全文获取类型
收费全文 | 10187篇 |
免费 | 705篇 |
国内免费 | 8篇 |
出版年
2024年 | 9篇 |
2023年 | 73篇 |
2022年 | 240篇 |
2021年 | 405篇 |
2020年 | 209篇 |
2019年 | 243篇 |
2018年 | 292篇 |
2017年 | 214篇 |
2016年 | 376篇 |
2015年 | 593篇 |
2014年 | 635篇 |
2013年 | 748篇 |
2012年 | 885篇 |
2011年 | 815篇 |
2010年 | 493篇 |
2009年 | 470篇 |
2008年 | 619篇 |
2007年 | 572篇 |
2006年 | 495篇 |
2005年 | 417篇 |
2004年 | 376篇 |
2003年 | 396篇 |
2002年 | 352篇 |
2001年 | 75篇 |
2000年 | 51篇 |
1999年 | 93篇 |
1998年 | 78篇 |
1997年 | 63篇 |
1996年 | 34篇 |
1995年 | 55篇 |
1994年 | 49篇 |
1993年 | 47篇 |
1992年 | 39篇 |
1991年 | 29篇 |
1990年 | 16篇 |
1989年 | 27篇 |
1988年 | 24篇 |
1987年 | 17篇 |
1986年 | 19篇 |
1985年 | 18篇 |
1984年 | 15篇 |
1983年 | 16篇 |
1982年 | 20篇 |
1981年 | 17篇 |
1980年 | 15篇 |
1979年 | 13篇 |
1978年 | 15篇 |
1977年 | 12篇 |
1975年 | 9篇 |
1974年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
161.
162.
Humayun Pervez Mohammad S. Iqbal Muhammad Younas Tahir Faiz-ul-Hassan Nasim Muhammad Iqbal Choudhary Khalid Mohammed Khan 《Journal of enzyme inhibition and medicinal chemistry》2013,28(6):848-854
A series of 15 previously reported N4-substituted isatin-3-thiosemicarbazones 3a-o has been screened for cytotoxic, antibacterial, antifungal and urease inhibitory activities. Compounds 3b, 3e and 3n proved to be active in cytotoxicity assay; 3e exhibited a high degree of cytotoxic activity (LD50 = 1.10 × 10? 5 M). Compound 3h exhibited significant antibacterial activity against B. subtilis, whereas compounds 3a, 3k and 3l displayed significant antifungal activity against one or more fungal strains i.e. T. longifusus, A. flavus and M. canis. In human urease enzyme inhibition assay, compounds 3g, 3k and 3m proved to be the most potent inhibitors, exhibiting relatively pronounced inhibition of the enzyme. These compounds, being non-toxic, could be potential candidates for orally effective therapeutic agents to treat certain clinical conditions induced by bacterial ureases like H. pylori urease. This study presents the first example of inhibition of urease by isatin-thiosemicarbazones and as such provides a solid basis for further research on such compounds to develop more potent inhibitors. 相似文献
163.
Olivia Weigert Caroline von Spee Reinmar Undeutsch Lutz Kloke Jens Y Humrich Gabriela Riemekasten 《Arthritis research & therapy》2013,15(1):R35
Introduction
The ability to ameliorate murine lupus renders regulatory T cells (Treg) a promising tool for the treatment of systemic lupus erythematosus (SLE). In consideration to the clinical translation of a Treg-based immunotherapy of SLE, we explored the potential of CD4+Foxp3+ Treg to maintain disease remission after induction of remission with an established cyclophosphamide (CTX) regimen in lupus-prone (NZBxNZW) F1 mice. As a prerequisite for this combined therapy, we also investigated the impact of CTX on the biology of endogenous Treg and conventional CD4+ T cells (Tcon).Methods
Remission of disease was induced in diseased (NZBxNZW) F1 mice with an established CTX regimen consisting of a single dose of glucocorticosteroids followed by five day course with daily injections of CTX. Five days after the last CTX injection, differing amounts of purified CD4+Foxp3+CD25+ Treg were adoptively transferred and clinical parameters, autoantibody titers, the survival and changes in peripheral blood lymphocyte subsets were determined at different time points during the study. The influence of CTX on the numbers, frequencies and proliferation of endogenous Treg and Tcon was analyzed in lymphoid organs by flow cytometry.Results
Apart from abrogating the proliferation of Tcon, we found that treatment with CTX induced also a significant inhibition of Treg proliferation and a decline in Treg numbers in lymphoid organs. Additional adoptive transfer of 1.5 × 106 purified Treg after the CTX regimen significantly increased the survival and prolonged the interval of remission by approximately five weeks compared to mice that received only the CTX regimen. The additional clinical amelioration was associated with an increase in the Treg frequency in the peripheral blood indicating a compensation of CTX-induced Treg deficiency by the Treg transfer.Conclusions
Treg were capable to prolong the interval of remission induced by conventional cytostatic drugs. This study provides valuable information and a first proof-of-concept for the feasibility of a Treg-based immunotherapy in the maintenance of disease remission in SLE. 相似文献164.
Mohammed A. E. Sallam Leroy B. Townsend 《Nucleosides, nucleotides & nucleic acids》2013,32(7):1215-1229
Abstract Treatment of 4-(D-gluco-pentitol-l-y1)-2-pheny1–2H-1,2,3-triazole (1) with p-toluenesulfonyl chloride in pyridine solution, afforded the homo-C-nucleoside analog, 4-(2,5-anhydro-D-gluco-pentitol-1-yl)-2-phenyl-2H-1,2,3-triazole (2) as well as its partial p-toluenesulfonyl derivative (3). 4-(5-Chloro-5-deoxy-D-gluco-pentitol-1-yl)-2-phenyl-2H-1,2,3-triazole (8), was isolated as a byproduct from the reaction. The structure and anomeric configuration of 2 was determined by acylation, 1H, 13C NMR, and NOE, spectroscopy as well as mass spectrometry. 相似文献
165.
Joseph B Song Youssef S Tanagho Mohammed Haseebuddin Brian M Benway Alana C Desai Sam B Bhayani Robert S Figenshau 《Reviews in urology》2013,15(2):84-91
Retrieval of foreign bodies from the genitourinary system, most commonly inserted for sexual satisfaction or as a result of a psychiatric illness, can pose a significant surgical challenge. Due to their breadth of size, shape, and location within the genitourinary system, endoscopic management can be difficult. Here, we review the management of four cases of foreign object insertion into the genitourinary system and their outcomes and management.Key words: Foreign body insertion, Sounding, Genitourinary foreign object, Endoscopic extractionForeign objects within the genitourinary tract present a challenging urologic finding due to the diversity and breadth of presentation. Although many objects are easily removed, more complex approaches may be required depending on the size, shape, and location of the object.1,2 In this case series, we discuss the endoscopic management of four patients who presented with foreign bodies in the urethra. Two patients inserted beads into their genitourinary tract for the purpose of sexual stimulation and two patients had a history of psychiatric illness with multiple insertions of a diverse range of foreign objects. In all four cases, endoscopic management was successful in removing the objects, with no need for an open approach such as perineal urethrotomy or open cystostomy. In case 2, in which an open approach was attempted at an outside hospital, this open approach was associated with intraoperative complications. 相似文献
166.
Adel M. Attia Morsala A. Sallam Ahmed A. Almehdi Mohammed M. Abbasi 《Nucleosides, nucleotides & nucleic acids》2013,32(10):2307-2315
Abstract N3 -β-D-glucopyranosyl, galactopyranosyl and xylopyranosyl 6-methyl-2-methylthiouracil and their 5-bromo derivatives have been synthesized by coupling an a-acetobromosugar with the corresponding thiouracil. The new modified thiouridine analogues were evaluated for their inhibitory activity against Human Immunodeficiency Virus (HIV) replication in MT-4 cells as well as for their cytotoxicity. 相似文献
167.
168.
169.
170.