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231.
B. Yassine-Diab P. Carmichael Fatima-Ezzahra L'Faqihi Giovanna Lombardi Sarah Deacock Claude de Préval Hélène Coppin R. I. Lechler 《Immunogenetics》1999,49(6):532-540
A comprehensive analysis was carried out of the tri-molecular complex of peptide, major histocompatibility class II molecule,
and T-cell receptor (TcR) involved in the recognition of the promiscuous HA (306–318) peptide, restricted by one of two closely
related HLA-DR alleles, HLA-DRB1*0101 and HLA-DRB1*0103. These two DR molecules differ by only three amino acids at positions 67, 70, and 71, in the third variable region of the
DRB1 chain. None of the HA (306–318)-specific T-cell clones restricted by these two DR molecules tolerated amino acid substitution
at the peptide-binding position 71, despite the fact that the substitution did not interfere with peptide binding. The majority
of the DRB1*0103-restricted clones tolerated substitution of the amino acid at the TcR-contacting position 70, while the DRB1*0101-restricted
T cells did not. Biased usage of TRVA and TRVB segments was observed for the DRB1*0103-restricted clones; in contrast, apparently
random usage was seen in the DRB1*0101-restricted T cells. Finally, limiting dilution analysis revealed a lower frequency
of T cells reactive with the HA peptide in a DRB1*0103 compared with a DRB1*0101 individual. Taken together these data suggest
that biased TcR gene usage may reflect a relatively low precursor frequency of T cells, and the need for clonal expansion of a limited set
of high avidity T cells.
Received: 7 August 1998 / Revised: 19 November 1998 相似文献
232.
Friel JK Andrews WL Jackson SE Longerich HP Mercer C McDonald A Dawson B Sutradhar B 《Biological trace element research》1999,67(3):225-247
To examine longitudinal and gestational effects of mineral content in human milk, we analyzed human milk from lactating mothers
of premature (PRT,n = 24, < 2000g birth weight, < 37 wk gestation) and fullterm (FT,n = 19, > 2500g, 39–41 wk gestation), living in Newfoundland, Canada. Samples were collected once a week for 8 wk with one final sample collected
at 3 mo. Milk samples collected in acid-washed containers were wet ashed with concentrated HNO3, and barium, cadmium, calcium, cesium, cobalt, copper, cerium, lanthanum, magnesium, manganese, molybdenum, nickel, lead,
rubidium, tin, strontium, and zinc were measured using inductively coupled plasma-mass spectrometry. Data were analyzed using
standard multiple-regression procedures with correlated data analyses to take account of the relationship between successive
weeks. Results indicated lower Ca and Pb in PRT milk. Calcium was the only nutritionally significant element to differ between
groups. Molybdenum in both PRT and FT milk showed a definite decrease with time, suggesting that the Mo content in milk is
homeostatically regulated. However, Ce, La, Ba, and Sn did not display any pattern indicative of biological regulation and
potential human requirement. 相似文献
233.
Trucco Carlotta Rolli Véronique Oliver F. Javier Flatter Eric Masson Murielle Dantzer Françoise Neidergang Claude Dutrillaux Bernard Ménissier-de murcia Josiane de Murcia Gilbert 《Molecular and cellular biochemistry》1999,193(1-2):53-60
A dual approach to the study of poly (ADP-ribose)polymerase (PARP) in terms of its structure and function has been developed in our laboratory. Random mutagenesis of the DNA binding domain and catalytic domain of the human PARP, has allowed us to identify residues that are crucial for its enzymatic activity.In parallel PARP knock-out mice were generated by inactivation of both alleles by gene targeting. We showed that: (i) they are exquisitely sensitive to -irradiation, (ii) they died rapidly from acute radiation toxicity to the small intestine, (iii) they displayed a high genomic instability to -irradiation and MNU injection and, (iv) bone marrow cells rapidly underwent apoptosis following MNU treatment, demonstrating that PARP is a survival factor playing an essential and positive role during DNA damage recovery and survival. 相似文献
234.
Claude N. Warren 《American anthropologist》2001,103(3):841-842
Assembling the Past: Studies in the Professionalization of Archaeology. Alice B. Kehoe and Mary Beth Emmerichs. eds. Albuquerque: University of New Mexico Press, 1999. 241 pp. 相似文献
235.
Yoshinori Asakawa Masao Toyota Tsunematsu Takemoto Claude Suire 《Phytochemistry》1979,18(8):1355-1357
Four novel secoaromadendrane-type sesquiterpene hemiacetals, plagiochilines C, D, E and F, together with the previously known (?)-bicyclogermacrene, have been isolated from the liverwort, Plagiochila asplenioides and their structures have been spectroscopically elucidated. From Plagiochila semidecurrens plagiochilines A and C have been obtained along with (?)-bicyclogermacrene and its related sesquiterpene hydrocarbons. 相似文献
236.
Le Naour F Charrin S Labas V Le Caer JP Boucheix C Rubinstein E 《Cancer immunology, immunotherapy : CII》2004,53(3):148-152
The tetraspanins form a family of about 30 molecules mainly expressed on the cell surface. They have been reported to be involved in many physiological or pathological processes, such as fertilization, immune response, development of the nervous system, and metastasis, as well as in infectious diseases (HCV, malaria, etc.). The tetraspanins may play a role as organizers of multimolecular complexes on the cell surface associating numerous proteins, the tetraspanin web. To better define the composition of the tetraspanin web, its characterization has been recently performed using mass spectrometry and proteomics. We report the proteomic analysis of tetraspanin complexes on B-lymphoid cells. Immunoprecipitation experiments were performed using mAbs directed against the tetraspanin CD9, and associated molecules were identified by MALDI-TOF (matrix assisted laser desorption ionization time of flight) mass spectrometry. This led to the identification of IgM as a novel component of the complexes. Thus, tetraspanins may connect several types of proteins with Ig domains, including HLA-DR, EWI-2, and IgM, that may play a role in immune responses.This work was presented at the first Cancer Immunology and Immunotherapy Summer School, 8–13 September 2003, Ionian Village, Bartholomeio, Peloponnese, Greece. 相似文献
237.
For drug development and pharmaceutical research, targeting the molecular abnormalities is considered as a new challenge. A number of diseases including cancer are linked to perturbation of tyrosine kinase (TK). Imatinib (Glivec or Gleevec, Novartis), the most potent inhibitor of c-abl TK, was recently developed. This molecule has been approved in the treatment of chronic myeloid leukemia (CML). However, emergence of clinical resistance regarding a low rate of CML patients leads to intensive research. In the current article, we discuss the data and the mechanism of the resistance phenomenon. This review illustrates the important requirement to transfer back the information from patient to laboratory in order to improve future drug design. 相似文献
238.
Antonio?L.?De?LaceyEmail author Alejandro?Pardo Víctor?M.?Fernández Sebastian?Dementin Geraldine?Adryanczyk-Perrier E.?Claude?Hatchikian Marc?Rousset 《Journal of biological inorganic chemistry》2004,9(5):636-642
The kinetics of the activation and anaerobic inactivation processes of Desulfovibrio gigas hydrogenase have been measured in D2O by FTIR spectroelectrochemistry. A primary kinetic solvent isotope effect was observed for the inactivation process but not for the activation step. The kinetics of these processes have been also measured after replacement of a glutamic residue placed near the active site of an analogous [NiFe] hydrogenase from Desulfovibrio fructosovorans. Its replacement by a glutamine affected greatly the kinetics of the inactivation process but only slightly the activation process. The interpretation of the experimental results is that the rate-limiting step for anaerobic inactivation is the formation from water of a -OH– bridge at the hydrogenase active site, and that Glu25 has a role in this step.Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/10.1007/s00775-004-0559-7 相似文献
239.
Bonnemain C Raynaud C Réglier-Poupet H Dubail I Frehel C Lety MA Berche P Charbit A 《Molecular microbiology》2004,51(5):1251-1266
Most bacteria contain one type I signal peptidase (Spase I) for cleavage of signal peptides from exported and secreted proteins. Here, we identified a locus encoding three contiguous Spase I genes in the genome of Listeria monocytogenes. The deduced Sip proteins (denoted SipX, SipY and SipZ) are significantly similar to SipS and SipT, the major SPase I proteins of Bacillus subtilis (38% to 44% peptidic identity). We studied the role of these multiple signal peptidases in bacterial pathogenicity by constructing a series of single- and double-chromosomal knock-out mutants. Inactivation of sipX did not affect intracellular multiplication of L. monocytogenes but significantly reduced bacterial virulence (approximately 100-fold). Inactivation of sipZ impaired the secretion of phospholipase C (PC-PLC) and listeriolysin O (LLO), restricted intracellular multiplication and almost abolished virulence (LD(50) of 10(8.3)), inactivation of sipY had no detectable effects. Most importantly, a mutant expressing only SipX was impaired in intracellular survival and strongly attenuated in the mouse (LD(50) of 10(7.2)), whereas, a mutant expressing only SipZ behaved like wild-type EGD in all the assays performed. The data establish that SipX and SipZ perform distinct functions in bacterial pathogenicity and that SipZ is the major Spase I of L. monocytogenes. This work constitutes the first report on the differential role of multiple Spases I in a pathogenic bacterium and suggests a possible post-translational control mechanism of virulence factors expression. 相似文献
240.