全文获取类型
收费全文 | 8820篇 |
免费 | 718篇 |
国内免费 | 47篇 |
专业分类
耳鼻咽喉 | 58篇 |
儿科学 | 264篇 |
妇产科学 | 178篇 |
基础医学 | 1152篇 |
口腔科学 | 212篇 |
临床医学 | 773篇 |
内科学 | 1918篇 |
皮肤病学 | 297篇 |
神经病学 | 841篇 |
特种医学 | 299篇 |
外科学 | 1403篇 |
综合类 | 61篇 |
一般理论 | 2篇 |
预防医学 | 640篇 |
眼科学 | 166篇 |
药学 | 631篇 |
中国医学 | 22篇 |
肿瘤学 | 668篇 |
出版年
2023年 | 52篇 |
2022年 | 102篇 |
2021年 | 217篇 |
2020年 | 142篇 |
2019年 | 225篇 |
2018年 | 281篇 |
2017年 | 215篇 |
2016年 | 210篇 |
2015年 | 231篇 |
2014年 | 320篇 |
2013年 | 365篇 |
2012年 | 506篇 |
2011年 | 538篇 |
2010年 | 341篇 |
2009年 | 308篇 |
2008年 | 447篇 |
2007年 | 464篇 |
2006年 | 452篇 |
2005年 | 386篇 |
2004年 | 321篇 |
2003年 | 351篇 |
2002年 | 267篇 |
2001年 | 272篇 |
2000年 | 268篇 |
1999年 | 244篇 |
1998年 | 81篇 |
1997年 | 88篇 |
1996年 | 79篇 |
1995年 | 61篇 |
1994年 | 76篇 |
1993年 | 57篇 |
1992年 | 185篇 |
1991年 | 148篇 |
1990年 | 140篇 |
1989年 | 162篇 |
1988年 | 124篇 |
1987年 | 124篇 |
1986年 | 107篇 |
1985年 | 114篇 |
1984年 | 59篇 |
1983年 | 64篇 |
1982年 | 29篇 |
1981年 | 29篇 |
1980年 | 21篇 |
1979年 | 35篇 |
1978年 | 43篇 |
1977年 | 22篇 |
1976年 | 27篇 |
1973年 | 19篇 |
1972年 | 20篇 |
排序方式: 共有9585条查询结果,搜索用时 0 毫秒
1.
Juan D. Gonzalez‐Sanz 《Nursing philosophy》2020,21(4)
The current situation in which the humanities are disparaged affects all university disciplines, including nursing, in whose historical evolution the humanities have always been present in one form or another. Looking beyond this disrepute, this study proposes that nursing renew its attention to classical philosophy. Specifically, it invites a close reading of Xenophon's Anabasis and Plato's Meno, to get three related goals: to show how the use of ancient texts are very valuable tools for the philosophical initiation of nursing students and can help them reflect on their choice of nursing as a practical activity; to reflect on the problem of virtue and the nature of the good life; and to show how the interaction with ancient texts allows students to reflect on questions and issues of life, theirs and others, that are not open to investigation through a purely scientific method. Consequently, both Anabasis and Meno readings strengthen the intellectual relationship between philosophy and nursing, enabling the latter to delve deeper into the key questions of its own thought as a discipline. 相似文献
2.
Marlen Z. Gonzalez Lane Beckes Joanna Chango Joseph P. Allen James A. Coan 《Social cognitive and affective neuroscience》2015,10(7):921-928
Neuroimaging studies using the social-exclusion paradigm Cyberball indicate increased dorsal anterior cingulate cortex (dACC) and right insula activity as a function of exclusion. However, comparatively less work has been done on how social status factors may moderate this finding. This study used the Cyberball paradigm with 85 (45 females) socio-economically diverse participants from a larger longitudinal sample. We tested whether neighborhood quality during adolescence would predict subsequent neural responding to social exclusion in young adulthood. Given previous behavioral studies indicating greater social vigilance and negative evaluation as a function of lower status, we expected that lower adolescent neighborhood quality would predict greater dACC activity during exclusion at young adulthood. Our findings indicate that young adults who lived in low-quality neighborhoods in adolescence showed greater dACC activity to social exclusion than those who lived in higher quality neighborhoods. Lower neighborhood quality also predicted greater prefrontal activation in the superior frontal gyrus, dorsal medial prefrontal cortex and the middle frontal gyrus, possibly indicating greater regulatory effort. Finally, this effect was not driven by subsequent ratings of distress during exclusion. In sum, adolescent neighborhood quality appears to potentiate neural responses to social exclusion in young adulthood, effects that are independent of felt distress. 相似文献
3.
4.
Heidi J Kalkwarf John A Shepherd Didier Hans Elena Gonzalez Rodriguez Joseph M Kindler Joan M Lappe Sharon Oberfield Karen K Winer Babette S Zemel 《Journal of bone and mineral research》2022,37(4):776-785
Trabecular bone score (TBS) is used for fracture prediction in adults, but its utility in children is limited by absence of appropriate reference values. We aimed to develop reference ranges for TBS by age, sex, and population ancestry for youth ages 5 to 20 years. We also investigated the association between height, body mass index (BMI), and TBS, agreement between TBS and lumbar spine areal bone mineral density (aBMD) and bone mineral apparent density (BMAD) Z-scores, tracking of TBS Z-scores over time, and precision of TBS measurements. We performed secondary analysis of spine dual-energy X-ray absorptiometry (DXA) scans from the Bone Mineral Density in Childhood Study (BMDCS), a mixed longitudinal cohort of healthy children (n = 2014) evaluated at five US centers. TBS was derived using a dedicated TBS algorithm accounting for tissue thickness rather than BMI. TBS increased only during ages corresponding to pubertal development with an earlier increase in females than males. There were no differences in TBS between African Americans and non-African Americans. We provide sex-specific TBS reference ranges and LMS values for calculation of TBS Z-scores by age and means and SD for calculation of Z-scores by pubertal stage. TBS Z-scores were positively associated with height Z-scores at some ages. TBS Z-scores explained only 27% and 17% of the variance of spine aBMD and BMAD Z-scores. Tracking of TBS Z-scores over 6 years was lower (r = 0.47) than for aBMD or BMAD Z-scores (r = 0.74 to 0.79), and precision error of TBS (2.87%) was greater than for aBMD (0.85%) and BMAD (1.22%). In sum, TBS Z-scores provide information distinct from spine aBMD and BMAD Z-scores. Our robust reference ranges for TBS in a well-characterized pediatric cohort and precision error estimates provide essential tools for clinical assessment using TBS and determination of its value in predicting bone fragility in childhood and adolescence. © 2022 American Society for Bone and Mineral Research (ASBMR). 相似文献
5.
6.
7.
Betlach Charles J. Arnold John D. Frost R. Wayne Leese Philip T. Gonzalez Mario A. 《Pharmaceutical research》1987,4(5):409-411
The bioavailability of a new sustained-release potassium chloride (KC1) tablet, designed for once-a-day dosing, was compared to a KC1 elixir using urinary excretion data. The study utilized 25 male volunteers dosed in a crossover design in a dietary/activity-controlled environment. The regimens consisted of a total of 80 mEq of potassium in three equally divided doses of elixir every 6 hr and a single 80-mEq dose using four 20-mEq sustained-release (SR) tablets. The mean time to maximum rate of potassium urinary excretion was 2.2 hr for the first elixir dose and 5.5 hr after the SR tablet (P < 0.01), thereby supporting the prolonged-release properties of this formulation. After correction for baseline urinary potassium excretion, the mean total 24-hr urinary potassium excretion was 42.18 mEq for the elixir and 40.41 mEq for the SR tablet. The results indicate that the absorption pattern from the SR tablet is equal to three doses of KC1 elixir dosed 6 hr apart. 相似文献
8.
Early bladder outlet obstruction in fetal lambs induces renal dysplasia and the prune-belly syndrome 总被引:3,自引:0,他引:3
A model of posterior urethral valves in fetal lambs was developed in order to evaluate the effect of intrauterine urinary obstruction on the developing kidney. Complete urethral obstruction was induced in five fetal lambs at 43 to 45 days of gestation. Two control fetal lambs underwent sham operations. At full term (140 days), two of the five experimental lambs and both control lambs were available for postmortem examination. Results of gross and histological examination of the control lambs were normal. In contrast, the kidneys of the experimental lambs were markedly asymmetrical in size. Histological examination of the kidneys in experimental lambs showed cystic dilatation of the collecting ducts and occasional cystic dilatation of Bowman's spaces, features compatible with obstruction. Also noted were peripheral cortical cysts and primitive tubules lined with cuboidal epithelium and surrounded by fibromuscular collarettes, characteristic of renal dysplasia. One of the infant lambs had many characteristics of the prune-belly syndrome, including a wrinkled, markedly distended abdomen, deficient abdominal wall musculature, flared chest wall, limb deformities, and undescended testes. These results suggest that early in utero urethral obstruction (at the beginning of the second third of gestation) causes renal dysplasia. The results also support the hypothesis that the prune-belly syndrome results from abdominal distention that occurs early in gestation. 相似文献
9.
Ignacio Alvarez Alvarez M.D. Pedro Sanchez Lazo Ph.D. Sofia Ramos Gonzalez Ph.D. J. Pablo Rodrigo Tapia M.D. Faustino Nunez Batalla M.D. Carlos Suarez Nieto M.D. 《American journal of otolaryngology》1997,18(6):375
Purpose: Increasingly, evidence has shown that human papillomavirus (HPV) plays a role in the induction of certain carcinomas. The presence of HPV sequences in 56 previously untreated oral and pharyngolaryngeal carcinomas was examined by the polymerase chain reaction (PCR).Materials and Methods: After DNA extraction, samples underwent 40 replication cycles with specific oligonucleotide primers corresponding to sequences from the E6 open-reading frame of HPV-6b, HPV-16, and HPV-18. To determine the E6 genomic integration, positive samples were processed with specific primers for the corresponding HPV L1 genes. Genomic HPV DNA cloned into PBR 322 was used as positive control.Results: HPV E6 DNA of the 6b and 16 types was detected in 14 patients (25%). The L1 gene was not present.Conclusion: Detected HPV E6 DNA might be integrated into the cell genome in the positive cases as indicated by the absence of the L1 gene-coding for the viral capside. Histological and clinical parameters, such as tumor location, degree of differentiation, stage, recurrence, and survival rates, were unrelated to the presence of HPV. 相似文献
10.