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141.
Neutrophils and other phagocytic cells support host defense by ingesting microbes and destroying them with reactive oxygen species or oxygen independent mechanisms. Production of ROS is initiated by the phagocyte NADPH oxidase (phox), an enzyme system composed of several constituents. During activation of the cell cytosolic phox proteins (p47phox, p67phox, p40phox, and Rac2) translocate to the plasma membrane and specific granules fuse with the plasma membrane increasing the amount of flavocytochrome b(558). The resultant assembly of phox components results in formation of a complete complex and expression of activity. In this study, we evaluated the oxidase activity of specific granules. In the SDS cell-free system, specific granules expressed oxidase activity in the presence of cytosol in a manner similar to plasma membrane. In contrast to plasma membrane, activity of specific granules was latent, diminishing rapidly over time. In addition, this subcellular fraction contained an inhibitor, possibly related to contamination with azurophilic granules explaining previously published discrepant results. Experiments with recombinant p47phox, p67phox, and dilute cytosol or fractionated cytosol as a source of Rac demonstrated that specific granules have requirements identical to specific granules for oxidase activity. Finally, analysis of neutrophils stimulated with PMA demonstrated translocation of p47phox and to p67phox to specific granules as well as plasma membrane. Both plasma membrane and specific granules from PMA stimulated cells expressed oxidase activity with addition of NADPH demonstrating an assembled oxidase complex. These studies establish a critical role for specific granules as a site for assembly and activation of the oxidase enzyme system and an important constituent for the microbicidal activity of the neutrophil. 相似文献
142.
Nancy Monroy Marisol López Alicia Cervantes Diana García-Cruz Gildardo Zafra Sonia Canún Juan Carlos Zenteno Susana Kofman-Alfaro 《American journal of medical genetics》2002,107(3):181-189
Turner syndrome is a chromosomal disorder in which all or part of one X chromosome is missing. The meiotic or mitotic origin of most cases remains unknown due to the difficulty in detecting hidden mosaicism and to the lack of meiotic segregation studies. We analyzed 15 Turner patients, 10 with a 45,X whereas the rest had a second cell line with abnormal X-chromosomes: a pseudodicentric, an isochromosome, one large and one small ring, and the last with a long arm deletion. Our aims were: to detect X cryptic mosaicism in patients with a 45,X constitution; to determine the parental origin of the abnormality; to infer the zygotic origin of the karyotype and to suggest the timing and mechanism of the error(s) leading to the formation of abnormal X chromosomes from maternal origin. Molecular investigation did not revealed heterozygosity for any microsatellite, excluding X mosaicism in the 45,X cases. Parental origin of the single X chromosome was maternal in 90% of these patients. Three of the structurally abnormal Xs were maternally derived whereas the other two were paternal. These results allowed us to corroborate breakpoints in these abnormal X chromosomes and suggest that the pseudodicentric chromosome originated from post-zygotic sister chromatid exchange, whereas the Xq deleted chromosome probably arose after a recombination event during maternal meiosis. 相似文献
143.
Summary This report describes procedures for the isolation and maintenance of monolayer culture of adult rat liver hepatic parenchymal cells. Isolation of the cells is accomplished using perfusion in situ with a calcium-free buffer followed by buffered collagenase. Gravity sedimentation and selective media are used to limit the contribution of nonparenchymal cells in the cultures. 相似文献
144.
The effects of vasopressin on membrane potential and tension were studied in isolated segments of basilar arteries from the
University of Iowa colonies of normotensive inbred Kyoto-Wistar rats (WKY) and stroke-prone spontaneously hypertensive rats
(SP-SHR). In the presence of vasopressin (0.01–0.3 IU/ml), basilar arteries from WKY, but not from SP-SHR, developed rhythmic
contractions. These contractions were recorded in 13 of 14 WKY basilar arteries, were unaffected by pretreatment with 6-hydroxydopamine,
and were characterized by 20–100 dyne oscillations in tension, occurring 1–3 cycles/min, and superimposed on the vasopressin-induced
contraction (averaging 60 dynes at 0.01 IU/ml or 160 dynes at 0.3 IU/ml). However, resting membrane potentials were not different
in SP-SHR vs. WKY at 37°C, and both strains showed about the same (11 mV) depolarization by 0.1 IU/ml of vasopressin. The
rhythmic contractions were enhanced by K+-free solution, and abolished in the presence of high K+ solution (30 mM), suggesting that active Na+−K+ transport may be involved in modulating the rhythmic activity. These findings are consistent with the hypothesis that the
vasopressin-induced rhythmic contractions in WKY basilar arteries are at least partly dependent on a reduced activity of electrogenic
Na+−K+ active transport in WKY as compared to SP-SHR.
This research was supported by Grant Nos. HL14388 and HL16328 from the National Institutes of Health. Dr. Rusch is the recipient
of Postdoctoral Fellowship HL06907. 相似文献
145.
J A López-Guerrero F Martínez-Abarca M Fresno L Carrasco M A Alonso 《Virus research》1991,20(1):23-29
To examine the influence of the host cell type on poliovirus RNA synthesis we compared the levels of (-) and (+) strand poliovirus RNA during infection of epithelial (HeLa and HEp-2), leukocytic (U-937, HL-60 and K-562) and nerve (IMR-32) cells. The levels of (-) strand RNA were higher in IMR-32, U-937, K-562 or HL-60 cells than those in HeLa or HEp-2 cells. By contrast, (+) strand RNA content was greater in HeLa or HEp-2 cells. Although significant levels of (+) strand RNA were detected in U-937, K-562 and HL-60 cells, no viral protein synthesis was detected by polyacrylamide gel electrophoretic analysis of metabolically labelled proteins. The molar ratio of poliovirus (-) and (+) RNAs was 2-3 fold higher in IMR-32, U-937 and K-562 cells than in HeLa or HL-60 cells and 5-6 fold higher than in HEp-2 cells. Differentiation of HL-60 cells with a variety of inducers produced differential effects on poliovirus (-) and (+) RNA content and modified the molar ratio of (-)/(+) strand RNAs. These findings indicate that host cell components play a critical role in the regulation of the amount of poliovirus (-) and (+) strand RNAs synthesized during infection. 相似文献
146.
Anita S. Kulharya Mark Maberry Mary K. Kukolich Donald W. Day Nancy R. Schneider Golder N. Wilson Vijay Tonk 《American journal of medical genetics. Part A》1995,55(2):165-170
We describe clinical and chromosomal findings in two patients with del(4q). Patient 1, with interstitial deletion (4)(q21.1q25), had craniofacial and skeletal anomalies and died at 8 months of hydrocephalus. Patient 2, with interstitial deletion (4)(q25q27), had craniofacial and skeletal anomalies with congenital hypotonia and developmental delay. These patients shared certain manifestations with other del(4q) patients but did not have Rieger anomaly. Clinical variability among patients with interstitial deletions of 4q may be related to variable expression, variable deletion, or imprinting of genes within the 4q region. © 1995 Wiley-Liss, Inc. 相似文献
147.
Raymond G. Goodwin Wenie S. Din Terri Davis-Smith Dirk M. Anderson Steven D. Gimpel Timothy A. Sato Charles R. Maliszewski Camilynn I. Brannan Neal G. Copeland Nancy A. Jenkins Terry Farrah Richard J. Armitage William C. Fanslow Craig A. Smith 《European journal of immunology》1993,23(10):2631-2641
4-1BB is an inducible T cell antigen that shows sequence homology to members of an emerging family of cytokine receptors, including those for tumor necrosis factor and nerve growth factor. To aid in the analysis of the function of 4-1BB we have utilized a soluble form of the molecule as a probe to identify and clone the gene which encodes its ligand. The ligand for 4-1BB is a type II membrane glycoprotein that has homology to tumor necrosis factor, lymphotoxin, and the ligands for CD40 and CD27, all of which are themselves ligands to receptors in this superfamily. The gene for 4-IBB is on mouse chromosome 4 and maps close to the p80 form of the tumor necrosis factor receptor as well as the gene for CD30. The gene for 4-IBB ligand maps to mouse chromosome 17, but considerably distal to the tumor necrosis factor and lymphotoxin genes. Interaction of 4-1BB with its ligand induces the proliferation of activated thymocytes and splenic T cells, a response which is mimicked on similar cell populations stimulated with an antibody to 4-1BB. 相似文献
148.
Nancy K Ostrom 《Annals of allergy, asthma & immunology》2006,96(5):655-665
OBJECTIVES: To summarize the potential variables that contribute to the increased risk of asthma in women, outline therapeutic strategies that address these variables, and review current treatment recommendations for both pregnant and nonpregnant women with asthma. DATA SOURCES: Literature searches (MEDLINE and cross-references) were performed using the keywords asthma and women in combination with the terms compliance, depression, emergency department, hormones, menstruation, mortality, National Asthma Education and Prevention Program, osteoporosis, pregnancy, prevalence, smoking, and treatment. Searches were limited to human studies with data published before 2005. STUDY SELECTION: The author selected relevant articles for inclusion in this review. RESULTS: Fluctuations in sex hormones, menstruation, pregnancy, obesity, depression, medication nonadherence, and smoking may contribute to increased asthma symptoms or severity in women. Asthma control may be improved if physicians address conditions and behaviors associated with asthma variability and severity in women. Notably, asthma must be managed aggressively in pregnant women, because uncontrolled asthma can lead to perinatal complications. Asthma treatment in women is optimized through patient and physician adherence to national guideline recommendations, including provision of patient education and asthma action plans. CONCLUSIONS: Multiple variables throughout the female life cycle may influence asthma control. Successful asthma management requires an ongoing partnership between the patient and her physician to address physiologic (eg, sex hormones, pregnancy, obesity, depression) and nonphysiologic (eg, smoking, medication nonadherence) factors that may contribute to decreased asthma control. 相似文献
149.
Phillips NJ Schilling B McLendon MK Apicella MA Gibson BW 《Infection and immunity》2004,72(9):5340-5348
We have investigated the lipid A of Francisella tularensis subsp. holarctica strain 1547-57, a type B strain, by using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry, nanoelectrospray quadrupole ion-trap mass spectrometry, and chemical methods. In accordance with the previously published structures of the lipid A from F. tularensis live vaccine strain (LVS) (ATCC 29684) (E. Vinogradov et al., Eur. J. Biochem. 269:6112-6118, 2002), all of the major lipid A forms from strain 1547-57 were tetraacylated. As in the LVS strain, the major fatty acids detected in the F. tularensis 1547-57 lipid A sample included 3-hydroxyoctadecanoic acid, 3-hydroxyhexadecanoic acid, hexadecanoic acid, and tetradecanoic acid. However, several of the lipid A components present in strain 1547-57 were of higher molecular weight than the previously published structures. A major component with an M(r) of 1,666 was found to contain three C(18:0)(3-OH) fatty acids, one C(16:0) fatty acid, one phosphate group, and one 161-Da moiety. This 161-Da moiety could be removed from the lipid A by treatment with aqueous hydrofluoric acid and was identified as galactosamine following peracetylation and analysis by gas chromatography-mass spectrometry. Detailed investigations of the M(r)-1,666 species by ion-trap mass spectrometry with multiple stages of fragmentation suggested that the galactosamine-1-phosphate was linked to the reducing terminus of the lipid A. Similar to the modification of lipid A with arabinosamine, lipopolysaccharide species from F. tularensis containing a phosphate-linked galactosamine could potentially influence its intracellular survival by conferring resistance to antimicrobial peptides. 相似文献
150.