全文获取类型
收费全文 | 984篇 |
免费 | 69篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 36篇 |
妇产科学 | 13篇 |
基础医学 | 139篇 |
口腔科学 | 23篇 |
临床医学 | 75篇 |
内科学 | 149篇 |
皮肤病学 | 16篇 |
神经病学 | 21篇 |
特种医学 | 143篇 |
外科学 | 87篇 |
综合类 | 41篇 |
一般理论 | 1篇 |
预防医学 | 29篇 |
眼科学 | 9篇 |
药学 | 56篇 |
中国医学 | 5篇 |
肿瘤学 | 201篇 |
出版年
2023年 | 10篇 |
2022年 | 13篇 |
2021年 | 20篇 |
2020年 | 19篇 |
2019年 | 21篇 |
2018年 | 31篇 |
2017年 | 21篇 |
2016年 | 29篇 |
2015年 | 31篇 |
2014年 | 52篇 |
2013年 | 61篇 |
2012年 | 60篇 |
2011年 | 49篇 |
2010年 | 35篇 |
2009年 | 38篇 |
2008年 | 55篇 |
2007年 | 39篇 |
2006年 | 27篇 |
2005年 | 32篇 |
2004年 | 25篇 |
2003年 | 24篇 |
2002年 | 24篇 |
2001年 | 13篇 |
2000年 | 11篇 |
1999年 | 14篇 |
1998年 | 45篇 |
1997年 | 34篇 |
1996年 | 20篇 |
1995年 | 14篇 |
1994年 | 15篇 |
1993年 | 19篇 |
1990年 | 14篇 |
1989年 | 12篇 |
1988年 | 11篇 |
1987年 | 11篇 |
1986年 | 13篇 |
1985年 | 18篇 |
1984年 | 4篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 7篇 |
1980年 | 11篇 |
1979年 | 2篇 |
1978年 | 9篇 |
1977年 | 8篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1972年 | 3篇 |
1971年 | 4篇 |
1968年 | 2篇 |
排序方式: 共有1064条查询结果,搜索用时 15 毫秒
11.
Determination of optimal cryoprotectants and procedures for their addition and removal from human spermatozoa 总被引:9,自引:7,他引:9
The objective was to test the hypothesis that the optimal cryoprotective
agent for cryopreservation of human spermatozoa would be a solute for which
cells have the highest plasma membrane permeability, resulting in the least
amount of volume excursion during its addition and removal. To test this
hypothesis, theoretical simulations were performed using membrane
permeability coefficients to predict optimal procedures for the addition
and removal of a cryoprotectant. Simulations were performed using data from
four different cryoprotectants: (i) glycerol, (ii) dimethyl sulphoxide,
(iii) propylene glycol and (iv) ethylene glycol. Thermodynamic formulations
were applied to determine approaches for the addition and removal of 1 M
and 2 M final concentrations of cryoprotectant, allowing the spermatozoa to
maintain a cell volume within their osmotic tolerance limits. Based on
these data, ethylene glycol was predicted to be optimal for minimizing
volume excursions among the solutes evaluated. These predictions were then
experimentally tested using glycerol as the control cryoprotectant and
ethylene glycol as the experimental cryoprotectant. The results indicate
that there was a higher (P < 0.05) recovery of motile spermatozoa after
cryopreservation when using 1 M ethylene glycol than with 1 M glycerol,
supporting the hypothesis that use of the cryoprotectant for which the cell
has the highest permeability will result in higher cell survival.
相似文献
12.
Kannangai R Ramalingam S Vijayakumar TS Vincent AA Abraham OC Subramanian S Rupali P Mathai D Jesudason MV Sridharan G 《Indian journal of medical microbiology》2003,21(4):274-276
Currently, antiretroviral therapy has become more affordable even in developing countries and it is being used in India. Fifteen HIV-1 infected individuals, who were on highly active antiretroviral therapy (HAART), were followed up for an average period of one year. The plasma viral load and CD4+ T cell estimation done at mean intervals of 5 months and 11 months after initiation of therapy showed a good response to therapy in 14 (93%) individuals. 相似文献
13.
Rapid particle agglutination test for human immunodeficiency virus: hospital-based evaluation 总被引:3,自引:0,他引:3
下载免费PDF全文
![点击此处可从《Journal of clinical microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ramalingam S Kannangai R Raj A A Jesudason MV Sridharan G 《Journal of clinical microbiology》2002,40(4):1553-1554
The performance of a rapid particle agglutination test for human immunodeficiency virus (HIV) (Capillus HIV type 1 [HIV-1]/HIV-2) on hospital samples is compared with enzyme-linked immunosorbent assays. The test had a sensitivity and specificity of 99 and 98.9%, respectively. In addition, the test was reactive on plasma samples from all individuals infected with HIV-1 subtype C. This test can safely be used for voluntary counseling and testing in India. 相似文献
14.
Donor insemination: Dutch parents' opinions about confidentiality and donor anonymity and the emotional adjustment of their children 总被引:1,自引:4,他引:1
Brewaeys A; Golombok S; Naaktgeboren N; de Bruyn JK; van Hall EV 《Human reproduction (Oxford, England)》1997,12(7):1591-1597
Results from a comparative study investigating 38 donor insemination (DI)
Dutch families with 4-8 year old children are presented. The aims of this
study were to investigate parents' opinions on the issues of
confidentiality and donor anonymity, to assess the emotional development of
the children, and to examine in DI families the association between secrecy
with regard to the use of a donor and the emotional adjustment of the
children. The DI families were compared to families with a child conceived
by in-vitro fertilization (IVF) and to families with a naturally conceived
child. Secrecy appeared to be associated with DI and not with IVF: 74% of
the DI parents intended not to inform the child about the way in which
she/he was conceived, whereas none of the IVF parents intended to keep the
secret. Only one set of DI parents and two sets of IVF parents had actually
told the child. As to donor anonymity, a spread of opinions appeared among
DI parents; 57% preferred an anonymous donor, 31% would have liked non-
identifying information about the donor, 9% preferred the donor's identity
to be registered and 3% remained unsure. Parents' major concern was to know
more about the medical/genetic background of the donor. Mothers and fathers
in the DI families differed in their opinions concerning the issues of
confidentiality and donor anonymity: fathers, more often than mothers, were
secretive with regard to the use of a donor and husbands, more often than
their wives, were in favour of donor anonymity. With regard to the
emotional development of the children, more emotional/behavioural problems
were revealed among DI children than among children who were naturally
conceived. No association was found between secrecy and the
emotional/behavioural adjustment of the children.
相似文献
15.
Immunoglobulin G, A, and M Responses in Serum and Circulating Immune Complexes Elicited by the 16-Kilodalton Antigen of Mycobacterium tuberculosis
下载免费PDF全文
![点击此处可从《Clinical and Vaccine Immunology : CVI》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Alamelu Raja K. R. Uma Devi B. Ramalingam Patrick J. Brennan 《Clinical and Vaccine Immunology : CVI》2002,9(2):308-312
The 16-kDa cytosolic antigen of M. tuberculosis was purified to homogeneity by molecular sieving chromatography, and the diagnostic potential of the antigen was evaluated in various categories of patients by enzyme-linked immunosorbent assay (ELISA). The immunoglobulin G (IgG), IgA, and IgM antibody levels to 16-kDa antigen were estimated in the two polar groups, namely, smear- and culture-positive pulmonary tuberculosis (S+C+) patients and healthy subjects (HS). Sensitivities of 62, 52 and 11% with specificities of 100, 97, and 95% were obtained for the three isotypes, respectively. The total number of positives by a combination of the three isotypes was analyzed in the polar groups, and the sensitivity improved to 83% with a specificity of 93%. Even when a combination of IgG and IgA alone was considered, the sensitivity was 82% with a specificity of 97%. Polyethylene glycol precipitation of the circulating immune complex (CIC) in sera was carried out. The CIC-bound antibodies to 16-kDa antigen were assessed by ELISA in the S+C+, S−C+, and S−C− categories of patients. Measuring the IgG-IgA-IgM combination positivities of the CIC-bound antibodies gave sensitivities of 97.5, 100, and 45.3%, respectively. The specificity of the assay with these combinations was maintained at 95.4%. 相似文献
16.
Reports about the effects of ascorbate (vitamin C) on cultured cells are confusing and conflicting. Some authors show inhibition of cell death by ascorbate, whereas others demonstrate that ascorbate is cytotoxic. In this report, using three different cell types and two different culture media (Dulbecco's modified Eagle's medium and RPMI 1640), we show that the toxicity of ascorbate is due to ascorbate-mediated production of H2O2, to an extent that varies with the medium used to culture the cells. For example, 1 mM ascorbate generates 161 +/- 39 microM H2O2 in Dulbecco's modified Eagle's medium and induces apoptosis in 50% of HL60 cells, whereas in RPMI 1640 only 83 +/- 17 microM H2O2 is produced and no apoptosis is detected. Apoptosis is prevented by catalase, and direct addition of H2O2 at the above concentration to the cells has similar effects to ascorbate. These results show that ascorbate itself is not toxic to the cell lines used and that effects of ascorbate in vivo cannot be predicted from studies on cultured cells. The ability of ascorbate to interact with different cell culture media to produce H2O2 at different rates could account for many or all of the conflicting results obtained using ascorbate in cultured cell assays. 相似文献
17.
18.
19.
Esaki Muthu Shankar Ramachandran Vignesh Kailapuri G Murugavel Pachamuthu Balakrishnan Ramalingam Sekar Charmaine AC Lloyd Suniti Solomon Nagalingeswaran Kumarasamy 《AIDS research and therapy》2007,4(1):1-7
Background
CD4+ T lymphocyte (CD4) cell count testing is the standard method for determining eligibility for antiretroviral therapy (ART), but is not widely available in sub-Saharan Africa. Total lymphocyte counts (TLCs) have not proven sufficiently accurate in identifying subjects with low CD4 counts. We developed clinical algorithms using TLCs, hemoglobin (Hb), and body mass index (BMI) to identify patients who require ART. 相似文献20.
Ramalingam?Saravanan Leelavinothan?PariEmail author 《BMC complementary and alternative medicine》2005,5(1):14