首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   17127篇
  免费   1146篇
  国内免费   22篇
耳鼻咽喉   167篇
儿科学   644篇
妇产科学   692篇
基础医学   2119篇
口腔科学   245篇
临床医学   2791篇
内科学   2999篇
皮肤病学   346篇
神经病学   1443篇
特种医学   268篇
外科学   1528篇
综合类   309篇
一般理论   17篇
预防医学   2157篇
眼科学   368篇
药学   1019篇
中国医学   20篇
肿瘤学   1163篇
  2024年   17篇
  2023年   113篇
  2022年   184篇
  2021年   411篇
  2020年   305篇
  2019年   400篇
  2018年   427篇
  2017年   315篇
  2016年   364篇
  2015年   430篇
  2014年   568篇
  2013年   841篇
  2012年   1329篇
  2011年   1438篇
  2010年   755篇
  2009年   603篇
  2008年   1199篇
  2007年   1251篇
  2006年   1156篇
  2005年   1176篇
  2004年   1116篇
  2003年   1067篇
  2002年   858篇
  2001年   120篇
  2000年   111篇
  1999年   105篇
  1998年   173篇
  1997年   173篇
  1996年   115篇
  1995年   93篇
  1994年   100篇
  1993年   90篇
  1992年   68篇
  1991年   63篇
  1990年   62篇
  1989年   61篇
  1988年   46篇
  1987年   39篇
  1986年   52篇
  1985年   45篇
  1984年   64篇
  1983年   55篇
  1982年   57篇
  1981年   45篇
  1980年   52篇
  1979年   37篇
  1978年   29篇
  1977年   21篇
  1976年   15篇
  1972年   15篇
排序方式: 共有10000条查询结果,搜索用时 32 毫秒
91.
The limb-girdle muscular dystrophies are a clinically and geneticallyheterogeneous group of disorders. We have ostudied two largeinbred families of different ethnic origin and excluded linkageto LGMD2 on chromosome 15q and SCARMD on chromosome 13. Proceedingto a genomic linkage search, we have now identified linkageto markers D2S134 and D2S136 on chromosome 2p (maximum lod score3.57 at zero recombination). The phenotype in the two familieswas similar, with onset in the pelvic girdle musculature inthe late teens and usually relatively slow progression. Thiswork Identifies a second locus for autosomal recessive limb-girdlemuscular dystrophy.  相似文献   
92.
We have investigated the fundamental properties of central auditory glycinergic synapses in early postnatal development in normal and congenitally deaf (dn/dn) mice. Glycinergic miniature inhibitory postsynaptic currents (mIPSCs) were recorded using patch-clamp methods in neurons from a brain slice preparation of the medial nucleus of the trapezoid body (MNTB), at 12-14 days postnatal age. Our results show a number of significant differences between normal and deaf mice. The frequency of mIPSCs is greater (50%) in deaf versus normal mice. Mean mIPSC amplitude is smaller in deaf mice than in normal mice (mean mIPSC amplitude: deaf, 64 pA; normal, 106 pA). Peak-scaled fluctuation analysis of mIPSCs showed that mean single channel conductance is greater in the deaf mice (deaf, 64 pS; normal, 45 pS). The mean decay time course of mIPSCs is slower in MNTB neurons from deaf mice (mean half-width: deaf, 2.9 ms; normal, 2.3 ms). Light- and electron-microscopic immunolabeling results showed that MNTB neurons from deaf mice have more (30%) inhibitory synaptic sites (postsynaptic gephyrin clusters) than MNTB neurons in normal mice. Our results demonstrate substantial differences in glycinergic transmission in normal and congenitally deaf mice, supporting a role for activity during development in regulating both synaptic structure (connectivity) and the fundamental (quantal) properties of mIPSCs at central glycinergic synapses.  相似文献   
93.
94.
Kåre  Berg  Ikuko  Kondo  Dennis  Drayna Richard  Lawn 《Clinical genetics》1990,37(6):473-480
A restriction site polymorphism in the Lp(a) apolipoprotein gene (the LPA gene) is reported. The basis for the polymorphism is presence or absence of an MspI restriction site that appears to be 3' to the last kringle IV structure of the gene. The "1" gene (presence of the restriction site) has a frequency of 0.316 and the "2" gene (absence of the restriction site) has a frequency of 0.684. Both members of each of 67 monozygotic (MZ) twin pairs had the same genotype and there was Mendelian segregation of the DNA variants in 40 families with a total of 75 children. There was a lower proportion of people with genotype 1-1 in the top quartile than in the 3 bottom quartiles of the population distribution of Lp(a) lipoprotein levels but the difference did not reach statistical significance.  相似文献   
95.
96.
This study explored premorbid, neurocognitive, behavioral, and familial factors in preschoolers, ages 3-6, who experienced a mild to moderate traumatic brain injury (TBI). Twenty-nine children with TBI, 33 children with mild to moderate injuries to other body regions, and 34 non-injured children participated in the study. Neuropsychological assessments and behavioral measures were administered at the time of hospitalization and 6 months later. In comparison to the non-injury children, preschool-aged children with TBI had higher rates of premorbid behavior difficulties, lower premorbid cognitive functioning, and poorer development of pre-academic skills. In addition, parents of children with TBI reported greater situational issues and life stressors than parents of children in the non-injured group. Some neurocognitive recovery was evident in the TBI group, but no differences were recognized in behavioral and family measures at the 6-month follow-up. This study emphasizes the relative effects of premorbid characteristics in later practice of preschool children who sustain TBI.  相似文献   
97.

Background

Variants in GBA are the most common genetic risk factor for Parkinson's disease (PD), and are especially prevalent in the Ashkenazi Jewish (AJ) population. However, most studies on GBA in AJ genotype only seven selected Gaucher-associated pathogenic variants rather than sequencing the whole gene, which may leave carriers of PD-associated GBA variants undiscovered.

Methods

GBA was fully sequenced using molecular inversion probes (MIPs) and Sanger sequencing in 735 AJ PD patients and 662 AJ controls, from Israel and New York. Additional AJ control data (n?=?3044) from the Inflammatory Bowel Disease Exome Portal was used.

Results

Full GBA sequencing increased the number of variants discovered by 17.4%, compared to targeted genotyping. An additional 17 PD patients were identified with GBA-associated PD. The p.E326K variant was found in 1.6% of AJ PD patients, making it the second most common PD-associated GBA variant in AJ. GBA variants were found in 18% of PD patients and 7.5% of controls (OR?=?2.7, 95%CI?=?1.9–3.8, p?<?0.0001).

Conclusion

Without full sequencing of GBA, or at minimum including p.E326K in the genotyping panel, a significant proportion of variant carriers go undiscovered and may be incorrectly assigned as non-carriers in studies or clinical trials.  相似文献   
98.
Ashdown's medium, Burkholderia pseudomallei selective agar (BPSA), and a commercial Burkholderia cepacia medium were compared for their abilities to grow B. pseudomallei from 155 clinical specimens that proved positive for this organism. The sensitivity of each was equivalent; the selectivity of BPSA was lower than that of Ashdown's or B. cepacia medium.  相似文献   
99.
This study examined risk and protective factors that differentiate low-income, abused African American women (N = 200) who attempted suicide from those who had never made a suicide attempt. Results from multivariate analyses revealed that numerous and/or severe negative life events, a history of child maltreatment, high levels of psychological distress and depression, hopelessness about the future, and alcohol and drug problems were factors associated with attempter status. Protective factors associated with nonattempter status included hopefulness, self-efficacy, coping skills, social support, and effectiveness in obtaining material resources. Culturally competent intervention approaches for abused women should target increasing their protective factors and reducing their risk factors to decrease the likelihood that these women engage in suicidal behavior.  相似文献   
100.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号