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   80907篇
  免费   7494篇
  国内免费   5306篇
耳鼻咽喉   576篇
儿科学   985篇
妇产科学   1237篇
基础医学   9790篇
口腔科学   1598篇
临床医学   10254篇
内科学   12642篇
皮肤病学   838篇
神经病学   4422篇
特种医学   2826篇
外国民族医学   32篇
外科学   7762篇
综合类   13041篇
现状与发展   14篇
一般理论   12篇
预防医学   5516篇
眼科学   2117篇
药学   8706篇
  81篇
中国医学   4367篇
肿瘤学   6891篇
  2024年   333篇
  2023年   1300篇
  2022年   3224篇
  2021年   4092篇
  2020年   3091篇
  2019年   2657篇
  2018年   2820篇
  2017年   2524篇
  2016年   2370篇
  2015年   3604篇
  2014年   4376篇
  2013年   4114篇
  2012年   6198篇
  2011年   6544篇
  2010年   4199篇
  2009年   3300篇
  2008年   4459篇
  2007年   4281篇
  2006年   3887篇
  2005年   3819篇
  2004年   2762篇
  2003年   2510篇
  2002年   2241篇
  2001年   1823篇
  2000年   1904篇
  1999年   1998篇
  1998年   1275篇
  1997年   1256篇
  1996年   980篇
  1995年   953篇
  1994年   779篇
  1993年   485篇
  1992年   563篇
  1991年   515篇
  1990年   435篇
  1989年   387篇
  1988年   304篇
  1987年   306篇
  1986年   236篇
  1985年   187篇
  1984年   123篇
  1983年   85篇
  1982年   62篇
  1981年   47篇
  1980年   33篇
  1979年   44篇
  1978年   18篇
  1974年   17篇
  1973年   17篇
  1966年   18篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
组织多肽特异性抗原在乳腺癌中的临床研究   总被引:16,自引:1,他引:15  
OBJECTIVE: To investigate the expression of serum tissue polypeptide-specific antigen (TPS) in breast cancer patients and its clinical value in such cases. METHODS: Altogether 160 subjects (90 patients with breast cancer, 40 with benign breast lesions, and 30 healthy subjects) were enrolled in this study. The serum TPS and CA153 levels were measured by ELISA in all the subjects. RESULTS: The levels and positivity rate of serum TPS and CA153 in breast cancer group were significantly higher than those in the normal subjects group and benign lesion group (P<0.01), and became even higher as the malignancy progressed. High serum TPS level was detected in the cancer patients in stage I. Serum TPS level was the most sensitive to bone metastasis of the malignancy, but its highest levels occurred in cases of lymphoid node metastasis (P<0.05). In patients who responded favorably to the treatment, serum TPS and CA153 levels were significantly reduced (P<0.05), but the reduction in TPS levels tended to be more obvious (P<0.05). CONCLUSION: Serum TPS can be used as a very useful and sensitive tumor marker in the diagnosis of breast cancer, especially in case of bone metastasis, and may be of great value in clinical decision-making and assessment of therapeutic effect.  相似文献   
102.
103.
104.
105.
Purpose: To study the changes of telomerase activity and cytotoxic effects by Cisplatin; cis-dichlorodiamine platinum (CDDP) in cultured human choroidal melanoma. Material and Methods: The primary cultured human choroidal melanoma cells were cultured in the presence and absence of CDDP with different concentration and time respectively. The toxic effects were evaluated by MTT and the level of telormarse was detected by PCR-ELISA assay. And the relationship between telomerase activity and cytotoxic effects were analyzed by a correlation analysis.Results: Following the increase of the concentration and the time of CDDP, gradually repressed telomerase activity was detected in cultured cells. Meanwhile, the restrain rate of the cells increased. The telomerase activity at 24h and 1μg/ml was repressed significantly compared with the control cells. However, the appearance of cell death lagged behind the decreasing of telomerase.Conclusions: CDDP is an effective telomerase inhibitor in cultured choroidal melan  相似文献   
106.
大学生应对方式研究   总被引:8,自引:0,他引:8  
介绍了大学生应对方式研究现状.重点阐述了大学生常用的应对方式、影响因素及应对方式对大学生心理健康的影响。  相似文献   
107.
Recent studies have shown inflammatory markers in affected neural tissues of amyotrophic lateral sclerosis (ALS) patients. We examined immunocytochemically spinal cord tissues of six patients with ALS, two with corticospinal tract degeneration secondary to cerebral infarcts and three control subjects without neuropathologic abnormalities. ALS spinal cords had dense macrophage infiltration (one log greater than control spinal cords) involving the white and gray matter, with heaviest infiltration of lateral and ventral columns and, in one patient, prefrontal gyrus and the occipital lobes of the brain. Macrophages in ALS spinal cord showed strong expression of cyclooxygenase-2 (COX-2) (one log greater than control tissues) and inducible nitric oxide synthase. In the gray matter, macrophages surrounded and appeared to phagocytize neurons (NeuN-positive) that appeared to be dying. Vessels showed damage to the tight junction protein ZO-1 in relation to perivascular CD40 receptor-positive macrophages and CD40 ligand-positive T lymphocytes. ALS spinal cords, but not control cords, were sparsely infiltrated with mast cells. In control cases with corticospinal tract degeneration following hemispheric cerebral infarction, macrophage infiltration of the white matter was COX-2-negative and restricted to lateral and anterior corticospinal tracts. Our data suggest that inflammation in ALS spinal cord and cortex is based on innate immune responses by macrophages and mast cells and adaptive immune responses by T cells.  相似文献   
108.
OBJECTIVE: To measure and compare Chinese mandibular genial tubercles measured anatomically and with computed tomography (CT). STUDY DESIGN AND SETTING: Spiral CT scans were taken of 40 adult human skulls; the superior genial spines were measured using anatomic and CT methods. RESULTS: The height and width of the superior genial spines, mandible thickness, and distance from the menton to the inferior and superior margins of the superior genial spines were 5.82 +/- 0.71, 6.98 +/- 1.35, 11.95 +/- 1.59, 11.08 +/- 2.05, and 16.91 +/- 2.30 mm from anatomic measurements and 6.17 +/- 0.71, 7.01 +/- 1.13, 12.19 +/- 1.64, 10.41 +/- 1.55, and 15.73 +/- 2.12 mm using spiral CT, respectively. The anatomic and CT measurements were correlated. CONCLUSION: Spiral CT of the genial tubercles can help locate the osteotomy in genioglossus advancement. SIGNIFICANCE: This study acquired reference data on Chinese genial tubercles demonstrating that CT measurements of the genial tubercles reflect their anatomy, which should allow accurately locate the osteotomy.  相似文献   
109.
Z D Lin  S Z Li  Y Z Liu  L Lu 《眼科学报》1989,5(3-4):84-6, 109
The intraocular pressure (IOP) course during the first postoperative month was measured with Goldmann applanation tonometry in 93 eyes. The patients include 30 eyes of intracapsular cataract extraction (ICCE), 32 eyes of extracapsular cataract extraction (ECCE) and 31 eyes of ECCE combined with posterior chamber intraocular lens (PC-IOL) implantation. The preoperative average IOP was 13.30 +/- 3.24 mmHg in 93 eyes. The first day after cataract extraction was 25.33 +/- 8.18 mmHg and 59 eyes (63.44%) had an IOP higher than 23 mmHg. On the second day it was 16.03 +/- 7.54 mmHg. On the third day it was 14.69 +/- 5.45 mmHg. On the seventh day it was 13.32 +/- 3.44 mmHg and only 2 eyes (2.14%) IOP was higher than 23 mmHg. The first postoperative month average IOP was 12.93 +/- 1.31 mmHg and it was above 23 mmHg in only one eye. When compared with preoperation a significant increase in IOP was found postoperatively. But on the seventh day and after the first month there was no significant difference (P greater than 0.05). The IOP rise among ICCE group, ECCE group and PC-IOL group did not differ significantly.  相似文献   
110.
Y C Lu 《中西医结合杂志》1989,9(12):734-6, 710
This paper deals with the anti-injurious effect of Qigong Waiqi on ozone toxicity. NIH male mice were randomly divided into three groups, O3 group, mice kept in 0.9 ppm O3 in a special room 12 hours/day for 12 days; Qigong group received Waiqi from a Qigong master for 30 minutes every morning in addition to what O3 group was treated; and a normal group for control. After 12 successive days, all the animals were decapitated and autopsy performed. Tissues taken from lung, liver, spleen and thymus were prepared for biochemical assay and microscopic examination. It was found that MDA content of lung and liver of O3 group was much higher than those of the control group and Qigong group. On the contrary, GSH-Px activity was significantly (P less than 0.001) lower than those of the control and Qigong groups. Both the MDA content and GSH-Px activity between the latter two groups were not significantly different. Microscopic examination revealed severe interstitial pneumonia with marked edema of lung and prominent leucocytic infiltration in liver of O3 group mice, but only slight changes were seen in Qigong group, so the differences were significant. The two immune organs of mice in O3 group were reduced in size and weight. Microscopic examination of immune organs of O3 group revealed thinner T lymphocyte population in cortex of thymus and periarterial sheath of spleen than those of Qigong group.(ABSTRACT TRUNCATED AT 250 WORDS)  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