全文获取类型
收费全文 | 11427篇 |
免费 | 674篇 |
国内免费 | 525篇 |
出版年
2023年 | 83篇 |
2022年 | 184篇 |
2021年 | 345篇 |
2020年 | 291篇 |
2019年 | 349篇 |
2018年 | 486篇 |
2017年 | 411篇 |
2016年 | 558篇 |
2015年 | 534篇 |
2014年 | 744篇 |
2013年 | 861篇 |
2012年 | 859篇 |
2011年 | 971篇 |
2010年 | 598篇 |
2009年 | 448篇 |
2008年 | 642篇 |
2007年 | 644篇 |
2006年 | 595篇 |
2005年 | 526篇 |
2004年 | 413篇 |
2003年 | 450篇 |
2002年 | 333篇 |
2001年 | 225篇 |
2000年 | 186篇 |
1999年 | 127篇 |
1998年 | 77篇 |
1997年 | 36篇 |
1996年 | 22篇 |
1995年 | 28篇 |
1994年 | 23篇 |
1993年 | 22篇 |
1992年 | 19篇 |
1991年 | 26篇 |
1990年 | 21篇 |
1989年 | 18篇 |
1987年 | 23篇 |
1986年 | 22篇 |
1985年 | 34篇 |
1984年 | 25篇 |
1983年 | 23篇 |
1982年 | 19篇 |
1981年 | 13篇 |
1980年 | 16篇 |
1979年 | 20篇 |
1978年 | 21篇 |
1977年 | 15篇 |
1953年 | 18篇 |
1952年 | 40篇 |
1888年 | 14篇 |
1887年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Xiaoqing Wu Xiaorui Xie Linjuan Su Na Lin Bin Liang Nan Guo Qingquan Chen Liangpu Xu Hailong Huang 《Journal of cellular and molecular medicine》2021,25(18):8929-8935
Pallister-Killian syndrome (PKS) is a rare sporadic genetic disorder usually caused by mosaicism of an extra isochromosome of 12p (i(12p)). This retrospective study analysed the prenatal ultrasound manifestations and molecular and cytogenetic results of five PKS foetuses. Samples of amniotic fluid and/or cord blood, skin biopsy and placenta were collected. Conventional karyotyping and single nucleotide polymorphism array (SNP array) were performed on all the amniotic fluid or cord blood samples. Copy number variants sequencing (CNV-seq) and fluorescence in situ hybridization (FISH) were also used for the validation for one foetus. All the five foetuses were from pregnancies with advanced parental age. Two foetuses involved structural abnormalities and one foetus had only soft markers, all of which included increased nuchal translucency. The rest two foetuses had normal ultrasounds in the second trimester, which has rarely been reported before. The karyotype revealed typical i(12p) in four cases and a small supernumerary marker chromosome consisting of 12p and 20p in the remaining one case. The proportion of cells with i(12p) ranged from 0 to 100% in cultural cells, while SNP array results suggested 2−4 copies of 12p. For one foetus, metaphase FISH showed normal results, but the interphase FISH suggested cell lines with two, three and four copies of 12p in the amniotic fluid. Advanced parental age may be an important risk factor for PKS, and there were no typical ultrasound manifestations related to PKS. A combination of karyotype analysis and molecular diagnosis is an effective method for the diagnosis of PKS. 相似文献
4.
Rafał Krętowski Anna Stypułkowska Marzanna Cechowska-Pasko 《Molecular and cellular biochemistry》2015,398(1-2):165-173
The inhibition of the 26S proteasome evokes endoplasmic reticulum stress, which has been shown to be implicated in the antitumoral effects of proteasome inhibitors. The cellular and molecular effects of the proteasome inhibitor—bortezomib—on human colon cancer cells are as yet poorly characterized. Bortezomib selectively induces apoptosis in some cancer cells. However, the nature of its selectivity remains unknown. Previously, we demonstrated that, in contrast to normal fibroblasts, bortezomib treatment evoked strong effect on apoptosis of breast cancer cells incubated in hypoxic and normoxic conditions. The study presented here provides novel information on the cellular effects of bortezomib in DLD-1 colon cancer cells line. We observe twofold higher percentage of apoptotic cells incubated for 48 h with 25 and 50 nmol/l of bortezomib in hypoxic conditions and four-, fivefold increase in normoxic conditions in comparison to control cells, incubated without bortezomib. It is of interest that bortezomib evokes strong effect on necrosis of DLD-1 colon cancer cell line. We observe the sixfold increase in necrosis of DLD-1 cells incubated with 25 or 50 nmol/l of bortezomib for 48 h in hypoxia and fourfold increase in normoxic conditions in comparison to adequate controls. We suggest that bortezomib may be candidates for further evaluation as chemotherapeutic agents for human colon cancer. 相似文献
5.
6.
Jacek Kęsy Beata Maciejewska Magdalena Sowa Magdalena Szumilak Krzysztof Kawałowski Maja Borzuchowska Jan Kopcewicz 《Plant Growth Regulation》2008,55(1):43-50
It has been shown that both IAA and ethylene application inhibit flower induction in the short-day plant Pharbitis nil. However application of IAA has elevated ethylene production in this plant, as well. Strong enhancement of ethylene production
is also correlated with the night-break effect, which completely inhibits flowering. In order to determine what the role of
IAA and ethylene is in the photoperiodic flower induction in Pharbitis nil, we measured changes in their levels during inductive and non-inductive photoperiods, and the effects of ethylene biosynthesis
and action inhibitors on inhibition of flowering by IAA. Our results have shown that the inhibitory effect of IAA on Pharbitis nil flowering is not physiological but is connected with its effect on ethylene biosynthesis. 相似文献
7.
Yanji Qu Lin Zhuo Na Li Yiqing Hu Weihua Chen Yun Zhou Jinwei Wang Qingmei Tao Jing Hu Xiaolu Nie Siyan Zhan 《PloS one》2015,10(4)
International hospital-based studies have indicated a high risk of cognitive impairment after stroke, evidence from community-based studies in China is scarce. To determine the prevalence of post-stroke cognitive impairment (PSCI) and its subtypes in stroke survivors residing in selected rural and urban Chinese communities, we conducted a community-based, cross-sectional study in 599 patients accounting for 48% of all stroke survivors registered in the 4 communities, who had suffered confirmed strokes and had undergone cognitive assessments via the Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), and Hachinski Ischemia Scale (HIS). Detection of PSCI was based on scores in these neuropsychological scales. Factors potentially impacting on occurrence of PSCI were explored by comparing demographic characteristics, stroke features, and cardiovascular risk factors between patients with and without PSCI. The overall prevalence of PSCI was 80.97% (95%CI: 77.82%-84.11%), while that of non-dementia PSCI (PSCI-ND) and post-stroke vascular dementia (PSD) was 48.91% (95%CI: 44.91%-52.92%) and 32.05% (95%CI: 28.32%-35.79%), respectively. Prior stroke and complications during the acute phase were independent risk factors for PSCI. The risk of recurrent stroke survivors having PSCI was 2.7 times higher than for first-episode survivors, and it was 3 times higher for those with complications during the acute phase than for those without. The higher prevalence of PSCI in this study compared with previous Chinese studies was possibly due to the combined effects of including rural stroke survivors, a longer period from stroke onset, and different assessment methods. There is an urgent need to recognize and prevent PSCI in stroke patients, especially those with recurrent stroke and complications during the acute phase. 相似文献
8.
9.
T. Cichocki B. Gonsior J. Glazur M. Höfert L. Jarczyk E. Rokita A. Strzałkowski M. Sych 《Biological trace element research》1987,13(1):167-177
The elemental composition of rabbit liver was determined by the PIXE and micro-PIXE methods. The mean concentrations of P,
S, Cl, K, Fe, Cu, Zn, and Rb measured by both methods were similar. The latter method also allowed for localization of elements
within lobule territory. It has been found that some elements are more prevalent in the veins (Cl, Fe) and others in the liver
parenchyma (P, Cu, Zn). Moreover, Zn showed the characteristic intralobular distribution. Some methodological aspects of microbeam
application to biological materials were also discussed. 相似文献
10.
Submitochondrial particles were prepared from bovine heart mitochondria, solubilized with Triton X-114 in the presence of lipids and submitted to hydroxylapatite chromatography. The eluate obtained, containing a mixture of mitochondrial carriers, was processed further by affinity chromatography using as ligand p-aminophenylsuccinate coupled via a diazo bond to aminohexyl-Sepharose 4B. The activity of the dicarboxylate exchanger was measured after reconstitution into asolectin vesicles at each step of the purification procedure. All samples studied were found to display substrate and inhibitor specificity similar to those described for the dicarboxylate carrier in mitochondria. The specific activity of the final material eluted from the affinity column was found to be about 1000-times higher than that of the Triton X-114 extract of submitochondrial particles. SDS-polyacrylamide gel electrophoresis analysis of the affinity chromatography eluate showed the presence of only two polypeptides. 相似文献