全文获取类型
收费全文 | 4597篇 |
免费 | 391篇 |
国内免费 | 12篇 |
专业分类
耳鼻咽喉 | 23篇 |
儿科学 | 137篇 |
妇产科学 | 81篇 |
基础医学 | 474篇 |
口腔科学 | 69篇 |
临床医学 | 433篇 |
内科学 | 800篇 |
皮肤病学 | 29篇 |
神经病学 | 399篇 |
特种医学 | 278篇 |
外科学 | 592篇 |
综合类 | 96篇 |
一般理论 | 5篇 |
预防医学 | 660篇 |
眼科学 | 99篇 |
药学 | 263篇 |
中国医学 | 50篇 |
肿瘤学 | 512篇 |
出版年
2021年 | 48篇 |
2019年 | 44篇 |
2018年 | 65篇 |
2017年 | 42篇 |
2016年 | 56篇 |
2015年 | 77篇 |
2014年 | 80篇 |
2013年 | 145篇 |
2012年 | 217篇 |
2011年 | 192篇 |
2010年 | 128篇 |
2009年 | 94篇 |
2008年 | 195篇 |
2007年 | 205篇 |
2006年 | 219篇 |
2005年 | 193篇 |
2004年 | 168篇 |
2003年 | 180篇 |
2002年 | 164篇 |
2001年 | 155篇 |
2000年 | 161篇 |
1999年 | 130篇 |
1998年 | 83篇 |
1997年 | 69篇 |
1996年 | 70篇 |
1995年 | 69篇 |
1994年 | 57篇 |
1993年 | 69篇 |
1992年 | 119篇 |
1991年 | 98篇 |
1990年 | 97篇 |
1989年 | 96篇 |
1988年 | 98篇 |
1987年 | 96篇 |
1986年 | 98篇 |
1985年 | 99篇 |
1984年 | 76篇 |
1983年 | 59篇 |
1982年 | 53篇 |
1981年 | 41篇 |
1980年 | 47篇 |
1979年 | 45篇 |
1978年 | 31篇 |
1977年 | 46篇 |
1976年 | 45篇 |
1975年 | 31篇 |
1974年 | 41篇 |
1973年 | 39篇 |
1972年 | 31篇 |
1969年 | 26篇 |
排序方式: 共有5000条查询结果,搜索用时 15 毫秒
131.
Norethisterone treatment to control timing of the IVF cycle 总被引:1,自引:0,他引:1
Wardle P.G.; Foster P.A.; Mitchell J.D.; McLaughlin E.A.; Williams J.A.C.; Corrigan E.; Ray B.D.; McDermott A.; Hull M.G.R. 《Human reproduction (Oxford, England)》1986,1(7):455-457
The use of norethisterone to control the timing of the precedingmenstrual cycle and in consequence the timing of the in-vitrofertilization (IVF) cycle has been evaluated in a therapeuticIVF programme in which oocyte recovery was limited to 2 dayseach week. A consecutive series of 181 cycles after norethisteroneand 29 untreated controls were compared. Menstruation occurred2 3 days after norethisterone as planned in 82% of patientsoverall and in 87% of patients whose menstrual cycle lengthvaried by no more than 2 days about the median. Norethisteronetreatment did not significantly affect the outcome of IVF treatmentcompared with the controls in respect to cycles abandoned (12versus 0%, respectively), peak follicular diameter (mean 18.1mm versus 18.3 mm 48 h before laparoscopy), oocyte recoveryrate (4.6 versus 4.5 per patient), oocyte morphology (63% versus52% mature), or fertilization rate (72 versus 65% of matureoocytes). Clinical pregnancies were too few for comparison (rates27 versus 9% per laparoscopy) but the overall rate (23%) indicatedeffectiveness of the methods. Prior norethisterone treatmentappears to be an effective and useful means of controlling thetiming of the oocyte recovery in IVF treatment. 相似文献
132.
Christensen KJ Riley BE Heffernan KA Love SB McLaughlin Sta Maria ME 《The Clinical neuropsychologist》2002,16(1):51-56
The Facial Recognition Test (Benton, Hamsher, Varney, & Spreen, 1983; Benton, Sivan, Hamsher, Varney, & Spreen, 1994) was examined in an age-, education- and gender-stratified sample of 346 healthy older adults. Internal consistency reliability estimates were.72 for the Long Form (FRLF),.53 for the Short Form, and.69 for a new short form. Mean FRLF scores did not change over a 1-year interval (p >.5), and the stability estimate was.71 (n = 100). The first of the methods below yielded the highest correlation between estimated and obtained FRLF scores in cross-validation (n = 67): (1) multiple regression based on oral reading and demographics, (2) multiple regression based on age, education and gender, and (3) mean scores by age group. 相似文献
133.
134.
Melissa N. McCracken Dimitrios N. Vatakis Dhaval Dixit Jami McLaughlin Jerome A. Zack Owen N. Witte 《The Journal of clinical investigation》2015,125(5):1815-1826
Adoptive transfer of tumor-reactive T cells can successfully reduce tumor burden; however, in rare cases, lethal on-target/off-tumor effects have been reported. A noninvasive method to track engineered cells with high sensitivity and resolution would allow observation of correct cell homing and/or identification of dangerous off-target locations in preclinical and clinical applications. Human deoxycytidine kinase triple mutant (hdCK3mut) is a nonimmunogenic PET reporter that was previously shown to be an effective tool to monitor whole-body hematopoiesis. Here, we engineered a construct in which hdCK3mut is coexpressed with the anti-melanoma T cell receptor F5, introduced this construct into human CD34 cells or PBMCs, and evaluated this approach in multiple immunotherapy models. Expression of hdCK3mut allowed engrafted cells to be visualized within recipient bone marrow, while accumulation of [18F]-L-FMAU in hdCK3mut-expressing T cells permitted detection of intratumoral homing. Animals that received T cells coexpressing hdCK3mut and the anti-melanoma T cell receptor had demonstrably higher signals in HLA-matched tumors compared with those in animals that received cells solely expressing hdCK3mut. Engineered T cells caused cytotoxicity in HLA/antigen-matched tumors and induced IFN-γ production and activation. Moreover, hdCK3mut permitted simultaneous monitoring of engraftment and tumor infiltration, without affecting T cell function. Our findings suggest that hdCK3mut reporter imaging can be applied in clinical immunotherapies for whole-body detection of engineered cell locations. 相似文献
135.
Cytotoxic T-cell response to ectromelia virus-infected cells. Different H-2 requirements for triggering precursor T-cell induction or lysis by effector T cells defined by the BALB/c-H-2(db) mutation 下载免费PDF全文
RV Blanden IFC McKenzie U Kees RW Melvold HI Kohn 《The Journal of experimental medicine》1977,146(3):869-880
The T(c)-cell response to ectromelia virus infection was studied in BALB/c-H-2(db) mice which carry a loss mutation in the H-2D region that results in the absence from cell surfaces of a molecule (D’) bearing certain public H-2 specificities. When infected, these mice showed a poor response of T(c) cells that recognize H-2D(d) plus virus-specific determinants on infected macrophage targets, but gave a normal response to H-2K d plus virus-specific antigens. However, their own infected macrophages do display wild-type antigenic patterns involving virus and H-2D(d) since they were killed as efficiently as wild-type (BALB/c,H- 2(d))-infected cells by T(c) cells specific only for H-2D(d) plus viral antigens. When tested in vitro, infected BALB/c-H-2(db) cells stimulated a poor T(c)-cell response to H-2D plus virus-specific antigens, but stimulated a normal response (in comparison with infected BALB/c macrophages) to H-2K(d) plus viral antigens. Uninfected BALB/c-H-2(db) cells stimulated a normal T(c)-cell response to minor H antigens or trinitrophenyl in association with H-2D(d), thus suggesting that the defective response to infection may reside in a failure of the relevant H-2D(d) antigens of mutant cells to physically associate with viral antigens. Close association of viral and H-2D-coded molecules was also suggested by ability of specific anti-H-2K or -H-2D to partially block T(c)-cell-mediated lysis of infected targets. These results were interpreted to mean that H-2Dd-dependent, virus- immune T(c) cells recognized an antigenic pattern consisting of virus- specific and H-2D(d) determinants with the latter borne on an H-2D molecule carrying serologically-defined H-2D(d) private specificities. A second H-2D(d)-coded molecule (D’) was not required for recognition and lysis by activated T(c) cells, but was apparently necessary for efficient stimulation of precursor T(c) cells, perhaps by promoting appropriate physical association of viral and H-2D(d) molecules. 相似文献
136.
Annonaceous acetogenins: recent progress 总被引:17,自引:0,他引:17
The Annonaceous acetogenins are promising new antitumor and pesticidal agents that are found only in the plant family Annonaceae. Chemically, they are derivatives of long-chain fatty acids. Biologically, they exhibit their potent bioactivities through depletion of ATP levels via inhibiting complex I of mitochondria and inhibiting the NADH oxidase of plasma membranes of tumor cells. Thus, they thwart ATP-driven resistance mechanisms. This review presents the progress made in the chemistry, biology, and development of these compounds since December 1995. 相似文献
137.
138.
Knopik VS Sparrow EP Madden PA Bucholz KK Hudziak JJ Reich W Slutske WS Grant JD McLaughlin TL Todorov A Todd RD Heath AC 《Psychological medicine》2005,35(5):625-635
BACKGROUND: Genetic influences have been shown to play a major role in determining the risk of attention-deficit hyperactivity disorder (ADHD). In addition, prenatal exposure to nicotine and/or alcohol has also been suggested to increase risk of the disorder. Little attention, however, has been directed to investigating the roles of genetic transmission and prenatal exposure simultaneously. METHOD: Diagnostic telephone interview data from parents of Missouri adolescent female twin pairs born during 1975-1985 were analyzed. Logistic regression models were fitted to interview data from a total of 1936 twin pairs (1091 MZ and 845 DZ pairs) to determine the relative contributions of parental smoking and drinking behavior (both during and outside of pregnancy) as risk factors for DSM-IV ADHD. Structural equation models were fitted to determine the extent of residual genetic and environmental influences on ADHD risk while controlling for effects of prenatal and parental predictors on risk. RESULTS: ADHD was more likely to be diagnosed in girls whose mothers or fathers were alcohol dependent, whose mothers reported heavy alcohol use during pregnancy, and in those with low birth weight. Controlling for other risk factors, risk was not significantly increased in those whose mothers smoked during pregnancy. After allowing for effects of prenatal and childhood predictors, 86% of the residual variance in ADHD risk was attributable to genetic effects and 14% to non-shared environmental influences. CONCLUSIONS: Prenatal and parental risk factors may not be important mediators of influences on risk with much of the association between these variables and ADHD appearing to be indirect. 相似文献
139.
Sheppard FR Kelher MR Moore EE McLaughlin NJ Banerjee A Silliman CC 《Journal of leukocyte biology》2005,78(5):1025-1042
The reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase is part of the microbicidal arsenal used by human polymorphonuclear neutrophils (PMNs) to eradicate invading pathogens. The production of a superoxide anion (O2-) into the phagolysosome is the precursor for the generation of more potent products, such as hydrogen peroxide and hypochlorite. However, this production of O2- is dependent on translocation of the oxidase subunits, including gp91phox, p22phox, p47phox, p67phox, p40phox, and Rac2 from the cytosol or specific granules to the plasma membrane. In response to an external stimuli, PMNs change from a resting, nonadhesive state to a primed, adherent phenotype, which allows for margination from the vasculature into the tissue and chemotaxis to the site of infection upon activation. Depending on the stimuli, primed PMNs display altered structural organization of the NADPH oxidase, in that there is phosphorylation of the oxidase subunits and/or translocation from the cytosol to the plasma or granular membrane, but there is not the complete assembly required for O2- generation. Activation of PMNs is the complete assembly of the membrane-linked and cytosolic NADPH oxidase components on a PMN membrane, the plasma or granular membrane. This review will discuss the individual components associated with the NADPH oxidase complex and the function of each of these units in each physiologic stage of the PMN: rested, primed, and activated. 相似文献
140.
Thomas McLaughlin Bruce Steinberg Thomas Mulholland Lars Friberg 《International journal of psychophysiology》2005,56(2):143-155
EEG feedback methods, which link the occurrence of alpha to the presentation of repeated visual stimuli, reduce the relative variability of subsequent, alpha-blocking event durations. The temporal association between electro-cortical field activation and regional cerebral blood flow (rCBF) led us to investigate whether the reduced variability of alpha-blocking durations with feedback is associated with a reduction in rCBF variability. Reduced variability in the rCBF response domain under EEG feedback control might have methodological implications for future brain-imaging studies. Visual stimuli were randomly presented to seven subjects, contingent upon the occurrence of alpha (alpha-contingent stimulation (ACS)) or alpha-blocking (not-alpha-blocking-contingent stimulation (NACS)) events. We employed a within-subjects design. rCBF was measured from multiple, cortical and sub-cortical regions. The primary dependent variables were the Mean, Standard Deviation and the ratio of Mean/Standard Deviation of: 1) the alpha-blocking response durations and 2) the temporally summated rCBF responses within the Visual Associative regions of interest (ROIs). Additional within-subjects rCBF measures were derived to quantify the variance-reducing effects of ACS across multiple, distributed areas of the brain. Both EEG and rCBF measures demonstrated decreased variability under ACS. This improved control was seen for localized as well as anatomically distributed rCBF measures. 相似文献