全文获取类型
收费全文 | 97258篇 |
免费 | 8773篇 |
国内免费 | 45篇 |
专业分类
106076篇 |
出版年
2023年 | 362篇 |
2022年 | 814篇 |
2021年 | 1688篇 |
2020年 | 956篇 |
2019年 | 1263篇 |
2018年 | 1555篇 |
2017年 | 1416篇 |
2016年 | 2289篇 |
2015年 | 3942篇 |
2014年 | 4462篇 |
2013年 | 5337篇 |
2012年 | 7169篇 |
2011年 | 6968篇 |
2010年 | 4437篇 |
2009年 | 4180篇 |
2008年 | 5934篇 |
2007年 | 5982篇 |
2006年 | 5581篇 |
2005年 | 5406篇 |
2004年 | 5197篇 |
2003年 | 5004篇 |
2002年 | 4690篇 |
2001年 | 1027篇 |
2000年 | 783篇 |
1999年 | 1048篇 |
1998年 | 1331篇 |
1997年 | 915篇 |
1996年 | 843篇 |
1995年 | 783篇 |
1994年 | 670篇 |
1993年 | 748篇 |
1992年 | 703篇 |
1991年 | 591篇 |
1990年 | 586篇 |
1989年 | 580篇 |
1988年 | 538篇 |
1987年 | 499篇 |
1986年 | 465篇 |
1985年 | 633篇 |
1984年 | 701篇 |
1983年 | 635篇 |
1982年 | 742篇 |
1981年 | 681篇 |
1980年 | 672篇 |
1979年 | 418篇 |
1978年 | 479篇 |
1977年 | 412篇 |
1976年 | 412篇 |
1974年 | 376篇 |
1973年 | 362篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Monoclonal antibodies (MAbs) were developed against recombinant ovine interleukin-5 (IL-5) produced in the baculovirus expression vector system. One MAb, D11 (isotype IgG1), neutralised the activity of both recombinant and native sources of IL-5 in a biological assay (Baf cell assay) but was only weakly reactive in immunocytochemistry. Conversely, a second MAb, A8 (isotype IgA), successfully detected IL-5 in immunocytochemistry but did not display neutralising activity. The development of these MAbs will enable the assay of ovine IL-5 in vitro and permit studies into the role of hypersensitivity reactions in sheep by neutralisation of IL-5 in vivo. 相似文献
992.
993.
Pascal Fournier Christian Maizeret David Jimenez Jean-Pierre Chusseau Stéphane Aulagnier François Spitz 《Acta theriologica》2007,52(1):1-12
The European minkMustela lutreola Linnaeus, 1761 and the European polecatMustela putorius Linnaeus, 1758 are related species sympatric in southwestern France. The European mink is rapidly disappearing whereas the
polecat maintains good populations. Seasonal habitat use of both species was compared in the Landes de Gascogne region to
identify if some vulnerability factors of the European mink were associated with habitats occupied by this mustelid. Potential
habitats were mapped using a satellite picture and 12 main types of habitats were defined. Animal locations were recorded
by radiotracking 9 European mink and 14 polecats from March 1996 to August 1999. Resting animals were located by triangulation,
and, when possible, resting places were described. Animals in activity were tracked by continuous monitoring. Data collected
revealed a strong preference of European mink for flooded habitats, particularly open marshes, flooded woodlands and moorlands.
They seldom left the corridor of the riparian forest and their resting places were mainly in flooded environments, above ground
(under herbs or bushes) or in cavities between tree roots. European polecats were less tightly linked to wetlands. Most of
their locations were in the pine forests outside the valleys and their resting places were mainly in burrows. The strong specialisation
of European mink in aquatic habitats is probably one of the main reasons for its decline because wetlands suffer drastic damages
throughout all of its range. Maintaining adequate water levels is crucial for satisfying habitat requirements of mink. 相似文献
994.
Rollo EE Hempson SJ Bansal A Tsao E Habib I Rittling SR Denhardt DT Mackow ER Shaw RD 《Journal of virology》2005,79(6):3509-3516
995.
Human pluripotent stem cells produce natural killer cells that mediate anti-HIV-1 activity by utilizing diverse cellular mechanisms 总被引:1,自引:0,他引:1
Ni Z Knorr DA Clouser CL Hexum MK Southern P Mansky LM Park IH Kaufman DS 《Journal of virology》2011,85(1):43-50
Cell-based therapies against HIV/AIDS have been gaining increased interest. Natural killer (NK) cells are a key component of the innate immune system with the ability to kill diverse tumor cells and virus-infected cells. While NK cells have been shown to play an important role in the control of HIV-1 replication, their functional activities are often compromised in HIV-1-infected individuals. We have previously demonstrated the derivation of NK cells from human embryonic stem cells (hESCs) with the ability to potently kill multiple types of tumor cells both in vitro and in vivo. We now demonstrate the derivation of functional NK cells from human induced pluripotent stem cells (iPSCs). More importantly, both hESC- and iPSC-derived NK cells are able to inhibit HIV-1 NL4-3 infection of CEM-GFP cells. Additional studies using HIV-1-infected human primary CD4(+) T cells illustrated that hESC- and iPSC-derived NK cells suppress HIV-1 infection by at least three distinct cellular mechanisms: killing of infected targets through direct lysis, antibody-dependent cellular cytotoxicity, and production of chemokines and cytokines. Our results establish the potential to utilize hESC- and iPSC-derived NK cells to better understand anti-HIV-1 immunity and provide a novel cellular immunotherapeutic approach to treat HIV/AIDS. 相似文献
996.
997.
998.
999.
1000.