首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   11649篇
  免费   992篇
  国内免费   39篇
耳鼻咽喉   123篇
儿科学   333篇
妇产科学   244篇
基础医学   1715篇
口腔科学   291篇
临床医学   1200篇
内科学   2226篇
皮肤病学   147篇
神经病学   795篇
特种医学   491篇
外国民族医学   2篇
外科学   1779篇
综合类   217篇
一般理论   20篇
预防医学   1132篇
眼科学   346篇
药学   746篇
中国医学   12篇
肿瘤学   861篇
  2022年   74篇
  2021年   183篇
  2020年   77篇
  2019年   157篇
  2018年   208篇
  2017年   145篇
  2016年   166篇
  2015年   199篇
  2014年   291篇
  2013年   413篇
  2012年   567篇
  2011年   605篇
  2010年   427篇
  2009年   419篇
  2008年   570篇
  2007年   625篇
  2006年   582篇
  2005年   632篇
  2004年   588篇
  2003年   513篇
  2002年   524篇
  2001年   274篇
  2000年   292篇
  1999年   247篇
  1998年   170篇
  1997年   154篇
  1996年   135篇
  1995年   122篇
  1994年   120篇
  1993年   120篇
  1992年   190篇
  1991年   161篇
  1990年   167篇
  1989年   188篇
  1988年   157篇
  1987年   166篇
  1986年   142篇
  1985年   151篇
  1984年   131篇
  1983年   127篇
  1982年   87篇
  1981年   99篇
  1980年   87篇
  1979年   110篇
  1978年   110篇
  1977年   69篇
  1976年   84篇
  1975年   78篇
  1974年   82篇
  1973年   73篇
排序方式: 共有10000条查询结果,搜索用时 390 毫秒
101.
Serotype distribution and antibiotic resistance (AR) among group B streptococci (GBS) affect GBS disease prevention strategies, but vary among patient groups. A multiplex PCR-based reverse line blot (mPCR/RLB) hybridisation assay was used to compare the distributions of GBS serotypes, serotype III subtypes and AR-associated genes among 666 invasive isolates from 663 patients, divided into five age groups: infants, early-onset (EO; 0-6 days) and late-onset (LO; 7-90 days); children (aged 3 months to 14 years); women of childbearing age (WCBA; aged 15-45 years); and other adults (males aged >15 years; females aged >45 years). Serotypes Ia and V and serosubtype III-1 accounted for 60% of infections. Serosubtype III-2, which corresponds to a virulent clone belonging to sequence type (ST)17, was relatively uncommon overall (7%), but was associated strongly with LO infant infections, in which it was significantly more common than in adult infections (25/104 (24%) vs. 9/392 (2%), p <0.0001) or in EO infections (25/104 (24%) vs. 14/155 (9%), p <0.005). Erythromycin resistance genes were found in 8% of all isolates (ermB 3%, ermA 2.5% and mefA/E 2%), in 11-15% of isolates of serotypes II and V and subtype III-1, but in none of the isolates of serosubtype III-2 (III-2, 0/49 vs. all others, 54/618 (9%), p <0.04). In summary, the virulent serosubtype III-2 was associated strongly with LO infant GBS infection, but was less likely than other serotypes or serosubtype III-1 to carry AR genes.  相似文献   
102.
103.
OBJECTIVE: To examine whether young adults have stereotypical beliefs toward children who have been treated for cancer. METHODS: Undergraduate participants read a vignette describing a child labeled either healthy (HL), in remission from cancer and no longer undergoing treatment (RCL), or in remission and still undergoing treatment (RCTL) and rated the child on the Ratings of the Child Questionnaire (ROCQ). Univariate and multivariate analyses of variance were conducted. RESULTS: Participants rated the HL child more positively than the RCL or RCTL child; the RCL and RCTL child ratings did not differ. Females evaluated the child more positively than did males. CONCLUSIONS: These results support previous findings of a childhood cancer stereotype. However, effect sizes were small, which may indicate a weak stereotype with these specific participants.  相似文献   
104.
105.
106.
To identify new autoantibody populations in patients with rheumatic diseases, a cDNA expression library was immunoscreened with a rheumatoid arthritis (RA) patient's serum which contains autoantibodies binding to uncharacterized polypeptides by Western-blotting. One clone encoding the amino-terminal region (Nt) [domain L and half of domain I] of human calpastatin was selected. Different fragments of the selected cDNA were prepared and the corresponding recombinant polypeptides were produced by in vitro translation and analysed by Western blotting. Most RA sera bound to recombinant amino-terminal region and domain I but not to domain L. This prompted us to use a recombinant polypeptide corresponding to the domain I of calpastatin as the antigen in a solid-phase ELISA to test sera from patients with various systemic rheumatic diseases and healthy controls.Anti-calpastatin domain I antibodies (ACAST-DI Ab), were detected by ELISA in RA, systemic lupus erythematosus (SLE), Sj?gren's syndrome and control sera at respective frequencies of 10, 9, 0 and 1%. These Ab did not have prognostic value in early RA; high levels were significantly associated with vasculitis in SLE. Antibodies reacting with the calpastatin amino-terminal region are produced during systemic rheumatic diseases and are predominantly directed against domain I. High levels of these Ab may constitute a marker of vasculitis in SLE.  相似文献   
107.
Tuberculosis is rising in the developing world due to poor health care, human immunodeficiency virus type 1 infection, and the low protective efficacy of the Mycobacterium bovis BCG vaccine. A new vaccination strategy that could protect adults in the developing world from tuberculosis could have a huge impact on public health. We show that BCG boosted by poxviruses expressing antigen 85A induced unprecedented 100% protection of guinea pigs from high-dose aerosol challenge with Mycobacterium tuberculosis, suggesting a strategy for enhancing and prolonging the efficacy of BCG.  相似文献   
108.
We report the molecular characterisation of two families with Angelman syndrome referred for prenatal diagnosis, in which atypical molecular findings resulted in counselling dilemmas. The first is a familial case of Angelman syndrome in which the two affected children have mutations which affect the imprinting mechanism, as shown by the presence of paternal DNA methylation patterns at D15S63 and SNRPN and biparental inheritance of 15q11-q13 markers. DNA prepared from a 21 week fetal blood sample detected a fetus with normal maternal and paternal DNA methylation patterns at D15S63, but inheritance of the same maternal chromosome 15q11-q13 as the two affected sibs. This is probably a result of germline mosaicism in the mother. The second is a case of Angelman syndrome with an atypical deletion of 15q11-q13, which involves both unusual proximal and distal breakpoints. The deletion was characterised in order to assess the risk of Angelman syndrome in a second pregnancy in the mother of this child.  相似文献   
109.
110.
In stimulated neutrophils, the majority of tyrosine phosphorylated proteins are concentrated in Triton X-100 or NP-40 insoluble fractions. Most immunobiochemical studies, whose objective is to study the functional relevance of tyrosine phosphorylation are, however, performed using the supernatants of cells lysed in non-ionic detergent-containing buffers (RIPA lysis buffers). This observation prompted us to develop an alternative lysis protocol. We established a procedure involving the sequential lysis of neutrophils in buffers of increasing tonicities that not only preserved and solubilized tyrosine phosphorylated proteins but also retained their enzymatic activities. The sequential lysis of neutrophils in hypotonic, isotonic and hypertonic buffers containing non-ionic detergents resulted in the solubilisation of a significant fraction of tyrosine phosphorylated proteins. Furthermore, we observed that in monosodium urate crystals-stimulated neutrophils, Lyn activity was enhanced in the soluble fraction recovered from the hypertonic fraction, but not from that of the first hypotonic lysis. The distribution of tyrosine phosphorylated proteins between the NP-40 soluble and insoluble fractions was both substrate- and agonist-dependent. In neutrophils stimulated with fMet-Leu-Phe, MSU crystals or by CD32 ligation, the tyrosine phosphorylated proteins were mostly insoluble. On the other hand, in GM-CSF-treated cells, the phosphoproteins were more equally distributed between the two fractions. The results of this study provide a new experimental procedure for the investigation of tyrosine phosphorylation pathways in activated human neutrophils which may also be applicable to other cell types.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号