全文获取类型
收费全文 | 1361747篇 |
免费 | 103599篇 |
国内免费 | 4390篇 |
专业分类
耳鼻咽喉 | 17259篇 |
儿科学 | 44292篇 |
妇产科学 | 36874篇 |
基础医学 | 201145篇 |
口腔科学 | 36629篇 |
临床医学 | 132171篇 |
内科学 | 264345篇 |
皮肤病学 | 26662篇 |
神经病学 | 114196篇 |
特种医学 | 49106篇 |
外国民族医学 | 366篇 |
外科学 | 188765篇 |
综合类 | 29450篇 |
现状与发展 | 1篇 |
一般理论 | 482篇 |
预防医学 | 116602篇 |
眼科学 | 29722篇 |
药学 | 100594篇 |
6篇 | |
中国医学 | 3236篇 |
肿瘤学 | 77833篇 |
出版年
2021年 | 11355篇 |
2019年 | 12080篇 |
2018年 | 16853篇 |
2017年 | 12724篇 |
2016年 | 13671篇 |
2015年 | 15672篇 |
2014年 | 21590篇 |
2013年 | 33194篇 |
2012年 | 45914篇 |
2011年 | 48598篇 |
2010年 | 28029篇 |
2009年 | 25849篇 |
2008年 | 44326篇 |
2007年 | 46805篇 |
2006年 | 47080篇 |
2005年 | 45466篇 |
2004年 | 43291篇 |
2003年 | 41292篇 |
2002年 | 39943篇 |
2001年 | 61164篇 |
2000年 | 62851篇 |
1999年 | 52645篇 |
1998年 | 14993篇 |
1997年 | 13586篇 |
1996年 | 13415篇 |
1995年 | 12713篇 |
1994年 | 11852篇 |
1993年 | 11126篇 |
1992年 | 41850篇 |
1991年 | 41000篇 |
1990年 | 39686篇 |
1989年 | 37573篇 |
1988年 | 34783篇 |
1987年 | 33881篇 |
1986年 | 32347篇 |
1985年 | 30826篇 |
1984年 | 23246篇 |
1983年 | 19761篇 |
1982年 | 11936篇 |
1979年 | 20948篇 |
1978年 | 14956篇 |
1977年 | 12190篇 |
1976年 | 11979篇 |
1975年 | 12217篇 |
1974年 | 14919篇 |
1973年 | 14592篇 |
1972年 | 13461篇 |
1971年 | 12504篇 |
1970年 | 11557篇 |
1969年 | 10476篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Balloon cell nevus of the iris 总被引:1,自引:0,他引:1
992.
L J Lesko J R Benotti J S Alpert P M Brady J E McCue B H Weiner I S Ockene 《Journal of pharmaceutical sciences》1986,75(10):952-954
The pharmacokinetics of intravenous bepridil (1-[2-(N-benzylanilino)-1-(isobutoxymethyl)ethyl]pyrrolidine ) were studied in 16 patients undergoing cardiac catheterization for evaluation of coronary disease, all with normal base-line hemodynamic and renal functions. Ten patients received 3 mg/kg and six patients received 4 mg/kg of bepridil infused over a period of 30 min. Plasma bepridil concentrations were measured by HPLC and analyzed by model-dependent and model-independent methods. The mean (+/- SD) maximum plasma bepridil concentrations at the end of the infusion were 2047 +/- 820 ng/mL (3 mg/kg) and 2478 +/- 1426 ng/mL (4 mg/kg). Postinfusion bepridil concentrations were best described by a two-compartment open model. The model-dependent harmonic mean distribution and elimination half-lives were 1.7 h (range: 1.1-2.2 h) and 19.7 h (range: 8.0-61.9 h), respectively. The harmonic mean elimination half-life from model-independent analysis was 14.9 h (range: 7.4-64.0 h). The arithmetic means of other model-independent kinetic parameters were systemic clearance, 0.524 +/- 0.215 L X kg-1 X h-1; Vd, 15.3 +/- 10.9 L/kg; and Vdss, 10.1 +/- 6.0 L/kg. Model-dependent and model-independent estimates of half-life and clearance agreed reasonably well. Bepridil was well tolerated, effecting little or no change in central hemodynamics or EKG intervals. The extensive distribution and relatively slow clearance of bepridil account for its long elimination half-life. Intravenous bepridil appears to be a safe calcium (II) antagonist that is suitable for once-a-day dosing. 相似文献
993.
Colonoscopy and bacteraemia: an experience in 50 patients 总被引:1,自引:0,他引:1
There is little consensus concerning the incidence of bacteraemia during colonoscopy and the need for antibiotic prophylaxis in susceptible patients. Hepatic abscesses in one patient which may have been related to prior colonoscopic examinations led the authors to carry out a prospective study of 50 patients undergoing colonoscopy. Multiple blood cultures were carried out to maximise the positive yield of transient bacteraemia and to attempt to determine the time when bacteraemia is most likely to occur. Five patients had positive blood cultures. In two patients S epidermidis was isolated, but only from the precolonoscopic blood sample. In three subjects enteric organisms were cultured from blood samples obtained during the procedure. In one of these three the same organism was cultured from the preendoscopic blood sample so that in only two patients (4%) could the bacteraemia be attributed to the colonoscopy. These results would suggest that the risk of bacteraemia during colonoscopy is low. 相似文献
994.
995.
996.
M A Keller J Faust L J Rolewic D D Stewart 《Journal of pediatric gastroenterology and nutrition》1986,5(3):439-443
Lymphocytes from 10 paired colostrum and peripheral blood specimens were examined to determine if the colostral T cell population differs from the peripheral blood T cell population in subset distribution. The percentages of lymphocytes staining with OKT3, OKT4, and OKT8 murine monoclonal antibody were determined. Lymphocytes from colostrum were 74.7 +/- 2.5% OKT3+, 50.6 +/- 2.3% OKT4+, 24.0 +/- 1.7% OKT8+, whereas peripheral blood lymphocytes were 78.7 +/- 1.9% OKT3+, 48.4 +/- 1.4% OKT4+, and 29.8 +/- 1.6% OKT8+. The percentage of colostrum lymphocytes positive for OKT3 was significantly although not strikingly lower than the OKT3 percentage for blood lymphocytes (p less than 0.05). This difference was due to the lower percentage of OKT8 positive lymphocytes in colostrum compared with blood (p less than 0.01). Although the T cell subset distribution of colostrum generally appears to be similar to that in the peripheral blood, there were small differences in OKT3 and OKT8 percentages that were statistically significant suggesting the possibility of some selectivity of the colostral T cell population. 相似文献
997.
B Sarmento D C Ferreira L Jorgensen M van de Weert 《European journal of pharmaceutics and biopharmaceutics》2007,65(1):10-17
The aim of the present study was to probe the structural integrity of insulin after being entrapped into chitosan/alginate nanoparticles produced by ionotropic polyelectrolyte pre-gelation. By manipulating the alginate:chitosan mass ratio and the pH during nanoparticle production, desired nanoparticles with a mean size of 850 (+/-88)nm and insulin association efficiency of 81 (+/-2)% were obtained. Insulin secondary structure was assessed by Fourier transform infrared (FTIR) and circular dichroism (CD) after entrapment into nanoparticles and after release from the particles under gastrointestinal simulated conditions. FTIR second-derivative spectra and area-overlap compared to an insulin standard confirmed that no significant conformational changes of insulin occurred in terms of alpha-helix and beta-sheet content. Far-UV-CD spectra corroborated the preservation of insulin structure during the nanoparticle production procedure. The presented nanoparticulate system is a promising carrier for insulin oral delivery since it preserves insulin structure and therefore also, potentially, its bioactivity. 相似文献
998.
H. Fjeldsøe-Nielsen M. Unemo H. Fredlund S. V. Hjorth L. M. Berthelsen H. M. Palmer A. Friis-Møller 《European journal of clinical microbiology & infectious diseases》2005,24(4):280-283
In the study presented here 26 recent Danish clinical isolates of prolyliminopeptidase (PIP)-negative Neisseria gonorrhoeae were phenotypically and genotypically characterized to investigate whether one or more PIP-negative strains are circulating in the Danish community. The profiles of these isolates were compared with those of three isolates from a recent outbreak of PIP-negative N. gonorrhoeae infection in the UK. Twenty-five of the Danish isolates and all three UK isolates had similar antibiograms and were designated serovar IB-4. Genotypic characterization by pulsed-field gel electrophoresis, porB1b gene sequencing, and opa-typing revealed that these isolates were indistinguishable or closely related. The results indicate that at least one PIP-negative N. gonorrhoeae strain is currently circulating in the Danish community, and this strain is indistinguishable from the one that caused an outbreak in the UK.An erratum to this article can be found at 相似文献
999.
AIMS: In normotensive women with Type 1 diabetes and microalbuminuria we previously found preterm delivery (< 34 weeks) in 23% of the pregnancies. Antihypertensive treatment was initiated in late pregnancy when preeclampsia was diagnosed and diastolic blood pressure > 90 mmHg. From April 2000 our routine was changed and early antihypertensive treatment with methyldopa was initiated if antihypertensive treatment was given prior to pregnancy, if urinary albumin excretion (UAE) was > 2 g/24 h, or blood pressure > 140/90 mmHg. The present study describes the impact of this more aggressive antiypertensive treatment in the prevalence of preterm delivery. METHODS: The old cohort (1995-1999) consisted of 26 and the new cohort (2000-2003) of 20 pregnant women with Type 1 diabetes and microalbuminuria. All were referred before gestational week 17. RESULTS: The cohorts were comparable with regard to age, diabetes duration, prepregnancy body mass index, HbA1c, blood pressure 121 (13)/71 (8) vs. 121 (14)/73 (8) mmHg [mean (sd)] and early UAE 69 (16-278) vs. 74 (30-287) mg/24 h (geometric mean and range). Antihypertensive treatment was initiated in the old cohort at 29 (20-33) weeks, n = 9, and in the new at 13 (0-34) weeks, n = 10. The prevalence of preterm delivery before 34 weeks was reduced from 23% to zero (P = 0.02), preterm delivery before 37 weeks from 62% to 40% (P = 0.15) and preeclampsia from 42% to 20% (P = 0.11). Perinatal mortality occurred in 4% vs. 0%. Birth weight was 3124 (767) g vs. 3279 (663) g. CONCLUSION: Introduction of early antihypertensive treatment with methyldopa in normotensive pregnant women with Type 1 diabetes and microalbuminuria resulted in a significant reduction in preterm delivery before gestational week 34. 相似文献
1000.
Lázaro Alessandro S Nunes Paulo Guimar?es Gandra Armindo Antonio Alves Lauro T Kubota Denise Vaz de Macedo 《Clinical journal of sport medicine》2006,16(5):418-421
OBJECTIVE: The authors tested the effect of blood sampling (skin versus venous puncture) on some biochemical and hematological blood parameters in athletes to answer whether skin puncture could be used as a substitute for venous puncture. DESIGN: Comparative study of 2 methods of blood samples collection. SETTING: The blood was collected in the same athletes at 3 different moments of the preparatory training phase. PARTICIPANTS: Fourteen male indoor soccer players (22 +/- 1 years old) and 7 female handball players (18 +/- 1 years old) participated. MAIN OUTCOME MEASUREMENT: Blood was collected in heparin and K3EDTA by Vacutainer BD or Microvette Sarstedt system for biochemical and hematological analyses, respectively. RESULTS: There were no significant statistical differences between the 2 methods for the values of creatine kinase, urea, creatinine, lymphocytes, and platelets. The other hematological analyzes and uric acid exhibited significant higher values in skin blood, although they were all within the normal expected range. A high degree of correlation was observed between the 2 techniques for all parameters. CONCLUSIONS: Skin puncture is a reliable, easy, accurate, and less invasive sampling method for assessing hematological and some biochemical parameters in athletes, respecting that blood samples should always be obtained from the same site, especially in follow-up studies. 相似文献