全文获取类型
收费全文 | 4638篇 |
免费 | 306篇 |
国内免费 | 32篇 |
出版年
2023年 | 71篇 |
2022年 | 51篇 |
2021年 | 118篇 |
2020年 | 87篇 |
2019年 | 105篇 |
2018年 | 177篇 |
2017年 | 141篇 |
2016年 | 202篇 |
2015年 | 177篇 |
2014年 | 241篇 |
2013年 | 368篇 |
2012年 | 356篇 |
2011年 | 346篇 |
2010年 | 210篇 |
2009年 | 199篇 |
2008年 | 241篇 |
2007年 | 232篇 |
2006年 | 224篇 |
2005年 | 175篇 |
2004年 | 175篇 |
2003年 | 193篇 |
2002年 | 138篇 |
2001年 | 105篇 |
2000年 | 107篇 |
1999年 | 80篇 |
1998年 | 30篇 |
1997年 | 31篇 |
1996年 | 21篇 |
1995年 | 13篇 |
1994年 | 8篇 |
1993年 | 11篇 |
1992年 | 30篇 |
1991年 | 29篇 |
1990年 | 23篇 |
1989年 | 17篇 |
1988年 | 19篇 |
1987年 | 19篇 |
1986年 | 23篇 |
1985年 | 22篇 |
1984年 | 16篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 7篇 |
1979年 | 11篇 |
1976年 | 7篇 |
1975年 | 9篇 |
1974年 | 14篇 |
1971年 | 8篇 |
1888年 | 6篇 |
1880年 | 7篇 |
排序方式: 共有4976条查询结果,搜索用时 140 毫秒
1.
Demet Tademir Ayegül Karaküük‐yidoan Mustafa Ulali Tuba Takin‐Tok Emne Eln Oru‐Emre Hasan Bayram 《Chirality》2015,27(2):177-188
A series of new chiral thiosemicarbazones derived from homochiral amines in both enantiomeric forms were synthesized and evaluated for their in vitro antiproliferative activity against A549 (human alveolar adenocarcinoma), MCF‐7 (human breast adenocarcinoma), HeLa (human cervical adenocarcinoma), and HGC‐27 (human stomach carcinoma) cell lines. Some of compounds showed inhibitory activities on the growth of cancer cell lines. Especially, compound 17b exhibited the most potent activity (IC50 4.6 μM) against HGC‐27 as compared with the reference compound, sindaxel (IC50 10.3 μM), and could be used as a lead compound to search new chiral thiosemicarbazone derivatives as antiproliferative agents. Chirality 27:177–188, 2015. © 2014 Wiley Periodicals, Inc. 相似文献
2.
In this paper, we propose an adversary model to facilitate forensic investigations of mobile devices (e.g. Android, iOS and Windows smartphones) that can be readily adapted to the latest mobile device technologies. This is essential given the ongoing and rapidly changing nature of mobile device technologies. An integral principle and significant constraint upon forensic practitioners is that of forensic soundness. Our adversary model specifically considers and integrates the constraints of forensic soundness on the adversary, in our case, a forensic practitioner. One construction of the adversary model is an evidence collection and analysis methodology for Android devices. Using the methodology with six popular cloud apps, we were successful in extracting various information of forensic interest in both the external and internal storage of the mobile device. 相似文献
3.
Halil Erhan Eroğlu Ahmet Aksoy Ergin Hamzaoğlu Ümit Budak Sevil Albayrak 《Cytotechnology》2009,59(1):65-72
Helichrysum Mill. (Asteraceae) species have been used in folk medicine for thousands of years in the world. The in vitro cytogenetic
effects in human lymphocytes of nine Helichrysum taxa used in Turkey folk medicine were investigated. Blood samples were obtained from healthy donors, non-smoking volunteers,
which were incubated and exposed to increasing concentrations of methanol extracts of Helichrysum taxa (0.01, 0.05, 0.1, 0.5 and 1 mg/mL). The inhibitory effects of H. stoechas (L.) Moench subsp. barrelieri (Ten.) Nyman, H. armenium DC. subsp. armenium, H. armenium DC. subsp. araxinum (Kirp.) Takht., H. plicatum DC. subsp. plicatum, H. compactum Boiss. and H. artvinense P.H.Davis & Kupicha on the mitotic index and replication index indicate that these taxa can have genotoxic and mutagenic
effects. They should therefore not be used freely in alternative medicine although their antiproliferative activity may suggest
anticarcinogenic properties. Increase effects of H. stoechas subsp. barrelieri, H. armenium subsp. armenium, H. armenium subsp. araxinum, H. chasmolycicum P.H.Davis, H. plicatum subsp. plicatum, H. compactum and H. artvinense on the micronucleus rates showed that these taxa can have genotoxic and carcinogenic effects. 相似文献
4.
5.
6.
7.
The authors study by means of immunoperoxidase method the pattern of thyroglobulin, triiodothyronine and thyroxine distribution in 58 cases of thyroid disorders: 15 euthyroid goiters, 10 Graves' disease, 7 Hashimoto's thyroiditis, 11 folliculo-papillary carcinomas (6 primary tumors and 5 lymph node metastases), 8 follicular carcinomas, 4 anaplastic carcinomas and 3 medullary carcinomas. Thyroglobulin, triiodothyronine and thyroxine were present in most of the thyroid disorders, excepting anaplastic and medullary carcinomas. Thyroglobulin and thyroxine were localized both in the follicular epithelium and in the colloid, whereas triiodothyronine was present especially in the follicular cells. The thyroid hormones distribution in benign lesions is rather similar. In carcinomas, the pattern of thyroglobulin, triiodothyronine and thyroxine is more heterogeneous, but generally the triiodothyronine distribution is similar to that of thyroglobulin. In some carcinomas, triiodothyronine and thyroxine showed a weak or negative immunostaining. The immunoperoxidase method is a valuable tool in the study of functional disturbances in the thyroid pathology and in the diagnosis of thyroid carcinoma metastases as well. Positive thyroid hormones staining clearly indicates the thyroid origin of metastases. 相似文献
8.
9.
This paper continues the previous investigation of the Department on the lymphoid tissue of central and peripheral lymphoid organs under different experimental conditions. The morphological reactional modalities of the intestinal lymphoid tissue in the male Wistar rat were followed up under endocrine imbalance conditions following cortisone administration. Seven days after administration cortisone induced a hyperplasia of the intestinal lymphoid tissue in parallel with a depletion of the lymph node parenchyma and a hypercellularity of bone marrow. After a 6-week postcortisone interval, the lymphoid tissue showed changes corresponding to a cellular depletion in parallel with the restoration of the lymph node parenchyma and a normocellular bone marrow. 相似文献
10.