全文获取类型
收费全文 | 683篇 |
免费 | 25篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 1篇 |
儿科学 | 38篇 |
妇产科学 | 1篇 |
基础医学 | 59篇 |
口腔科学 | 25篇 |
临床医学 | 95篇 |
内科学 | 122篇 |
皮肤病学 | 3篇 |
神经病学 | 5篇 |
特种医学 | 182篇 |
外科学 | 46篇 |
综合类 | 10篇 |
预防医学 | 49篇 |
眼科学 | 8篇 |
药学 | 51篇 |
肿瘤学 | 35篇 |
出版年
2023年 | 2篇 |
2021年 | 7篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 3篇 |
2015年 | 5篇 |
2014年 | 6篇 |
2013年 | 17篇 |
2012年 | 9篇 |
2011年 | 16篇 |
2010年 | 16篇 |
2009年 | 12篇 |
2008年 | 21篇 |
2007年 | 34篇 |
2006年 | 23篇 |
2005年 | 26篇 |
2004年 | 11篇 |
2003年 | 8篇 |
2002年 | 8篇 |
2001年 | 16篇 |
2000年 | 12篇 |
1999年 | 11篇 |
1998年 | 32篇 |
1997年 | 45篇 |
1996年 | 26篇 |
1995年 | 30篇 |
1994年 | 19篇 |
1993年 | 13篇 |
1992年 | 4篇 |
1991年 | 13篇 |
1990年 | 12篇 |
1989年 | 20篇 |
1988年 | 29篇 |
1987年 | 20篇 |
1986年 | 28篇 |
1985年 | 26篇 |
1984年 | 12篇 |
1983年 | 11篇 |
1982年 | 17篇 |
1981年 | 8篇 |
1980年 | 16篇 |
1979年 | 13篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 14篇 |
1975年 | 7篇 |
1974年 | 2篇 |
1940年 | 2篇 |
排序方式: 共有730条查询结果,搜索用时 15 毫秒
1.
2.
3.
MGC Hendriks P Dogterom JT Ebels B Oosterhuis LR Geertsema T Hulot G Bianchetti and JHG Jonkman 《Fundamental & clinical pharmacology》1998,12(5):559-565
Summary— In the present study we have compared the steady state biopharmaceutic characteristics of four diltiazem once daily controlled release capsules: Mono-Tildiem LP 300® (300 mg), Adizem® XL (300 mg)1, Cardizem® (300 mg) and Dilacor® (240 mg). Sixteen healthy male volunteers (aged 22.9 ± 3.3 years, range 19–31 years) completed an open label, multiple oral dose, randomized, four-period crossover study without a washout period in between. The volunteers received each diltiazem formulation once daily for four days. Trough diltiazem and metabolites plasma concentrations were determined on days 3 and 4. The 24-h plasma concentration-time profiles were assessed after the dose on day 4 of each period. The following steady state pharmacokinetic parameters for diltiazem were calculated: the minimum plasma concentration (cmin), the maximum plasma concentration (cmax), the time to reach that concentration (tmax), the time interval during which the plasma concentration exceeds 50% of cmax (t50), the area under the plasma concentration-time curve (AUC72–96) and the peak-to-trough fluctuation (PTF). For the metabolites of diltiazem, N-mono-desmethyl-diltiazem (NDM) and desacetyldiltiazem (DAD), AUC72–96 (AUCNDM and AUCDAD) and the ratio metabolite/parent compound were calculated. Steady state was achieved on day 3. Except one, all controlled release formulations have satisfactory controlled release properties allowing once daily administration. However, significant (P < 0.05) differences were found between the pharmacokinetic characteristics which do not allow exchange of the various formulations. Concentrations well below 50 ng·mL-1 in the morning hours were observed for Dilacor® (240 mg) and Adizem® XL (300 mg), which could be a disadvantage of these formulations as it is well-known that ischaemic events occur at a higher rate during that part of the day. The plasma concentration profiles of NDM and DAD, the major circulating metabolites, parallel the plasma concentration profiles for the parent compound. From a clinical point of view, all treatments were well tolerated. 相似文献
4.
Intestinal obstruction proximal to a transition zone without an interposed physical barrier usually indicates Hirschsprung disease. The authors report one case of focal small bowel muscular thinning just distal to a transition zone that produced clinical and radiographic findings that simulated long-segment Hirschsprung disease in a 2-day-old infant. 相似文献
5.
6.
Development of hatching blastocysts from immature human oocytes following in-vitro maturation and fertilization using a co-culture system 总被引:8,自引:0,他引:8
Hwu YM; Lee RK; Chen CP; Su JT; Chen YW; Lin SP 《Human reproduction (Oxford, England)》1998,13(7):1916-1921
Recently, in-vitro maturation (IVM) of immature human oocytes recovered
from non-stimulated follicles has been applied in the treatment of
infertility. However, in previous reports, very few embryos cultured in
conventional medium have reached the expanded blastocyst stage following
in-vitro maturation and fertilization (IVM/IVF). The objective of this
study was to investigate whether the developmental competence of human
embryos following IVM/IVF could be enhanced by the use of a human ampullary
cell co-culture system. Immature human oocytes were aspirated from small
follicles at Caesarean section and then cultured in medium containing human
menopausal gonadotrophin for 36 to 48 h, followed by insemination. Zygotes
were randomly cultured either in conventional culture medium alone or in
the co-culture system. Of 48 embryos cultured in conventional medium alone,
all arrested at the 2-16- cell stage on day 3 after insemination. Of 46
embryos cultured in the co-culture system, 26 embryos (56.5%) arrested at
the 2-16-cell stage. Six embryos (13%) developed to the morula stage.
Fourteen embryos (30.4%) developed to expanded blastocysts and two
blastocysts were hatching on day 7 after insemination. We conclude that
co-culture significantly enhances the development of blastocysts in embryos
resulting from IVM/IVF.
相似文献
7.
8.
Lactate production in isolated perfused rat lung 总被引:1,自引:0,他引:1
9.
Queenan JT Jr; Veeck LL; Toner JP; Oehninger S; Muasher SJ 《Human reproduction (Oxford, England)》1997,12(7):1573-1576
In-vitro fertilization patients (n = 15) at risk of ovarian
hyperstimulation syndrome (OHSS) (oestradiol > or =4500 pg/ml on the day
of human chorionic gonadotrophin administration and 25 or more follicles of
intermediate or large size) underwent aspiration of all follicles and
cryopreservation of all fertilized oocytes at the pronuclear stage.
Patients were monitored for up to 2 weeks post- retrieval. Subsequent
transfer of cryopreserved-thawed embryos was performed in programmed cycles
using exogenous oestrogen and progesterone for endometrial preparation. Two
patients (13%) developed OHSS necessitating hospitalization and vaginal
aspiration of ascitic fluid. Two other patients (13%) developed moderate
OHSS requiring ascitic fluid vaginal aspiration in the office setting, with
dramatic improvement of the condition. Subsequent transfer of
cryopreserved- thawed embryos yielded a clinical pregnancy rate of 58% per
transfer and ongoing or delivery rates of 42 and 67% per transfer and per
patient respectively. By eliminating pregnancy potential with
cryopreservation of all prezygotes and examining the pregnancy potential
with subsequent cryopreserved-thawed transfers, it is concluded that OHSS
is reduced, but not eliminated for patients at risk. Subsequent transfer of
cryopreserved-thawed prezygotes in a programmed cycle with exogenous
steroids yields an excellent pregnancy rate.
相似文献
10.
Xiao Xu Pamela R. Soulos Jeph Herrin ShiYi Wang Craig Evan Pollack Suzanne B. Evans James B. Yu Cary P. Gross 《Health services research》2021,56(3):497
ObjectiveTo examine variation in trajectories of abandoning conventionally fractionated whole‐breast irradiation (CF‐WBI) for adjuvant breast radiotherapy among physician peer groups and the associated cost implications.Data SourcesMedicare claims data were obtained from the Chronic Conditions Data Warehouse for fee‐for‐service beneficiaries with breast cancer in 2011‐2014.Study DesignWe used social network methods to identify peer groups of physicians that shared patients. For each physician peer group in each time period (T1 = 2011‐2012 and T2 = 2013‐2014), we calculated a risk‐adjusted rate of CF‐WBI use among eligible women, after adjusting for patient clinical characteristics. We applied a latent class growth analysis to these risk‐adjusted rates to identify distinct trajectories of CF‐WBI use among physician peer groups. We further estimated potential savings to the Medicare program by accelerating abandonment of CF‐WBI in T2 using a simulation model.Data Collection/Extraction MethodsUse of conventionally fractionated whole‐breast irradiation was determined from Medicare claims among women ≥ 66 years of age who underwent adjuvant radiotherapy after breast conserving surgery.Principal FindingsAmong 215 physician peer groups caring for 16 988 patients, there were four distinct trajectories of abandoning CF‐WBI: (a) persistent high use (mean risk‐adjusted utilization rate: T1 = 94.3%, T2 = 90.6%); (b) decreased high use (T1 = 81.3%, T2 = 65.3%); (c) decreased medium use (T1 = 60.1%, T2 = 44.0%); and (d) decreased low use (T1 = 31.6%, T2 = 23.6%). Peer groups with a smaller proportion of patients treated at free‐standing radiation facilities and a larger proportion of physicians that were surgeons tended to follow trajectories with lower use of CF‐WBI. If all physician peer groups had practice patterns in T2 similar to those in the “decreased low use” trajectory, the Medicare program could save $83.3 million (95% confidence interval: $58.5 million‐$112.2 million).ConclusionsPhysician peer groups had distinct trajectories of abandoning CF‐WBI. Physician composition and setting of radiotherapy were associated with the different trajectories. Distinct practice patterns across the trajectories had important cost implications. 相似文献