全文获取类型
收费全文 | 26283篇 |
免费 | 1406篇 |
国内免费 | 135篇 |
专业分类
耳鼻咽喉 | 269篇 |
儿科学 | 420篇 |
妇产科学 | 360篇 |
基础医学 | 3622篇 |
口腔科学 | 815篇 |
临床医学 | 1808篇 |
内科学 | 6755篇 |
皮肤病学 | 435篇 |
神经病学 | 1597篇 |
特种医学 | 809篇 |
外科学 | 4132篇 |
综合类 | 128篇 |
一般理论 | 1篇 |
预防医学 | 987篇 |
眼科学 | 618篇 |
药学 | 1816篇 |
中国医学 | 80篇 |
肿瘤学 | 3172篇 |
出版年
2023年 | 126篇 |
2022年 | 269篇 |
2021年 | 453篇 |
2020年 | 258篇 |
2019年 | 345篇 |
2018年 | 467篇 |
2017年 | 373篇 |
2016年 | 459篇 |
2015年 | 457篇 |
2014年 | 584篇 |
2013年 | 737篇 |
2012年 | 1123篇 |
2011年 | 1277篇 |
2010年 | 696篇 |
2009年 | 613篇 |
2008年 | 1106篇 |
2007年 | 1206篇 |
2006年 | 1200篇 |
2005年 | 1236篇 |
2004年 | 1170篇 |
2003年 | 1178篇 |
2002年 | 1091篇 |
2001年 | 906篇 |
2000年 | 919篇 |
1999年 | 887篇 |
1998年 | 322篇 |
1997年 | 248篇 |
1996年 | 265篇 |
1995年 | 217篇 |
1994年 | 194篇 |
1993年 | 180篇 |
1992年 | 693篇 |
1991年 | 624篇 |
1990年 | 581篇 |
1989年 | 658篇 |
1988年 | 553篇 |
1987年 | 517篇 |
1986年 | 519篇 |
1985年 | 480篇 |
1984年 | 310篇 |
1983年 | 235篇 |
1982年 | 138篇 |
1981年 | 105篇 |
1980年 | 116篇 |
1979年 | 219篇 |
1978年 | 178篇 |
1977年 | 138篇 |
1974年 | 116篇 |
1971年 | 120篇 |
1969年 | 127篇 |
排序方式: 共有10000条查询结果,搜索用时 12 毫秒
51.
52.
Nuclear size and shape on histological specimens were used to quantify nuclear abnormality in gastric tubular tumors. A valid technique for this morphometrical analysis by image processing was developed. Furthermore, the present study examined the nuclear size and shape to determine if they were reliable criteria to be used for differential diagnosis. Nuclear area, maximum diameter and maximum width on the histological specimens were defined as factors to represent nuclear size. Nuclear aspect ratio represented nuclear shape. Histological features revealed varied degrees of condensation of nuclei; this was due to different protocols for preparing the histological specimens. This finding indicated that the size of intermediate lymphocytes on the same specimens should be measured as a control in order to estimate the degree of nuclear condensation. The present study also demonstrated that at least 200 nuclei should be measured on the histological specimens to obtain accurate nuclear size and shape. Histologically, the nuclei in benign tubular adenoma and borderline lesions tended to be spindle-shaped, while those in well-differentiated type tubular adenocarcinoma tended to be round and swollen. The nuclei in borderline lesions were larger than those in benign tubular adenoma and smaller than those in well-differentiated type tubular adenocarcinoma. Our results for the above 4 factors corresponded well with these histological findings. The nuclear size and shape on histological specimens were concluded to be reliable criteria for assessing nuclear abnormality in gastric tubular tumors and useful ones for differential diagnosis. 相似文献
53.
Ishizaki K.; Yoon D. M.; Yoshida N.; Yamazaki M.; Arai K.; Fujita T. 《British journal of anaesthesia》1995,75(5):636-638
We have studied the effect of intrathecal administration of N-methyl-D-
aspartate (NMDA) receptor antagonists on the minimum alveolar anaesthetic
concentration (MAC) of isoflurane in rats. In Wistar rats fitted with
indwelling intrathecal catheters, we determined the MAC of isoflurane after
administration of a competitive NMDA receptor antagonist, APV (0.01, 0.1,
1.0, 10, 30 micrograms), a non-competitive NMDA receptor antagonist, MK801
(0.1, 1.0, 10, 30 micrograms). NMDA (0.01, 0.1, 1.0, 10, 30 micrograms) and
saline. APV at all doses except 0.01 micrograms decreased MAC by 17.1-32%
(P < 0.001 and P < 0.0001). Although MK801 at 10 and 30 micrograms
reduced MAC by 24.3-31.7% (P < 0.001 and P < 0.0001), lower doses did
not affect MAC. Intrathecal administration of NMDA reversed these decreases
in MAC, but not to control values with APV 10 and 30 micrograms and MK801
30 micrograms. We suspect that NMDA and NMDA receptor antagonists play
important roles in the spinal cord in determining the MAC of isoflurane.
相似文献
54.
During past 30 years, we experienced 253 patients who underwent surgery for myasthenia gravis. Among these patients, 9 were associated with Graves' disease. No patients had thymoma. Five patients underwent thymectomy after they had become euthyroid by medical treatment, though four patients required subtotal thyroidectomy before thymectomy. One patient developed myasthenic crisis following thyroidectomy and was treated with respirator for 5 days. But thymectomy was performed without myasthenic crisis in these four patients between 25 days and 60 days after thyroidectomy. They have been doing well and no see-saw phenomenon was presented. Thymectomy is safe and effective even in the patients with Graves's disease, and we recommend to perform it after they become euthyroid by medical or surgical treatment. 相似文献
55.
Hamatani K; Yoshida K; Kondo H; Toki H; Okabe K; Motoi M; Ikeda S; Mori S; Shimaoka K; Akiyama M 《Blood》1989,74(1):423-429
Expression of six proto-oncogenes (fos, myc, myb, Ki-ras, Ha-ras, and N- ras) in 43 cases of non-Hodgkin's lymphoma was analyzed by means of in situ hybridization. Biotinylated DNA probes of the six oncogenes and those of immunoglobulin H (IgH) gene and T-cell receptor beta (TCR beta) chain gene were used. The results of in situ hybridization performed under blind conditions by IgH gene and TCR beta chain gene probes were compatible with those of typing by cell surface markers. The nuclear protein-related proto-oncogenes, fos, myc, and myb, were expressed in about 70% to 80% of all cases regardless of phenotype, histology, or histologic grade. On the contrary, genes of ras family were expressed in more limited numbers of cases except for the Ki-ras gene, which was more frequently expressed by cases of the T-cell immunophenotype with a high malignancy grade. The results of dot hybridization with RNA extracted from some cases were compatible with those of in situ hybridization, further demonstrating the specificity of in situ hybridization. 相似文献
56.
T Oida Y Terauchi K Yoshida A Kagemoto Y Sekine 《Xenobiotica; the fate of foreign compounds in biological systems》1989,19(7):781-793
1. Three conjugated metabolites of haloperidol were isolated from urine of patients on haloperidol and purified by h.p.l.c. with immunological detection, using three types of anti-haloperidol antisera. 2. Structures of the metabolites were: a sulphate conjugate of the 2-hydroxylated 4-fluorophenyl ring of reduced haloperidol (MH-1), a glucuronide conjugate at the same position as MH-1 (MH-2), and a glucuronide conjugate of the hydroxy group of haloperidol (MH-3). 3. MH-3 was the main urinary metabolite in volunteers receiving haloperidol, who excreted 18% of the dose in the 24 h urine as MH-3, while other conjugates were less than 1%. MH-3 could not be hydrolysed with beta-glucuronidase, due to steric hindrance. 4. Immunological detection of conjugated metabolites is very useful in metabolic studies in humans because of its sensitivity and specificity. 相似文献
57.
58.
59.
Tsunao Imamura Rie Takeshita Rikako Koyama Chikao Okuda Kazuo Takeuchi Masamichi Matsuda Masashi Hashimoto Goro Watanabe Hitoshi Yoshida Michio Imawari 《Digestive endoscopy》2006,18(4):303-307
Background: Pancreatic carcinoma is one of the most lethal cancers. Because pancreatic carcinoma is still very difficult to diagnose in its early stage, many of these patients will be considered unsuitable for surgery. If a cytological diagnosis is obtained at initial endoscopic retrograde cholangiopancreatography (ERCP), suitable treatment will be initiated without delay. Methods: To increase the number of exfoliated cells from the pancreatic duct, we devised a new technique, pancreatic duct lavage fluid (PDLF), following bronchoalveolar lavage fluid. The present paper reports the effectiveness of cytological examination using PDLF in the diagnosis of pancreatic carcinoma. We examined 18 pancreatic carcinoma cases. After the endoscopic retrograde pancreatography (ERP), PDLF was collected from a double‐lumen catheter inserted into the main pancreatic duct. Saline injected from the lumen for the injection, and PDLF was aspirated from the other lumen for the guidewire at the same time. The cytological examination was performed using PDLF. Results: Exfoliated cells were more frequently found in PDLF from all patients. In 15 cases (83%), cytological examination of PDLF revealed positive cytological results as the diagnosis of pancreatic carcinoma. Conclusion: Cytological examination using PDLF has a high sensitivity for detection of pancreatic carcinoma. The new examination, PDLF, is simple, safe and effective, so we expect PDLF to become widely popular. 相似文献
60.
In order to investigate how the ganglia in ganglionated plexus were distributed throughout the overall region of the gallbladder, the gallbladder was dissected from guinea-pig and washed with Krebs solution via the cystic duct. This gallbladder was distended with 2 ml of the mixed solution of OsO4 and ZnI2 injected with a syringe via the cystic duct and the cystic duct was immediately tied with a thread. The gallbladder was placed in excess of the mixed solution for 7-10 hours. The gallbladder was longitudinally divided into two approximately equal parts and each was prepared for microscopic investigation. The one preparation was the ventral side of the gallbladder and the other preparation was its dorsal side. These preparations were viewed through a photomicroscope. The obtained results were as follows: 1. Ganglia which involved several nerve cells were observed. Ganglia and nerve bundles connecting the fellow ganglia formed an irregular network, that is, the so-called ganglionated plexus. These nerve bundles were connected with the perivascular nerves which ran parallel to and around blood vessels in several places of the wall of the gallbladder. 2. Ganglia were full of variety in size and shape. That is to say, the shape of ganglia is arranged in various patterns such as oval, spherical, triangular, square and so on. When the size of ganglia were shown by surface area of ganglia which were viewed within the sweep of photomicroscope, the size of ganglia were divided into three large groups, the small ganglia in the range of 1,400 microns2-3,500 microns 2, the large ganglia in the range of 3,500 microns2-10,000 microns2 and the extra-large ganglia in the range of 10,000 microns2-38,000 microns2. Per one gallbladder, 240 +/- 41 (n = 3) small ganglia, 263 +/- 28 (n = 3) large ganglia and 8 +/- 1 (n = 3) extra-large ganglia were found. And these ganglia were irregularly scattered all over the wall of gallbladder. Small ganglia were found more numerous than large ganglia in the cervical portion of the gallbladder. On the other hand, small ones were slightly fewer than large ganglia in the remainder portion of the gallbladder. 3. The ganglionated plexus contained 511 +/- 69 (n = 3) ganglia.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献