全文获取类型
收费全文 | 4348篇 |
免费 | 334篇 |
国内免费 | 86篇 |
专业分类
耳鼻咽喉 | 110篇 |
儿科学 | 164篇 |
妇产科学 | 67篇 |
基础医学 | 642篇 |
口腔科学 | 68篇 |
临床医学 | 497篇 |
内科学 | 710篇 |
皮肤病学 | 64篇 |
神经病学 | 385篇 |
特种医学 | 420篇 |
外科学 | 563篇 |
综合类 | 85篇 |
一般理论 | 3篇 |
预防医学 | 376篇 |
眼科学 | 14篇 |
药学 | 361篇 |
中国医学 | 2篇 |
肿瘤学 | 237篇 |
出版年
2021年 | 44篇 |
2020年 | 34篇 |
2019年 | 33篇 |
2018年 | 49篇 |
2017年 | 31篇 |
2016年 | 57篇 |
2015年 | 68篇 |
2014年 | 103篇 |
2013年 | 192篇 |
2012年 | 174篇 |
2011年 | 187篇 |
2010年 | 109篇 |
2009年 | 119篇 |
2008年 | 143篇 |
2007年 | 225篇 |
2006年 | 177篇 |
2005年 | 170篇 |
2004年 | 157篇 |
2003年 | 165篇 |
2002年 | 181篇 |
2001年 | 75篇 |
2000年 | 89篇 |
1999年 | 80篇 |
1998年 | 122篇 |
1997年 | 119篇 |
1996年 | 98篇 |
1995年 | 98篇 |
1994年 | 67篇 |
1993年 | 69篇 |
1992年 | 67篇 |
1991年 | 65篇 |
1990年 | 61篇 |
1989年 | 84篇 |
1988年 | 92篇 |
1987年 | 63篇 |
1986年 | 71篇 |
1985年 | 82篇 |
1984年 | 52篇 |
1983年 | 42篇 |
1982年 | 63篇 |
1981年 | 52篇 |
1980年 | 60篇 |
1979年 | 48篇 |
1978年 | 45篇 |
1977年 | 55篇 |
1976年 | 47篇 |
1975年 | 56篇 |
1974年 | 34篇 |
1973年 | 26篇 |
1971年 | 25篇 |
排序方式: 共有4768条查询结果,搜索用时 15 毫秒
1.
Sarah Averbach Othman Kakaire Rachel McDiehl Christine Dehlendorf Felicia Lester Jody Steinauer 《Contraception》2019,99(2):87-93
Objective
This study assessed whether immediate postpartum insertion of levonorgestrel contraceptive implants is associated with a difference in infant growth from birth to 6 months, onset of lactogenesis, or breastfeeding continuation at 3 and 6 months postpartum compared to delayed insertion at 6 to 8 weeks postpartum.Study design
We conducted a randomized trial of women in Uganda who desired contraceptive implants postpartum. We randomly assigned participants to receive either immediate (within 5 days of delivery) or delayed (6 to 8 weeks postpartum) insertion of a two-rod levonorgestrel contraceptive implant system. This is a prespecified secondary analysis evaluating breastfeeding outcomes. The primary outcome of this secondary analysis was change in infant weight; infants were weighed and measured at birth and 6 months. We used a validated questionnaire to assess onset of lactogenesis daily in person while participants were in the hospital, and then daily by phone after they left the hospital, until lactogenesis was documented. We used interviewer-administered questionnaires to assess breastfeeding continuation and concerns at 3 months and 6 months postpartum.Results
Among the 96 women randomized to the immediate group and the 87 women to the delayed group, the mean change in infant weight from birth to 6 months was similar between groups: 4632?g in the immediate group and 4407?g in the delayed group (p=.26). Among the 97 women who had not experienced lactogenesis prior to randomization, the median time to onset of lactogenesis did not differ significantly between the immediate and delayed groups (65?h versus 63?h; p=.84). Similar proportions of women in the immediate and delayed groups reported exclusive breastfeeding at 3 months (74% versus 71%; p=.74) and 6 months (48% versus 52%; p=.58).Conclusion
We found no association between the timing of postpartum initiation of levonorgestrel contraceptive implants and change in infant growth from birth to 6 months, onset of lactogenesis, or breastfeeding continuation at 3 or 6 months postpartum.Implications
This study provides evidence that immediate postpartum initiation of contraception implants does not have a deleterious effect on infant growth or initiation or continuation of breastfeeding. 相似文献2.
Lester A. Klein 《Neurourology and urodynamics》1987,6(2):95-99
The trigone sensitivity test, a complementary test to cystometry, has been proposed as a method for distinguishing certain clinical disorders. Pressure is applied to the trigone region of the bladder by pulling upon a Foley catheter with the balloon inflated and the amount of force needed to induce an urge to void is recorded. Although the trigone sensitivity test has been proposed as a test of exteroceptive function, it is possible that deeper receptors, perhaps proprioceptors, are actually responsible for the awareness of the urge to void during the study. The present investigation compared the trigone sensitivity test with provoked detrusor contraction in 107 patients. The findings indicate that variations in the two responses occur independently of each other. It is concluded that different neural pathways are responsible for the two functions. The hypothesis that exteroceptive and not proprioceptive nerves are being measured during trigone sensitivity testing is supported by these findings. 相似文献
3.
Infantile Digital Fibroma Treated With Mohs Micrographic Surgery 总被引:2,自引:0,他引:2
John G. Albertini MD Maj USAF MC Michael Jude Welsch MD CPT USA MC Leo A. Conger MD LTC USA MC Lester F. Libow MD COL USA MC Dirk M. Elston MD COL USA MC 《Dermatologic surgery》2002,28(10):959-961
BACKGROUND: Infantile digital fibroma (IDF) is a rare benign fibrous tumor of childhood that frequently recurs despite local excision. Conservative, nonsurgical management may result in regression and/or joint deformity. OBJECTIVE: To describe the histologic features of IDF and discuss a case excised using Mohs micrographic surgery (MMS). METHODS: Case report and review of the clinical, histologic, and ultrastructural features. RESULTS: Characteristic inclusion bodies of actin were identified with hematoxylin and eosin, Masson's trichrome, and rapid actin immunostain. The tumor was debulked and the majority was removed after one stage of MMS, except where the deep margin approached the joint space. The defect healed by secondary intention. At 2 years the patient had no recurrence or functional joint deformity. CONCLUSION: MMS is a surgical treatment option for IDF. 相似文献
4.
Coronary artery bypass grafts: visualization with MR imaging 总被引:1,自引:0,他引:1
5.
Fengxiu Ouyang Binyan Wang Lester M. Arguelles Xiping Xu Jianhua Yang Zhiping Li Liuliu Wang Xue Liu Genfu Tang Houxun Xing Craig Langman Xiaobin Wang 《Archives of osteoporosis》2007,2(1-2):29-43
Summary We prospectively examined bone growth patterns in 894 children aged 6–17 years at the baseline visit, with a 6-year follow-up.
Results show bone “tracking” over a six-year interval and sexual dimorphism of bone attained levels and timing of peak bone
growth. Our findings underscore childhood and adolescence as critical periods for building bone and developing gender differences.
Introduction Bone growth patterns were prospectively examined in 894 Chinese children (496 males), aged 6–17 yrs, from a population-based
twin cohort. Whole-body bone area (BA), bone mineral content (BMC), and bone mineral density (BMD) were measured by DEXA at
baseline and a 6-yr follow-up.
Methods Graphic smoothing plots and generalized estimating equations were used to model bone attained levels, growth, and “tracking”.
Results Attained levels of BMC and BA increased curvilinearly with age. Male attained levels were higher than females after age ∼15 yr,
but BMD was lower between 13–17 yrs (Tanner stage I to IV). In both genders, peak BMC and BMD growth lagged ∼2 yrs behind
peak BA growth, which lagged 2 yrs behind peak height growth. Peak bone growth occurred 1–3 yrs later in males. Over the 6-yr
follow-up, all bone measurements “tracked”, but “shifting” across ranks also occurred, and baseline tertile ranking influenced
bone growth. Females with early menarche had higher attained levels than females with late menarche at age 12–13 yrs.
Conclusion Our findings confirm and expand previous studies on peak bone growth conducted in Caucasian cohorts, particularly sexually
dimorphic and maturational effects. The significant “tracking” of bone measurements in this 6-yr follow-up study underscores
the importance that osteoporosis prevention should begin in childhood and adolescence.
Fengxiu Ouyang and Binyan Wang contributed equally to this article.
Source(s) of support: This study is supported in part by grant R01 HD049059, R01 HL0864619 and R01 AR045651 from the National
Institute of Health and by the Food Allergy Project. 相似文献
6.
Steven D. Wexner MD FACS FRCS FRCS Lester Rosen MD Todd H. Baron MD FASGE 《Gastrointestinal endoscopy》2007,65(7):1104-1105
7.
8.
This paper was originally developed by Calu Lester, the founder of KWICFAN, which took a novel approach to grass roots AIDS education in the black community. Calu died of AIDS before completing the work and the paper was completed by Larry L. Saxxon, who was both a friend of Calu's and an AIDS program consultant.
The paper presents a critical perspective of black America's response to the AIDS epidemic. The findings are frightening. Denial within the black community, coupled with a lack of support from the agencies responsible for funding AIDS education, has created a potential epidemiological nightmare. IV drug use continues to be a critical problem of frightening magnitude, allowing an efficient vehicle of HIV transmission. Most sadly of all, the social conditions that create and perpetuate the problematic drug abuse patterns still continue in black America. Black people are clearly becoming the new face of AIDS. 相似文献
The paper presents a critical perspective of black America's response to the AIDS epidemic. The findings are frightening. Denial within the black community, coupled with a lack of support from the agencies responsible for funding AIDS education, has created a potential epidemiological nightmare. IV drug use continues to be a critical problem of frightening magnitude, allowing an efficient vehicle of HIV transmission. Most sadly of all, the social conditions that create and perpetuate the problematic drug abuse patterns still continue in black America. Black people are clearly becoming the new face of AIDS. 相似文献
9.
D. Chemla P. Démolis M. Thyrault D. Annane Y. Lecarpentier and JF Giudicelli 《Fundamental & clinical pharmacology》1996,10(4):393-399
Summary— The influence of local resistance and cardiac performance on peripheral blood acceleration was investigated in 14 healthy male volunteers. Steady and pulsatile flow was studied in the brachial and in the common carotid arteries, ie, two territories that exhibit marked differences in resistive characteristics. Instantaneous blood velocity (V), mean blood velocity (Vm ) and artery diameter (D) were evaluated at rest by an ultrasonic range-gated pulsed Doppler flowmeter using a double transducer probe, thus allowing the calculation of mean blood flow (Q). Mean local resistance (R) was obtained by dividing the mean arterial pressure by Q. The peak value of the local acceleration of the blood was obtained by computer-assisted calculation of the first derivative of instantaneous blood velocity (Gmax = +dV/dtmax ). Peak aortic blood acceleration (GAo) was simultaneously measured from the suprasternal notch using a pulsed Doppler velocity meter. In the brachial and the common carotid arteries, Gmax was of a similar magnitude (551 ±30 and 555 ± 44 cm/s2 , respectively) despite major differences in the respective D, Vm , Q and R values. In neither artery was there a relationship between Gmax and either resting Q or R. At the brachial artery level, Gmax was positively related to GAo ( r = 0.79, P = 0.0008). At the common carotid artery level, there was a weak, although non significant relationship between Gmax and GAo ( P = 0.08). Our results indicate that the local acceleration of peripheral blood flow in the brachial artery is related rather to upstream central impulse than to downstream hemodynamics, and suggest some regional differences in the hemodynamic determinants of the local acceleration of peripheral blood flow. 相似文献
10.