全文获取类型
收费全文 | 200302篇 |
免费 | 12429篇 |
国内免费 | 523篇 |
学科分类
医药卫生 | 213254篇 |
出版年
2023年 | 1045篇 |
2022年 | 1509篇 |
2021年 | 4492篇 |
2020年 | 2978篇 |
2019年 | 4328篇 |
2018年 | 5812篇 |
2017年 | 4307篇 |
2016年 | 4155篇 |
2015年 | 4754篇 |
2014年 | 6563篇 |
2013年 | 8552篇 |
2012年 | 13188篇 |
2011年 | 13713篇 |
2010年 | 7068篇 |
2009年 | 6244篇 |
2008年 | 10693篇 |
2007年 | 11460篇 |
2006年 | 10724篇 |
2005年 | 10901篇 |
2004年 | 10153篇 |
2003年 | 9283篇 |
2002年 | 7279篇 |
2001年 | 5156篇 |
2000年 | 5102篇 |
1999年 | 4550篇 |
1998年 | 1848篇 |
1997年 | 1558篇 |
1996年 | 1479篇 |
1995年 | 1260篇 |
1994年 | 1216篇 |
1993年 | 1155篇 |
1992年 | 2754篇 |
1991年 | 2647篇 |
1990年 | 2396篇 |
1989年 | 2392篇 |
1988年 | 2176篇 |
1987年 | 1989篇 |
1986年 | 1867篇 |
1985年 | 1788篇 |
1984年 | 1304篇 |
1983年 | 1057篇 |
1982年 | 616篇 |
1981年 | 556篇 |
1980年 | 543篇 |
1979年 | 952篇 |
1978年 | 640篇 |
1977年 | 496篇 |
1975年 | 557篇 |
1974年 | 550篇 |
1973年 | 554篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Characterization of anti-endothelial cell antibodies in systemic lupus erythematosus (SLE). 总被引:4,自引:2,他引:2 下载免费PDF全文
J M van der Zee C E Siegert T A de Vreede M R Daha F C Breedveld 《Clinical and experimental immunology》1991,84(2):238-244
IgG anti-endothelial antibodies (AEA), as measured by ELISA or immunoblotting technique could be detected in serum samples of 56 out of 64 patients with SLE (88%) and mainly occurred in monomeric form. AEA were not cell specific, because the binding reactivity was absorbed partially by both fibroblasts and peripheral blood mononuclear cells. No correlation was found between the presence of AEA and anti-nuclear antibodies. Immunoblotting revealed reactivity of AEA against endothelial antigens ranging in size from 15 to 200 kD. AEA titres were significantly higher in patients with joint or skin abnormalities, compared with patients without these abnormalities. A significant correlation was found between nephritis in SLE and the presence of AEA reactivity against endothelial membrane antigens of 38, 41 and 150 kD. These data show that the pattern of AEA reactivity in serum of SLE patients is heterogeneous, and suggest that AEA against a limited number of antigens may be involved in the pathogenesis of nephritis in SLE. 相似文献
993.
In vitro effects of sulfadiazine and its metabolites alone and in combination with pyrimethamine on Toxoplasma gondii. 总被引:1,自引:0,他引:1 下载免费PDF全文
E Schoondermark-van de Ven T Vree W Melchers W Camps J Galama 《Antimicrobial agents and chemotherapy》1995,39(3):763-765
Sulfadiazine and the metabolites N4-acetyl-sulfadiazine, 4-OH-sulfadiazine, 5-OH-sulfadiazine, 5-OH-glucuronide-sulfadiazine, and 5-OH-sulfate-sulfadiazine were tested separately and in combination with pyrimethamine for the inhibitory activity on Toxoplasma gondii growth in vitro. Except for N4-acetyl-sulfadiazine, all sulfa compounds possessed anti-Toxoplasma activity. The addition of 0.05 micrograms of pyrimethamine per ml, a concentration which in itself is not inhibitory, potentiated the microbial activity of sulfadiazine and its metabolites 100 fold. 相似文献
994.
995.
Ceftazidime pharmacokinetics in preterm infants: effect of postnatal age and postnatal exposure to indomethacin. 总被引:1,自引:0,他引:1 下载免费PDF全文
J N van den Anker W C Hop R C Schoemaker B J van der Heijden H J Neijens R de Groot 《British journal of clinical pharmacology》1995,40(5):439-443
1. The effects of postnatal age and postnatal exposure to indomethacin on the pharmacokinetic parameters of ceftazidime (CAZ) were investigated in 23 preterm infants (gestational age 28.7 +/- 1.7 weeks; weight 1086 +/- 311 g) on day 3 and day 10 after birth. 2. CAZ (25 mg kg-1) was administered by intravenous bolus injection. Blood samples were drawn from an arterial catheter at 0, 0.5, 1, 2, 4, 8, and 12 h after the dose and CAZ concentrations in serum were determined by h.p.l.c. CAZ pharmacokinetics followed a one-compartment open model. 3. The glomerular filtration rate (GFR) of all infants was studied by means of the 24 h continuous inulin infusion technique. 4. The total body clearance of CAZ (34.7 +/- 9.2 vs 50.6 +/- 19.6 ml h-1, P < 0.05; 30.7 +/- 5.9 vs 41.6 +/- 9.0 ml h-1 kg-1, P < 0.05) and GFR (0.72 +/- 0.11 vs 0.91 +/- 0.15 ml min-1, P < 0.05) increased, whereas the apparent volume of distribution (425 +/- 147 vs 352 +/- 108 ml, P < 0.05; 363 +/- 59 vs 292 +/- 44 ml kg-1, P < 0.005) and the elimination half-life (8.7 +/- 2.8 vs 5.0 +/- 0.9 h, P < 0.005) decreased significantly between day 3 and day 10 after birth. Clearance of CAZ increased with increasing GFR (r = 0.81, P < 0.001). 5. In infants with postnatal exposure to indomethacin the changes in CAZ pharmacokinetics were markedly reduced. 6. These results indicate that the dosage regimen of CAZ should be adjusted after the first week of life except in infants who were postnatally exposed to indomethacin. 相似文献
996.
997.
The health insurance status of US Latino women: A profile from the 1982-1984 HHANES. 总被引:2,自引:2,他引:0 下载免费PDF全文
OBJECTIVES: This research studied the correlates of health insurance status among three major subpopulations (Mexican, Puerto Rican, and Cuban) of adult (ages of 20 to 64) Latino women. METHODS: Data from the Hispanic Health and Nutrition Examination Survey (HHANES), 1982-1984, were examined to determine the percentages of health insurance coverage among the sample populations and to assess the relationship between access to coverage and selected sociodemographic employment/income, ancestry, and acculturation variables. RESULTS: Variations in health insurance coverage existed by Latina subpopulation. While Puerto Rican women had the highest percentage of any health insurance coverage, Mexican-origin women (particularly those 50 to 64 years old) had the lowest. For all three Latina groups, health insurance coverage was greater among those who reported a family income above the poverty level than among those whose income fell below the poverty level; employment location, acculturation variables, and ancestry were also related to coverage. CONCLUSIONS: Eligibility requirements, particularly for Mexican-and Cuban-origin women, need to be streamlined, and innovative health insurance programs need to be developed to increase access of Latinas to health insurance. 相似文献
998.
Methotrexate for the treatment of unruptured tubal pregnancy: a prospective nonrandomized study. 总被引:3,自引:0,他引:3
Amélie Gervaise Sylvie Capella-Allouc Fran?ois Audibert Catherine Rongières-Bertrand Yves Vincent Hervé Fernandez 《JSLS, Journal of the Society of Laparoendoscopic Surgeons》2003,7(3):233-238
BACKGROUND AND OBJECTIVES: The aim of this study was to compare in a prospective nonrandomized study, the efficacy of 2 methods of administering methotrexate (MTX) in the treatment of ectopic pregnancy (EP): transvaginal injection under sonographic control or intramuscular injection (IM). METHODS: Patients with EP who met specific inclusion criteria for medical treatment were treated with MTX: 63 patients (group 1) were treated by IM and 47 patients (group 2) by transvaginal local injection. In group 1, 50 mg/m2 of MTX was injected intramuscularly; in group 2, transvaginal injection of 1 mg/kg of MTX was injected into the ectopic sac under sonographic control. When an additional dose of MTX was required, it was administrated IM at the dosage of 50 mg/m2 in both groups. RESULTS: The overall success rate, defined by a posttreatment normal hCG level (< 10 mUI/mL) was 71.4% in group 1 versus 91.5% in group 2 (P < 0.01); for patients with hCG levels < 2000 mUI/mL, 83% and 96%, respectively (not significant); for patients with hCG > or = 2000 mUI/mL, 37.5% and 86.4%, respectively (P < 0.01). CONCLUSION: In the medical treatment of EP, the efficacy of MTX is greater when administered by local transvaginal injection than by IM injection. We propose local treatment every time EP can be punctured, especially when hCG levels are > or = 2000 mUI/mL. 相似文献
999.
Cost-effectiveness of diagnostic imaging work-up and treatment for patients with intermittent claudication in The Netherlands. 总被引:1,自引:0,他引:1
K Visser S O de Vries P J E H M Kitslaar J M A van Engelshoven M G M Hunink 《European journal of vascular and endovascular surgery》2003,25(3):213-223
OBJECTIVE: to determine the societal cost-effectiveness of various management strategies, including both the diagnostic imaging work-up and treatment, for patients with intermittent claudication in The Netherlands. METHODS: a decision-analytic model was used and included probability and quality of life data available from the literature. A cost-analysis was performed in a university setting in The Netherlands. Imaging work-up options included magnetic resonance angiography (MRA), color-guided duplex ultrasound, or intraarterial digital subtraction angiography (DSA) and treatment options were percutaneous transluminal angioplasty with selective stent placement if feasible or bypass surgery. Management strategies were defined as combinations of imaging work-up and treatment options. A conservative strategy with no imaging work-up and walking exercises was considered as reference. Main outcome measures were quality-adjusted life years (QALYs), lifetime costs (euro), and incremental cost-effectiveness (CE) ratios. The base-case analysis evaluated 60-year-old men with severe unilateral intermittent claudication of at least one year duration. RESULTS: the range in QALYs and costs across management strategies that considered angioplasty as only treatment option was small (maximum difference: 0.0033 QALYs and 451 euros). Similarly, the range was small across management strategies that considered angioplasty if feasible otherwise bypass surgery (maximum difference: 0.0033 QALYs and 280 euros). MRA in combination with angioplasty (6.1487 QALYs and 8556 euros) had a CE ratio of 20,000 euros/QALY relative to the conservative strategy. The most effective strategy was DSA in combination with angioplasty if feasible otherwise bypass surgery (6.2254 QALYs and 18,583 euros) which had a CE ratio of 131,000 euros/QALY relative to MRA in combination with angioplasty. CONCLUSION: the results suggest that the imaging work-up with non-invasive imaging modalities can replace DSA for the work-up of patients with intermittent claudication without a substantial loss in effectiveness and a minimal cost-reduction. Management strategies including angioplasty are cost-effective in the Netherlands but although strategies including bypass surgery are more effective, their incremental costs are very high. 相似文献
1000.