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991.
Wang F Wang W Wähälä K Adlercreutz H Ikonen E Tikkanen MJ 《American journal of physiology. Endocrinology and metabolism》2008,295(6):E1455-E1461
Dehydroepiandrosterone-fatty acyl esters (DHEA-FAE) belong to a unique family of naturally occurring hydrophobic steroid hormone derivatives that are transported in circulating lipoproteins and may act as a source of dehydroepiendrosterone (DHEA) and other biologically active steroid hormones in cells. Here, we studied the metabolic fate of low-density lipoprotein-associated [(3)H]DHEA-FAE ([(3)H]DHEA-FAE-LDL) and the possible role of lysosomal acid lipase (LAL) in the hydrolysis of DHEA-FAE in cultured human cells. When HeLa cells were incubated with [(3)H]DHEA-FAE-LDL, the accumulation of label in the cellular fraction increased with incubation time and could be inhibited by excess unlabeled LDL, suggesting LDL receptor or LDL receptor-related receptor-dependent uptake. During 48 h of chase, decreasing amounts of [(3)H]DHEA-FAE were found in the cellular fraction, while in the medium increasing amounts of unesterified [(3)H]DHEA and its two metabolites, [(3)H]-5alpha-androstanedione (5alpha-adione) and [(3)H]androstenedione (4-adione), appeared. As LDL-cholesteryl ester hydrolysis is dependent on LAL activity, we depleted LAL from HeLa cells using small interfering RNAs and compared the hydrolysis of [(3)H]DHEA-FAE-LDL and [(3)H]cholesteryl-FAE-LDL. The results demonstrated a more modest but significant reducing effect on the hydrolysis of [(3)H]DHEA-FAE compared with [(3)H]cholesteryl-FAE. Moreover, experiments in LAL-deficient human fibroblasts (Wolman disease patient cells) showed that [(3)H]DHEA-FAE hydrolysis was not completely dependent on LAL activity. In summary, LDL-transported [(3)H]DHEA-FAE entered cells via LDL receptor or LDL receptor-related receptor-mediated uptake, followed by intracellular hydrolysis and further metabolism into 5alpha-adione and 4-adione that were excreted from cells. Although LAL contributed to the deesterification of DHEA-FAE, it was not solely responsible for the hydrolysis. 相似文献
992.
Melissa K. Wilson Alison B. Lane Bibiana F. Law William G. Miller Lynn A. Joens Michael E. Konkel Bryan A. White 《Microbial ecology》2009,58(4):843-855
Campylobacter jejuni is one of the leading bacterial causes of food-borne illness in the USA. Molecular typing methods are often used in food
safety for identifying sources of infection and pathways of transmission. Moreover, the identification of genetically related
isolates (i.e., clades) may facilitate the development of intervention strategies for control and prevention of food-borne
diseases. We analyzed the pan genome (i.e., core and variable genes) of 63 C. jejuni isolates recovered from chickens raised in conventional, organic, and free-range poultry flocks to gain insight into the
genetic diversity of C. jejuni isolates recovered from different environments. We assessed the discriminatory power of three genotyping methods [i.e., pulsed-field
gel electrophoresis (PFGE), multilocus sequence typing (MLST), and repetitive extragenic palindromic polymerase chain reaction
(rep-PCR)]. The rep-PCR fingerprint was generated by determining the presence of repetitive sequences that are interspersed throughout
the genome via repetitive extragenic palindromic PCR, enterobacterial repetitive intergenic consensus sequence PCR (ERIC-PCR),
and BOX element PCR (BOX-PCR) and combining the data to form a composite fingerprint. The genetic fingerprints were subjected
to computer-assisted pattern analysis. Comparison of the three genotypic methods revealed that repREB-PCR showed greater discriminatory
power than PFGE and MLST. ERIC-PCR and BOX-PCR yielded the highest number of PCR products and greatest reproducibility. Regardless
of the genotyping method, C. jejuni isolates recovered from chickens reared in conventional, organic, and free-range environments all exhibit a high level of
genotypic diversity. 相似文献
993.
Seong-In Na Yeong Ouk Kim Seok-Hwan Yoon Sung-min Ha Inwoo Baek Jongsik Chun 《Journal of microbiology (Seoul, Korea)》2018,56(4):280-285
Genome-based phylogeny plays a central role in the future taxonomy and phylogenetics of Bacteria and Archaea by replacing 16S rRNA gene phylogeny. The concatenated core gene alignments are frequently used for such a purpose. The bacterial core genes are defined as single-copy, homologous genes that are present in most of the known bacterial species. There have been several studies describing such a gene set, but the number of species considered was rather small. Here we present the up-to-date bacterial core gene set, named UBCG, and software suites to accommodate necessary steps to generate and evaluate phylogenetic trees. The method was successfully used to infer phylogenomic relationship of Escherichia and related taxa and can be used for the set of genomes at any taxonomic ranks of Bacteria. The UBCG pipeline and file viewer are freely available at https://www.ezbiocloud.net/tools/ubcg and https://www.ezbiocloud.net/tools/ubcg_viewer, respectively. 相似文献
994.
995.
Duangrudee Cherdwongcharoensuk Maria João Oliveira Artur Perez Águas 《Biological trace element research》2010,136(2):197-203
The in vivo dynamics of selenium (Se) and mercury (Hg) interaction was studied in mouse tissues using direct visualization
of individual Se, Hg, and SeHg particles on the surface of circulating erythrocytes. This high-resolution detection of Se
and Hg was obtained by scanning electron microscopy coupled to X-ray microanalysis. BALB/c mice were injected in the peritoneal
cavity with Se and Hg salts, and the animals were sacrificed 3 min after the Hg injection. Only a minority (9%) of the metal
dots seen on mouse liver erythrocytes were SeHg complexes when Se and Hg salts were mixed together before injection. In contrast,
the majority (73%) of metal dots on liver erythrocytes were SeHg complexes if Se was injected at least 5 min before Hg injection.
All metal dots on liver erythrocytes were of SeHg complexes if Se was injected 9 or 12 min before the Hg injection. We conclude
that the formation of stable in vivo SeHg complexes requires preliminary interaction of Se with a putative serum factor before
complexes between Se and Hg are formed and are bound to the erythrocyte cell surface. 相似文献
996.
A lack of selectable markers was a hindrance in investigating gene function in Metarhizium robertsii. A reliable Agrobacterium-mediated transformation system based on the use of chlorimuron ethyl as the selectable marker was developed which could serve as a useful tool to inactivate genes involved in insect pathogenicity. 相似文献
997.
998.
Attenuation of hypertension by systemic delivery of retroviral vector containing type I angiotensin II receptor antisense cDNA 总被引:1,自引:0,他引:1
Despite recent strides in the traditional pharmacological therapies in the control and management of hypertension, a successful prevention and cure for this disease by conventional drug strategy remain at a standstill. We have begun to investigate the conceptual possibility of the use of gene therapy in the control of hypertension. In this article we describe an experimental protocol that provides proof of the principle that antisense (AS) inhibition of Type I angiotensin II receptor (AT(1)-R) could prevent development of hypertension on a long-term basis. A retrovirus-based vector has been used to deliver AT(1)R-AS with high efficiency that attenuates development of high blood pressure and hypertension-associated cardiac and vascular pathophysiology in the spontaneously hypertensive rat. 相似文献
999.
Experimental residual dipolar couplings (RDCs) in combination with structural models have the potential for accelerating the
protein backbone resonance assignment process because RDCs can be measured accurately and interpreted quantitatively. However,
this application has been limited due to the need for very high-resolution structural templates. Here, we introduce a new
approach to resonance assignment based on optimal agreement between the experimental and calculated RDCs from a structural
template that contains all assignable residues. To overcome the inherent computational complexity of such a global search,
we have adopted an efficient two-stage search algorithm and included connectivity data from conventional assignment experiments.
In the first stage, a list of strings of resonances (CA-links) is generated via exhaustive searches for short segments of
sequentially connected residues in a protein (local templates), and then ranked by the agreement of the experimental 13Cα chemical shifts and 15N-1H RDCs to the predicted values for each local template. In the second stage, the top CA-links for different local templates
in stage I are combinatorially connected to produce CA-links for all assignable residues. The resulting CA-links are ranked
for resonance assignment according to their measured RDCs and predicted values from a tertiary structure. Since the final
RDC ranking of CA-links includes all assignable residues and the assignment is derived from a “global minimum”, our approach
is far less reliant on the quality of experimental data and structural templates. The present approach is validated with the
assignments of several proteins, including a 42 kDa maltose binding protein (MBP) using RDCs and structural templates of varying
quality. Since backbone resonance assignment is an essential first step for most of biomolecular NMR applications and is often
a bottleneck for large systems, we expect that this new approach will improve the efficiency of the assignment process for
small and medium size proteins and will extend the size limits assignable by current methods for proteins with structural
models. 相似文献
1000.
Zechang Xin Duguang Li Feiyu Mao Yan Du Xiaodong Wang Peng Xu Zhennan Li Jianjun Qian Jie Yao 《Journal of cellular physiology》2020,235(11):8416-8423
Plastin-3 plays a key role in cancer cell proliferation and invasion, but its prognostic value in pancreatic cancer (PACA) remains poorly defined. In this study, we show that PLS3 messenger RNA is overexpressed in PACA tissue compared with normal tissue. We accumulated 207 cases of PACA specimens to perform immunohistochemical analysis and demonstrated that PLS3 levels correlate with T-classification (p < .001) and pathology (p < .001). Furthermore, overall survival rates (p < .001) in tumors with high PLS3 expression were poor, as assessed through Kaplan–Meier survival analysis. PLS3 was found to be an independent prognostic factor for PACA through multivariate Cox regression analysis. Moreover, we found that PLS3 enhances the proliferation and invasion of tumor cells as assessed through Cell Counting Kit-8, wounding healing assays, and Transwell assays. The upregulation of PLS3 also led to enhanced phosphatidylinositol-3 kinase/protein kinase B signaling in PACA cells. These data suggest that PLS3 is a biomarker to estimate PACA progression and represents a molecular target for PACA therapy. 相似文献