全文获取类型
收费全文 | 4763篇 |
免费 | 211篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 44篇 |
儿科学 | 58篇 |
妇产科学 | 67篇 |
基础医学 | 511篇 |
口腔科学 | 119篇 |
临床医学 | 336篇 |
内科学 | 1166篇 |
皮肤病学 | 71篇 |
神经病学 | 266篇 |
特种医学 | 266篇 |
外科学 | 865篇 |
综合类 | 12篇 |
一般理论 | 1篇 |
预防医学 | 144篇 |
眼科学 | 58篇 |
药学 | 346篇 |
中国医学 | 13篇 |
肿瘤学 | 642篇 |
出版年
2023年 | 38篇 |
2022年 | 65篇 |
2021年 | 92篇 |
2020年 | 74篇 |
2019年 | 85篇 |
2018年 | 94篇 |
2017年 | 88篇 |
2016年 | 78篇 |
2015年 | 101篇 |
2014年 | 113篇 |
2013年 | 152篇 |
2012年 | 225篇 |
2011年 | 252篇 |
2010年 | 138篇 |
2009年 | 120篇 |
2008年 | 193篇 |
2007年 | 246篇 |
2006年 | 223篇 |
2005年 | 230篇 |
2004年 | 242篇 |
2003年 | 261篇 |
2002年 | 246篇 |
2001年 | 173篇 |
2000年 | 194篇 |
1999年 | 143篇 |
1998年 | 55篇 |
1997年 | 32篇 |
1996年 | 27篇 |
1995年 | 33篇 |
1994年 | 34篇 |
1993年 | 17篇 |
1992年 | 84篇 |
1991年 | 103篇 |
1990年 | 74篇 |
1989年 | 68篇 |
1988年 | 54篇 |
1987年 | 68篇 |
1986年 | 55篇 |
1985年 | 47篇 |
1984年 | 39篇 |
1983年 | 24篇 |
1979年 | 22篇 |
1978年 | 28篇 |
1973年 | 20篇 |
1972年 | 22篇 |
1970年 | 18篇 |
1969年 | 27篇 |
1968年 | 19篇 |
1967年 | 16篇 |
1966年 | 17篇 |
排序方式: 共有4985条查询结果,搜索用时 15 毫秒
21.
Although treatment of one unusually aggressive case of postmenopausal endometriosis with an aromatase inhibitor has been strikingly successful, large clinical trials are required to establish whether aromatase inhibitors will have a significant role in the medical management of endometriosis. Introduction of aromatase inhibitors into the treatment of endometriosis underscores the importance of basic research leading to the development of novel strategies in reproductive disorders. It was shown earlier that aromatase activity was not detectable in normal endometrium. Aromatase, however, is expressed inappropriately in endometriosis and stimulated by prostaglandin E2. Aromatase activity gives rise to local biosynthesis of oestrogen, which, in turn, stimulates prostaglandin E2 production, thus establishing a positive feedback cycle. This favours accumulation of oestrogen and prostaglandins in endometriosis, which is an inflammatory disorder dependent on oestrogen for growth. 相似文献
22.
Hery?Wijayanto Yuriko?Hirai Yosirou?Kamanaka Akira?Katho Dondin?Sajuthi Hirohisa?HiraiEmail author 《Chromosome research》2005,13(7):715-722
The course of chromosome evolution in small apes is still not clear, though painting analyses have opened the way for elucidating
the puzzle. Even the C-banding pattern of the lar-group of gibbons (the genus Hylobates) is not clarified yet, although our previous studies suggested that lar-group gibbons have a unique C-banding pattern. We
therefore made observations to establish C-banded karyotypes of the agile gibbons included in the lar-group. The data were
compared with those of siamangs (the genus Symphalangus), which carry distinctive C-bands, to determine the chromosomal patterns in each group. C-banded chromosomes of agile gibbons
showed several terminal, interstitial and paracentric bands, whose patterns are specific for each chromosome, whereas the
C-bands of siamangs were located only at the terminal and centromeric regions in most chromosomes. Moreover, the C-bands of
agile gibbons and siamangs were shown to be G+C-rich and A+T-rich DNA, respectively, by DAPI/C-band sequential staining. Additionally,
PRINS labelling with a telomere primer revealed that agile gibbons have telomeric DNA only at chromosome ends where there
is no C-band (non-telomeric heterochromatin), whereas the telomeric DNA of siamangs is located in the terminal C-banded regions
(telomeric heterochromatin). Although the evolutionary mechanisms in small apes are still unknown, C-banding patterns and
distribution of telomeric DNA sequences should provide valuable data to deduce the evolutionary pathways of small apes. 相似文献
23.
Ei-ichi Akiyama Yuriko Takamura Yu Nagase 《Macromolecular chemistry and physics.》1992,193(6):1509-1519
Polyimide/polydimethylsiloxane (PI/PDMS) graft copolymer was prepared following the macromonomer method. First, 3-(3,5-diaminobenzyloxy)propyl-terminated polydimethylsiloxane (DAB-PDMS) was prepared by hydrosilylation of allyl 3,5-dinitrobenzyl ether with hydrosilyl-terminated PDMS, followed by catalytic reduction of the two nitro groups. PI/PDMS graft copolymer was synthesized by polycondensation of DAB-PDMS with 4,4′-oxydianiline (ODA) and 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), followed by chemical imidation. The average degree of polymerization of the PDMS chain was in the range between 7 and 25. The resulting graft copolymers were soluble in several organic solvents. Membranes were prepared by solvent casting, followed by heating at 220°C in vacuo, upon which the membranes became hardly soluble in organic solvents. The gas permeability coefficients of the graft copolymer membranes were much greater than those of the polyimide homopolymer and of the same order as that of a PDMS membrane. Furthermore, a selective permeation of organic liquids, e.g., tetrahydrofuran, acetone and acetonitrile, was observed in the pervaporation of aqueous organic liquids through the copolymer membrane. 相似文献
24.
Kazuo Takayama Kanichi Yagawa Akiko Takahashi Hironori Nishio Morio Sudo Nobuyuki Sasaki Toru Yoshida Masanobu Satoh Hisaaki Abiko Akio Nunokawa Mitsuo Okazaki 《Pathology international》1969,19(4):547-562
A typical case of the D uchenne type of progressive muscular dystrophy with autopsy findings was presented. Changes in the myocardial and smooth muscle of many organs were found, and the skeletal muscles also revealed florid changes.
Histopathological examination of the skeletal muscle was made in detail through light and electron microscopic observation. 相似文献
Histopathological examination of the skeletal muscle was made in detail through light and electron microscopic observation. 相似文献
25.
26.
Rhodopseudomonas sphaeroides lipid A derivatives block in vitro induction of tumor necrosis factor and endotoxin tolerance by smooth lipopolysaccharide and monophosphoryl lipid A.
下载免费PDF全文
![点击此处可从《Infection and immunity》网站下载免费的PDF全文](/ch/ext_images/free.gif)
B E Henricson P Y Perera N Qureshi K Takayama S N Vogel 《Infection and immunity》1992,60(10):4285-4290
Rhodopseudomonas (Rhodobacter) sphaeroides diphosphoryl lipid A is a relatively inert species of lipid A but has been shown to antagonize the effects of toxic lipopolysaccharide (LPS) both in vivo and in vitro. The antagonist and its monophosphoryl derivative were examined for the ability to block tumor necrosis factor synthesis and reverse tolerance induction in vitro in macrophage cultures stimulated with bioactive preparations of smooth LPS, rough LPS, diphosphoryl lipid A, and monophosphoryl lipid A. Inhibition of agonist activity and reversal of tolerance by these novel penta-acylated lipid A antagonists provides new insight into macrophage-LPS interactions. 相似文献
27.
Takeki Tsutsui Yuriko Tanaka Yuko Matsudo J. Carl Barrett 《Methods in Cell Science》1995,17(2):155-160
Immortalization of normal human fibroblasts is a very rare event. Multiple genes such as p53 and cellular senescence genes are possibly involved in immortalization of human fibroblasts, suggesting that multiple treatments with carcinogens are required for the immortalization. We describe here the procedure for immortalization of human fibroblasts (MDAH 087) from Li-Fraumeni cancer syndrome with a germ-line p53 mutation. The cells were subjected to multiple treatments with aflatoxin B1 (AFB1) in the presence of exogenous metabolic activation with rat liver post-mitochondrial supernatant (PMS), and 3 of 9 MDAH 087 cell cultures treated 1–3 times with 0.1–1 µg/ml AFB1 became immortal, defined as continuous growth for over 300 population doublings after the first treatment. However, cultures of human fibroblasts from a normal embryo treated under the same conditions failed to escape senescence. The results indicate that the model of human fibroblasts with a mutated p53 allele exposed to AFB1 is potentially useful for studying mechanisms of chemically induced immortalization. 相似文献
28.
29.
Activity-inducible protein Homer1a/Vesl-1S promotes redistribution of postsynaptic protein Homer1c/Vesl-1L in cultured rat hippocampal neurons 总被引:2,自引:0,他引:2
Inoue Y Honkura N Kato A Ogawa S Udo H Inokuchi K Sugiyama H Ogawa S 《Neuroscience letters》2004,354(2):143-147
In cultured rat hippocampal neurons, overexpression of Homer1a/Vesl-1S, an inducible protein upregulated by seizure or long-term potentiation, caused a reduction of punctate distribution of a postsynaptic protein Homer1c/Vesl-1L, without significant decrease in its total amount. Clusters of F-actin were also decreased. Treatments of cells with BDNF or a proteasome inhibitor, which cause increase in the expression level of endogenous Homer1a, also resulted in the reduction of Homer1c puncta. These results indicate that the accumulation of Homer1a, either exogenously expressed or endogenously induced, caused redistribution and dispersion of postsynaptic clusters of Homer1c and F-actin, suggesting an important role of Homer1a in synaptic remodeling. 相似文献
30.
Fukao T Yamada T Tanabe M Terauchi Y Ota T Takayama T Asano T Takeuchi T Kadowaki T Hata Ji J Koyasu S 《Nature immunology》2002,3(3):295-304
Mice that lack the p85alpha regulatory subunit of phosphatidylinositol-3 kinase (PI3K) are deficient in gastrointestinal and peritoneal mast cells but have dermal mast cells. Accordingly, these mice show impaired bacterial clearance in response to acute septic peritonitis and are highly susceptible to infection by the intestinal nematode Strongyloides venezuelensis. Systemic anaphylactic shock responses, however, are intact. We found that although reconstitution of PI3Kminus sign/minus sign mice with bone marrow--derived mast cells (BMMCs) restored anti-bacterial immunity, only T helper type 2 (TH2)-conditioned BMMCs, not "standard" BMMCs, were able to restore anti-nematode immunity. This finding highlights the importance of the TH2 response in the control of nematode infection. Thus, PI3K likely plays an essential role in host immune responses by regulating both the development and induction of mast cells. 相似文献