全文获取类型
收费全文 | 57484篇 |
免费 | 4693篇 |
国内免费 | 175篇 |
专业分类
耳鼻咽喉 | 512篇 |
儿科学 | 1655篇 |
妇产科学 | 1091篇 |
基础医学 | 7594篇 |
口腔科学 | 1000篇 |
临床医学 | 6350篇 |
内科学 | 11045篇 |
皮肤病学 | 827篇 |
神经病学 | 4859篇 |
特种医学 | 2647篇 |
外科学 | 9460篇 |
综合类 | 802篇 |
一般理论 | 57篇 |
预防医学 | 5587篇 |
眼科学 | 1267篇 |
药学 | 4087篇 |
1篇 | |
中国医学 | 56篇 |
肿瘤学 | 3455篇 |
出版年
2023年 | 291篇 |
2022年 | 260篇 |
2021年 | 1158篇 |
2020年 | 663篇 |
2019年 | 1093篇 |
2018年 | 1321篇 |
2017年 | 960篇 |
2016年 | 1046篇 |
2015年 | 1255篇 |
2014年 | 1822篇 |
2013年 | 2547篇 |
2012年 | 3821篇 |
2011年 | 3907篇 |
2010年 | 2177篇 |
2009年 | 1923篇 |
2008年 | 3423篇 |
2007年 | 3662篇 |
2006年 | 3564篇 |
2005年 | 3454篇 |
2004年 | 3194篇 |
2003年 | 3039篇 |
2002年 | 2872篇 |
2001年 | 894篇 |
2000年 | 859篇 |
1999年 | 859篇 |
1998年 | 775篇 |
1997年 | 632篇 |
1996年 | 608篇 |
1995年 | 604篇 |
1994年 | 504篇 |
1993年 | 481篇 |
1992年 | 565篇 |
1991年 | 507篇 |
1990年 | 519篇 |
1989年 | 525篇 |
1988年 | 475篇 |
1987年 | 422篇 |
1986年 | 427篇 |
1985年 | 472篇 |
1984年 | 389篇 |
1983年 | 329篇 |
1982年 | 287篇 |
1981年 | 250篇 |
1980年 | 241篇 |
1979年 | 254篇 |
1978年 | 247篇 |
1977年 | 199篇 |
1976年 | 205篇 |
1975年 | 196篇 |
1974年 | 210篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Kathleen Pierson Donald Addington Jean Addington Scott Patten 《Revue canadienne de psychiatrie》2006,51(11):715-718
OBJECTIVE: To assess whether pharmacokinetic drug interactions occur when sertraline is added to antipsychotic medications. METHOD: Forty-eight patients with remitted DSM-IV schizophrenia and comorbid major depression were randomized to placebo for 6 weeks or sertraline 50 mg for 4 weeks followed by sertraline 50 mg to 100 mg for 2 weeks for nonresponders. Treatment with the patients' usual antipsychotic continued. Weekly clinical outcome assessments occurred for 6 weeks, and serum samples for drug monitoring were collected at Weeks 1, 5, and 6. Serum concentrations of sertraline and antipsychotics were measured with standard assays. RESULTS: In both placebo- and sertraline-treated groups, most patients displayed minor fluctuations in antipsychotic serum levels over 6 weeks. There was no clinical evidence of drug interactions in the sertraline-treated group. CONCLUSIONS: Clinically significant adverse effects did not occur despite variable antipsychotic serum levels with or without sertraline. Concern about pharmacokinetic interactions should not deter the use of sertraline for depression in individuals with schizophrenia. 相似文献
22.
AIMS: To establish all-cause and cause-specific death rates, and risk factors for mortality in insulin-treated diabetic individuals living in the province of Canterbury, New Zealand. METHODS: Insulin-treated diabetic subjects (n = 995) on the Canterbury Diabetes Registry were followed up over 15 years and vital status determined. Death rates were standardized and hazard regression was used to model the effects of demographic covariates on relative survival time. RESULTS: There were 419 deaths in 11 226.3 person-years of follow-up with a standardized mortality ratio (SMR) of 2.0 (95% confidence interval (CI) 1.8-2.2). Relative mortality was greatest for the group aged 0-29 years (SMR 3.0 (95% CI 2.4-3.7)). After controlling for diabetes duration and gender, a 10-year increment in age of onset was associated with a 33% decrease in relative hazard (95% CI 29-36%), indicating that excess mortality due to diabetes declines with rising age of onset. After controlling for age of onset and gender, each 10-year increment in duration of diabetes is associated with a 26% decrease in relative hazard (95% CI 24-29%), indicating that with longer survival the mortality hazard approaches the general population hazard. Relative mortalities were increased for cardiovascular, renal and respiratory disease, but not malignancy. Relative mortality from acute metabolic complications was increased in the subgroup with age of onset of diabetes < 30 years and requiring insulin within 1 year of diagnosis. CONCLUSIONS: Mortality rates are high for insulin-treated diabetic individuals relative to the general population. 相似文献
23.
Background
Hospital episode statistics (HES) is a UK national database for the National Health Service (NHS), now available online. The purpose of this study was to observe trends in ophthalmic operations performed during the period from 1998 to 2004, using this data. 相似文献24.
Matthew S Lewis Paul Maruff Brendan S Silbert Lis A Evered David A Scott 《Archives of clinical neuropsychology》2006,21(5):421-427
The reliable change index (RCI) expresses change relative to its associated error, and is useful in the identification of post-operative cognitive dysfunction (POCD). This paper examines four common RCIs that each account for error in different ways. Three rules incorporate a constant correction for practice effects and are contrasted with the standard RCI that had no correction for practice. These rules are applied to 160 patients undergoing coronary artery bypass graft (CABG) surgery who completed neuropsychological assessments preoperatively and 1 week post-operatively using error and reliability data from a comparable healthy non-surgical control group. The rules all identify POCD in a similar proportion of patients, but the use of the within subject standard deviation, expressing the effects of random error, as an error estimate is a theoretically appropriate denominator when a constant error correction, removing the effects of systematic error, is deducted from the numerator in a RCI. 相似文献
25.
26.
27.
28.
W J Scott C A Duggan C M Schreiner M D Collins 《Toxicology and applied pharmacology》1990,103(2):238-254
The effects of acetazolamide on the developing rodent limb bud were postulated to result from a reduction of intracellular pH (pHi). Embryonic intracellular pH was calculated from transplacental distribution of the weak acid, 5,5'-dimethyloxazolidine-2,4-dione, in teratogenically sensitive (C57BL/6) and resistant (SWV) inbred mice. pHi was reduced by acetazolamide treatment in C57 embryos and limb buds but not in SWV samples. Acetazolamide teratogenesis can be exacerbated by coadministration of amiloride, presumably through inhibition of Na+/H+ exchange attributable to the latter agent. pHi reduction after such treatment was more profound than after acetazolamide alone, providing further support for the central hypothesis. pH was also reduced in other embryonic (embryo plasma) and extraembryonic compartments (exocoelomic fluid, amniotic fluid). pH changes in these compartments could also lead or contribute to abnormal development. 相似文献
29.
H Tryphonas F Iverson Y So E A Nera P F McGuire L O'Grady D B Clayson P M Scott 《Toxicology letters》1986,30(2):137-150
Sublethal doses (0.00, 0.25, 0.50 and 1.00 mg/kg b.w./day) of vomitoxin (deoxynivalenol; DON) were studied for their effects on humoral and cellular immunity and serum proteins of inbred, male Swiss Webster mice in a series of 4 separate experiments. Vomitoxin was added to basal diet (less than the detection limit, i.e., less than 0.05 micrograms of vomitoxin per g of feed) and administered to mice for 5 weeks beginning at 21 days of age. Mice in experiment 2 were fed the basal diet for 40 days in addition to the 5-week treatment with vomitoxin. The 1.00 mg/kg dose of vomitoxin resulted in a statistically significant reduction in the serum levels of alpha 1 and alpha 2-globulins, an increase in total serum albumin, and a reduction in feed consumption and body weight gain compared to the control group. The 0.50 mg/kg dose of vomitoxin resulted in significantly reduced serum levels of alpha 2- and beta-globulins while a significant reduction of feed consumption was evident only during Week 4. Similarly, body weight gain in this group of mice was significantly reduced during Week 2 but increased to normal levels during Week 3 and remained parallel to the control for Week 4 and 5. Both levels (0.50 and 1.00 mg/kg) of vomitoxin resulted in a reduced, dose-related, time-to-death interval following a challenge with L. monocytogenes and increased proliferative capacity of splenic lymphocyte cultures stimulated with the phytohemagglutinin P (PHA-P) mitogen compared to the control group of mice. The 0.25 mg/kg dose of vomitoxin did not have any significant effects on the parameters studied. A reasonable estimation of a 'no effect' level for immunologic effects in mice based on these and previous immunological studies would seem to be between 0.25 and 0.50 mg/kg b.w./day. 相似文献
30.
Neal S. Rote R. Jane Lau Mark R. Harrison D. Ware Branch James R. Scott 《Journal of reproductive immunology》1987,10(4):261-272
Pregnancy-induced hypertension (PIH) can be complicated by maternal or fetal thrombocytopenia, or both. In order to investigate possible immunologic causes of these thrombocytopenias, platelet-associated IgG (PAIgG) and IgM (PAIgM) were measured in mothers with PIH and in their infants and compared with those from patients with autoimmune thrombocytopenic purpura (ATP), a known immunodestructive platelet disorder. Many PIH patients (33.3%) and most ATP patients (68.1%) had elevated levels of maternal PAIgG. In both diseases, the amount of PAIgG was directly proportional with the degree of thrombocytopenia (r = 0.446 in PIH and R = 0.668 for ATP). But in neither disease did the degree of maternal thrombocytopenia correlate with the degree of neonatal thrombocytopenia (r = 0.153 for PIH and R = 0.175 for ATP). Umbilical cord samples from PIH patients contained PAIgG (53.3%) and PAIgM (53.8%), whereas the umbilical cord samples from ATP patients had elevated amounts of PAIgG but not PAIgM. PAIgM in the umbilical cord blood could not be accounted for by IgM rheumatoid factors, IgM-containing immune complexes, or non-specific adsorption because of elevated total IgM levels. The umbilical cord blood PAIgM was probably not of maternal origin because it was observed even when the maternal blood contained no PAIgM and maternal IgM is not normally transported transplacentally. Therefore, the PAIgM appears to be of fetal origin. These results suggest that both maternal and fetal immunologic mechanisms may be involved in PIH-induced thrombocytopenia; if so, this is one of the first reported examples of a possible fetal autoimmune response. 相似文献