,31(9):2729-2738
Quality of Life Research - There is a paucity of empirically estimated health state utility (HSU) values to estimate health-related quality of life among individuals with sickle cell disease (SCD).... 相似文献
95.
Shipkin Rebecca Blackledge Kristin Jacob Jane Bosoy Frederick Schertz Katherine Bachmann Gloria 《Maternal and child health journal》2022,26(5):1005-1014
Maternal and Child Health Journal - This study assessed whether the use of a peer-to-peer educational book, written and illustrated by women who experienced common mental disorders (CMDs) in the... 相似文献
96.
Maternal and Child Health Journal - This study aims to explore association between maternal depressive symptoms and infant feeding practice at hospital discharge. Data were obtained from a birth... 相似文献
97.
98.
Tania Lorena Mcwilliams Di Twigg Joyce Hendricks Fiona Melanie Wood Jane Ryan Anthony Keil 《Burns : journal of the International Society for Burn Injuries》2021,47(3):569-575
AimTo evaluate the impact of the implementation of a best practice infection prevention and control bundle on healthcare associated burn wound infections in a paediatric burns unit.BackgroundBurn patients are vulnerable to infection. For this patient population, infection is associated with increased morbidity and mortality, thereby representing a significant challenge for burns clinicians who care for them.MethodsAn interrupted time series was used to compare healthcare associated burn wound infections in paediatric burn patients before and after implementation of an infection prevention and control bundle. Prospective surveillance of healthcare associated burn wound infections was conducted from 2012 to 2014. Other potential healthcare associated infection rates were also reviewed over the study period, including urinary tract infections, pneumonia, upper respiratory tract infections and sepsis. An infection prevention and control bundle developed in collaboration between the paediatric burn unit and infection control clinicians was implemented in 2013 in addition to previous standard practice.ResultsDuring the study period a total of 626 patients were admitted to the paediatric burns unit. Healthcare associated burn wound infections reduced from 34 in 2012 to 0 in 2014 following the implementation of the infection prevention and control bundle. Pneumonia and sepsis also reduced to 0 in 2013 and 2014, however one upper respiratory tract infection occurred in 2013 and urinary tract infections persisted in 2013.ConclusionThe implementation of an infection prevention and control bundle was effective in reducing healthcare associated burn wound infections, pneumonia and sepsis within our paediatric burns unit. Urinary tract infections remain a challenge for future improvement. 相似文献
99.
100.