全文获取类型
收费全文 | 4843篇 |
免费 | 267篇 |
国内免费 | 21篇 |
专业分类
耳鼻咽喉 | 102篇 |
儿科学 | 123篇 |
妇产科学 | 64篇 |
基础医学 | 711篇 |
口腔科学 | 78篇 |
临床医学 | 482篇 |
内科学 | 1125篇 |
皮肤病学 | 133篇 |
神经病学 | 372篇 |
特种医学 | 103篇 |
外科学 | 674篇 |
综合类 | 38篇 |
一般理论 | 3篇 |
预防医学 | 160篇 |
眼科学 | 93篇 |
药学 | 370篇 |
中国医学 | 27篇 |
肿瘤学 | 473篇 |
出版年
2023年 | 27篇 |
2022年 | 48篇 |
2021年 | 82篇 |
2020年 | 40篇 |
2019年 | 74篇 |
2018年 | 79篇 |
2017年 | 79篇 |
2016年 | 91篇 |
2015年 | 101篇 |
2014年 | 126篇 |
2013年 | 157篇 |
2012年 | 250篇 |
2011年 | 295篇 |
2010年 | 147篇 |
2009年 | 132篇 |
2008年 | 242篇 |
2007年 | 263篇 |
2006年 | 245篇 |
2005年 | 227篇 |
2004年 | 265篇 |
2003年 | 244篇 |
2002年 | 247篇 |
2001年 | 132篇 |
2000年 | 101篇 |
1999年 | 114篇 |
1998年 | 64篇 |
1997年 | 44篇 |
1996年 | 33篇 |
1995年 | 28篇 |
1994年 | 31篇 |
1993年 | 26篇 |
1992年 | 70篇 |
1991年 | 73篇 |
1990年 | 63篇 |
1989年 | 87篇 |
1988年 | 56篇 |
1987年 | 69篇 |
1986年 | 83篇 |
1985年 | 98篇 |
1984年 | 46篇 |
1983年 | 55篇 |
1982年 | 30篇 |
1979年 | 44篇 |
1978年 | 32篇 |
1977年 | 26篇 |
1975年 | 29篇 |
1974年 | 26篇 |
1973年 | 23篇 |
1970年 | 31篇 |
1969年 | 27篇 |
排序方式: 共有5131条查询结果,搜索用时 0 毫秒
31.
Kidney-derived aspartic protease-like protein (KAP), initially identified in the mouse kidney, is a novel aspartic protease exclusively expressed in the lung and spleen as well as the kidney. Its orthologues have been identified in the human and rat, and termed napsin. We performed in situ hybridization analysis to determine the cellular expression of napsin mRNA in the kidney, lung, and lymphatic organs of adult mice and to demonstrate, for the first time, its expression patterns in ontogeny. In the adult mouse kidney, extremely intense signals for napsin mRNA were observed in the proximal straight and convoluted tubules, in agreement with a previous study. The first signals for napsin mRNA during nephrogenesis occurred selectively in mesonephric tubules at embryonic day 13, and in metanephric tubules from embryonic day 14. In the lung, a distribution restricted to type II alveolar cells or their precursors was found from embryonic day 15, at the onset of type II cell differentiation, to the adult stage. In the spleen, the mRNA was expressed in lymph nodules of the white pulp and the marginal zone-namely, B-lymphocyte-rich regions from postnatal day 0 to adult. The lymph node and Peyer's patch displayed similar expression patterns, but T cell-dependent areas in these organs and the thymus lacked such signals. These findings suggest that mouse napsin possesses crucial functional roles not only in the kidney but also in the lung and lymphatic tissues, even during fetal stages. 相似文献
32.
Comparison of human, simian, and bovine rotaviruses for requirement of sialic acid in hemagglutination and cell adsorption 总被引:19,自引:0,他引:19
Human rotaviruses (Wa, KUN, MO) showed hemagglutination (HA) only with fixed 1-day-old chicken erythrocytes, and their HA activities were completely destroyed by trypsin activation of virions. Simian SA-11 and bovine NCDV had HA activities not only against fixed erythrocytes but also against fresh erythrocytes from various species. Their HA activities against fixed erythrocytes were also inhibited by trypsin activation, but those against fresh erythrocytes were not. Neuraminidase treatment of fixed erythrocytes did not inhibit HA by trypsin-untreated rotaviruses. In contrast, HA of fresh human erythrocytes by SA-11 and NCDV was completely inhibited by neuraminidase treatment of erythrocytes or glycophorin A, the major erythrocyte sialoglycoprotein. Adsorption and infection of SA-11 and NCDV to monkey kidney MA104 cells were also inhibited by neuraminidase treatment of cells. Adsorption and infection of human rotaviruses were not, however, affected by treatment of cells with neuraminidase from Vibrio cholerae or Arthrobacter ureafaciens or with potassium periodate. Therefore, HA of fixed chicken erythrocytes by trypsin-untreated human and animal rotaviruses may be independent of sialic acids, whereas that of fresh erythrocytes by SA-11 and NCDV is sialic acid dependent and probably mediated by glycophorin A. Sialic acids also constitute an essential part of the cellular receptors for SA-11 and NCDV, whereas those for human rotaviruses were quite resistant to treatments known to destroy major types of sialic acids. 相似文献
33.
Matsuo Matsushita Michiko Ikeda 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1970,10(5):501-511
Summary Projections from the spinal gray matter to the cerebellar nuclei in the cat have been studied using Nauta's silver technique. Following unilateral section of the ventrolateral cord at the cervical level, heavy degeneration is seen in the nucleus medialis on both sides. Scanty degeneration is present bilaterally in the nucleus interpositus. The degeneration is most intense on the contralateral side. Scanty degeneration is also present bilaterally in subnucleus medialis parvicellularis (SMP) (Flood and Jansen, 1961). No degeneration is seen in nucleus lateralis. Following unilateral section of the dorsolateral cord at the cervical level, scanty degeneration is present bilaterally in nucleus medialis and nucleus interpositus anterior. The degeneration is more pronounced ipsilaterally and is also seen in SMP on both sides. No degeneration is present in nucleus lateralis. Fibers from the ventral and dorsal spinocerebellar tracts (VSCT and DSCT) terminate bilaterally in nuclei medialis and interpositus, with the VSCT as the most important connection. 相似文献
34.
IL-1 is required for allergen-specific Th2 cell activation and the development of airway hypersensitivity response 总被引:1,自引:0,他引:1
Nakae S Komiyama Y Yokoyama H Nambu A Umeda M Iwase M Homma I Sudo K Horai R Asano M Iwakura Y 《International immunology》2003,15(4):483-490
IL-1 is a pro-inflammatory cytokine consisted of two molecular species, IL-1alpha and IL-1beta, and the IL-1 receptor antagonist (IL-1Ra) is a natural inhibitor of both molecules. Although it is suggested that IL-1 potentiates immune responses mediated by T(h)2 cells, the role of IL-1 in asthma still remains unclear. In this study, we demonstrate that the ovalbumin (OVA)-induced airway hypersensitivity response (AHR) in IL-1alpha/beta-deficient (IL-1alpha/beta(-/-)) mice was significantly reduced from the levels seen in wild-type mice, whereas the responses seen in IL-1Ra(-/-) mice were profoundly exacerbated, suggesting that IL-1 is required for T(h)2 cell activation during AHR. OVA-specific T cell proliferation, IL-4 and IL-5 production by T cells, and IgG1 and IgE production by B cells in IL-1alpha/beta(-/-) mice were markedly reduced compared with these responses in wild-type mice; such responses were enhanced in IL-1Ra(-/-) mice. Using IL-1alpha(-/-) and IL-1beta(-/-) mice, we determined that both IL-1alpha and IL-1beta are involved in this reaction. Both IgG1 and IgE levels were reduced in IL-1beta(-/-) mice, while only IgE levels were affected in IL-1alpha(-/-) mice, indicating a functional difference between IL-1alpha and IL-1beta. These observations indicate that IL-1 plays important roles in the development of AHR. 相似文献
35.
Zou Jian-Ping; Yamamoto Norihiko; Fujii Tetsuya; Takenaka Hiroshi; Kobayashi Michiko; Herrmann Steven H.; Wolf Stanley F.; Fujiwara Hiromi; Hamaoka Toshiyuki 《International immunology》1995,7(7):1135-1145
Unfractionated spleen cells taken from tumor-bearing mice 2weeks after tumor implantation contained tumor-primed T cellswhich produced cytokines including IL-2 and IFN- when culturedin vitro. With progressive tumor growth this initial lymphokine-producingcapacity decreased. Here, we investigated the ability of IL-12to (I) restore suppressed IFN- production, (II) cause tumorregression and (II) induce anti-tumor protective immunity. Additionof rIL-12 to spleen cell cultures from 4- to 10-week-old tumor-bearingmice resulted in a striking enhancement in the production ofIFN- compared with cultures of these cells in the absence ofrIL-12 or of normal spleen cells in the presence of rIL-12.Five I.p. injections of rIL-12 into mice bearing s.c. tumorsinduced complete tumor regression. This was found when rIL-12was given at early (1–2 weeks), intermediate (4–5weeks) or even late (7 weeks) stages of tumor growth. Furthermore,IL-12-treated mice which rejected the primary tumor exhibitedcomplete resistance to a rechallenge with the same tumor butdid not reject a second syngenetic tumor. Immunohistochemicalanalyses following IL-12 treatment revealed that CD4+ and CD8+T cells infiltrate the tumor. More importantly, IFN- mRNA expressionwas observed in fresh tumor masses from tumor-bearing mice receivingIL-12 treatment The importance of IFN- was further demonstratedby the observation that the systemic administration of anti-IFN-mAb prior to IL-12 treatment completely abrogated the anti-tumoreffect of IL-12. Thus, these results indicate that administrationof modest levels of rIL-12 to tumor-bearing mice results intumor regression through mechanisms involving reversal of suppressedIFN- production by anti-tumor T cells and the establishmentof a tumor-specific protective immune response. 相似文献
36.
We have previously developed a temperature-responsive cell culture surface by grafting poly(N-isopropylacrylamide) that changes its surface hydrophobicity in response to temperature. While this surface shows similar hydrophobicity to that of commercial polystyrene cell culture surfaces and facilitates cell adhesion and proliferation at 37 degrees C, grafted polymer becomes hydrophilic below 32 degrees C and releases spread cultured cells without trypsin. Temperature-regulated cell detachment requires cell metabolic activity requiring ATP consumption, signal transduction, and cytoskeleton reorganziation. Precoating these surfaces with fibronectin (FN) improves spreading of less adhesive cultured hepatocytes and reducing culture temperature releases cultured cells from FN-adsorbed grafted surfaces. Immunostaining with anti-FN antibody revealed that only FN located beneath cultured cells is removed from culture surfaces after reducing temperature. FN adsorbed to surface areas lacking direct cell attachment remained surface-bound after reducing temperature. A novel concept of active cell detachment is also discussed. 相似文献
37.
K. Kawamura M.D. T. Konno 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1979,35(1):161-175
Summary The retrograde labeling of cortical neurons with horseradish peroxidase (HRP) was used to investigate the morphological features of neurons in various cortical areas projecting to the superior colliculus in the cat.Corticotectal cells were found to be labeled in layer V of the entire cerebral cortex. The number of labeled cells and their locations varied according to the sites of injections of HRP in the colliculus. Most of the Corticotectal cells identified in the present study were small (9–20 m in diameter, 66%) and medium (20–40 urn, 30%) pyramidal neurons and only 4% of them were large (more than 40 m). The labeled cells, 261 in total number, had somal diameters of 20.8±8.0 m (mean and SD). The range of sizes of the labeled neurons was different in different cortical areas. For example, the labeled neurons in the Clare-Bishop area had a greater proportion of large diameter cells than in other areas.The present findings are largely in agreement with the previous data of anterograde degeneration methods with respect to the topographical correlation of the Corticotectal projections. However, in some cortical areas, e.g., the sensorimotor and the first visual (area 17) cortex of the lateral surface of the hemisphere, relatively small numbers of Corticotectal neurons appear to have been labeled by retrogradely transported HRP. The sparsity of the labeled neurons in certain cortical areas may reflect the existence of Corticotectal neurons with axon collaterals supplying brain structures other than the superior colliculus.Abbreviations A.c.
Aqueductus cerebri
- AEct
Gyrus ectosylvius anterior
- AEs
Sulcus ectosylvius anterior
- AI
Stratum album intermediale
- AL
Gyrus lateralis anterior
- AP
Stratum album profundum
- AS
Gyrus sylvius anterior
- Cd
Nucleus caudatus
- F.l.m.
Fasciculus longitudinalis medialis
- GI
Stratum griseum intermediale
- GP
Stratum griseum profundum
- GS
Stratum griseum superficiale
- Ic
Inferior colliculus
- L
Left
- MEct
Gyrus ectosylvius medius
- MS
Gyrus sylvius medius
- MSup
Gyrus suprasylvius medius
- N.r.
Nucleus ruber
- O
Stratum opticum
- P
Pontine nuclei
- P.c.
Pedunculus cerebri
- PEct
Gyrus ectosylvius posterior
- P.g.
Periaqueductal gray matter
- PSigm
Gyrus sigmoideus posterior
- PSup
Gyrus suprasylvius posterior
- R
Right
- Sc
Superior colliculus
- S.n.
Substantia nigra
- Z
Statum zonale
- II
Optic nerve
- III and IV
Motor nuclei of cranial nerves 相似文献
38.
39.
New techniques in immunochemical analysis were reviewed briefly. Introduction of these new techniques into routine tests has made test results more precise and informative than before. By using one of these techniques, time-resolved fluoroimmunoassay, serum concentrations of CA 50 were quantitated in various malignancies. Clinical usefulness of its quantitation was proved especially in the diagnosis of pancreatic cancer. 相似文献
40.
Tashiro M Konishi M Iwamoto T Shigekawa M Kurihara S 《Pflügers Archiv : European journal of physiology》2000,440(6):819-827
Cytoplasmic concentrations of Ca2+ ([Ca2+]i) and Mg2+ ([Mg2+]i) were measured with fluorescent indicators in CCL39 cells, a cell line established from Chinese hamster lung fibroblasts, transfected with complementary deoxyribonucleic acid (cDNA) of the Na+-Ca2+ exchanger isolated either from canine heart (NCX1) or from rat brain (NCX3). Raising extracellular [Mg2+] to 10 mM increased Mg2+ influx and the resultant change in [Mg2+]i (delta[Mg2+]i) was monitored with furaptra under Ca2+-free conditions. In control (vector-transfected) cells, delta[Mg2+]i at 45 min was similar with or without extracellular Na+ (130 mM or 0 mM) and when [Na+]i was raised by 1 mM ouabain treatment. delta[Mg2+]i in NCX1-transfected cells was attenuated significantly in the presence of 130 mM Na+, but became comparable to (or slightly larger than) that in control cells on either removal of extracellular Na+ or treatment with 1 mM ouabain. Cells expressing NCX3 showed an intermediate dependence of delta[Mg2+]i on Na+, probably reflecting a lower degree of expression of the exchanger protein. Extracellular Na+-dependent changes in [Ca2+]i (measured with fura-2 in the presence of extracellular Ca2+ and 10 microM ionomycin, a Ca2+ ionophore) were minimal in control cells, marked in the NCX1-transfected cells and intermediate in the NCX3-transfected cells. These results suggest that the Na+-Ca2+ exchanger (either NCX1 or NCX3) can transport Mg2+ and may play a role in the extrusion of magnesium from cells. 相似文献