全文获取类型
收费全文 | 7296篇 |
免费 | 303篇 |
国内免费 | 54篇 |
专业分类
耳鼻咽喉 | 143篇 |
儿科学 | 156篇 |
妇产科学 | 45篇 |
基础医学 | 957篇 |
口腔科学 | 270篇 |
临床医学 | 438篇 |
内科学 | 1903篇 |
皮肤病学 | 240篇 |
神经病学 | 496篇 |
特种医学 | 310篇 |
外科学 | 1224篇 |
综合类 | 14篇 |
预防医学 | 191篇 |
眼科学 | 96篇 |
药学 | 374篇 |
中国医学 | 15篇 |
肿瘤学 | 781篇 |
出版年
2023年 | 56篇 |
2022年 | 75篇 |
2021年 | 138篇 |
2020年 | 76篇 |
2019年 | 100篇 |
2018年 | 131篇 |
2017年 | 108篇 |
2016年 | 115篇 |
2015年 | 179篇 |
2014年 | 227篇 |
2013年 | 277篇 |
2012年 | 374篇 |
2011年 | 394篇 |
2010年 | 221篇 |
2009年 | 218篇 |
2008年 | 352篇 |
2007年 | 414篇 |
2006年 | 461篇 |
2005年 | 424篇 |
2004年 | 488篇 |
2003年 | 444篇 |
2002年 | 495篇 |
2001年 | 136篇 |
2000年 | 117篇 |
1999年 | 142篇 |
1998年 | 115篇 |
1997年 | 108篇 |
1996年 | 101篇 |
1995年 | 87篇 |
1994年 | 81篇 |
1993年 | 74篇 |
1992年 | 95篇 |
1991年 | 88篇 |
1990年 | 96篇 |
1989年 | 62篇 |
1988年 | 49篇 |
1987年 | 57篇 |
1986年 | 51篇 |
1985年 | 48篇 |
1984年 | 37篇 |
1983年 | 31篇 |
1982年 | 39篇 |
1981年 | 45篇 |
1980年 | 26篇 |
1979年 | 21篇 |
1978年 | 25篇 |
1977年 | 20篇 |
1976年 | 21篇 |
1975年 | 22篇 |
1973年 | 14篇 |
排序方式: 共有7653条查询结果,搜索用时 0 毫秒
51.
Mice deficient in the B cell adaptor for phosphoinositide 3-kinase (BCAP) have reduced numbers of mature B lymphocytes, which show defects in cell survival and proliferation. We found here that the NF-kappa B (Rel) pathway was impaired in BCAP-deficient mature B cells and that NF-kappa B target genes, indispensable for cell survival and division, were not induced in response to B cell receptor (BCR) stimulation. Among the NF-kappa B (Rel) family, expression of c-Rel was specifically reduced in BCAP-deficient B cells. Retrovirus-mediated reintroduction of c-Rel restored the pool size of immunoglobulin (Ig)M(lo)IgD(hi) mature B cells in the spleen as well as proliferative responses to BCR stimulation. These results indicate BCAP is essential in the maintenance of mature B cells through functional coupling with c-Rel. 相似文献
52.
Harimaya A Tarkkanen J Mattila P Fujii N Ylikoski J Himi T 《Clinical and diagnostic laboratory immunology》2005,12(9):1130-1134
We evaluated the immunological potential of adenoidal lymphocytes from children with recurrent otitis media. Interleukin-4 release and CD69 expression were lower in adenoidal lymphocytes than in peripheral blood lymphocytes (PBL). Our results suggest that there may be a difference between the immunological potential of adenoidal lymphocytes and that of PBL in children with otitis. 相似文献
53.
Minoru Shinohara Motoki Kouzaki Takeshi Yoshihisa Tetsuo Fukunaga 《European journal of applied physiology》1997,76(4):314-319
The mechanical activity of the human quadriceps muscle during maximal incremental cycle ergometry was investigated by mechanomyography (MMG). MMG and surface electromyography (EMG) recordings of vastus lateralis muscle activity were obtained from nine males. Cycle ergometry was performed at 60?rev/min and work load was incremented step wise by 20?W (3.2?Nm) every minute until volitional fatigue. The mean amplitudes of MMG (mMMG) and EMG (mEMG) during the contraction phase were calculated from the last six contractions in each load. The duration, load and work rate of exercise at exhaustion were 13.3 (1.6)?min, 44.1 (5.5)?Nm, 276.7 (34.7)?W, respectively. A linear relationship between mMMG and load was evident in each subject (r?=?0.868–0.995), while mEMG seemed to dissociate as the load became greater. In the grouped mean data, mMMG was linearly related to load whether aligned to the absolute (r?=?0.995) or maximal (r?=?0.995) load. Involvement of the noise component was further investigated by studying passive cycling by four subjects. Pedals were rotated passively for the first half of each stage (PAS) and the subject then pushed the pedals for the second half (ACT). In the lighter load region, the mMMG of ACT was as small as that of PAS. However, the change in the mMMG of PAS was very small compared with that of ACT. In conclusion, this study demonstrates a linear relationship between the mMMG of the quadriceps muscle and work load during maximal incremental cycle ergometry. The effect of movement noise was thought to be small and stable. 相似文献
54.
B cell development is perturbed in bone marrow from c-fos/v-jun doubly transgenic mice 总被引:2,自引:0,他引:2
Fujita Kenji; Miki Nobuhiko; Mojica Mariluz P.; Takao Shintaro; Phuchareon Janyaporn; Nishikawa Shin-Ichi; Sudo Tetsuo; Tokuhisa Takeshi 《International immunology》1993,5(2):227-230
c-fos and c-jun gene products form a heterodimeric complex (AP-1)that regulates target gene expression by binding to a specificDNA sequence motif. In order to study a role of AP-1 (Fos/Jun)in growth and differentiation of immature B lineage cells, wehave established and mated two independent transgenic mice carryingthe mouse c-fos gene or the viral v-Jun gene fused to the H-2Kpromoter. IL-7 dependent bone marrow cell culture from doublytransgenic (H2-fos/jun) mice demonstrated severe delay of earlyB cell development. Proliferation of pre-B cells in the freshbone marrow from HZ-fos/jun mice to IL-7 stimulation was verylow. These results suggest that the deregulated production ofAP-1 perturbs IL-7 mediated proliferation and differentiationof immature B cells. 相似文献
55.
Ping Ii Hiroshi Kawachi Tetsuo Morioka Mlchiaki Orikasa Takashi Oite Zhen Sheng Shi Fujio Shimizu 《Pathology international》1997,47(7):430-435
The effects of treditional Chinese medlclne (Salrel-to) on experimental glomerulonephritls Induced In rats by monodonal antibody (mAb) 1–22–3 lnjectlon was examined. The level of proteinuria in the Sairel-to-treated group was significantly lower than that In the PBS treated group. This suppressive effect was caused by the major component of Sealer-to, Syo-salko-to but not by another component, Gorel-san. The suppressive effect of Syo-salko-to was Identified In Its components ( Bupleuri radix, Pindilae tuber and Zingibers rhizoma ), but not In the other combined components ( Ginseng radix and Zizyphl fructus ). Further study weeled that the suppressive effects of the combined components were mainly derived from Bupleuri radix . It was demonstrated that the actual active Ingredient is probably Salkosaponin-d. Light microscopy revealed that Sairel-to and Its effective components suppressed the proliferation of mesanglal cells and mesanglal matrix expansion. Semi quantitative morphological studies of glomerular lesions on the eighth day showed that Syo-salko-to and Its combined components ( Bupleuri radix, Zinglberis rhizoma and Pinelliae tuber ) suppressed mesanglal matrix expansion significantly compared with phosphate-buffered saline control groups (matrix score: 28.0±19.1 vs 102.3±14.1; 30.9±30.1 vs 102.3±14.1, p<0.005, respectively). It was concluded that Salkosaponln-d, as well as Bupleuri radix , Syo-salko-to and Sairel-to can suppress proteinurla and morphological changes In the rat glomerulonephritls model Induced by mAb 1–22–3. 相似文献
56.
S. Oh-ishi Takako Kizaki Tomomi Ookawara Koji Toshinai Shukoh Haga Fujio Karasawa Tetsuo Satoh Naokazu Nagata L. L. Ji Hideki Ohno 《Pflügers Archiv : European journal of physiology》1998,435(6):767-774
The aim of the current study was to elucidate the synergism of dietary calcium restriction and exhaustive exercise in the
antioxidant enzyme system of rat soleus muscle, and to investigate the involvement of neutrophils in exercise-induced muscle
damage. Forty-eight male Wistar rats were assigned to the following groups: control (C) or calcium-restricted [1 month (1 M)
or 3 months (3 M)]. Each group was subdivided into acutely exercised or non-exercised groups. Soleus muscle from each rat
was analysed to determine the levels of antioxidant enzymes [Mn-superoxide dismutase (SOD), Cu,Zn-SOD, glutathione peroxidase
(GPX), and catalase (CAT)]. Dietary calcium restriction resulted in calcium deficiency and upregulated the antioxidant enzymes
examined except GPX. Conversely, exhaustive exercise significantly decreased GPX and CAT, but not SODs activities in the calcium-restricted
(1 M and/or 3 M) rats. Contents of immunoreactive Mn-SOD and Cu,Zn-SOD were only increased in the 3 M rats. During calcium
restriction, the mRNA expression of both forms of SOD showed initial upregulation, followed by downregulation. Exhaustive
exercise significantly increased the mRNA expressions only in the 3 M rats. Moreover, exhaustive exercise markedly increased
myeloperoxidase activity in soleus muscles from the 1 M and 3 M rats compared with the C rats, and significantly enhanced
the ability of neutrophils to generate superoxide in the 3 M rats. The results demonstrate that dietary calcium restriction
upregulates certain antioxidant enzyme activities in rat soleus muscle, indicating an enhanced resistance to potential increases
in intracellular reactive oxygen species. The results also suggest that exhaustive exercise may cause oxidative damage in
soleus muscle of calcium-deficient rats through the activation of neutrophils.
Received: 4 August 1997 / Received after revision: 29 September 1997 / Accepted: 26 November 1997 相似文献
57.
Kazunaga Agematsu Tetsuji Kobata Feng-Chun Yang Takayuki Nakazawa Keitaro Fukushima Masashi Kitahara Tetsuo Mori Kanji Sugita Chikao Morimoto Atsushi Komiyama 《European journal of immunology》1995,25(10):2825-2829
CD27 is a T cell activation antigen expressed on a majority of peripheral blood T cells. CD27 is also expressed on a subpopulation of human B cells, and it is reported that CD27+ B cells secrete both IgG and IgM. CD70, a ligand for CD27, is expressed on activated T and B cells, suggesting an interaction between T and B cells via CD27/CD70 ligation. Here, we analyze B cell immunoglobulin synthesis using a CD70 transfectant and present functional data showing that B cells secrete large amounts of IgG and IgM as a result of the CD27/CD70 interaction. A flow cytometric analysis showed that CD27 expression was increased and CD70 was expressed on tonsillar and peripheral blood B cells after activation with Staphylococcus aureus Cowan strain (SAC) plus interleukin (IL-2). In addition, the proliferation of B cells was enhanced mildly by the addition of CD70 transfectant, and its proliferation was blocked by anti-CD70 mAb. More importantly, the CD70 transfectant enhanced IgG and IgM production by purified B cells greatly in the presence of SAC plus IL-2. The enhancement was completely blocked by the addition of either anti-CD70 mAb or anti-CD27 mAb. Strongly suggesting that the interaction of CD27 with its ligand, CD70, on B cells plays an important role in B cell growth and differentiation to produce IgG and IgM. 相似文献
58.
Shuichi Seki Hiroki Sakaguchi Nobuyoshi Kawakita Atsushi Yanai Tetsuo Kuroki Kenzo Kobayashi 《Virchows Archiv : an international journal of pathology》1993,422(2):133-143
The proliferative activity and ultrastructural characteristics of proliferating biliary epithelial cells were analysed immunohistocytochemically in 39 biopsied liver specimens from patients with acute viral hepatitis, chronic hepatitis and liver cirrhosis using a monoclonal antibody against DNA polymerase (DNA-PA). In acute viral hepatitis with perivenular confluent necrosis, proliferation of typical bile ducts was found frequently in portal areas. In chronic aggressive hepatitis and cirrhosis, ductular proliferation of both typical and atypical forms was found in enlarged portal and periportal areas and in confluent necrotic areas. The number of proliferating biliary epithelial cells that stained positive for DNA-PA was small. There were very few positively stained cells in atypical bile ducts in confluent necrotic areas of cirrhosis. Atypical bile ducts seen in chronic aggressive hepatitis, cirrhosis and acute hepatitis with confluent necrosis were positively stained for both cytokeratins 8 and 19. In cirrhosis, the number of stained biliary epithelial cells in typical bile ducts was larger than the number of such cells in atypical bile ducts (P< 0.01). By electron microscopy, the cells positively stained for DNA-PA were mostly so-called clear cells with irregular nuclei containing coarse nucleoplasm, and a few small cells with scanty cytoplasm and few organelles. 相似文献
59.
60.
T. Ebina A. Sato K. Umezu N. Ishida S. Ohyama A. Oizumi K. Aikawa S. Katagiri N. Katsushima A. Imai S. Kitaoka H. Suzuki T. Konno 《Medical microbiology and immunology》1985,174(4):177-185
After immunizing 8-month pregnant Holstein cows with human rotavirus, Wa strain, cow colostrum containing neutralizing antibody to human rotavirus, designated as Rota colostrum, was obtained. After randomly grouping 13 infants from a single orphanage, 6 infants received 20 ml of Rota colostrum every morning and 7 control infants received 20 ml of market milk. One month later, rotavirus associated diarrhea was observed in 6 of the 7 infants given milk and 1 out of the 6 infants given Rota colostrum. Orally administered Rota colostrum significantly protected infants from diarrhea caused by rotavirus (P < 0.05). Two out of 5 Rota colostrum recipients who were free from diarrhea showed rises in complement fixation (CF) antibody titer after the rotavirus infection epidemic. Thus, Rota colostrum prevented the outbreak of diarrhea but did not prevent immunological responses to natural rotavirus infection. In the therapeutic trial Rota colostrum had no effect on duration of diarrhea, bowel movements or virus shedding in stool. However, there were no side-effects of Rota colostrum. 相似文献