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41.
Androgen receptor YAC transgenic mice carrying CAG 45 alleles show trinucleotide repeat instability 总被引:1,自引:15,他引:1
La Spada AR; Peterson KR; Meadows SA; McClain ME; Jeng G; Chmelar RS; Haugen HA; Chen K; Singer MJ; Moore D; Trask BJ; Fischbeck KH; Clegg CH; McKnight GS 《Human molecular genetics》1998,7(6):959-967
X-linked spinal and bulbar muscular atrophy (SBMA) is caused by a CAG
repeat expansion in the first exon of the androgen receptor (AR) gene.
Disease-associated alleles (37-66 CAGs) change in length when transmitted
from parents to offspring, with a significantly greater tendency to shift
size when inherited paternally. As transgenic mice carrying human AR cDNAs
with 45 and 66 CAG repeats do not display repeat instability, we attempted
to model trinucleotide repeat instability by generating transgenic mice
with yeast artificial chromosomes (YACs) carrying AR CAG repeat expansions
in their genomic context. Studies of independent lines of AR YAC transgenic
mice with CAG 45 alleles reveal intergenerational instability at an overall
rate of approximately 10%. We also find that the 45 CAG repeat tracts are
significantly more unstable with maternal transmission and as the
transmitting mother ages. Of all the CAG/CTG repeat transgenic mice
produced to date the AR YAC CAG 45 mice are unstable with the smallest
trinucleotide repeat mutations, suggesting that the length threshold for
repeat instability in the mouse may be lowered by including the appropriate
flanking human DNA sequences. By sequence-tagged site content analysis and
long range mapping we determined that one unstable transgenic line has
integrated an approximately 70 kb segment of the AR locus due to
fragmentation of the AR YAC. Identification of the cis - acting elements
that permit CAG tract instability and the trans -acting factors that
modulate repeat instability in the AR YAC CAG 45 mice may provide insights
into the molecular basis of trinucleotide repeat instability in humans.
相似文献
42.
Immunization reverses memory deficits without reducing brain Abeta burden in Alzheimer's disease model 总被引:13,自引:0,他引:13
Dodart JC Bales KR Gannon KS Greene SJ DeMattos RB Mathis C DeLong CA Wu S Wu X Holtzman DM Paul SM 《Nature neuroscience》2002,5(5):452-457
We have previously shown that chronic treatment with the monoclonal antibody m266, which is specific for amyloid beta-peptide (Abeta), increases plasma concentrations of Abeta and reduces Abeta burden in the PDAPP transgenic mouse model of Alzheimer's disease (AD). We now report that administration of m266 to PDAPP mice can rapidly reverse memory deficits in both an object recognition task and a holeboard learning and memory task, but without altering brain Abeta burden. We also found that an Abeta/antibody complex was present in both the plasma and the cerebrospinal fluid of m266-treated mice. Our data indicate that passive immunization with this anti-Abeta monoclonal antibody can very rapidly reverse memory impairment in certain learning and memory tasks in the PDAPP mouse model of AD, owing perhaps to enhanced peripheral clearance and (or) sequestration of a soluble brain Abeta species. 相似文献
43.
K M Bang E J Greene H W Williams B A Leath R Matthews 《Journal of the National Medical Association》1988,80(8):865-872
A comprehensive family practice clerkship program at Howard University College of Medicine has been conducted since 1970. This institution is one of three predominantly black institutions offering a family practice program. The senior clerkship is mandatory and at least 20 to 25 percent of each class elect to participate in a four-to six- week family practice preceptorship. As a result of the clerkship''s success, over 50 percent of the program''s graduates actively practice in primary medical manpower shortage or medically underserved areas. 相似文献
44.
Immunoblot analysis of immunoglobulin G response to the Lyme disease agent (Borrelia burgdorferi) in experimentally and naturally exposed dogs. 总被引:10,自引:8,他引:10 下载免费PDF全文
R T Greene R L Walker W L Nicholson H W Heidner J F Levine E C Burgess M Wyand E B Breitschwerdt H A Berkhoff 《Journal of clinical microbiology》1988,26(4):648-653
Immunoblots were used to study the immunoglobulin G response to Borrelia burgdorferi in experimentally and naturally exposed dogs. Adsorption studies confirmed that the antibodies were specific for B. burgdorferi. Experimentally exposed dogs were asymptomatic. Naturally exposed dogs included both asymptomatic animals and animals showing signs compatible with Lyme disease. Naturally exposed dogs were from four geographic regions of the country. No differences were detected between immunoblot patterns of naturally exposed symptomatic or asymptomatic dogs from different areas of the country. The immunoblot patterns obtained with sera from experimentally exposed dogs were different from those obtained with sera from naturally exposed dogs and were characterized by reactivity to fewer and different protein bands. Immunoblot analysis using an OspA-protein-producing Escherichia coli recombinant showed that experimentally exposed dogs produced antibodies to OspA, whereas naturally exposed dogs did not. Modifications of the immune response over time, different routes of antigen presentation, and strain variation are factors postulated to account for the observed differences. 相似文献
45.
An immunohistochemical method for the detection of progesterone receptors (PgR) using the monoclonal anti-PgR antibody KD 68 was utilized to study paraffin-embedded tissue sections from women with endometrial carcinoma and hyperplasia. Stromal as well as myometrial nuclear PgR were nearly always apparent. In carcinoma, 11/24 (46%) of cases showed epithelial positivity, whereas in hyperplasia 8/9 (89%) were PgR-positive (P less than 0.05). Initial biochemical PgR assays by the dextran-coated charcoal method were compared with results of PgR-immunocytochemical assays (ICA) in the paraffin-embedded tissue and were in concordance in 92%. In the one discordant specimen, PgR-ICA-negative tumor cells were seen infiltrating PgR-ICA-positive myometrium, and the biochemical assay was thus felt to be falsely positive. Twelve additional cases of endometrial carcinoma were also studied for estrogen receptor (ER) by immunocytochemistry. Two were positive for both ER and PgR, while five were negative for both receptors. The immunocytochemical methods described allow for analysis of routinely fixed, paraffin-embedded specimens, thus permitting analysis of very small specimens and archival material. 相似文献
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P?Mallick J?Chakrabarti Mallick B?Guha AR?Khuda-BukhshEmail author 《BMC complementary and alternative medicine》2003,3(1):7
Background
Arsenic in groundwater and its accumulation in plants and animals have assumed a menacing proportion in a large part of West Bengal, India and adjoining areas of Bangladesh. Because of the tremendous magnitude of the problem, there seems to be no way to tackle the problem overnight. Efforts to provide arsenic free water to the millions of people living in these dreaded zones are being made, but are awfully inadequate. In our quest for finding out an easy, safe and affordable means to combat this problem, a homeopathic drug, Arsenicum Album-30, appears to yield promising results in mice. The relative efficacies of two micro doses of this drug, namely, Arsenicum Album-30 and Arsenicum Album-200, in combating arsenic toxicity have been determined in the present study on the basis of some accepted biochemical protocols. 相似文献50.